U.S. patent application number 17/304604 was filed with the patent office on 2021-11-25 for methods of making metal bond and vitreous bond abrasive articles, and abrasive article precursors.
The applicant listed for this patent is 3M INNOVATIVE PROPERTIES COMPANY. Invention is credited to Negus B. Adefris, Thomas J. Anderson, Carsten Franke, Maiken Givot, Brian D. Goers, Michael C. Harper, Malte Korten, Elizaveta Y. Plotnikov, Brian A. Shukla, Robert L.W. Smithson.
Application Number | 20210362297 17/304604 |
Document ID | / |
Family ID | 1000005767674 |
Filed Date | 2021-11-25 |
United States Patent
Application |
20210362297 |
Kind Code |
A1 |
Franke; Carsten ; et
al. |
November 25, 2021 |
METHODS OF MAKING METAL BOND AND VITREOUS BOND ABRASIVE ARTICLES,
AND ABRASIVE ARTICLE PRECURSORS
Abstract
The present disclosure provides methods of making a vitreous
bond abrasive article and a metal bond abrasive article. The
methods include sequential steps. Step a) includes a subprocess
including sequentially: i) depositing a layer of loose powder
particles in a confined region; and ii) selectively applying heat
via conduction or irradiation, to heat treat an area of the layer
of loose powder particles. The loose powder particles include
abrasive particles and organic compound particles, as well as
vitreous bond precursor particles or metal particles. The layer of
loose powder particles has substantially uniform thickness. Step b)
includes independently carrying out step a) a number of times to
generate an abrasive article preform comprising the bonded powder
particles and remaining loose powder particles. Step c) includes
separating remaining loose powder particles from the abrasive
article preform. Step d) includes heating the abrasive article
preform to provide the vitreous bond abrasive article comprising
the abrasive particles retained in a vitreous bond material, or to
provide the metal bond abrasive article. A method of making a metal
bond abrasive optionally includes infusing an abrasive article
preform with a molten lower melting metal and solidifying the
molten lower melting metal to provide the metal bond abrasive
article. The present disclosure further provides a vitreous bond
abrasive article precursor and a metal bond abrasive article
precursor. Also, methods including receiving, by a manufacturing
device having a processor, a digital object specifying data for an
abrasive article, and generating the abrasive article with the
manufacturing device.
Inventors: |
Franke; Carsten; (St. Paul,
MN) ; Givot; Maiken; (St. Paul, MN) ; Korten;
Malte; (Moorenweis, DE) ; Smithson; Robert L.W.;
(Mahtomedi, MN) ; Goers; Brian D.; (Minneapolis,
MN) ; Adefris; Negus B.; (St. Paul, MN) ;
Anderson; Thomas J.; (Cottage Grove, MN) ; Shukla;
Brian A.; (Woodbury, MN) ; Harper; Michael C.;
(Hudson, WI) ; Plotnikov; Elizaveta Y.; (St. Paul,
MN) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
3M INNOVATIVE PROPERTIES COMPANY |
St. Paul |
MN |
US |
|
|
Family ID: |
1000005767674 |
Appl. No.: |
17/304604 |
Filed: |
June 23, 2021 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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|
16070316 |
Jul 16, 2018 |
11072053 |
|
|
PCT/US2017/013867 |
Jan 18, 2017 |
|
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17304604 |
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62281349 |
Jan 21, 2016 |
|
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62315044 |
Mar 30, 2016 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B22F 10/00 20210101;
B33Y 70/00 20141201; Y02P 10/25 20151101; B24D 3/06 20130101; B29C
64/153 20170801; B33Y 80/00 20141201; B22F 2998/10 20130101; B24D
7/10 20130101; B24D 18/00 20130101; B24D 3/14 20130101; B24D 5/10
20130101; B22F 10/10 20210101; B24D 18/009 20130101; B33Y 10/00
20141201 |
International
Class: |
B24D 3/06 20060101
B24D003/06; B24D 3/14 20060101 B24D003/14; B24D 5/10 20060101
B24D005/10; B24D 7/10 20060101 B24D007/10; B33Y 80/00 20060101
B33Y080/00; B33Y 10/00 20060101 B33Y010/00; B33Y 70/00 20060101
B33Y070/00; B29C 64/153 20060101 B29C064/153; B24D 18/00 20060101
B24D018/00; B22F 10/10 20060101 B22F010/10; B22F 10/00 20060101
B22F010/00 |
Claims
1. A vitreous bond abrasive article precursor comprising abrasive
particles bonded together by a vitreous bond precursor material and
an organic compound, wherein the vitreous bond abrasive article
precursor further comprises at least one of: at least one tortuous
cooling channel extending at least partially through the vitreous
bond abrasive article precursor; or at least one arcuate cooling
channel extending at least partially through the vitreous bond
abrasive article precursor.
2. The vitreous bond abrasive precursor of claim 1, wherein the
abrasive particles comprise at least one of silicon carbide, boron
carbide, silicon nitride, or metal oxide ceramic particles.
3. A method of making a metal bond abrasive article, the method
comprising sequential steps: a) a subprocess comprising
sequentially: i) depositing a layer of loose powder particles in a
confined region, wherein the loose powder particles comprise higher
melting metal particles, abrasive particles, and organic compound
particles, and wherein the layer of loose powder particles has
substantially uniform thickness; and ii) selectively applying heat
via conduction or irradiation, to heat treat an area of the layer
of loose powder particles; b) independently carrying out step a) a
plurality of times to generate an abrasive article preform
comprising the bonded powder particles and remaining loose powder
particles, wherein in each step a), the loose powder particles are
independently selected; c) separating substantially all of the
remaining loose powder particles from the abrasive article preform;
d) infusing the abrasive article preform with a molten lower
melting metal, wherein at least some of the higher melting metal
particles do not completely melt when contacted by the molten lower
melting metal; and e) solidifying the molten lower melting metal to
provide the metal bond abrasive article.
