U.S. patent application number 15/982959 was filed with the patent office on 2018-09-20 for method for manufacturing cutting blade, and cutting blade.
This patent application is currently assigned to TOKYO SEIMITSU CO., LTD.. The applicant listed for this patent is TOKYO SEIMITSU CO., LTD.. Invention is credited to Masato NAKAMURA.
Application Number | 20180264627 15/982959 |
Document ID | / |
Family ID | 59090357 |
Filed Date | 2018-09-20 |
United States Patent
Application |
20180264627 |
Kind Code |
A1 |
NAKAMURA; Masato |
September 20, 2018 |
METHOD FOR MANUFACTURING CUTTING BLADE, AND CUTTING BLADE
Abstract
This method for manufacturing a cutting blade includes: a mixing
step of adding a liquid dispersion medium to a mixed powder
containing a resin powder of a thermocompression-bondable resin,
abrasive grains and fibrous fillers; a compression step of cold
pressing, in a forming die, the mixed powder to which the
dispersion medium has been added to form an original plate of a
blade main body; and a sintering step of hot pressing and sintering
the original plate.
Inventors: |
NAKAMURA; Masato; (Tokyo,
JP) |
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Applicant: |
Name |
City |
State |
Country |
Type |
TOKYO SEIMITSU CO., LTD. |
Tokyo |
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JP |
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Assignee: |
TOKYO SEIMITSU CO., LTD.
|
Family ID: |
59090357 |
Appl. No.: |
15/982959 |
Filed: |
May 17, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP2016/087906 |
Dec 20, 2016 |
|
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15982959 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B24D 18/0009 20130101;
B24D 5/12 20130101; B24D 3/06 20130101; B24D 3/00 20130101; B24D
3/02 20130101; B24D 3/344 20130101; B24D 3/32 20130101 |
International
Class: |
B24D 3/32 20060101
B24D003/32; B24D 5/12 20060101 B24D005/12; B24D 3/06 20060101
B24D003/06 |
Foreign Application Data
Date |
Code |
Application Number |
Dec 21, 2015 |
JP |
2015-248991 |
Claims
1. A cutting blade comprising: a blade main body having a disc
shape; and a cutting edge formed on an outer peripheral edge
portion of the blade main body, wherein the blade main body
comprises: a resin phase formed of a thermocompression-bondable
resin; and abrasive grains and fibrous fillers dispersed in the
resin phase, when the blade main body is divided into a plurality
of regions at a mutually equal angle around the central axis of the
blade main body, a content rate of the fibrous fillers measured in
each region is from 90 to 110% with respect to an overall content
rate of the fibrous fillers in the blade main body as a whole, and
the fibrous fillers are not oriented in a certain direction and
randomly oriented in a plane substantially perpendicular to the
central axis of the blade main body.
2. The cutting blade according to claim 1, wherein when the blade
main body is divided into a plurality of regions at a mutually
equal angle around the central axis of the blade main body, and an
average value of densities measured in the regions is taken as an
average density, the density measured in each region is from 90 to
110% with respect to the average density.
3. The cutting blade according to claim 1, wherein the overall
content rate of the fibrous fillers in the blade main body as a
whole is from 20 to 60 vol %.
4. The cutting blade according to claim 1, wherein a warpage amount
of the blade main body is equal to or less than 300 .mu.m.
5. The cutting blade according to claim 1, wherein a flatness of
the blade main body is equal to or less than 20 .mu.m.
6. The cutting blade according to claim 1, wherein a thickness of
the blade main body is equal to or less than 1.1 mm.
7. A method for manufacturing the cutting blade according to claim
1, the method comprising: a mixing step of adding a liquid
dispersion medium to a mixed powder containing a resin powder of a
thermocompression-bondable resin, abrasive grains and fibrous
fillers; a compression step of cold pressing a mixture of the
dispersion medium and the mixed powder in a forming die to form an
original plate of a blade main body; and a sintering step of hot
pressing and sintering the original plate.
8. The method for manufacturing a cutting blade according to claim
7, wherein the mixing step comprises: a step of filling the forming
die with the mixed powder containing the resin powder of the
thermocompression-bondable resin, the abrasive grains and the
fibrous filler; a step of flattening a surface of the mixed powder;
and a step of dropwise adding the liquid dispersion medium onto the
mixed powder.
9. The method for manufacturing a cutting blade according to claim
7, wherein a liquid having a kinematic viscosity of 2.3 mm.sup.2/s
or less is used as the dispersion medium.
Description
[0001] The present application is a continuation of international
application No. PCT/JP2016/087906, filed on Dec. 20, 2016, which
claims priority on Japanese Patent Application No. 2015-248991
filed on Dec. 21, 2015, the content of which is incorporated herein
by reference.
TECHNICAL FIELD
[0002] The present invention relates to a method for manufacturing
a cutting blade for cutting a workpiece such as an electronic
material part used, for example, for a semiconductor product or the
like, and a cutting blade.
BACKGROUND ART
[0003] High precision is required for grooving of a workpiece such
as an electronic material part used for a semiconductor product or
the like, or processing for dividing a workpiece into individual
pieces by cutting (hereinafter abbreviated as cutting). For such
cutting process, a disc-shaped cutting blade (thin blade
grindstone) is used.
[0004] The cutting blade includes a blade main body having a disc
shape and a cutting edge formed on an outer peripheral edge portion
of the blade main body. The blade main body is formed by dispersing
abrasive grains of diamond, cBN, or the like and fillers in a
bonding phase (bonding agent) such as a resin phase (solid phase of
a resin) or a metal phase (solid phase of a metal). For this
reason, the blade main body includes the bonding phase, and the
abrasive grains and the fillers dispersed in the bonding phase. A
cutting blade in which the blade main body is formed of a resin
phase (cutting blade in which the blade main body includes a resin
phase as a bonding phase) is called a resin bonded blade (resin
bonded grindstone).
[0005] In producing this type of cutting blade, the following
methods have been conventionally used.
[0006] In the conventional manufacturing method shown in FIGS. 8(a)
to 8(c), first, in FIG. 8(a), a mixed powder MP obtained by mixing
a resin powder serving as a raw material of the resin phase,
abrasive grains and fillers is filled in a die. Next, in FIG. 8(b),
the surface of the mixed powder MP filled in the die is flattened
by manual operation, machine, or the like. Then, in FIG. 8(c), the
mixed powder MP is hot pressed and sintered. Further, although not
specifically shown, after the hot press process, an outer
periphery/inner periphery machining process, and in some cases, a
lapping treatment (process of flattening blade surfaces (both side
surfaces)) is performed to adjust the shape of the blade main body
and form a cutting blade as a product.
[0007] Further, in the methods for manufacturing cutting blades of
the following Patent Documents 1 and 2, a slurry containing a
bonding agent is prepared, and the slurry is formed into a plate
shape (sheet body) by a doctor blade method, and then die cutting,
degreasing (removal of the binder added at the time of slurry
preparation) and sintering are performed. It should be noted that
when a resin bonded blade is manufactured, a binder is not used,
and an alcohol or the like is used as a solvent for a resin serving
as a bonding agent. By volatilizing this solvent, a plate-shaped
molded article is obtained.
[0008] This type of cutting blade is required to perform cutting at
higher speed rotation. That is, it is required to perform the
cutting process by rotating the cutting blade at a higher speed. In
order to perform the cutting process at high speed rotation, it is
necessary to increase the strength of the cutting blade. As a
technique for increasing the strength of the cutting blade, fibrous
fillers are dispersed in the blade main body.
[0009] However, in the methods for manufacturing a cutting blade
using the doctor blade method as in Patent Documents 1 and 2, in
the case of using fibrous fillers, orientation of the fibrous
fillers are aligned in the extending direction of the sheet body
during the doctor blade process. More specifically, a recessed
portion having a shape of a sheet body (cutting blade) is provided
on the upper surface of a die, and the slurry is disposed on the
upper surface of the die. Subsequently, the doctor blade is slid
while in contact with the upper surface of the die, and the slurry
is filled in the recessed portion and excess slurry is removed. At
this time, the fibrous fillers are oriented in the extending
direction of the sheet body (sliding direction of the doctor
blade). For this reason, the fibrous fillers are oriented in a
direction parallel to a specific radial direction of the cutting
blade. As a result, the strength of the cutting blade varied in the
circumferential direction of the blade.
[0010] In the method for manufacturing a cutting blade of Patent
Document 3 described below, fibrous fillers are used as fillers. A
solvent, abrasive grains and the fibrous fillers are mixed with the
material of the resin phase to prepare a slurry. This slurry is
dropwise added onto the rotation center of a rotating body such as
a spin coater. The slurry dropwise added onto the rotating body
expands due to centrifugal force to become a sheet body. At this
time, the fibrous fillers in the slurry are oriented so as to
extend radially from the rotation center. Then, the sheet body is
molded into a circular plate shape, and the molded body is
hot-pressed to form a blade main body.
[0011] According to this method, orientation of the fibrous fillers
only in a certain direction is prevented, and the strength of the
cutting blade is equalized over the entire blade circumferential
direction.
[0012] However, the conventional method for manufacturing a cutting
blade has the following problems.
[0013] In the conventional manufacturing method shown in FIGS. 8(a)
to 8(c), in the step of FIG. 8(b), even when the surface of the
mixed powder MP in the die is smoothed so that the surface of the
mixed powder MP is apparently flattened, the packing density of the
mixed powder MP varies. Therefore, in the case where fibrous
fillers are used as fillers, the fibrous fillers do not uniformly
disperse inside the blade main body, and the blade strength
varies.
[0014] Further, as disclosed in Patent Documents 1 to 3, when
manufacturing a cutting blade by molding a sheet body from a
slurry, it was impossible to deal with a thermocompression-bondable
resin. In other words, for example, with respect to a
thermocompression-bondable resin such as a polyimide resin or the
like, since there is no good solvent (that is, a solvent with high
solubility for the resin), it was difficult to form a sheet body
from the slurry, and the production itself was difficult.
[0015] It should be noted that in the doctor blade methods of
Patent Documents 1 and 2, in the case where the content rate of the
fibrous fillers in the entire blade main body is low (for example,
in the case where it is 30 vol % or less), the sheet body can be
formed in some cases. However, since the orientation of the fibrous
fillers is aligned in a certain direction (extending direction of
the sheet body) as described above, the strength of the cutting
blade cannot be equalized in the blade circumferential
direction.
PRIOR ART DOCUMENTS
Patent Documents
[0016] Patent Document 1: Japanese Unexamined Patent Application,
First Publication No. H10-193267
[0017] Patent Document 2: Japanese Unexamined Patent Application,
First Publication No. H10-193268
[0018] Patent Document 3: Japanese Unexamined Patent Application,
First Publication No. 2015-98070
DISCLOSURE OF THE INVENTION
Problems to be Solved by the Invention
[0019] The present invention has been made in view of such
circumstances, and the present invention aims to provide a method
for manufacturing a cutting blade and a cutting blade, and the
method that can easily manufacture a cutting blade including a
resin phase of a thermocompression-bondable resin and in which
fibrous fillers can be uniformly dispersed inside the blade main
body without being oriented in a certain direction; and thereby,
the strength is uniformly increased in the entire circumferential
direction of the blade.
Solution for Solving the Problem
[0020] A method for manufacturing a cutting blade according to one
aspect of the present invention includes: a mixing step of adding a
liquid dispersion medium to a mixed powder containing a resin
powder of a thermocompression-bondable resin, abrasive grains and
fibrous fillers; a compression step of cold pressing, in a forming
die, the mixed powder to which the dispersion medium has been added
to form an original plate of a blade main body; and a sintering
step of hot pressing and sintering the original plate.
[0021] In addition, a cutting blade according to one aspect of the
present invention includes: a blade main body having a disc shape;
and a cutting edge formed on an outer peripheral edge portion of
the blade main body, wherein the blade main body includes: a resin
phase formed of a thermocompression-bondable resin; and abrasive
grains and fibrous fillers dispersed in the resin phase, and when
the blade main body is divided into a plurality of regions at a
mutually equal angle around the central axis of the blade main
body, a content rate of the fibrous fillers measured in each region
is from 90 to 110% with respect to an overall content rate of the
fibrous fillers in the blade main body as a whole (entire blade
main body).
[0022] In the method for manufacturing a cutting blade according to
one aspect of the present invention, a liquid dispersion medium
(dispersion medium in the form of a liquid) is added to a mixed
powder containing a resin powder of a thermocompression-bondable
resin, abrasive grains and fibrous fillers. Subsequently, the mixed
powder containing the liquid dispersion medium is cold pressed in a
forming die such as a metal mold or the like. Therefore, at the
time of this cold pressing process, the dispersion medium enters
the gaps between the powder particles of the mixed powder, and it
is possible to promote the powder flow utilizing the liquid
flow.
[0023] It should be noted that the "thermocompression-bondable
resin" as referred to in one aspect of the present invention is
included in thermosetting resins, and is a type of resin in which
the resin powder serving as the raw material of the resin phase is
formed so as to be in a state where the polymerization reaction is
by and large (almost) completed, and which forms the resin phase by
being integrated through thermocompression bonding during the
sintering step. In other words, the "thermocompression-bondable
resin" is a resin classified as a thermosetting resin. The resin
powder as a raw material of the resin phase is composed of a
thermosetting resin in a state in which the polymerization reaction
is almost completed. During the sintering step, the resin powder is
integrated by thermocompression bonding to form a resin phase.
Examples of such thermocompression-bondable resins include
polyimide resins, certain phenol resins, polybenzimidazole (PBI
(registered trademark)), and the like.
[0024] Further, as the "dispersion medium", for example,
chlorofluorocarbon (CFC) substitutes such as a fluorine-based inert
liquid or the like can be used.
[0025] In addition, the "fibrous filler" refers to a filler having
an elongated shape in which the average (value) of the aspect ratio
(ratio represented by the formula: (length)/(outer diameter)) is 5
or more. As the fibrous filler, for example, various materials such
as metals, carbon, glass, and the like can be used. It should be
noted that examples of the fibrous filler also include those having
an aspect ratio of 1,000 or more (so-called whiskers).
[0026] That is, in one aspect of the present invention, by applying
pressure in a forming die to a mixture of a mixed powder and a
dispersion medium in the compression step, the dispersion medium
acts like a lubricant, so that the resin powder, the abrasive
grains and the fibrous fillers uniformly diffuse in the forming
die. For this reason, variation in the density of the original
plate of the blade main body to be produced is remarkably
suppressed to a low level, and the fibrous fillers are uniformly
dispersed in the original plate.
[0027] At this time, although the fibrous fillers face toward a
direction intersecting with the thickness direction of the blade
main body (that is, any one direction of all directions (360
degrees) in a plane substantially perpendicular to the central axis
of the blade main body), the fibrous fillers are not oriented in a
certain direction, and the fibrous fillers are brought into a
non-oriented dispersed state having no regularity in orientation
(that is, randomly oriented). In other words, since a plurality of
fibrous fillers are randomly oriented, they are substantially
oriented and dispersed in all directions (360 degrees).
[0028] It should be noted that during this compression step, since
the cold pressing (cold compression) is performed,
thermocompression bonding of the resin powder does not proceed and
the fluidity of the resin powder is secured in a stable manner.
[0029] Then, the original plate of this blade main body is hot
pressed and sintered. As described above, since variation in the
density of the original plate is suppressed to a low level, the
occurrence of sink marks or the like in the blade main body at the
time of sintering can be suppressed. As a result, it is possible to
manufacture a blade main body in which warpage and flatness are
suppressed to low levels.
[0030] It should be noted that sink marks are indentations or
depressions generated by the shrinkage caused by materials. In the
case where the variation in the density of the original plate is
large, at the time of sintering, a portion with low density shrinks
more than other portions, and there is a possibility that
indentations or depressions may occur. The indentations and
depressions caused by this shrinkage are called sink marks.
[0031] Further, since the fibrous fillers are uniformly dispersed
from the time of molding the original plate, even in the blade main
body obtained by sintering the original plate, the fibrous fillers
are uniformly dispersed in the circumferential direction and the
radial direction of the blade. Therefore, it is possible to obtain
an excellent cutting blade having no variation in strength. More
specifically, as described above, since the fibrous fillers are not
oriented in a certain direction and randomly oriented in an
unspecified direction (all directions (360 degrees)) in a plane
substantially perpendicular to the central axis of the blade main
body, the fibrous fillers function like aggregates and the strength
is equally increased in the entire blade circumferential
direction.
[0032] In addition, since the fibrous fillers are uniformly
dispersed in random orientation in the blade main body, the
following actions and effects can also be obtained. [0033]
Improvement of wear resistance. [0034] Suppression of blade
thinning. [0035] Moderate self-sharpening action. [0036]
Improvement of toughness. [0037] Improvement of heat
resistance.
[0038] That is, since the fibrous fillers are uniformly dispersed
in the blade main body in random orientation, the blade main body
does not easily wear at predetermined portions in the
circumferential direction, and the wear progresses uniformly over
the entire circumferential direction. As a result, the abrasion
amount of the blade as a whole is also suppressed, and the wear
resistance is improved. In addition, since the wear resistance is
improved, the tool life is prolonged (tool life is improved).
[0039] Further, the fibrous fillers are randomly oriented in a
plane substantially perpendicular to the central axis of the blade
main body. Therefore, with respect to both side surfaces (front and
back surfaces of the blade) facing the thickness direction of the
blade main body, for example, the circumferential surface and the
longitudinal cross section (cross section along the extending
direction of the filler) of the fibrous filler having an elongated
columnar shape are exposed, so that exposure of end surfaces facing
the extending direction of the fibrous filler and the transverse
cross section (cross section perpendicular to the extending
direction of the filler) can be suppressed. On the other hand, with
respect to the outer circumferential surface facing outward in the
radial direction of the blade main body, it varies in that some of
the fibrous fillers expose their circumferential surfaces and
longitudinal cross sections, while some fibrous fillers expose
their end surfaces and transverse cross sections.
[0040] Therefore, the ratio of the exposed area of the fibrous
fillers per unit area of the outer surface of the blade with
respect to the both side surfaces of the blade main body becomes
large. In comparison with this, the ratio of the exposed area of
the fibrous fillers per unit area of the outer surface of the blade
with respect to the outer circumferential surface of the blade main
body becomes small. That is, with respect to the exposed area of
the fibrous fillers per unit area of the outer surface of the
blade, the exposed area of the fibrous fillers on both side
surfaces becomes larger than the exposed area of the fibrous
fillers on the outer circumferential surface of the blade main
body. For this reason, on the outer peripheral surface of the blade
main body, it is possible to appropriately allow wear to proceed
and to maintain the sharpness of the cutting edge satisfactorily
(it is possible to promote the self-sharpening action). Further, on
both side surfaces of the blade main body, it is possible to
suppress the progress of wear and to suppress the blade thinning.
Therefore, in the cut surface formed on the workpiece by the
cutting process, defects such as inclinations due to the blade
thinning hardly occur, and the quality of the cutting process is
markedly enhanced.
[0041] Further, in one aspect of the present invention, the blade
strength is improved by uniform dispersion and random orientation
of the fibrous fillers. For this reason, for example, compared with
a case where the blade strength is to be enhanced by simply using
particulate fillers having high hardness without using fibrous
fillers which is unlike one aspect of the present invention, it is
possible to promote a moderate self-sharpening action in one aspect
of the present invention.
[0042] That is, when attempting to enhance the blade strength by
using the conventional particulate fillers, a characteristic
orientation cannot be imparted to the particulate fillers; and
therefore, a method of simply increasing the hardness of the
particulate fillers is adopted. However, as the hardness of the
particulate fillers increases, the holding power of the abrasive
grains becomes too high at the cutting edge; and thereby, it
becomes difficult to form a new blade (the self-sharpening action
is reduced). For this reason, the sharpness cannot be maintained
satisfactorily.
[0043] On the other hand, if fibrous fillers are used as is the
case with one aspect of the present invention, the blade strength
can be increased without increasing the hardness of the fillers;
and therefore, it is possible to promote a moderate self-sharpening
action and to maintain the sharpness satisfactorily.
[0044] In addition, since the fibrous fillers are uniformly
dispersed and randomly oriented inside the blade main body, these
fibrous fillers act like aggregates, and the toughness of the blade
main body is improved. For this reason, the strength of the cutting
blade is increased while the impact resistance is also improved,
and in particular, rigidity is sufficiently secured even in the
cutting process during high speed rotation, and high-quality
cutting precision can be maintained.
[0045] Further, since the fibrous fillers are uniformly dispersed
and randomly oriented, it is possible to improve the thermal
conductivity between the fibrous fillers inside the blade main
body. For this reason, for example, in the case of using metal
fibers, carbon fibers or the like having a high thermal
conductivity as the fibrous fibers, the frictional heat generated
at the outer peripheral edge portion (cutting edge) of the blade
main body during the cutting process is thermally dissipated in the
blade at an early stage through the fibrous fillers, and the
cooling efficiency is also improved; and thereby, the heat
resistance of the cutting blade is improved.
[0046] It should be noted that most of the dispersion medium added
to the mixed powder before cold pressing flows out from the mixed
powder (original plate of the blade main body) at the time of cold
pressing and is removed. Further, the dispersion medium remaining
on the original plate of the blade main body after cold pressing
can be removed from the blade main body, for example, by
volatilization before hot pressing in the sintering step. At this
time, since the dispersion medium is present in a slight space
between the powder particles, formation of the blade main body in a
porous form by volatilization of the dispersion medium is
prevented. Further, in this case, since the dispersion medium does
not remain in the blade main body produced through the sintering
step, the performance of the blade main body is not adversely
affected by the dispersion medium.
[0047] More specifically, it is preferable that the timing at which
the dispersion medium is volatilized in the sintering step is
before the start of the thermocompression bonding of the resin
powder by hot pressing. In other words, it is preferable that all
of the dispersion medium is volatilized before conducting the hot
pressing process (before the sintering step). As a result, the
space in which the dispersion medium has been present between the
powder particles is occupied (replaced) by the resin phase, so that
traces of the dispersion medium are not left in the blade main body
after sintering. Therefore, the dispersion medium and its traces do
not adversely affect the performance of the blade main body.
[0048] More specifically, in the cutting blade manufactured
according to one aspect of the present invention, the blade main
body is divided into a plurality of regions at a mutually equal
angle around the central axis of the blade main body (for example,
four regions obtained by dividing the blade main body into four
equal parts around the central axis), and the content rate of the
fibrous fillers obtained in each region is suppressed to 90 to 110%
with respect to the overall content rate of the fibrous fillers in
the entire blade main body. That is, the ratio (percentage) of the
content rate of the fibrous fillers in each region with respect to
the overall content rate of the fibrous fillers in the entire blade
main body is from 90 to 110%.
[0049] In other words, the fibrous fillers are uniformly contained
in each region of the blade main body, and the fibrous fillers are
uniformly dispersed over the entire region of the blade main body.
This is because, as described above, the fibrous fillers have
already been uniformly dispersed over the entire blade in the
original plate of the blade main body that has undergone the
compression step by cold pressing. Therefore, the manufactured
blade main body has excellent rigidity with no variation in
strength over the entire blade.
[0050] It should be noted that the content rate of the fibrous
fillers in each region of the blade main body can be obtained, for
example, by the following method.
[0051] First, the entire side surface of the blade main body is
polished in the thickness direction to expose the fibrous fillers
disposed inside the side surface in the thickness direction. Next,
the polished side surface of the blade main body is photographed by
a scanning electron microscope (SEM) or the like. By binarizing the
photographed image, an image data that can distinguish between the
fibrous filler and other members is created. In this image data,
the blade main body is divided into a plurality of regions at a
mutually equal angle around the central axis of the blade main body
(for example, four regions obtained by dividing the blade main body
into four equal parts around the central axis). The ratio of the
area occupied by the fibrous fillers with respect to the area of
each region (the entire area of the region) is determined. This
ratio is defined as the content rate of the fibrous fillers in each
region of the blade main body.
[0052] However, the method of determining the content rate of the
fibrous fillers in each region of the blade main body is not
limited to the above method.
[0053] In addition, the overall content rate of the fibrous fillers
in the entire blade main body may be obtained from the above image
data or may be obtained from the ratio of the volume of the fibrous
fillers with respect to the volume of the entire blade main
body.
[0054] Further, in the cutting blade manufactured according to one
aspect of the present invention, the blade main body is divided
into a plurality of regions at a mutually equal angle around the
central axis of the blade main body (for example, eight regions
obtained by dividing the blade main body into eight equal parts
around the central axis), and an average value of the densities
measured in the regions is taken as the average density. The
density measured in each region can be suppressed to, for example,
90 to 110% with respect to this average density. That is, the ratio
(percentage) of the density of each region with respect to the
average density value is, for example, from 90 to 110%. In other
words, the density difference (variation in density) is suppressed
to a low level over the entire region of the blade main body. This
is because, as described above, the density difference has already
been suppressed to a low level in the original plate of the blade
main body that has undergone the compression step by cold pressing.
Therefore, the warpage and flatness of the produced blade main body
are suppressed to low levels.
[0055] More specifically, in the cutting blade manufactured
according to one aspect of the present invention, for example, the
warpage amount of the blade main body can be suppressed to 300
.mu.m or less. Further, the flatness of the blade main body can be
suppressed to 20 .mu.m or less.
[0056] In addition, the flatness of both side surfaces facing the
thickness direction of the blade main body obtained after sintering
is suppressed to a low level as described above. Therefore, even in
a field of application where high-quality cutting precision is
particularly required, it is possible to satisfy the expected
(desired) flatness without flattening both side surfaces of the
blade main body by a lapping treatment.