4. The method of claim 3, wherein the higher melting metal
particles have a melting point that is at least 50 degrees Celsius
higher than the temperature of the molten lower melting metal.
5. The method of claim 3, further comprising, between steps c) and
d), burning off at least a portion of the organic compound
material.
6. A method of making a metal bond abrasive article, the method
comprising sequential steps: a) a subprocess comprising
sequentially: i) depositing a layer of loose powder particles in a
confined region, wherein the loose powder particles comprise metal
particles, abrasive particles, and organic compound particles, and
wherein the layer of loose powder particles has substantially
uniform thickness; ii) selectively applying heat via conduction or
irradiation, to heat treat an area of the layer of loose powder
particles; b) independently carrying out step a) a plurality of
times to generate an abrasive article preform comprising the bonded
powder particles and remaining loose powder particles, wherein the
abrasive article preform has a predetermined shape, and wherein in
each step a), the loose powder particles are independently
selected; c) separating substantially all of the remaining loose
powder particles from the abrasive article preform; and d) heating
the abrasive article preform to provide the metal bond abrasive
article.
7. The method of claim 6, wherein the metal particles comprise a
combination of higher melting metal particles and lower melting
metal particles, wherein the higher melting metal particles have a
melting point that is at least 50 degrees Celsius higher than the
temperature of the molten lower temperature metal.
8. A metal bond abrasive article precursor comprising metallic
particles and abrasive particles bonded together by an organic
compound material, wherein the metal bond abrasive article
precursor further comprises at least one of: at least one tortuous
cooling channel extending at least partially through the metal bond
abrasive article precursor; at least one arcuate cooling channel
extending at least partially through the metal bond abrasive
article precursor.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. application Ser.
No. 16/070,316, filed Jul. 16, 2018, which is a national stage
filing under 35 U.S.C. 371 of PCT/US2017/013867, filed Jan. 18,
2017, which claims the benefit of U.S. Application No. 62/281,349,
filed Jan. 21, 2016 and U.S. Application No. 62/315,044, filed Mar.
30, 2016, the disclosures of which are incorporated by reference in
their entirety herein.
TECHNICAL FIELD
[0002] The present disclosure broadly relates to methods of making
abrasive articles having abrasive particles in a metallic bonding
matrix or a vitreous bonding matrix.
BACKGROUND
[0003] Traditionally, vitrified bond abrasive articles (e.g.,
abrasive wheels, abrasive segments, and whetstones) are made by
compressing a blend of abrasive particles (e.g., diamond, cubic
boron nitride, alumina, or SiC), a vitreous bond precursor (e.g.,
glass frit, ceramic precursor) an optional pore inducer (e.g.,
glass bubbles, naphthalene, crushed coconut or walnut shells, or
acrylic glass or PMMA), and a temporary organic binder in a liquid
vehicle (e.g., aqueous solutions of phenolic resin, polyvinyl
alcohol, urea-formaldehyde resin, or dextrin). The abrasive
particles, vitreous bond precursor, and usually the pore inducer
are typically dry blended together. The temporary organic binder
solution is then added to wet out the grain mix. The blended mix is
then placed in a hardened steel mold treated with a mold release.
The filled mold is then compressed in a press to form a molded
green body. The green body then is ejected from the mold, and
subsequently heated until the temporary organic binder is burned
out and the vitreous bond precursor is converted into a vitreous
bond matrix (also referred to in the art as "vitreous bond" and
"vitreous binder".
[0004] Traditionally, metal bond abrasive articles are made by
mixing an abrasive grit, such as diamond, cubic boron nitride
(cBN), or other abrasive grains with a non-melting metal powder
(e.g., tungsten, stainless steel, or others), a melting metal
powder (e.g., bronze or copper), or a combination thereof. Pore
inducers, temporary binders and other additives may be added. The
mixture is then introduced into a mold that has been coated with a
mold release agent. The filled mold is then compressed in a press
to form a molded green body. The green body then is ejected from
the mold and subsequently heated in a furnace at high temperature
to melt a portion of the metal composition, or it is infused with a
molten metal. The heating is typically done in a suitable
controlled atmosphere of inert or reducing gas (e.g., nitrogen,
argon, hydrogen) or in a vacuum.
[0005] There are many disadvantages to these manufacturing
approaches: each abrasive article shape requires a special mold;
the molds typically are expensive and have a long lead time to
make; any design change requires the manufacture of a new mold;
there are limitations to the shapes that can be molded, complicated
shapes with undercuts or internal structures such as cooling
channels are generally not possible; molds wear out and have a
limited number of units that can be manufactured per mold; while
the molds are filled with the abrasive mixture, separation of the
components can occur, leading to inhomogeneous abrasive components
and density variation, which is easily visible and may cause
performance variations. Moreover, the processes are often manual
and labor intensive.
[0006] In selective laser sintering, a layer of powder comprising a
metal powder and an abrasive grain is spread in a uniform layer in
an inert atmosphere enclosure. In predetermined areas, the powder
is heated by a laser beam to heat the metal powder to its sintering
temperature. A disadvantage of traditional laser sintering is that
a high powered laser is required (e.g., in the range of 30-150
watts) and that the inert atmosphere needs to be maintained
throughout the printing process.