[0057] It should be noted that the warpage amount of the blade main
body is measured by the following method. As shown in FIGS. 5(a)
and 5(b), a cutting blade 10 is placed on a surface plate S. While
rotating the surface plate S, a laser beam L of a laser
interferometer is irradiated to the cutting blade 10 to measure the
height (the height from the surface plate S) of the entire
circumference of the cutting blade 10. The blade thickness is
subtracted from the maximum value (height at the position farthest
from the surface plate S) of the measured values, and the obtained
value is taken as the warpage amount of the blade main body. It
should be noted that this measurement is performed on both surfaces
(both side surfaces facing the thickness direction) of the blade
main body, and the larger numerical value is adopted.
[0058] Further, the flatness of the blade main body is measured by
the following method. The blade main body is divided into a
plurality of regions at a mutually equal angle around the central
axis of the blade main body (for example, eight regions obtained by
dividing the blade main body into eight equal parts around the
central axis). In each region, the thickness of the blade main body
is measured with a micrometer or the like. The maximum difference
in the variation of measured values (the difference between the
maximum thickness and the minimum thickness) is the flatness of the
blade main body.
[0059] As described above, since the warpage and the flatness of
the blade main body are suppressed to low levels, the following
actions and effects can be obtained when a workpiece is cut with
this cutting blade.
[0060] That is, since the deflection of the cutting blade in the
thickness direction is suppressed, the cutting width is suppressed
to a small value, and the product yield of the workpiece can be
improved. In addition, a force from the cutting blade to the
workpiece in the cutting width direction (the width direction of
the cutting line formed on the workpiece by the cutting process)
hardly acts. For this reason, the cutting blade smoothly cuts into
the workpiece, and the occurrence of burrs, chipping or the like on
the cut surface is prevented. Therefore, the quality of the
electronic material parts (products) and the like obtained by
dividing the workpiece into individual pieces can be stably
increased.
[0061] Furthermore, since it is unnecessary to perform a lapping
treatment on the blade surface, there is no possibility that the
abrasive grains protrude from the resin phase by this lapping
treatment. That is, in one aspect of the present invention, the
blade main body obtained through the sintering step includes the
abrasive grains disposed further to the inside than the side
surface of the blade main body in the thickness direction, and
there are no abrasive grains protruding outward in the thickness
direction from the side surface. For this reason, it is possible to
remarkably suppress problems such as the abrasive grains protruding
from the side surface of the blade main body to roughen the cut
surface of the workpiece and lower the processing quality (generate
burrs, chipping or the like) during the cutting process. Therefore,
the cutting precision can be particularly enhanced by this effect
that no abrasive grains protrude from the side surface in
conjunction with the effect that the flatness can be suppressed to
a low level as described above.
[0062] More specifically, conventionally, particularly in the case
of attempting to reduce the thickness of the blade main body to 1.1
mm or less, it has been essential to carry out a lapping treatment
in order to suppress the flatness of the blade surface to a small
value and to reduce the thickness of the blade main body down to
the expected thickness (thin it down to the desired thickness). For
this reason, it was impossible to prevent the abrasive grains from
protruding from the side surface of the blade main body.
[0063] On the other hand, according to one aspect of the present
invention, even if the thickness of the blade main body is reduced
to, for example, 1.1 mm or less, the flatness has already been
suppressed to a small value after sintering; and therefore, the
lapping treatment is unnecessary. As a result, it is possible to
reliably prevent the abrasive grains from protruding from the side
surface of the blade main body. That is, both side surfaces of the
blade main body that have undergone the sintering step are in a
state where the surface is formed flat by the pressing process and
there is no protrusion of abrasive grains. For this reason, by
omitting the lapping treatment, it is possible to reduce the number
of abrasive grains protruding from the blade surface to zero.
[0064] Furthermore, since it is unnecessary to perform a lapping
treatment, not only the production is facilitated, but also it
becomes unnecessary to form the blade main body with a large
thickness in advance in anticipation of the lapping treatment as in
the prior art, and the material cost is reduced.
[0065] Further, in the prior art, the reaction force received by
the cutting blade when cutting the workpiece acted unevenly against
the portion having a large amount of warpage. In one aspect of the
present invention, the warpage and flatness of the blade main body
are suppressed to low levels; and thereby, the above problems are
prevented. In other words, according to one aspect of the present
invention, since the above reaction force is more likely to act
uniformly over the entire circumference in the circumferential
direction of the cutting blade, and the application of a large load
to a predetermined portion is prevented, the tool life of the
cutting blade is prolonged (the tool life is improved).
[0066] Further, in manufacturing a cutting blade in which the
cutting precision is markedly enhanced as described above, in
comparison with the conventional manufacturing method, a
particularly complicated manufacturing process is not used in one
aspect of the present invention. More specifically, in one aspect
of the present invention, by passing through a simple process of
cold pressing a mixed powder to which a dispersion medium has been
added in a forming die, variation in the density of the blade main
body (original plate) is suppressed, while the fibrous fillers are
uniformly dispersed and the fibrous fillers are randomly oriented.
As a result, since the above-mentioned excellent actions and
effects can be achieved, it is easy to manufacture the cutting
blade.
[0067] As described above, according to the method for
manufacturing a cutting blade of one aspect of the present
invention, it is possible to include a resin phase composed of a
thermocompression-bondable resin, and the fibrous fillers can be
uniformly dispersed without orienting the fibrous fillers in a
certain direction inside the blade main body. As a result, it is
possible to easily manufacture a cutting blade in which the
strength is uniformly increased in the entire blade circumferential
direction.
[0068] Further, according to the cutting blade of one aspect of the
present invention, since the strength is uniformly increased in the
entire circumferential direction of the blade, the cutting process
can be stably performed at high speed rotation.
[0069] In addition, in the above method for manufacturing a cutting
blade, it is preferable that the mixing step includes: a step of
filling the forming die with the mixed powder containing the resin
powder of the thermocompression-bondable resin, the abrasive grains
and the fibrous filler; a step of flattening a surface of the mixed
powder; and a step of dropwise adding the liquid dispersion medium
onto the mixed powder.
[0070] In this case, since the mixing step includes the step of
flattening the surface of the mixed powder filled in the forming
die, the flow amount of the mixed powder until it diffuses
uniformly into the forming die in the compression step which is a
subsequent step of this mixing step can be suppressed to a low
level. For this reason, the following actions and effects are
achieved (obtained) more stably.
[0071] The above-described effect that variation in the density of
the original plate of the blade main body can be suppressed to a
low level.
[0072] The effect that the fibrous fillers are uniformly dispersed
in the interior of the original plate while the fibrous fillers are
randomly oriented without being oriented in a certain
direction.
[0073] In addition, since the mixing step includes the step of
dropwise adding the dispersion medium to the mixed powder whose
surface has been flattened, the dispersion medium is more easily
mixed uniformly with the mixed powder. In other words, since the
dispersion medium easily spreads all over the mixed powder as a
whole and increases the affinity therewith, the powder flow of the
mixed powder making use of (utilizing) the liquid flow of the
dispersion medium is uniformly distributed over the entire interior
of the forming die in the compression step which is a subsequent
step of this mixing step. Therefore, the following actions and
effects are achieved (obtained) more stably.
[0074] The above-described effect that variation in the density of
the original plate of the blade main body can be suppressed to a
low level.
[0075] The effect that the fibrous fillers are uniformly dispersed
in the interior of the original plate while the fibrous fillers are
randomly oriented without being oriented in a certain
direction.
[0076] In addition, in the above method for manufacturing a cutting
blade, it is preferable that a liquid having a kinematic viscosity
of 2.3 mm.sup.2/s or less is used as the dispersion medium.
[0077] In this case, since the kinematic viscosity of the
dispersion medium is 2.3 mm.sup.2/s or less (2.3 cSt or less), the
dispersion medium spreads between the powder particles of the mixed
powder, and increases the affinity with the powder particles of the
mixed powder to facilitate the liquid flow over a wide range, and
the dispersion medium also effectively functions as a lubricant to
promote the powder flow of the mixed powder. As a result, in the
compression step, the effect of uniformly diffusing the mixed
powder into the forming die can be obtained more remarkably.
[0078] More specifically, in the case where the kinematic viscosity
of the dispersion medium is equal to or less than 2.3 mm.sup.2/s,
the warpage and flatness of the blade main body obtained after
sintering are remarkably suppressed to low levels, and the strength
of the entire blade is remarkably increased.
[0079] It should be noted that the above-described "kinematic
viscosity" is a kinematic viscosity required at the time of cold
pressing in the compression step, and refers to, for example, the
kinematic viscosity of a liquid at 25.degree. C.
[0080] In addition, in the above cutting blade, when the blade main
body is divided into a plurality of regions at a mutually equal
angle around the central axis of the blade main body, and an
average value of densities measured in the regions is taken as an
average density, it is preferable that the density measured in each
region is from 90 to 110% with respect to the average density.
[0081] Further, in the above cutting blade, it is preferable that
the overall content rate of the fibrous fillers in the blade main
body as a whole (entire blade main body) is from 20 to 60 vol
%.
[0082] In this case, since the overall content rate of the fibrous
fillers in the entire blade main body is from 20 to 60 vol %, it is
possible to reliably achieve the actions and effects brought about
by the fibrous fillers as described above, while preventing
reduction in the blade rigidity due to inclusion of an excessive
amount of the fibrous fillers.
[0083] That is, since the overall content rate of the fibrous
fillers is equal to or more than 20 vol %, the above-described
actions and effects due to the dispersion of the fibrous fillers in
the blade main body can be reliably obtained. In addition, since
the overall content rate of the fibrous fillers is equal to or less
than 60 vol %, it is possible to suppress the excessive reduction
of the resin phase serving as a bonding agent interposed between
the fibrous fillers; and thereby, the function of the resin phase
is stabilized.
[0084] Further, in the above cutting blade, it is preferable that a
warpage amount of the blade main body is equal to or less than 300
.mu.m.
[0085] In addition, in the above cutting blade, it is preferable
that a flatness of the blade main body is equal to or less than 20
.mu.m.
[0086] Since the variation in the density of the blade main body is
suppressed to a low level, the warpage amount of the blade main
body can be suppressed to as low as 300 .mu.m or less. In addition,
the flatness of the blade main body can be suppressed to as low as
20 .mu.m or less. For this reason, at the time of manufacturing the
cutting blade, it is possible to reduce (omit) operations such as a
lapping treatment for flattening the blade surfaces (both side
surfaces).
[0087] Therefore, while improving the ease of manufacturing the
cutting blade, the cutting precision by the cutting blade can be
remarkably enhanced.
[0088] More specifically, in a conventional cutting blade, as
described with reference to FIGS. 8(a) to 8(c), since variation
tends to occur in the packing density inside the mixed powder in
the forming die at the time of manufacturing the blade, the
flatness of the side surface of the blade main body obtained after
sintering was, more or less, as large as 100 .mu.m (about 100
.mu.m). For this reason, in the field of application where the
cutting precision was particularly required, both side surfaces of
the blade main body were subjected to a lapping treatment for
planarization. However, even if the resin phase is removed by the
lapping treatment, abrasive grains with high hardness tend to
remain in a state of being protruded from the side surface, and it
was difficult to satisfy the expected (desired) flatness.
[0089] On the other hand, according to the cutting blade of one
aspect of the present invention, since the variations in the
packing density inside the mixed powder in the forming die can be
suppressed to a small value, the flatness of the side surface of
the blade main body obtained after sintering can be suppressed to
as low as 20 .mu.m or less. Therefore, even in a field of
application where the cutting precision is particularly required,
it is possible to satisfy the expected (desired) flatness without
flattening both side surfaces of the blade main body by a lapping
treatment.
[0090] Furthermore, since it is unnecessary to subject the blade
surface to a lapping treatment, there is no possibility that the
abrasive grains protrude from the resin phase by this lapping
treatment. In other words, there are no abrasive grains protruding
in the thickness direction on the side surface of the blade main
body obtained through the sintering step; and therefore, the
cutting precision can be particularly enhanced by this effect that
no abrasive grains protrude from the side surface in conjunction
with the effect that the flatness can be suppressed to a low level
as described above.
[0091] In addition, in the above cutting blade, it is preferable
that the thickness of the blade main body is equal to or less than
1.1 mm.
[0092] Since the strength of the cutting blade is increased in the
entire region of the blade main body as described above, it is easy
to reduce the thickness of the blade main body to 1.1 mm or less
while ensuring the rigidity of the blade main body.
[0093] Therefore, it is possible to more remarkably obtain the
effect that the cutting width of the workpiece can be suppressed to
a small value to improve the product yield while satisfactorily
maintaining the cutting precision.
Effects of the Invention
[0094] According to the method for manufacturing a cutting blade of
one aspect of the present invention, it is possible to include a
resin phase composed of a thermocompression-bondable resin, and the
fibrous fillers can be uniformly dispersed without orienting the
fibrous fillers in a certain direction inside the blade main body.