SUMMARY
[0007] In a first aspect, the present disclosure provides a method
of making a vitreous bond abrasive article, the method including
sequential steps. Step a) includes a subprocess including
sequentially: i) depositing a layer of loose powder particles in a
confined region; and ii) selectively applying heat via conduction
or irradiation, to heat treat an area of the layer of loose powder
particles. The loose powder particles include vitreous bond
precursor particles, abrasive particles, and organic compound
particles. The layer of loose powder particles has substantially
uniform thickness. Step b) includes independently carrying out step
a) a plurality of times to generate an abrasive article preform
comprising the bonded powder particles and remaining loose powder
particles. In each step a), the loose powder particles are
independently selected. Step c) includes separating substantially
all of the remaining loose powder particles from the abrasive
article preform; and step d) includes heating the abrasive article
preform to provide the vitreous bond abrasive article comprising
the abrasive particles retained in a vitreous bond material.
[0008] In a second aspect, the present disclosure provides a
vitreous bond abrasive article precursor including abrasive
particles bonded together by a vitreous bond precursor material and
an organic compound, wherein the vitreous bond abrasive article
precursor further includes at least one of at least one tortuous
cooling channel extending at least partially through the vitreous
bond abrasive article precursor; or at least one arcuate cooling
channel extending at least partially through the vitreous bond
abrasive article precursor.
[0009] In a third aspect, the present disclosure provides a method
of making a metal bond abrasive article, the method comprising
sequential steps. Step a) includes a subprocess including
sequentially: i) depositing a layer of loose powder particles in a
confined region; and ii) selectively applying heat via conduction
or irradiation, to heat treat an area of the layer of loose powder
particles. The loose powder particles include higher melting metal
particles, abrasive particles, and organic compound particles. The
layer of loose powder particles has substantially uniform
thickness. Step b) includes independently carrying out step a) a
plurality of times to generate an abrasive article preform
comprising the bonded powder particles and remaining loose powder
particles. In each step a), the loose powder particles are
independently selected. Step c) includes separating substantially
all of the remaining loose powder particles from the abrasive
article preform. Step d) includes infusing the abrasive article
preform with a molten lower melting metal, wherein at least some of
the higher melting metal particles do not completely melt when
contacted by the molten lower melting metal. Step e) includes
solidifying the molten lower melting metal to provide the metal
bond abrasive article.
[0010] In a fourth aspect, the present disclosure provides a method
of making a metal bond abrasive article, the method including
sequential steps. Step a) includes a subprocess including
sequentially: i) depositing a layer of loose powder particles in a
confined region; and ii) selectively applying heat via conduction
or irradiation, to heat treat an area of the layer of loose powder
particles. The loose powder particles include metal particles,
abrasive particles, and organic compound particles. The layer of
loose powder particles has substantially uniform thickness. Step
includes b) independently carrying out step a) a plurality of times
to generate an abrasive article preform comprising the bonded
powder particles and remaining loose powder particles, wherein the
abrasive article preform has a predetermined shape. In each step
a), the loose powder particles are independently selected. Step c)
includes separating substantially all of the remaining loose powder
particles from the abrasive article preform. Step d) includes
heating the abrasive article preform to provide the metal bond
abrasive article.
[0011] In a fifth aspect, the present disclosure provides a metal
bond abrasive article precursor including metallic particles and
abrasive particles bonded together by an organic compound material,
wherein the metal bond abrasive article precursor further includes
at least one of: at least one tortuous cooling channel extending at
least partially through the metal bond abrasive article precursor;
and at least one arcuate cooling channel extending at least
partially through the metal bond abrasive article precursor.
[0012] In a sixth aspect, the present disclosure provides a
non-transitory machine readable medium having data representing a
three-dimensional model of a vitreous bond abrasive article, when
accessed by one or more processors interfacing with a 3D printer,
causes the 3D printer to create a vitreous bond abrasive article
precursor of the vitreous bond abrasive article. The vitreous bond
abrasive article precursor includes abrasive particles bonded
together by a vitreous bond precursor material and an organic
compound. The vitreous bond abrasive article precursor further
includes at least one of at least one tortuous cooling channel
extending at least partially through the vitreous bond abrasive
article precursor; or at least one arcuate cooling channel
extending at least partially through the vitreous bond abrasive
article precursor.
[0013] In a seventh aspect, the present disclosure provides a
method including retrieving, from a (e.g., non-transitory) machine
readable medium, data representing a 3D model of a vitreous bond
abrasive article. A vitreous bond abrasive article precursor of the
vitreous bond abrasive article preform includes abrasive particles
bonded together by a vitreous bond precursor material and an
organic compound. The vitreous bond abrasive article precursor
further includes at least one of at least one tortuous cooling
channel extending at least partially through the vitreous bond
abrasive article precursor; or at least one arcuate cooling channel
extending at least partially through the vitreous bond abrasive
article precursor. The method further includes executing, by one or
more processors, a 3D printing application interfacing with a
manufacturing device using the data; and generating, by the
manufacturing device, a physical object of the vitreous bond
abrasive article precursor.
[0014] In an eighth aspect, the present disclosure provides a
method including receiving, by a manufacturing device having one or
more processors, a digital object comprising data specifying a
plurality of layers of a vitreous bond abrasive article precursor.
The vitreous bond abrasive article precursor includes abrasive
particles bonded together by a vitreous bond precursor material and
an organic compound. The vitreous bond abrasive article precursor
further includes at least one of at least one tortuous cooling
channel extending at least partially through the vitreous bond
abrasive article precursor; or at least one arcuate cooling channel
extending at least partially through the vitreous bond abrasive
article precursor. The method further includes generating, with the
manufacturing device by an additive manufacturing process, the
vitreous bond abrasive article precursor based on the digital
object.