As a result, it is possible to easily manufacture a cutting blade
in which the strength is uniformly increased in the entire blade
circumferential direction.
[0095] Further, according to the cutting blade of one aspect of the
present invention, since the strength is uniformly increased in the
entire circumferential direction of the blade, the cutting process
can be stably performed at high speed rotation.
BRIEF DESCRIPTION OF THE DRAWINGS
[0096] FIG. 1 is a side view (plan view) showing a cutting blade
according to one embodiment of the present invention.
[0097] FIG. 2 is a cross sectional view taken along the line A-A in
FIG. 1.
[0098] FIG. 3 is an enlarged view of a portion B of FIG. 2.
[0099] FIG. 4 is a view for explaining a variation in a content
rate of fibrous fillers in each region of a blade main body.
[0100] FIG. 5 is a view for explaining a method for measuring a
warpage amount of the blade main body.
[0101] FIG. 6 is a view for explaining a method for manufacturing a
cutting blade according to one embodiment of the present
invention.
[0102] FIG. 7 is a view for explaining burrs generated at the time
of cutting a workpiece.
[0103] FIG. 8 is a view for explaining a method for manufacturing a
conventional cutting blade.
EMBODIMENTS FOR CARRYING OUT THE INVENTION
[0104] Hereinafter, a cutting blade 10 according to an embodiment
of the present invention and a manufacturing method thereof will be
described with reference to the drawings.
[0105] Examples of the electronic material parts to be cut and
manufactured by the cutting blade 10 of the present embodiment
include those that are cut and divided from a semiconductor wafer,
like a semiconductor element, and then mounted on a lead frame and
subjected to resin molding, and, for example, also those described
below.
[0106] (a) Electronic material parts, such as those referred to as
QFN (quad flat non-leaded packages), that are manufactured by
collectively mounting a large number of devices on a lead frame,
and collectively molding and then cutting these into individual
pieces.
[0107] (b) Electronic material parts having a substrate in which
Ni, Au, Cu or the like is plated on the inner circumferential
surface of a through hole formed in a base made of a glass epoxy
resin, and divided into individual pieces by cutting, like an
optical transmission module based on the IrDA (Infrared Data
Association) standard (hereinafter simply abbreviated as IrDA).
[0108] The cutting blade 10 of the present embodiment is used to
precisely cut a workpiece, such as these types of electronic
material parts.
[0109] As shown in FIGS. 1 and 2, the cutting blade 10 includes a
blade main body 1 having a disc shape and a cutting edge 1A formed
at an outer peripheral edge portion of the blade main body 1.
[0110] Although not specifically shown, the blade main body 1 of
the cutting blade 10 is attached to the main shaft of a cutting
apparatus via a flange. The cutting blade 10 is fed in a direction
perpendicular to the central axis O while being rotated around the
central axis O of the blade main body 1; and thereby, the workpiece
is cut at the outer peripheral edge portion (cutting edge 1A)
projecting outward in the radial direction from the flange in the
blade main body 1.
[0111] In the present embodiment, a direction along the central
axis O of the blade main body 1 (the direction in which the central
axis O extends) is referred to as a thickness direction of the
blade main body 1 or simply as a direction of the central axis O.
Further, this thickness direction may be referred to as the cutting
width direction of the cutting blade 10 (corresponding to the width
direction of the cutting line formed on the workpiece by the
cutting process).
[0112] Moreover, a direction orthogonal to (perpendicular to) the
central axis O is referred to as a radial direction, and a
direction orbiting around the central axis O is referred to as a
circumferential direction.
[0113] The size (that is, the thickness) along the thickness
direction of the blade main body 1 is, for example, 0.1 mm or more
and 1.1 mm or less. Therefore, the blade main body 1 has an
extremely thin disc shape. It should be noted that in FIG. 2, in
order to make the shape of the cutting blade 10 easier to
understand, the thickness of the blade main body 1 is shown thicker
than the actual thickness.
[0114] In addition, a mounting hole 4 having a circular hole shape
centered on the central axis O and penetrating the blade main body
1 in the thickness direction is formed in a central portion (on the
central axis O) in the radial direction of the blade main body 1.
Therefore, more specifically, the blade main body 1 has an annular
plate shape. The "blade main body 1 having a disc shape" as
referred to in the present embodiment includes the blade main body
1 having an annular plate shape.
[0115] As shown in FIG. 3, the cutting edge 1A of the blade main
body 1 is formed to include: an outer circumferential surface of
the blade main body 1 which has an extremely small width equal to
the thickness of the blade main body 1; each of outer peripheral
edge portions in both side surfaces 1B, 1B facing the thickness
direction of the blade main body 1; and a pair of edge portions
forming an intersecting ridgeline between the outer peripheral edge
portions and the outer circumferential surface.
[0116] The blade main body 1 includes: a resin phase 2 formed of a
thermocompression-bondable resin; abrasive grains 3 dispersed in
the resin phase 2 and composed of a material harder than the resin
phase 2; and fibrous fillers 5 dispersed in the resin phase 2 and
composed of a material softer than the abrasive grains 3. That is,
the blade main body 1 includes the resin phase 2, the abrasive
grains 3 dispersed in the resin phase 2, and the fibrous fillers 5
dispersed in the resin phase 2.
[0117] It should be noted that the content rates of the resin phase
2, the abrasive grains 3 and the fibrous fillers 5 in the blade
main body 1 are the same as the mixing rates of the resin powder,
the abrasive grains 3 and the fibrous fillers 5 in a mixed powder
MP used in the production process described later.
[0118] The resin phase 2 is a resin bonding agent phase (resin bond
matrix material) containing as a main component, for example, a
synthetic resin such as a polyimide resin, a portion of phenol
resins (certain phenol resins) and polybenzimidazole (PBI
(registered trademark)).
[0119] It should be noted that the "thermocompression-bondable
resin" as referred to in the present embodiment is included in
thermosetting resins, and is a type of resin in which the resin
powder serving as the raw material of the resin phase 2 is formed
so as to be in a state where the polymerization reaction is by and
large (almost) completed, and which forms the resin phase 2 by
being integrated through thermocompression bonding during the
sintering step.
[0120] The abrasive grains 3 contain either diamond abrasive grains
or cBN abrasive grains. In the present embodiment, diamond abrasive
grains are used as the abrasive grains 3.
[0121] The fibrous filler 5 refers to a filler having an elongated
shape in which the average (value) of the aspect ratio (ratio
represented by the formula: (length)/(outer diameter)) is 5 or
more. As the fibrous filler 5, for example, various materials such
as metals, carbon, glass, and the like can be used. It should be
noted that examples of the fibrous filler 5 also include those
having an aspect ratio of 1,000 or more (so-called whiskers). The
aspect ratio of the fibrous fillers 5 is preferably 5 or more and
100 or less.
[0122] In the present embodiment, although a single type of
material is used as the fibrous filler 5 to be dispersed in the
blade main body 1, the material is not limited thereto, and a
plurality of types of fibrous fillers 5 may be dispersed in the
blade main body 1. That is, a plurality of types of fibrous fillers
5 having different lengths, aspect ratios, materials and the like
with each other may be used. Furthermore, as a filler, a
particulate filler may be used together with the fibrous filler
5.
[0123] Both the abrasive grains 3 and the fibrous fillers 5 are
composed of a material harder than the resin phase 2. The abrasive
grains 3 mainly contribute to the improvement of cutting
processability, and the fibrous fillers 5 mainly contributes to the
improvement of rigidity of the blade main body 1. It should be
noted that the materials of the abrasive grains 3 and the fibrous
fillers 5 are not limited to those described in the present
embodiment.
[0124] As shown in FIG. 3, the abrasive grains 3 do not protrude
from both side surfaces 1B, 1B facing the thickness direction of
the blade main body 1. Further, the fibrous fillers 5 also do not
protrude from both side surfaces 1B, 1B facing the thickness
direction of the blade main body 1. In other words, the abrasive
grains 3 and the fibrous fillers 5 are entirely disposed further to
the inside than the side surface 1B of the blade main body 1 in the
thickness direction.
[0125] It should be noted that regarding the outer edge (outer
peripheral edge) of the blade main body 1 in the radial direction,
due to a dressing treatment or the like of the cutting edge 1A,
either one of the abrasive grains 3 and the fibrous fillers 5 may
be protruded from the resin phase 2 within a range so that they do
not protrude at a portion of the side surface 1B other than the
outer peripheral edge to the outside in the thickness
direction.
[0126] In the example shown in FIG. 3, either one of the abrasive
grains 3 and the fibrous fillers 5 protrude from the outer
circumferential surface facing outward in the radial direction of
the blade main body 1.
[0127] In the cutting blade 10 of the present embodiment, the blade
main body 1 is divided into a plurality of regions at a mutually
equal angle around the central axis O of the blade main body 1. The
content rate of the fibrous fillers 5 measured in each region is
set to 90 to 110% with respect to the overall content rate of the
fibrous fillers 5 in the entire blade main body 1.
[0128] It should be noted that the content rate of the fibrous
fillers 5 in each region of the blade main body 1 can be obtained,
for example, by the following method.
[0129] First, the entire side surface 1B of the blade main body 1
is polished in the thickness direction to expose the fibrous
fillers 5 disposed inside the side surface 1B in the thickness
direction. Next, the polished side surface 1B of the blade main
body 1 is photographed by a scanning electron microscope (SEM) or
the like. By binarizing the photographed image, an image data that
can distinguish between the fibrous filler 5 and other members is
created. In this image data, the blade main body 1 is divided into
a plurality of regions at a mutually equal angle around the central
axis O of the blade main body 1 (for example, four regions obtained
by dividing the blade main body 1 into four equal parts around the
central axis O). The ratio of the area occupied by the fibrous
fillers 5 with respect to the area of each region (the entire area
of the region) is determined. This ratio is defined as the content
rate of the fibrous fillers 5 in each region of the blade main body
1.
[0130] However, the method of determining the content rate of the
fibrous fillers 5 in each region of the blade main body 1 is not
limited to the above method.
[0131] In addition, the overall content rate of the fibrous fillers
5 in the entire blade main body 1 may be obtained from the above
image data or may be obtained from the ratio of the volume of the
fibrous fillers 5 with respect to the volume of the entire blade
main body 1.
[0132] More specifically, in the present embodiment, as shown in
FIG. 4, the blade main body 1 is divided into four equal parts
around the central axis O of the blade main body 1 to be divided
into four regions. With respect to the overall content rate of the
fibrous fillers 5 in the entire blade main body 1, all of the
content rates of the fibrous fillers 5 in the four regions fall
within the range of 90 to 110% (within .+-.10% when the overall
content rate is taken as 100%). That is, the ratio (percentage) of
the content rate of the fibrous fillers 5 in each region with
respect to the overall content rate of the fibrous fillers 5 in the
entire blade main body 1 is in the range of 90 to 110%.
[0133] More specifically, in the cutting blade 10 of the present
embodiment, the content rate of the fibrous fillers 5 in each
region is within the range of 95 to 105% with respect to the
overall content rate of the fibrous fillers 5 (within .+-.5% when
the overall content rate is taken as 100%).
[0134] It should be noted that in the present specification, the
expression "when X is taken as 100%, Y is within the range of .+-.Z
%" means that the ratio of Y with respect to X (Y/X) (percentage)
is within the range of (100-Z) % to (100+Z) %.
[0135] It should be noted that in the present embodiment, although
the blade main body 1 is divided into four equal parts around the
central axis O of the blade main body 1 to be divided into four
regions, and the content rate of the fibrous fillers 5 is
determined in each region, the method is not limited thereto. That
is, the blade main body 1 may be divided into a plurality of
regions at a mutually equal angle around the central axis O of the
blade main body 1, and the content rate of the fibrous fillers 5
may be determined in each region. Therefore, the number of equally
divided regions is not limited to four. However, in order to secure
the accuracy of the content rate of the fibrous fillers 5, it is
preferable that the number of equally divided regions is at least 4
or more.
[0136] Further, in the present embodiment, the overall content rate
of the fibrous fillers 5 in the entire blade main body 1 is from 20
to 60 vol %. That is, the ratio of the volume of the fibrous
fillers 5 with respect to the volume of the entire blade main body
1 is from 20 to 60%. It should be noted that the overall content
rate of the fibrous fillers 5 in the entire blade main body 1 is
more preferably 30 vol % or more and 50 vol % or less.
[0137] In addition, in the cutting blade 10 of the present
embodiment, the blade main body 1 is divided into a plurality of
regions at a mutually equal angle around the central axis O of the
blade main body 1, and an average value of the densities measured
in the regions is taken as the average density. The density
measured in each region is from 90 to 110% with respect to this
average density. That is, the ratio (percentage) of the density of
each region with respect to the average density value is within the
range of 90 to 110%.
[0138] That is, although not specifically shown, the blade main
body 1 is divided into eight equal parts around the central axis O
of the blade main body 1 to be divided into eight regions. Then,
the average value of the densities measured in the eight regions is
defined as the average density. All the densities measured in the
eight regions are within the range of 90 to 110% with respect to
this average density (within .+-.10% when the average density is
taken as 100%).
[0139] More specifically, in the cutting blade 10 of the present
embodiment, the density measured in each region is within the range
of 95 to 105% with respect to the average density (within .+-.5%
when the average density is taken as 100%).
[0140] It should be noted that in the present embodiment, although
the blade main body 1 is divided into eight equal parts around the
central axis O of the blade main body 1 to be divided into eight
regions, and the density is measured in each region, the method is
not limited thereto. That is, the blade main body 1 may be divided
into a plurality of regions at a mutually equal angle around the
central axis O of the blade main body 1, and the density may be
measured in each region. Therefore, the number of equally divided
regions is not limited to eight. However, in order to secure the
measurement accuracy, it is preferable that the number of equally
divided regions is at least 4 or more.
[0141] Further, in the cutting blade 10, the warpage amount of the
blade main body 1 is equal to or less than 300 .mu.m. It should be
noted that the warpage amount of the blade main body 1 is obtained
as follows.
[0142] As shown in FIGS. 5(a) and 5(b), the cutting blade 10 is
placed on the surface plate S. By irradiating the laser beam L of
the laser interferometer to the cutting blade 10 while rotating the
surface plate S around the central axis, the height of the entire
circumference of the cutting blade 10 (the height from the surface
plate S) is measured. Then, a value obtained by subtracting the
thickness of the blade main body 1 from the maximum value (the
height at the position farthest from the surface plate S) among the
values obtained by the measurement is defined as the warpage
amount. It should be noted that this measurement is performed on
both surfaces (both side surfaces 1B, 1B facing the thickness
direction) of the blade main body 1, and the larger numerical value
is adopted.
[0143] Further, in the cutting blade 10, the flatness of the blade
main body 1 is equal to or less than 20 .mu.m. It should be noted
that the flatness of the blade main body 1 is obtained as
follows.
[0144] The blade main body 1 is divided into a plurality of regions
at a mutually equal angle around the central axis O of the blade
main body 1 (for example, eight regions obtained by dividing the
blade main body 1 into eight equal parts around the central axis
O). Then, in each region, the thickness of the blade main body 1 is
measured with a micrometer or the like. The maximum difference in
the variation of measurement values (the difference between the
maximum value and the minimum value of the thickness) is taken as
the flatness.
[0145] It should be noted that the blade main body 1 may be divided
into a plurality of regions at a mutually equal angle around the
central axis O of the blade main body 1, and the thickness may be
measured in each region. Therefore, the number of equally divided
regions is not limited to eight. However, in order to secure the
measurement accuracy, it is preferable that the number of equally
divided regions is at least 4 or more.
[0146] Next, a method for manufacturing the above-mentioned cutting
blade 10 will be described with reference to FIG. 6.
[0147] The method for manufacturing the cutting blade 10 of the
present embodiment includes: a mixing step of adding a liquid
dispersion medium DM to a mixed powder MP containing a resin powder
of a thermocompression-bondable resin, abrasive grains 3 and
fibrous fillers 5; a compression step of cold pressing the mixed
powder MP to which the dispersion medium DM has been added in a
forming die to form an original plate 11 of a blade main body 1; a
sintering step of hot pressing and sintering the original plate 11;
and a finishing step of adjusting the shapes of the outer
circumference and the inner circumference of the blade main body 1
obtained by sintering the original plate 11.
[0148] The mixing step includes: a step of filling a forming die
with a mixed powder MP containing a resin powder of a
thermocompression-bondable resin, abrasive grains 3 and fibrous
fillers 5, as shown in FIG. 6(a); a step of flattening the surface
of the mixed powder MP filled in the forming die, as shown in FIG.
6(b); and a step of dropwise adding a liquid dispersion medium DM
onto the mixed powder MP whose surface has been flattened, as shown
in FIG. 6(c).
[0149] In the step of flattening the surface of the mixed powder
MP, the entire surface (upper surface) of the mixed powder MP is
smoothed to a uniform height by manual operation, machine, or the
like. Further, in the step of dropwise adding the dispersion medium
DM to the mixed powder MP, the dispersion medium DM is uniformly
dropped onto the entire surface of the mixed powder MP.
[0150] It should be noted that as the "dispersion medium DM"
referred to in the present embodiment, for example,
chlorofluorocarbon (CFC) substitutes such as a fluorine-based inert
liquid or the like can be used. In addition, as the dispersion
medium DM, it is preferable to use a liquid having a kinematic
viscosity of 2.3 mm.sup.2/s or less (2.3 cSt or less).
[0151] It should be noted that the term "kinematic viscosity" used
in the present embodiment is a kinematic viscosity required at the
time of cold pressing in the compression step described later, and
refers to, for example, the kinematic viscosity of a liquid at
25.degree. C.
[0152] Specifically, as a substance name used for the dispersion
medium DM, for example, tetradecafluorohexane, perfluorocarbonate
(C5 to C9) and the like can be mentioned.
[0153] More specifically, the following products or the like can be
used as the dispersion medium DM. [0154] 3M Company: FLUORINERT
(registered trademark) FC 72: kinematic viscosity 0.4 cSt [0155] 3M
Company: FLUORINERT (registered trademark) FC 84: kinematic
viscosity 0.55 cSt [0156] 3M Company: FLUORINERT (registered
trademark) FC 3283: kinematic viscosity 0.82 cSt [0157] 3M Company:
FLUORINERT (registered trademark) FC 40: kinematic viscosity 2.2
cSt
[0158] It should be noted that as described in JIS Z 8803: 2011,
the unit "cSt" for kinematic viscosity is in a relationship
represented by the formula: 1 cSt=1 mm.sup.2/s.
[0159] Further, in a premixing step (step of mixing in advance)
which is a step prior to the above mixing step, the mixed powder MP
is produced by mixing in advance the resin powder composed of a
thermocompression-bondable resin, the abrasive grains 3 and the
fibrous fillers 5. That is, in the premixing step, the resin powder
of the thermocompression-bondable resin, the abrasive grains 3 and
the fibrous fillers 5 are mixed in advance to prepare a mixed
powder MP, and the liquid dispersion medium DM is mixed with the
mixed powder MP in the subsequent mixing step.
[0160] In the compression step, as shown in FIG. 6(d), the mixed
powder MP to which the dispersion medium DM has been added through
the mixing step is cold compressed (cold pressed) in the forming
die.
[0161] It should be noted that the term "cold press" as used in the
present embodiment refers to, for example, a compression process at
normal temperature, and more specifically, a compression process at
a temperature lower than the temperature at which thermocompression
bonding of the resin powder occurs. More specifically, the
temperature for the cold pressing process is preferably equal to or
less than 60.degree. C., and the pressure for the cold pressing
process is preferably equal to or less than 100 MPa. By this cold
pressing process, most of the dispersion medium DM contained in the
mixed powder MP is caused to flow out from the mixed powder MP to
the outside.
[0162] Further, in the present embodiment, a metal mold is used as
the forming die. However, at least in the steps prior to the
compression step, a mold made of a material other than a metal
material may be used as the forming die.
[0163] In the sintering step, the original plate 11 of the blade
main body 1 is compressed (hot pressed) while being heated in the
forming die.
[0164] It should be noted that the term "hot press" as used in the
present embodiment refers to a compression process in a temperature
range where thermocompression bonding of the resin powder is
performed.
[0165] Preferred conditions for the hot pressing process are shown
below.
[0166] (a) When the thermocompression-bondable resin is a phenol
resin, the hot pressing temperature is from 180 to 220.degree. C.,
the pressure is equal to or more than 10 MPa, and the hot pressing
time is equal to or more than 25 minutes.
[0167] (b) When the thermocompression-bondable resin is a polyimide
resin, the hot pressing temperature is equal to or more than
350.degree. C., the pressure is equal to or more than 50 MPa, and
the hot pressing time is equal to or more than 25 minutes.
[0168] (c) When the thermocompression-bondable resin is
polybenzimidazole, the hot pressing temperature is equal to or more
than 400.degree. C., the pressure is equal to or more than 50 MPa,
and the hot pressing time is equal to or more than 25 minutes.
[0169] More specifically, for example, when the
thermocompression-bondable resin is a polyimide resin, the original
plate 11 is hot-pressed under conditions where a temperature of a
hot plate of the forming die is 330.degree. C., a metal mold
temperature is 320.degree. C. or more, a time is 30 minutes, and a
pressure is 10 tons.
[0170] Further, after hot pressing, it is preferable to carry out a
heat treatment in a heating furnace at a temperature of 180 to
450.degree. C. for 8 hours or more to complete the sintering of the
blade main body 1. The heat treatment is preferably performed in a
state (no-load state) in which no load is applied to the original
plate 11. The duration (time) of the heat treatment is preferably
24 hours or less. When the thermocompression-bondable resin is a
phenol resin, the temperature of the heat treatment is preferably
from 180 to 220.degree. C. When the thermocompression-bondable
resin is a polyimide resin or polybenzimidazole, the temperature of
the heat treatment is preferably from 350 to 450.degree. C.
[0171] In the finishing step, the blade main body 1 obtained by
heat curing (thermally curing) the original plate 11 through the
sintering step is subjected to finishing processing by cutting or
grinding the outer circumference and the inner circumference so as
to obtain outer and inner diameters with predetermined sizes.
Further, in this finishing step, regarding the outer peripheral
edge of the blade main body 1, the cutting edge 1A may be subjected
to a dressing treatment.
[0172] As a result, the cutting blade 10 of the present embodiment
can be obtained.
[0173] In the method for manufacturing the cutting blade 10 of the
present embodiment described above, the liquid dispersion medium DM
is added to the mixed powder MP containing the resin powder of a
thermocompression-bondable resin, the abrasive grains 3 and the
fibrous fillers 5 to obtain a mixture, and the mixture is cold
pressed in a forming die such as a metal mold or the like.
Therefore, at the time of this cold pressing process, the
dispersion medium DM enters the gaps between the powder particles
of the mixed powder MP, and it is possible to promote the powder
flow utilizing the liquid flow.
[0174] That is, in the present embodiment, by applying pressure in
a forming die to a mixture of the mixed powder MP and the
dispersion medium DM in the compression step, the dispersion medium
DM acts like a lubricant, so that the resin powder, the abrasive
grains 3 and the fibrous fillers 5 uniformly diffuse in the forming
die. For this reason, variation in the density of the original
plate 11 of the blade main body 1 to be produced is remarkably
suppressed to a low level, and the fibrous fillers 5 are uniformly
dispersed in the original plate 11.
[0175] At this time, although the fibrous fillers 5 face toward a
direction intersecting with the thickness direction of the blade
main body 1 (that is, any one direction of all directions (360
degrees) in a plane substantially perpendicular to the central axis
O of the blade main body 1), the fibrous fillers 5 are not oriented
in a certain direction, and the fibrous fillers 5 are brought into
a non-oriented dispersed state having no regularity in orientation
(that is, randomly oriented). In other words, since a plurality of
fibrous fillers 5 are randomly oriented, they are substantially
oriented and dispersed in all directions (360 degrees).
[0176] It should be noted that during this compression step, since
the cold pressing (cold compression) is performed,
thermocompression bonding of the resin powder does not proceed and
the fluidity of the resin powder is secured in a stable manner.
[0177] Then, the original plate 11 of this blade main body 1 is hot
pressed and sintered. As described above, since variation in the
density of the original plate 11 is suppressed to a low level, the
occurrence of sink marks or the like in the blade main body 1 at
the time of sintering can be suppressed. As a result, it is
possible to manufacture the blade main body 1 in which warpage and
flatness are suppressed to low levels.
[0178] Further, since the fibrous fillers 5 are uniformly dispersed
from the time of molding the original plate 11, even in the blade
main body 1 obtained by sintering the original plate 11, the
fibrous fillers 5 are uniformly dispersed in the circumferential
direction and the radial direction of the blade. Therefore, it is
possible to obtain an excellent cutting blade 10 having no
variation in strength. More specifically, as described above, since
the fibrous fillers 5 are randomly oriented in an unspecified
direction (all directions (360 degrees)) in a plane substantially
perpendicular to the central axis O of the blade main body 1
without being oriented in a certain direction, the fibrous fillers
5 function like aggregates and the strength is uniformly increased
in the entire blade circumferential direction.
[0179] In addition, since the fibrous fillers 5 are uniformly
dispersed in random orientation in the blade main body 1, the
following actions and effects can also be obtained. [0180]
Improvement of wear resistance. [0181] Suppression of blade
thinning. [0182] Moderate self-sharpening action. [0183]
Improvement of toughness. [0184] Improvement of heat
resistance.