[0015] In a ninth aspect, the present disclosure provides a system
including a display that displays a 3D model of a vitreous bond
abrasive article; and one or more processors that, in response to
the 3D model selected by a user, cause a 3D printer to create a
physical object of a vitreous bond abrasive article precursor of
the vitreous bond abrasive article. The vitreous bond abrasive
article precursor includes abrasive particles bonded together by a
vitreous bond precursor material and an organic compound. The
vitreous bond abrasive article precursor further includes at least
one of at least one tortuous cooling channel extending at least
partially through the vitreous bond abrasive article precursor; or
at least one arcuate cooling channel extending at least partially
through the vitreous bond abrasive article precursor.
[0016] In a tenth aspect, the present disclosure provides a
non-transitory machine readable medium having data representing a
three-dimensional model of a metal bond abrasive article, when
accessed by one or more processors interfacing with a 3D printer,
causes the 3D printer to create the metal bond abrasive article
precursor of the metal bond abrasive article. The metal bond
abrasive article precursor includes metallic particles and abrasive
particles bonded together by an organic compound material. The
metal bond abrasive article precursor further includes at least one
of at least one tortuous cooling channel extending at least
partially through the metal bond abrasive article precursor; and at
least one arcuate cooling channel extending at least partially
through the metal bond abrasive article precursor.
[0017] In an eleventh aspect, the present disclosure provides a
method including retrieving, from a non-transitory machine readable
medium, data representing a 3D model of a metal bond abrasive
article precursor. The metal bond abrasive article precursor
includes metallic particles and abrasive particles bonded together
by an organic compound material. The metal bond abrasive article
precursor further includes at least one of at least one tortuous
cooling channel extending at least partially through the metal bond
abrasive article precursor; and at least one arcuate cooling
channel extending at least partially through the metal bond
abrasive article precursor. The method further includes executing,
by one or more processors, a 3D printing application interfacing
with a manufacturing device using the data; and generating, by the
manufacturing device, a physical object of the metal bond abrasive
article precursor.
[0018] In a twelfth aspect, the present disclosure provides a
method including receiving, by a manufacturing device having one or
more processors, a digital object comprising data specifying a
plurality of layers of a metal bond abrasive article precursor. The
metal bond abrasive article precursor includes metallic particles
and abrasive particles bonded together by an organic compound
material. The metal bond abrasive article precursor further
includes at least one of at least one tortuous cooling channel
extending at least partially through the metal bond abrasive
article precursor; and at least one arcuate cooling channel
extending at least partially through the metal bond abrasive
article precursor. The method further includes generating, with the
manufacturing device by an additive manufacturing process, the
metal bond abrasive article precursor based on the digital
object.
[0019] In a thirteenth aspect, the present disclosure provides a
system including a display that displays a 3D model of a metal bond
abrasive article; and one or more processors that, in response to
the 3D model selected by a user, cause a 3D printer to create a
physical object of a metal bond abrasive article precursor of the
metal bond abrasive article. The metal bond abrasive article
precursor includes metallic particles and abrasive particles bonded
together by an organic compound material. The metal bond abrasive
article precursor further includes at least one of at least one
tortuous cooling channel extending at least partially through the
metal bond abrasive article precursor; and at least one arcuate
cooling channel extending at least partially through the metal bond
abrasive article precursor.
[0020] Features and advantages of the present disclosure will be
further understood upon consideration of the detailed description
as well as the appended claims.
BRIEF DESCRIPTION OF DRAWINGS
[0021] FIG. 1A is a schematic process flow diagram of a method of
making a vitreous bond or metal bond abrasive article according to
the present disclosure.
[0022] FIG. 1B is a schematic cross-sectional side view of the
third step of the process of FIG. 1A with a thermal print head heat
source.
[0023] FIG. 1C is a schematic cross-sectional side view of the
third step of the process of FIG. 1A with a heated tip heat
source.
[0024] FIG. 1D is a schematic cross-sectional side view of the
third step of the process of FIG. 1A with a laser heat source.
[0025] FIG. 2 is a schematic cross-sectional top view of an
exemplary vitreous bond or metal bond abrasive wheel 200,
preparable according to the present disclosure.
[0026] FIG. 3 is a schematic cross-sectional top view of an
exemplary vitreous bond or metal bond abrasive wheel 300,
preparable according to the present disclosure.
[0027] FIG. 4 is a schematic perspective view of an exemplary
vitreous bond or metal bond abrasive segment 400, preparable
according to the present disclosure.
[0028] FIG. 5 is a schematic perspective view of a vitreous bond or
metal bond abrasive wheel 500, preparable according to the present
disclosure.
[0029] FIG. 6A is a schematic perspective view of a unitary
structured abrasive disc 600, preparable according to the present
disclosure.
[0030] FIG. 6B is a schematic top view of unitary structured
abrasive disc 600.
[0031] FIG. 7A is a schematic perspective view of a unitary
structured abrasive disc 700, preparable according to the present
disclosure.
[0032] FIG. 7B is a schematic top view of unitary structured
abrasive disc 700.
[0033] FIG. 8 is a schematic perspective view of rotary abrasive
tool 800, preparable according to the present disclosure.
[0034] FIG. 9 is a schematic perspective view of an exemplary
dental bur 900, preparable according to the present disclosure.
[0035] FIG. 10 is a schematic front view of an exemplary computing
device 1000.
[0036] FIG. 11 is a block diagram of a generalized system 1150 for
additive manufacturing of a vitreous bond or metal bond abrasive
article.
[0037] FIG. 12 is a block diagram of a generalized manufacturing
process for a vitreous bond or metal bond abrasive article.
[0038] FIG. 13 is a high-level flow chart of an exemplary vitreous
bond or metal bond abrasive article manufacturing process.
[0039] FIG. 14 is a high-level flow chart of an exemplary vitreous
bond or metal bond abrasive article additive manufacturing
process.
[0040] Repeated use of reference characters in the specification
and drawings is intended to represent the same or analogous
features or elements of the disclosure. It should be understood
that numerous other modifications and embodiments can be devised by
those skilled in the art, which fall within the scope and spirit of
the principles of the disclosure. The figures may not be drawn to
scale.
DETAILED DESCRIPTION
[0041] Methods of making vitreous bond abrasive articles and metal
bond abrasive articles according to the present disclosure include
a common additive subprocess. The subprocess comprises
sequentially, preferably consecutively (although not required),
carrying out at least three steps. Advantageously, the methods
involve selectively applying heat via conduction or irradiation
without requiring any high powered equipment as the heat source and
without the need for an inert atmosphere.
[0042] FIG. 1A schematically depicts an exemplary powder bed
process 100 used in making a vitreous bond abrasive article or a
metal bond abrasive article.
[0043] In the first step, a layer 138 of loose powder particles 110
from powder chamber 120a with movable piston 122a is deposited in a
confined region 140 in powder chamber 120b with movable piston
122b. The layer 138 should be of substantially uniform thickness.
For example, the thickness of the layer may vary less than 50
microns, preferably less than 30 microns, and more preferably less
than 10 microns. The layers may have any thickness up to about 1
millimeter, as long as heat can bind all the loose powder where it
is applied. Preferably, the thickness of the layer is from about 10
microns to about 500 microns, 10 microns to about 250 microns, more
preferably about 50 microns to about 250 microns, and more
preferably from about 100 microns to about 200 microns.
[0044] The abrasive particles may comprise any abrasive particle
used in the abrasives industry. Preferably, the abrasive particles
have a Mohs hardness of at least 4, preferably at least 5, more
preferably at least 6, more preferably at least 7, more preferably
at least 8, more preferably at least 8.5, and more preferably at
least 9. In certain embodiments, the abrasive particles comprise
superabrasive particles. As used herein, the term "superabrasive"
refers to any abrasive particle having a hardness greater than or
equal to that of silicon carbide (e.g., silicon carbide, boron
carbide, cubic boron nitride, and diamond).
[0045] Specific examples of suitable abrasive materials include
aluminum oxide (e.g., alpha alumina) materials (e.g., fused,
heat-treated, ceramic, and/or sintered aluminum oxide materials),
silicon carbide, titanium diboride, titanium nitride, boron
carbide, tungsten carbide, titanium carbide, aluminum nitride,
diamond, cubic boron nitride (CBN), garnet, fused alumina-zirconia,
sol-gel derived abrasive particles, metal oxides such as cerium
oxide, zirconium oxide, titanium oxide, and combinations thereof.
In certain embodiments, the abrasive particles comprise metal oxide
ceramic particles. Examples of sol-gel derived abrasive particles
can be found in U.S. Pat. No. 4,314,827 (Leitheiser et al.), U.S.
Pat. No. 4,623,364 (Cottringer et al.); U.S. Pat. No. 4,744,802
(Schwabel), U.S. Pat. No. 4,770,671 (Monroe et al.); and U.S. Pat.
No. 4,881,951 (Monroe et al.). Agglomerate abrasive particles that
comprise finer abrasive particles in a vitreous bond matrix (e.g.,
as described in U.S. Pat. No. 6,551,366 (D'Souza et al.)) may also
be used.
[0046] As noted above, the loose powder particles include organic
compound particles, which were discovered to be capable of holding
together the abrasive particles (as well as other types of
particles present in the loose powder particles) upon the select
application of heat. In many embodiments, the organic compound
particles have a melting point between 50 degrees Celsius and 250
degrees Celsius, inclusive, such as between 100 degrees Celsius to
180 degrees Celsius, inclusive. Stated another way, in certain
embodiments, the organic compound particles have a melting point of
at least 50 degrees Celsius, or at least 60, or at least 70, or at
least 80, or at least 90, or at least 100, or at least 110, or at
least 120, or at least 130 degrees Celsius; and a melting point of
up to 250 degrees Celsius, or up to 240, or up to 230, or up to
220, or up to 210, or up to 200, or up to 190, or up to 180, or up
to 170, or up to 160 degrees Celsius.
[0047] The organic compound particles are not particularly limited,
and are optionally selected from waxes, sugars, dextrins,
thermoplastics having a melting point of no greater than 250
degrees Celsius, acrylates, methacrylates, and combinations
thereof.
[0048] Suitable waxes include for example and without limitation,
materials of vegetable, animal, petroleum, and/or mineral derived
origin. Representative waxes include carnauba wax, candelilla wax,
oxidized Fischer-Tropsch wax, microcrystalline wax, lanolin,
bayberry wax, palm kernel wax, mutton tallow wax, polyethylene wax,
polyethylene copolymer wax, petroleum derived waxes, montan wax
derivatives, polypropylene wax, oxidized polyethylene wax, and
combinations thereof.
[0049] Suitable sugars include for example and without limitation,
lactose, trehalose, glucose, sucrose, levulose, dextrose, and
combinations thereof.
[0050] Suitable dextrins include for example and without
limitation, gamma-cyclodextrin, alpha-cyclodextrin,
beta-cyclodextrin, glucosyl-alpha-cyclodextrin,
maltosyl-alpha-cyclodextrin, glucosyl-beta-cyclodextrin,
maltosyl-beta-cyclodextrin, 2-hydroxy-beta-cyclodextrin,
2-hydroxypropyl-beta-cyclodextrin,
2-hydroxypropyl-gamma-cyclodextrin, hydroxyethyl-beta-cyclodextrin,
methyl-beta-cyclodextrin, sulfobutylether-alpha-cyclodextrin,
sulfobutylether-beta-cyclodextrin,
sulfobutylether-gamma-cyclodextrin, and combinations thereof.