[0185] That is, since the fibrous fillers 5 are uniformly dispersed
in the blade main body 1 in random orientation, the blade main body
1 does not easily wear at predetermined portions in the
circumferential direction, and the wear progresses uniformly over
the entire circumferential direction. As a result, the abrasion
amount of the blade as a whole is also suppressed, and the wear
resistance is improved. In addition, since the wear resistance is
improved, the tool life is prolonged.
[0186] Further, the fibrous fillers 5 are randomly oriented in a
plane substantially perpendicular to the central axis O of the
blade main body 1. Therefore, with respect to both side surfaces
(front and back surfaces of the blade) 1B, 1B facing the thickness
direction of the blade main body 1, for example, the
circumferential surface and the longitudinal cross section (cross
section along the extending direction of the filler 5) of the
fibrous filler 5 having an elongated columnar shape are exposed, so
that exposure of end surfaces facing the extending direction of the
fibrous filler 5 and the transverse cross section (cross section
perpendicular to the extending direction of the filler 5) can be
suppressed. On the other hand, with respect to the outer
circumferential surface facing outward in the radial direction of
the blade main body 1, it varies in that some of the fibrous
fillers 5 expose their circumferential surfaces and longitudinal
cross sections, while some fibrous fillers expose their end
surfaces and transverse cross sections.
[0187] Therefore, the ratio of the exposed area of the fibrous
fillers 5 per unit area of the outer surface of the blade with
respect to the both side surfaces 1B, 1B of the blade main body 1
becomes large. In comparison with this, the ratio of the exposed
area of the fibrous fillers 5 per unit area of the outer surface of
the blade with respect to the outer circumferential surface of the
blade main body 1 becomes small. That is, with respect to the
exposed area of the fibrous fillers 5 per unit area of the outer
surface of the blade, the exposed area of the fibrous fillers 5 on
both side surfaces 1B, 1B becomes larger than the exposed area of
the fibrous fillers 5 on the outer circumferential surface of the
blade main body 1. For this reason, on the outer circumferential
surface of the blade main body 1, it is possible to appropriately
allow wear to proceed and to maintain the sharpness of the cutting
edge 1A satisfactorily (it is possible to promote the
self-sharpening action). Further, on both side surfaces 1B, 1B of
the blade main body 1, it is possible to suppress the progress of
wear and to suppress the blade thinning. Therefore, in the cut
surface formed on the workpiece by the cutting process, defects
such as inclinations due to the blade thinning hardly occur, and
the quality of the cutting process is markedly enhanced.
[0188] Further, in the present embodiment, the blade strength is
improved by uniform dispersion and random orientation of the
fibrous fillers 5. For this reason, for example, compared with a
case where the blade strength is to be enhanced by simply using a
particulate fillers having high hardness without using the fibrous
fillers 5 which is unlike the present embodiment, it is possible to
promote a moderate self-sharpening action in the present
embodiment.
[0189] That is, when attempting to enhance the blade strength by
using the conventional particulate fillers, a characteristic
orientation cannot be imparted to the particulate fillers; and
therefore, a method of simply increasing the hardness of the
particulate filler is adopted. However, as the hardness of the
particulate fillers increases, the holding power of the abrasive
grains 3 becomes too high at the cutting edge 1A; and thereby, it
becomes difficult to form a new blade (the self-sharpening action
is reduced). For this reason, the sharpness cannot be maintained
satisfactorily.
[0190] On the other hand, if the fibrous fillers 5 are used as is
the case with the present embodiment, the blade strength can be
increased without increasing the hardness of the fillers; and
therefore, it is possible to promote a moderate self-sharpening
action and to maintain the sharpness satisfactorily.
[0191] In addition, since the fibrous fillers 5 are uniformly
dispersed and randomly oriented inside the blade main body 1, these
fibrous fillers 5 act like aggregates, and the toughness of the
blade main body 1 is improved. For this reason, the strength of the
cutting blade 10 is increased while the impact resistance is also
improved, and in particular, rigidity is sufficiently secured even
in the cutting process during high speed rotation, and high-quality
cutting precision can be maintained.
[0192] Further, since the fibrous fillers 5 are uniformly dispersed
and randomly oriented, it is possible to improve the thermal
conductivity between the fibrous fillers 5 inside the blade main
body 1. For this reason, for example, in the case of using metal
fibers, carbon fibers or the like having a high thermal
conductivity as the fibrous fibers 5, the frictional heat generated
at the outer peripheral edge portion (cutting edge 1A) of the blade
main body 1 during the cutting process is thermally dissipated in
the blade at an early stage through the fibrous fillers 5, and the
cooling efficiency is also improved; and thereby, the heat
resistance of the cutting blade 10 is improved.
[0193] It should be noted that most of the dispersion medium DM
added to the mixed powder MP before cold pressing flows out from
the mixed powder MP (the original plate 11 of the blade main body
1) at the time of cold pressing and is removed. Further, the
dispersion medium DM remaining on the original plate 11 of the
blade main body 1 after cold pressing can be removed from the blade
main body 1, for example, by volatilization before hot pressing in
the sintering step. At this time, since the dispersion medium DM is
present in a slight space between the powder particles, formation
of the blade main body 1 in a porous form by volatilization of the
dispersion medium DM is prevented. Further, in this case, since the
dispersion medium DM does not remain in the blade main body 1
produced through the sintering step, the performance of the blade
main body 1 is not adversely affected by the dispersion medium
DM.
[0194] More specifically, it is preferable that the timing at which
the dispersion medium DM is volatilized in the sintering step is
before the start of the thermocompression bonding of the resin
powder by hot pressing. In other words, it is preferable that all
of the dispersion medium DM is volatilized before conducting the
hot pressing process (before the sintering step). As a result, the
space in which the dispersion medium DM has been present between
the powder particles is occupied (replaced) by the resin phase 2,
so that traces of the dispersion medium DM are not left in the
blade main body 1 after sintering. Therefore, the dispersion medium
DM and its traces do not adversely affect the performance of the
blade main body 1.
[0195] More specifically, in the cutting blade 10 manufactured
according to the present embodiment, the blade main body 1 is
divided into a plurality of regions at a mutually equal angle
around the central axis O of the blade main body 1 (in the example
of the present embodiment, four regions obtained by dividing the
blade main body 1 into four equal parts around the central axis O).
The content rate of the fibrous fillers 5 obtained in each region
can be suppressed to 90 to 110% with respect to the overall content
rate of the fibrous fillers 5 in the entire blade main body 1.
[0196] In other words, the fibrous fillers 5 are uniformly
contained in each region of the blade main body 1, and the fibrous
fillers 5 are uniformly dispersed over the entire region of the
blade main body 1. This is because, as described above, the fibrous
fillers 5 have already been uniformly dispersed over the entire
blade in the original plate 11 of the blade main body 1 that has
undergone the compression step by cold pressing. Therefore, the
manufactured blade main body 1 has excellent rigidity with no
variation in strength over the entire blade.
[0197] In addition, in the cutting blade 10 manufactured according
to the present embodiment, the blade main body 1 is divided into a
plurality of regions at a mutually equal angle around the central
axis O of the blade main body 1 (in the example of the present
embodiment, eight regions obtained by dividing the blade main body
1 into eight equal parts around the central axis O), and an average
value of the densities measured in the regions is taken as the
average density. The density measured in each region can be
suppressed to 90 to 110% with respect to this average density. In
other words, the density difference (variation in density) is
suppressed to a low level over the entire region of the blade main
body 1. This is because, as described above, the density difference
has already been suppressed to a low level in the original plate 11
of the blade main body 1 that has undergone the compression step by
cold pressing. Therefore, warpage and flatness of the produced
blade main body 1 are suppressed to low levels.
[0198] More specifically, in the cutting blade 10 manufactured
according to the present embodiment, the warpage amount of the
blade main body 1 can be suppressed to 300 .mu.m or less. Further,
the flatness of the blade main body 1 can be suppressed to 20 .mu.m
or less.
[0199] In addition, the flatness of both side surfaces 1B, 1B
facing the thickness direction of the blade main body 1 obtained
after sintering is suppressed to a low level as described above.
Therefore, even in a field of application where high-quality
cutting precision is particularly required, it is possible to
satisfy the expected flatness without flattening both side surfaces
1B, 1B of the blade main body 1 by a lapping treatment.
[0200] As described above, since the warpage and the flatness of
the blade main body 1 are suppressed to low levels, the following
actions and effects can be obtained when a workpiece is cut with
the cutting blade 10.
[0201] That is, since the deflection of the cutting blade 10 in the
thickness direction is suppressed, the cutting width is suppressed
to a small value, and the product yield of the workpiece can be
improved. In addition, a force from the cutting blade 10 to the
workpiece in the cutting width direction (the width direction of
the cutting line formed on the workpiece by the cutting process)
hardly acts. For this reason, the cutting blade 10 smoothly cuts
into the workpiece, and the occurrence of burrs, chipping or the
like on the cut surface is prevented. Therefore, the quality of the
electronic material parts (products) and the like obtained by
dividing the workpiece into individual pieces can be stably
increased.
[0202] Furthermore, since it is unnecessary to perform a lapping
treatment on the blade surface, there is no possibility that the
abrasive grains 3 protrude from the resin phase 2 by this lapping
treatment. That is, in the present embodiment, the blade main body
1 obtained through the sintering step includes the abrasive grains
3 disposed further to the inside than the side surface 1B of the
blade main body 1 in the thickness direction, and there are no
abrasive grains 3 protruding outward in the thickness direction
from the side surface 1B. For this reason, it is possible to
remarkably suppress problems such as the abrasive grains 3
protruding from the side surface 1B of the blade main body 1 to
roughen the cut surface of the workpiece and lower the processing
quality (generate burrs, chipping or the like) during the cutting
process. Therefore, the cutting precision can be particularly
enhanced by this effect that no abrasive grains 3 protrude from the
side surface 1B in conjunction with the effect that the flatness
can be suppressed to a low level as described above.
[0203] More specifically, conventionally, particularly in the case
of attempting to reduce the thickness of the blade main body to 1.1
mm or less, it has been essential to carry out a lapping treatment
in order to suppress the flatness of the blade surface to a small
value and to reduce the thickness of the blade main body down to
the expected thickness (thin it down to the desired thickness). For
this reason, it was impossible to prevent the abrasive grains from
protruding from the side surface of the blade main body.
[0204] On the other hand, according to the present embodiment, even
if the thickness of the blade main body 1 is reduced to 1.1 mm or
less, the flatness has already been suppressed to a small value
after sintering; and therefore, the lapping treatment is
unnecessary. As a result, it is possible to reliably prevent the
abrasive grains 3 from protruding from the side surface 1B of the
blade main body 1. That is, both side surfaces 1B, 1B of the blade
main body 1 that have undergone the sintering step are in a state
where the surface is formed flat by the pressing process and there
is no protrusion of the abrasive grains 3. For this reason, by
omitting the lapping treatment, it is possible to reduce the number
of abrasive grains 3 protruding from the blade surface to zero.
[0205] Furthermore, since it is unnecessary to perform a lapping
treatment, not only the production is facilitated, but also it
becomes unnecessary to form the blade main body with a large
thickness in advance in anticipation of the lapping treatment as in
the prior art, and the material cost is reduced.
[0206] Further, in the prior art, the reaction force received by
the cutting blade 10 when cutting the workpiece acted unevenly
against the portion having a large amount of warpage. In the
present embodiment, the warpage and the flatness of the blade main
body 1 are suppressed to low levels; and thereby, the above
problems are prevented. In other words, according to the present
embodiment, since the above reaction force is more likely to act
uniformly over the entire circumference in the circumferential
direction of the cutting blade 10, and the application of a large
load to a predetermined portion is prevented, the tool life of the
cutting blade 10 is prolonged.
[0207] Further, in manufacturing the cutting blade 10 in which the
cutting precision is markedly enhanced as described above, in
comparison with the conventional manufacturing method shown in
FIGS. 8(a) to 8(c), a particularly complicated manufacturing
process is not used in the present embodiment. More specifically,
in the present embodiment, by passing through a simple process of
cold pressing the mixed powder MP to which the dispersion medium DM
has been added in a forming die, variation in the density of the
blade main body 1 (original plate 11) is suppressed, while the
fibrous fillers 5 are uniformly dispersed and the fibrous fillers 5
are randomly oriented. As a result, since the above-mentioned
excellent actions and effects can be achieved, it is easy to
manufacture the cutting blade 10.
[0208] As described above, according to the method for
manufacturing the cutting blade 10 of the present embodiment, it is
possible to include the resin phase 2 composed of a
thermocompression-bondable resin, and the fibrous fillers 5 can be
uniformly dispersed without orienting the fibrous fillers 5 in a
certain direction inside the blade main body 1. As a result, it is
possible to easily manufacture the cutting blade 10 in which the
strength is uniformly increased in the entire blade circumferential
direction.