[0051] Suitable thermoplastics include for example and without
limitation, thermoplastics having a melting point of no greater
than 250 degrees Celsius, such as polyethyleneterephthalate (PET),
polylactic acid (PLA), polyvinyl chloride (PVC), polymethyl
methacrylate (PMMA), polypropylene (PP), bisphenol-A polycarbonate
(BPA-PC), polysulfone (PSF), polyether imide (PEI), and
combinations thereof.
[0052] Suitable acrylates and methacrylates include for example and
without limitation, urethane acrylates, epoxy acrylates, polyester
acrylates, acrylated (meth)acrylics, polyether acrylates, acrylated
polyolefins, and combinations thereof, or their methacrylate
analogs.
[0053] The organic compound particles are typically present in an
amount of 2.5 weight percent to 30 weight percent of the loose
powder particles, inclusive, such as 5 weight percent to 20 weight
percent of the loose powder particles, inclusive. Stated another
way, in certain embodiments the organic compound particles are
present in an amount of at least 2.5 weight percent, or at least 3
weight percent, or at least 4 weight percent, or at least 5 weight
percent, or at least 7 weight percent, or at least 8 weight
percent, or at least 10 weight percent, or at least 12 weight
percent of the loose powder particles; and up to 30 weight percent,
or up to 28 weight percent, or up to 25 weight percent, or up to 23
weight percent, or up to 20 weight percent, or up to 18 weight
percent of the loose powder particles. Typically, the average
particle size of the organic compound particles ranges from about 1
micrometer to about 100 micrometers, preferably about 5 micrometers
to about 50 micrometers, and most preferably about 10 micrometers
to about 30 micrometers.
[0054] When forming a vitreous bond abrasive article, the loose
powder particles comprise vitreous bond precursor particles,
abrasive particles, and organic compound particles. When forming a
metal bond abrasive article, the loose powder particles comprise
metal particles, abrasive particles, and organic compound
particles. In certain embodiments of forming a metal bond abrasive
article, the metal particles comprise higher melting metal
particles.
[0055] The vitreous bond precursor particles may comprise particles
of any material that can be thermally converted into a vitreous
material. Examples include glass frit particles, ceramic particles,
ceramic precursor particles, and combinations thereof.
[0056] The vitreous bond which binds together the abrasive grain in
accordance with this disclosure can be of any suitable composition
which is known in the abrasives art. The vitreous bond phase, also
variously known in the art as a "ceramic bond", "vitreous phase",
"vitreous matrix", or "glass bond" (e.g., depending on the
composition) may be produced from one or more oxide (e.g., a metal
oxide and/or boria) and/or at least one silicate as frit (i.e.,
small particles), which upon being heated to a high temperature
react to form an integral vitreous bond phase. Examples include
glass particles (e.g., recycled glass frit, water glass frit),
silica frit (e.g., sol-gel silica frit), alumina trihydrate
particles, alumina particles, zirconia particles, and combinations
thereof. Suitable frits, their sources and compositions are well
known in the art.
[0057] Abrasive articles are typically prepared by forming a green
structure comprised of abrasive grain, the vitreous bond precursor,
an optional pore former, and a temporary binder. The green
structure is then fired. The vitreous bond phase is usually
produced in the firing step of the process for producing the
abrasive article of this disclosure. Typical firing temperatures
are in the range of from 540.degree. C. to 1700.degree. C.
(1000.degree. F. to 3100.degree. F.). It should be understood that
the temperature selected for the firing step and the composition of
the vitreous bond phase must be chosen so as to not have a
detrimental effect on the physical properties and/or composition of
abrasive particles contained in the vitreous bond abrasive
article.
[0058] Useful glass frit particles may include any glass frit
material known for use in vitreous bond abrasive articles. Examples
include glass frit selected from the group consisting of silica
glass frit, silicate glass frit, borosilicate glass frit, and
combinations thereof. In one embodiment, a typical vitreous binding
material contains about 70-90% SiO.sub.2+B.sub.2O.sub.3, 1-20%
alkali oxides, 1-20% alkaline earth oxides, and 1-20% transition
metal oxides. In another embodiment, the vitreous binding material
has a composition of about 82 wt % SiO.sub.2+B.sub.2O.sub.3, 5%
alkali metal oxide, 5% transition series metal oxide, 4%
Al.sub.2O.sub.3, and 4% alkaline earth oxide. In another
embodiment, a frit having about 20% B.sub.2O.sub.3, 60% silica, 2%
soda, and 4% magnesia may be utilized as the vitreous binding
material. One of skill in the art will understand that the
particular components and the amounts of those components can be
chosen in part to provide particular properties of the final
abrasive article formed from the composition.
[0059] The size of the glass frit can vary. For example, it may be
the same size as the abrasive particles, or different. Typically,
the average particle size of the glass frit ranges from about 0.01
micrometer to about 100 micrometers, preferably about 0.05
micrometer to about 50 micrometers, and most preferably about 0.1
micrometer to about 25 micrometers. The average particle size of
the glass frit in relation to the average particle size of the
abrasive particles having a Mohs hardness of at least about 4 can
vary. Typically, the average particle size of the glass frit is
about 1 to about 200 percent of the average particle size of the
abrasive, preferably about 10 to about 100 percent, and most
preferably about 15 to about 50 percent.
[0060] Typically, the weight ratio of vitreous bond precursor
particles to abrasive particles in the loose powder particles
ranges from about 10:90 to about 90:10. The shape of the vitreous
bond precursor particles can also vary. Typically, they are
irregular in shape (e.g., crushed and optionally graded), although
this is not a requirement. For example, they may be spheroidal,
cubic, or some other predetermined shape.
[0061] Preferably, the coefficient of thermal expansion of the
vitreous bond precursor particles is the same or substantially the
same as that of the abrasive particles.
[0062] One preferred vitreous bond has an oxide-based mole percent
(%) composition of SiO.sub.2 63.28; TiO.sub.2 0.32; Al.sub.2O.sub.3
10.99; B.sub.2O.sub.3 5.11; Fe.sub.2O.sub.3 0.13; K.sub.2O 3.81;
Na.sub.2O 4.20; Li.sub.2O 4.98; CaO 3.88; MgO 3.04 and BaO 0.26.
Firing of these ingredients is typically accomplished by raising
the temperature from room temperature to the desired sintering
temperature (e.g., 1149.degree. C. (2100.degree. F.)), over a
prolonged period of time (e.g., about 25-26 hours), holding at the
maximum temperature (e.g., for several hours), and then cooling the
fired article to room temperature over an extended period of time
(e.g., 25-30 hours).
[0063] It is known in the art to use various additives in the
making of vitreous bonded abrasive articles both to assist in the
making of the abrasive article and/or improve the performance of
such articles. Such conventional additives which may also be used
in the practice of this disclosure include but are not limited to
lubricants, fillers, pore inducers, and processing aids. Examples
of lubricants include, graphite, sulfur, polytetrafluoroethylene
and molybdenum disulfide. Examples of pore inducers include glass
bubbles and organic particles. Concentrations of the additives as
are known in the art may be employed for the intended purpose of
the additive, for example. Preferably, the additives have little or
no adverse effect on abrasive particles employed in the practice of
this disclosure.
[0064] The vitreous bond precursor particles may comprise ceramic
particles. In such cases sintering and/or fusing of the ceramic
particles forms the vitreous matrix. Any sinterable and/or fusible
ceramic material may be used. Preferred ceramic materials include
alumina, zirconia, and combinations thereof. The inorganic vitreous
bond precursor optionally includes a precursor of alpha alumina. In
certain embodiments, the abrasive particles and the vitreous bond
material have the same chemical composition.
[0065] If desired, alpha-alumina ceramic particles may be modified
with oxides of metals such as magnesium, nickel, zinc, yttria, rare
earth oxides, zirconia, hafnium, chromium, or the like. Alumina and
zirconia abrasive particles may be made by a sol-gel process, for
example, as disclosed in U.S. Pat. No. 4,314,827 (Leitheiser et
al.); U.S. Pat. No. 4,518,397 (Leitheiser et al.); U.S. Pat. No.
4,574,003 (Gerk); U.S. Pat. No. 4,623,364 (Cottringer et al.); U.S.
Pat. No. 4,744,802 (Schwabel); and U.S. Pat. No. 5,551,963
(Larmie).
[0066] The vitreous bond precursor particles may be present in an
amount from 10 to 40 volume percent of the combined volume of the
vitreous bond precursor particles and abrasive particles,
preferably from 15 to 35 volume percent of the abrasive
composition.
[0067] In the case of the metal bond precursor particles, the
optional higher melting metal particles may comprise any metal from
group 2 through to group 15 of the Periodic Table of the elements,
for example. Alloys of these metals, and optionally with one or
more elements (e.g., metals and/or non-metals such as carbon,
silicon, boron) in groups 1 and 15 of the Periodic Table, may also
be used. Examples of suitable metal particles include powders
comprising magnesium, aluminum, iron, titanium, niobium, tungsten,
chromium, tantalum, cobalt, nickel, vanadium, zirconium,
molybdenum, palladium, platinum, copper, silver, gold, cadmium,
tin, indium, tantalum, zinc, alloys of any of the foregoing, and
combinations thereof.
[0068] Higher melting metal particles preferably having a melting
point of at least about 1100.degree. C., and more preferably at
least 1200.degree. C., although lower melting metals may also be
used. Examples include stainless steel (about 1360-1450.degree.
C.), nickel (1452.degree. C.), steel (1371.degree. C.), tungsten
(3400.degree. C.), chromium (1615.degree. C.), Inconel (Ni+Cr+Fe,
1390-1425.degree. C.), iron (1530.degree. C.), manganese
(1245-1260.degree. C.), cobalt (1132.degree. C.), molybdenum
(2625.degree. C.), Monel (Ni+Cu, 1300-1350.degree. C.), niobium
(2470.degree. C.), titanium (1670.degree. C.), vanadium
(1900.degree. C.), antimony (1167.degree. C.), Nichrome (Ni+Cr,
1400.degree. C.), alloys of the foregoing (optionally also
including one or more of carbon, silicon, and boron), and
combinations thereof. Combinations of two or more different higher
melting metal particles may also be used.
[0069] The loose powder particles may optionally further comprise
lower melting metal particles (e.g., braze particles). The lower
melting metal particles preferably have a maximum melting point
that is at least 50.degree. C. lower (preferably at least
75.degree. C. lower, at least 100.degree. C., or even at least
150.degree. C. lower) than the lowest melting point of the higher
melting metal particles. As used herein, the term "melting point"
includes all temperatures in a melting temperature range of a
material. Examples of suitable lower melting metal particles
include particles of metals such as aluminum (660.degree. C.),
indium (157.degree. C.), brass (905-1083.degree. C.), bronze
(798-1083.degree. C.), silver (961.degree. C.), copper
(1083.degree. C.), gold (1064.degree. C.), lead (327.degree. C.),
magnesium (671.degree. C.), nickel (1452.degree. C., if used in
conjunction with higher melting point metals), zinc (419.degree.