[0209] Further, according to the cutting blade 10 of the present
embodiment, since the strength is uniformly increased in the entire
circumferential direction of the blade, the cutting process can be
stably performed at high speed rotation.
[0210] In addition, in the method for manufacturing the cutting
blade 10 of the present embodiment, the mixing step includes: a
step of filling a forming die with the mixed powder MP containing
the resin powder of a thermocompression-bondable resin, the
abrasive grains 3 and the fibrous fillers 5; a step of flattening
the surface of the mixed powder MP; and a step of dropwise adding a
liquid dispersion medium DM onto the mixed powder MP whose surface
has been flattened. Therefore, the following actions and effects
are achieved.
[0211] That is, in this case, since the mixing step includes the
step of flattening the surface of the mixed powder MP filled in the
forming die, the flow amount of the mixed powder MP until it
diffuses uniformly into the forming die in the compression step
which is a subsequent step of this mixing step can be suppressed to
a low level. For this reason, the following actions and effects are
achieved more stably.
[0212] The above-described effect that variation in the density of
the original plate 11 of the blade main body 1 can be suppressed to
a low level.
[0213] The effect that the fibrous fillers 5 are uniformly
dispersed in the interior of the original plate 11 while the
fibrous fillers 5 are randomly oriented without being oriented in a
certain direction.
[0214] In addition, since the mixing step includes the step of
dropwise adding the dispersion medium DM to the mixed powder MP
whose surface has been flattened, the dispersion medium DM is more
easily mixed uniformly with the mixed powder MP. In other words,
since the dispersion medium DM easily spreads all over the mixed
powder MP as a whole and increases the affinity therewith, the
powder flow of the mixed powder MP making use of (utilizing) the
liquid flow of the dispersion medium DM is uniformly distributed
over the entire interior of the forming die in the compression step
which is a subsequent step of this mixing step. Therefore, the
following actions and effects are achieved more stably.
[0215] The above-described effect that variation in the density of
the original plate 11 of the blade main body 1 can be suppressed to
a low level.
[0216] The effect that the fibrous fillers 5 are uniformly
dispersed in the interior of the original plate 11 while the
fibrous fillers 5 are randomly oriented without being oriented in a
certain direction.
[0217] Further, in the method for manufacturing the cutting blade
10 of the present embodiment, since a liquid having a kinematic
viscosity of 2.3 mm.sup.2/s or less is used as the dispersion
medium DM, the dispersion medium DM spreads between the powder
particles of the mixed powder MP, and increases the affinity with
the powder particles of the mixed powder MP to facilitate the
liquid flow over a wide range, and the dispersion medium DM also
effectively functions as a lubricant to promote the powder flow of
the mixed powder MP. As a result, in the compression step, the
effect of uniformly diffusing the mixed powder MP into the forming
die can be obtained more remarkably.
[0218] More specifically, in the case where the kinematic viscosity
of the dispersion medium DM is equal to or less than 2.3
mm.sup.2/s, the warpage and flatness of the blade main body 1
obtained after sintering are remarkably suppressed to low levels,
and the strength of the entire blade is remarkably increased.
[0219] In addition, in the cutting blade 10 of the present
embodiment, since the overall content rate of the fibrous fillers 5
in the entire blade main body 1 is from 20 to 60 vol %, it is
possible to reliably achieve the actions and effects brought about
by the fibrous fillers 5 as described above, while preventing
reduction in the blade rigidity due to inclusion of an excessive
amount of the fibrous fillers 5.
[0220] That is, since the overall content rate of the fibrous
fillers 5 is equal to or more than 20 vol %, the above-described
actions and effects due to the dispersion of the fibrous fillers 5
in the blade main body 1 can be reliably obtained. In addition,
since the overall content rate of the fibrous fillers 5 is equal to
or less than 60 vol %, it is possible to suppress the excessive
reduction of the resin phase 2 serving as a bonding agent
interposed between the fibrous fillers 5; and thereby, the function
of the resin phase 2 is stabilized.
[0221] Further, in the cutting blade 10 of the present embodiment,
the blade main body 1 is divided into a plurality of regions at a
mutually equal angle around the central axis O of the blade main
body 1, and an average value of the densities measured in the
regions is taken as the average density. The density measured in
each region is from 90 to 110% with respect to the average
density.
[0222] Further, the warpage amount of the blade main body 1 is
equal to or less than 300 .mu.m, and the flatness of the blade main
body 1 is equal to or less than 20 .mu.m.
[0223] In the cutting blade 10, the density measured in each region
is from 90 to 110% with respect to the average density (within
.+-.10% when the average density is taken as 100%), and variation
in the density of the blade main body 1 is suppressed to a low
level. Therefore, the warpage amount of the blade main body 1 can
be suppressed to as low as 300 .mu.m or less. In addition, the
flatness of the blade main body 1 can be suppressed to as low as 20
.mu.m or less. For this reason, at the time of manufacturing the
cutting blade 10, it is possible to reduce (omit) operations such
as a lapping treatment for flattening the blade surfaces (both side
surfaces 1B, 1B).
[0224] Therefore, while improving the ease of manufacturing the
cutting blade 10, the cutting precision by the cutting blade 10 can
be remarkably enhanced.
[0225] More specifically, in a conventional cutting blade, as
described with reference to FIGS. 8(a) to 8(c), since variation
tends to occur in the packing density inside the mixed powder in
the forming die at the time of manufacturing the blade, the
flatness of the side surface of the blade main body obtained after
sintering was, more or less, as large as 100 .mu.m (about 100
.mu.m). For this reason, in the field of application where the
cutting precision was particularly required, both side surfaces of
the blade main body were subjected to a lapping treatment for
planarization. However, even if the resin phase is removed by the
lapping treatment, abrasive grains with high hardness tend to
remain in a state of being protruded from the side surface, and it
was difficult to satisfy the expected flatness.
[0226] On the other hand, according to the cutting blade 10 of the
present embodiment, since the variation in the packing density
inside the mixed powder MP in the forming die can be suppressed to
a small value, the flatness of the side surface 1B of the blade
main body 1 obtained after sintering can be suppressed to as low as
20 .mu.m or less. Therefore, even in a field of application where
the cutting precision is particularly required, it is possible to
satisfy the expected flatness without flattening both side surfaces
1B, 1B of the blade main body 1 by a lapping treatment.
[0227] Furthermore, since it is unnecessary to subject the blade
surface to a lapping treatment, there is no possibility that the
abrasive grains 3 protrude from the resin phase 2 by this lapping
treatment. In other words, since there are no abrasive grains 3
protruding in the thickness direction on the side surface 1B of the
blade main body 1 obtained through the sintering step; and
therefore, the cutting precision can be particularly enhanced by
this effect that no abrasive grains 3 protrude from the side
surface 1B in conjunction with the effect that the flatness can be
suppressed to a low level as described above.
[0228] Further, in the cutting blade 10 of the present embodiment,
the thickness of the blade main body 1 is equal to or less than 1.1
mm.
[0229] Since the strength of the cutting blade 10 is increased in
the entire region of the blade main body 1 as described above, it
is easy to reduce the thickness of the blade main body 1 to 1.1 mm
or less while ensuring the rigidity of the blade main body 1.
[0230] Therefore, it is possible to more remarkably obtain the
effect that the cutting width of the workpiece can be suppressed to
a small value to improve the product yield while satisfactorily
maintaining the cutting precision.
[0231] It should be noted that the present invention is not limited
to the above-described embodiments, and various modifications can
be made without departing from the features of the present
invention.
[0232] For example, in the cutting blade 10 of the above-described
embodiment, although the blade main body 1 is formed by providing
one layer of the resin phase 2 in which the abrasive grains 3 and
the fibrous fillers 5 are dispersed, a plurality of layers of such
resin phase 2 may be laminated in the thickness direction to form
the blade main body 1. In this case, a plurality of the original
plates 11 of the blade main body 1 obtained through the compression
step are stacked in the thickness direction, and hot pressed and
sintered in the sintering step.
[0233] In addition, in the above-described embodiment, although the
mixing step in the manufacturing method of the cutting blade 10
includes a step of filling the forming die with the mixed powder MP
containing the resin powder, the abrasive grains 3 and the fibrous
fillers 5, a step of flattening the surface of the mixed powder MP,
and a step of dropwise adding the dispersion medium DM onto the
mixed powder MP, the present invention is not limited thereto. That
is, in the mixing step, for example, the dispersion medium DM may
be dropwise added without flattening the surface of the mixed
powder MP, or the dispersion medium DM may be dropwise added to the
mixed powder MP and then the resulting mixture may be filled into
the forming die. However, as described in the above embodiment, in
the case where the mixing step includes the above-described three
steps, in the original plate 11 of the blade main body 1 that has
undergone the compression step which is a subsequent step of this
mixing step, the effect that variation in the density can be
suppressed to a low level, and that the fibrous fillers 5 are
uniformly dispersed can be more remarkably obtained. Therefore, it
is preferable that the mixing step includes the above-described
three steps.
[0234] Further, in the above-described embodiment, although the
abrasive grains 3 composed of either diamond or cBN are dispersed
in the resin phase 2, the present invention is not limited thereto.
That is, particles composed of a hard material other than diamond
and cBN may be dispersed in the resin phase 2 as the abrasive
grains 3.
[0235] In addition, in the above-described embodiment, for example,
although a polyimide resin, a certain phenol resin,
polybenzimidazole (PBI (registered trademark)) or the like is used
as the thermocompression-bondable resin for forming the resin phase
2, the present invention is not limited thereto, and other
thermocompression-bondable resins may be used.
[0236] Further, the blade main body 1 is divided into a plurality
of regions at a mutually equal angle around the central axis O of
the blade main body 1, and an average value of the densities
measured in the regions is taken as the average density. It is
explained that the density measured in each region is from 90 to
110% with respect to the average density. This means that, for
example, even if the type of the resin powder serving as the raw
material of the resin phase 2 changes and the average density
changes, all the density values (the density value of each region)
measured in a plurality of regions equally divided around the
central axis O are within the range of 90 to 110% with respect to
the average density. However, the present invention is not limited
to the case where the density measured in each region with respect
to the average density falls within the range of 90 to 110%.
[0237] Further, the blade main body 1 is divided into a plurality
of regions at a mutually equal angle around the central axis O of
the blade main body 1, and the content rate of the fibrous fillers
5 in each region is measured. It is explained that the content rate
of the fibrous fillers 5 in each region is from 90 to 110% with
respect to the overall content rate of the fibrous fillers 5 in the
entire blade main body 1. This means that, for example, even if the
overall content rate of the fibrous fillers 5 in the entire blade
main body 1 varies within the range of 20 to 60 vol % described in
the above embodiment, all the content rate values of the fibrous
fillers 5 (the content rate value of the fibrous fillers 5 in each
region) measured in a plurality of regions equally divided around
the central axis O are within the range of 90 to 110% with respect
to the overall content rate.
[0238] It should be noted that the present invention is not limited
to the case where the overall content rate of the fibrous fillers 5
in the entire blade main body 1 falls within the range of 20 to 60
vol %.
[0239] Further, in the above-described embodiment, for example,
although chlorofluorocarbon (CFC) substitutes such as a
fluorine-based inert liquid or the like is used as the dispersion
medium DM, the present invention is not limited thereto. That is,
the dispersion medium DM may be a CFC substitute other than the
fluorine-based inert liquid or a liquid other than the CFC
substitute.
[0240] In addition, in the above-described embodiment, although it
is explained that the cutting blade 10 is used for cutting, for
example, an electronic material part which is a composite material
including a metal material in a resin, such as QFN or IrDA, as a
workpiece, the present invention is not limited thereto. That is,
the cutting blade 10 is used for semiconductor devices (electronic
material parts), and may also be used in the step of precisely
cutting a workpiece including a brittle material (hard brittle
material) such as glass, a ceramic, quartz or the like.
[0241] In addition, the respective configurations (constituent
elements) described in the above embodiments, modifications,
explanatory notes and the like may be combined, and additions,
omissions, substitutions, and other modifications can be made
without departing from the features of the present invention.
Further, the present invention is not limited by the embodiments
described above, but is limited only by the scope of the
claims.
Examples
[0242] Hereinafter, the present invention will be described in more
detail with reference to examples. However, the present invention
is not limited to these examples.
<Confirmation of Variation in Content Rate of Fibrous
Fillers>
[0243] A cutting blade 10 manufactured by the method for
manufacturing the cutting blade 10 described in the above
embodiment will be referred to as Example 1, a cutting blade
manufactured by the conventional manufacturing method shown in
FIGS. 8(a) to 8(c) will be referred to as Comparative Example 1,
and a cutting blade manufactured by the doctor blade method will be
referred to as Comparative Example 2. With respect to these three
types of cutting blades, those in which the overall content rate of
the fibrous fillers in the entire blade main body was 19 vol %, 20
vol %, 30 vol %, 40 vol %, 50 vol %, 60 vol % or 61 vol % were
prepared, respectively.
[0244] It should be noted that in each of the cutting blades, the
blade main body was formed of a resin phase, and the same material
(raw material) was used for the resin powder serving as the raw
material of the resin phase. More specifically, a polyimide resin
which was a thermocompression-bondable resin was used as the resin
powder. Further, the same material was also used for the abrasive
grains and the fibrous fillers to be dispersed in the resin phase.
The content rate of the abrasive grains in the blade main body was
set to be equal to each other among the cutting blades.
[0245] In manufacturing the cutting blade 10 of Example 1,
FLUORINERT (registered trademark) FC 72 (manufactured by 3M
Company, kinematic viscosity: 0.4 cSt) was used as the dispersion
medium DM.
[0246] The dimensions of the blade main body of each cutting blade
were as follows. [0247] Outer diameter: .phi. 58 mm [0248] Inner
diameter: .phi. 40 mm [0249] Thickness: 1.1 mm
[0250] Then, in each of the cutting blades, as shown in FIG. 4, the
blade main body was equally divided into four regions around the
central axis O of the blade main body, and the content rate of the
fibrous fillers was measured in each region. Further, when the
overall content rate of the fibrous fillers in the entire blade
main body as described above was taken as 100%, ranges within which
each content rate of the fibrous fillers measured in the four
regions falls, with respect to 100% of the overall content rate of
the fibrous fillers, were identified. More specifically, the ratio
(percentage) of the content rate of the fibrous fillers in each
region with respect to the overall content rate of the fibrous
fillers was determined, and the range of variation in the ratio was
obtained.
[0251] It should be noted that the expressions "when X is taken as
100%, Y is within the range of .+-.Z %" and "Y is within the range
of .+-.Z % with respect to 100% of X" mean that the ratio of Y with
respect to X (Y/X) (percentage) is within the range of (100-Z) % to
(100+Z) %. Further, the overall content rate of the fibrous fillers
was substantially the same as the designed value (target
value).
[0252] The measurement results are shown in Table 1 below.
[0253] In Table 1, the circle indicates that the content rate of
the fibrous fillers in each region was within the range of .+-.5%
with respect to 100% of the overall content rate of the fibrous
fillers. The triangular mark indicates that the content rate of the
fibrous fillers in each region was within the range of .+-.15% with
respect to 100% of the overall content rate of the fibrous fillers.
The x mark (cross mark) indicates that the content rate of the
fibrous fillers in each region was outside the range of .+-.15%
with respect to 100% of the overall content rate of the fibrous
fillers. More specifically, the x mark indicates that among the
content rate values of the fibrous fillers in each region, there
was a value outside the range of .+-.15% with respect to 100% of
the overall content rate of the fibrous fillers.
TABLE-US-00001 TABLE 1 <Comparison of variation in content rate
of fibrous fillers> Overall content rate Comparative Comparative
of fibrous fillers Example 1 Example 1 Example 2 19 vol %
.smallcircle. .DELTA. .DELTA. 20 vol % .smallcircle. x x 30 vol %
.smallcircle. x x 40 vol % .smallcircle. x Molding was not 50 vol %
.smallcircle. x possible 60 vol % .smallcircle. x 61 vol %
.smallcircle. .DELTA.
Criteria:
[0254] All of the content rate values measured in the regions fell
within the range of .+-.5% with respect to the overall content
rate: .largecircle. All of the content rate values measured in the
regions fell within the range of .+-.15% with respect to the
overall content rate: .DELTA. There was a content rate value
measured in the region that did not fall within the range of
.+-.15% with respect to the overall content rate: x
[0255] From the results in Table 1, it can be seen that in the
cutting blade 10 of Example 1, all of the content rates of the
fibrous fillers 5 measured in the regions fell within the range of
.+-.10% (that is, from 90 to 110%) with respect to the overall
content rate of 100%. More specifically, all of the content rates
of the fibrous fillers 5 in the regions fell within the range of
.+-.5% (that is, 95 to 105%) with respect to the overall content
rate of 100%.
[0256] On the other hand, in the cutting blades of Comparative
Examples 1 and 2, among the content rate values of the fibrous
fillers measured in the regions, there was a value outside the
range of .+-.15% (that is, a value of less than 85% or more than
115%) with respect to the overall content rate of 100%, and the
variation in the content rate of the fibrous fillers was large. It
should be noted that in Comparative Example 2, when the overall
content rate of the fibrous fillers was 40 vol % or more, it was
not possible to form the sheet body from the slurry, and the
molding process could not be performed.
<Abrasion Test>
[0257] The cutting blade 10 manufactured by the same manufacturing
method as in Example 1 described above will be referred to as
Example 2, a cutting blade manufactured by the same manufacturing
method as in Comparative Example 1 described above will be referred
to as Comparative Example 3 and a cutting blade manufactured by the
same manufacturing method as in Comparative Example 2 described
above will be referred to as Comparative Example 4. A comparative
test of blade abrasion amount was carried out using each cutting
blade.
[0258] Also in this abrasion test, with respect to each of the
cutting blades of Example 2, Comparative Example 3 and Comparative
Example 4, those in which the overall content rate of the fibrous
fillers in the entire blade main body was 19 vol %, 20 vol %, 30
vol %, 40 vol %, 50 vol %, 60 vol % or 61 vol % were prepared,
respectively. It should be noted that in Comparative Example 4,
when the overall content rate of the fibrous fillers was 40 vol %
or more, it was not possible to form the sheet body from the
slurry, and the molding process could not be performed.
[0259] The dimensions of the blade main body of each cutting blade
were as follows. [0260] Outer diameter: .phi. 58 mm [0261] Inner
diameter: .phi. 40 mm [0262] Thickness: 1.1 mm
[0263] Further, the specification of SDC 170-100 was adopted for
the used blades of Example 2, Comparative Example 3 and Comparative
Example 4.
[0264] The test conditions were as follows. [0265] Cutting machine
used: A-WD 100A, manufactured by Tokyo Seimitsu Co., Ltd. [0266]
Spindle rotation speed: 15,000 m.sup.-1 [0267] Cut: 0.8 mm [0268]
Feed rate: 100 mm/s [0269] Amount of cooling water: 1.2 L+1.2 L
[0270] Dresser plate: A2-2 mm, manufactured by Tokyo Seimitsu Co.,
Ltd. [0271] Number of grooves: 30 grooves.times.5 sets
[0272] Then, the cutting blade mounted on the cutting machine was
rotated, and grooving was performed on the dresser plate to confirm
the blade abrasion amount.
[0273] The test results are shown in Table 2 below.
TABLE-US-00002 TABLE 2 <Comparison of blade abrasion amount>
(.mu.m) Overall content rate Comparative Comparative of fibrous
fillers Example 2 Example 3 Example 4 19 vol % 358 551 1003 20 vol
% 316 664 982 30 vol % 263 701 1215 40 vol % 248 857 Molding was
not 50 vol % 312 1002 possible 60 vol % 387 1213 61 vol % 403
1412
[0274] From the results in Table 2, it was confirmed that the
abrasion amount of each of the cutting blades 10 of Example 2 was
all less than 500 the abrasion amount was remarkably suppressed,
and the wear resistance was enhanced. In Example 2, the variation
in the density of the blade main body 1 was suppressed to a low
level, and the fibrous fillers 5 were uniformly dispersed. For this
reason, the abrasion amount progressing inward in the radial
direction from the outer circumference of the blade was made
uniform throughout the circumferential direction. As a result, it
is considered that the wear resistance was enhanced because there
was no place where wear was allowed to proceed at an early stage,
and the progress of abrasion as a whole was also suppressed.
[0275] Further, above all, with respect to the cutting blades 10 in
which the overall content rate of the fibrous fillers 5 was from 20
to 60 vol %, it was confirmed that the abrasion amount was all less
than 400 and excellent wear resistance could be obtained.
[0276] On the other hand, in Comparative Examples 3 and 4, the
abrasion amounts of the cutting blades all exceeded 550 and the
amount of abrasion was large. It should be noted that there was a
trend where the blade abrasion amount increased as the overall
content rate of the fibrous fillers increased.
<Cutting Test>
[0277] The cutting blade 10 manufactured by the same manufacturing
method as in the above-described Example 1 will be referred to as
Example 3, a cutting blade manufactured by the same manufacturing
method as in Comparative Example 1 described above will be referred
to as Comparative Example 5 and a cutting blade manufactured by the
same manufacturing method as in Comparative Example 2 described
above will be referred to as Comparative Example 6. A comparative
test of processing quality was carried out using each cutting
blade.
[0278] Also in this cutting test, with respect to each of the
cutting blades of Example 3, Comparative Example 5 and Comparative
Example 6, those in which the overall content rate of the fibrous
fillers in the entire blade main body was 19 vol %, 20 vol %, 30
vol %, 40 vol %, 50 vol %, 60 vol % or 61 vol % were prepared,
respectively. It should be noted that in Comparative Example 6,
when the overall content rate of the fibrous fillers was 40 vol %
or more, it was not possible to form the sheet body from the
slurry, and the molding process could not be performed.
[0279] The dimensions of the blade main body of each cutting blade
were as follows. [0280] Outer diameter: .phi. 58 mm [0281] Inner
diameter: .phi. 40 mm [0282] Thickness: 1.1 mm
[0283] Further, the specification of SDC 170-100 was adopted for
the used blades of Example 3, Comparative Example 5, and
Comparative Example 6.
[0284] The test conditions were as follows. [0285] Cutting machine
used: A-WD 100A, manufactured by Tokyo Seimitsu Co., Ltd. [0286]
Spindle rotation speed: 25,000 m.sup.-1 [0287] Feed rate: 30 mm/s
[0288] Tape cut: 0.5 mm [0289] Amount of cooling water: 2.0 L+2.0 L
[0290] Workpiece: QFN package (composite material of resin and
copper)
[0291] Then, the cutting blade mounted on the cutting machine was
rotated to cut the QFN package, and the processing quality was
confirmed. The processing quality was assessed by the following
method. As shown in FIG. 7, the workpiece was cut (diced) into
cubic shapes (the workpiece was cut into a plurality of cubic
chips). Next, the length of a burr 20 in a singulated chip was
measured. The length of the burr 20 was measured on 10 chips per
workpiece. It should be noted that in the case where the burr size
was equal to or less than 75 .mu.m, it was assessed that the
processing quality of the chip was secured.
[0292] The test results are shown in Table 3 below.
TABLE-US-00003 TABLE 3 <Comparison of electrode burr size>
(.mu.m) Overall content rate Comparative Comparative of fibrous
fillers Example 3 Example 5 Example 6 19 vol % 39 71 129 20 vol %
41 83 134 30 vol % 22 96 161 40 vol % 21 102 Molding was not 50 vol
% 29 99 possible 60 vol % 27 132 61 vol % 41 171
[0293] From the results in Table 3, it became clear that as
compared with the burr size of the chip cut by each cutting blade
of Comparative Example 5 and the burr size of the chip cut by each
cutting blade of Comparative Example 6, the burr size of the chip
cut by each cutting blade 10 of Example 3 could be remarkably
suppressed to a low level. Further, in Example 3, all the burr
sizes were suppressed to 75 .mu.m or less. In Example 3, the
variation in the density of the blade main body 1 was suppressed to
a low level, and the warpage and the flatness of the blade main
body 1 were suppressed to low levels. As a result, it is considered
that since the resistance acting on the cut surface of the chip was
reduced, the burr size was suppressed remarkably to a small value.
In addition, the fibrous fillers 5 were uniformly dispersed in the
blade main body 1, and the blade thinning of the cutting edge 1A
was suppressed. As a result, it is considered that the burr size
was remarkably suppressed to a small value because the processing
quality of the cut surface was maintained satisfactorily.
INDUSTRIAL APPLICABILITY
[0294] The cutting blade of the present invention is suitably
applied to a step of cutting a workpiece such as an electronic
material part used for a semiconductor product or the like.
Examples of the electronic material parts include a part in which a
semiconductor element is mounted on a lead frame and resin-molded,
a quad flat non-leaded package (QFN), and an optical transmission
module based on the IrDA (Infrared Data Association) standard.
Further, the cutting blade of the present invention is also
suitably applied to a step of precisely cutting a workpiece
including a brittle material (hard brittle material) such as glass,
ceramics, quartz or the like.
[0295] The method for manufacturing a cutting blade according to
the present invention is suitably applied to a step of
manufacturing a blade for cutting a workpiece such as the
above-mentioned electronic material parts.
REFERENCE SIGNS LIST
[0296] 1: Blade main body [0297] 1A: Cutting edge [0298] 2: Resin
phase [0299] 3: Abrasive grain [0300] 5: Fibrous filler [0301] 10:
Cutting blade [0302] 11: Original plate of blade main body [0303]
DM: Dispersion medium [0304] MP: Mixed powder [0305] O: Central
axis of blade main body
* * * * *