C.), tin (232.degree. C.), active metal brazes (e.g., InCuAg,
TiCuAg, CuAg), alloys of the foregoing, and combinations
thereof.
[0070] Typically, the weight ratio of high melting metal particles
and/or optional lower melting metal particles to the abrasive
particles ranges from about 10:90 to about 90:10, although this is
not a requirement.
[0071] The loose powder particles may optionally further comprise
other components such as, for example, pore inducers, fillers,
and/or fluxing agent particles. Examples of pore inducers include
glass bubbles and organic particles. In some embodiments, the lower
melting metal particles may also serve as a fluxing agent; for
example as described in U.S. Pat. No. 6,858,050 (Palmgren).
[0072] The loose powder particles may optionally be modified to
improve their flowability and the uniformity of the layer spread.
Methods of improving the powders include agglomeration, spray
drying, gas or water atomization, flame forming, granulation,
milling, and sieving. Additionally, flow agents such as, for
example, fumed silica, nanosilica, stearates, and starch may
optionally be added.
[0073] In order to achieve fine resolution, the loose powder
particles are preferably sized (e.g., by screening) to have a
maximum size of less than or equal to 400 microns, preferably less
than or equal to 250 microns, more preferably less than or equal to
200 microns, more preferably less than or equal to 150 microns,
less than or equal to 100 microns, or even less than or equal to 80
microns, although larger sizes may also be used. In certain
embodiments, the loose powder particles have an average particle
diameter of less than or equal to one micron (e.g., "submicron");
for example less than or equal to 500 nanometers (nm), or even less
than or equal to 150 nm. The various components of the loose powder
particles may have the same or different maximum particle sizes,
D.sub.90, D.sub.50, and/or D.sub.10 particle size distribution
parameters.
[0074] Referring to FIG. 1A again, heat 170 is selectively applied
via conduction or irradiation, to heat treat an (e.g.,
predetermined) area 180 of the layer 138. The source 150 of the
heat is not particularly limited, and includes for instance and
without limitation, a single source or a multipoint source.
Suitable single point sources include for instance, a heated tip
156 and a laser 158. A heated tip typically includes a heated metal
tip or a heated ceramic tip, such as a metal tip found on a common
soldering tool. The skilled practitioner can select a suitable low
powered laser, for instance, the CUBE 405-100C Diode Laser System
from Coherent Inc. (Santa Clara, Calif.). Useful multipoint sources
include a thermal print head, such as commonly used in direct
thermal printing or thermal transfer printing, and two or more
lasers. For instance, one suitable thermal print head is model
KEE-57-24GAG4-STA, available from KYOCERA Corporation (Kyoto,
Japan). Hence, referring to FIG. 1B, the third step of the process
of FIG. 1A is shown with a thermal print head 152 heat source. A
film 154 is disposed on the layer 138 to provide a barrier between
the thermal print head 152 heat source and the area 180 of the
layer 138. Suitable films include, for instance and without
limitation, polyethylene terephthalate (PET), polyethylene
naphthalate (PEN), polyimide, polytetrafluoroethylene (PTFE),
perfluoroalkoxy (PFA), and other films known to be stable at high
temperatures.
[0075] Referring to FIG. 1C, the third step of the process of FIG.
1A is shown with a single tip 156 heat source. A film 154 is
disposed on the layer 138 to provide a barrier between the single
tip 156 heat source and the area 180 of the layer 138. Referring
now to FIG. 1D, the third step of the process of FIG. 1A is shown
with a laser 158 heat source. FIG. 1D further includes the laser
beam 170 being directed at the area 180 of the layer 138. No film
is provided in this illustrated exemplary embodiment.
[0076] The heat softens and/or melts organic compound particles in
the selected area 180 of the layer 138, to bond the loose powder
particles together according to a predetermined pattern (and
ultimate 3-D shape upon multiple repetitions). In certain
embodiments in which the heat is applied using a single heated tip,
the tip optionally further applies pressure to the (e.g.,
predetermined) area of the layer of loose powder particles. An
advantage of applying pressure is that the pressure may be
effective to densify the powder particles, especially when the
loose powder particles contain a large amount of organic compound
particles.
[0077] Referring again to FIG. 1A, the organic compound material
bonds together the loose powder particles in at least one
predetermined region (or area) of the loose powder particles to
form a layer of bonded powder particles; for example, by softening
and/or melting at least a portion of the organic compound
particles.
[0078] The above steps are then repeated (step 185) with changes to
the region where applying heat is carried out according to a
predetermined design resulting through repetition, layer on layer,
in a three-dimensional (3-D) abrasive article preform. In each
repetition, the loose powder particles may be independently
selected; that is, some or all of the loose powder particles may be
the same as, or different from those in adjacent deposited
layers.
[0079] The abrasive article preform comprises the bonded powder
particles and remaining loose powder particles. Once sufficient
repetitions have been carried out to form the abrasive article
preform, it is preferably separated from substantially all (e.g.,
at least 85 percent, at least 90 percent, preferably at least 95
percent, and more preferably at least 99 percent) of the remaining
loose powder particles, although this is not a requirement. In
certain embodiments, at least a portion of the organic compound
material is burned off (e.g., volatilizing and/or decomposing)
following the separation of the bonded powder particles and prior
to or concurrently with infusing with a metal.
[0080] If desired, multiple particle reservoirs each containing a
different powder may be used. Likewise, multiple different organic
compound particles may be used. This results in different
powders/binders distributed in different and discrete regions of
the abrasive article. For example, relatively inexpensive, but
lower performing abrasive particles and/or vitreous bond precursor
particles may be relegated to regions of a vitrified bond abrasive
article where it is not particularly important to have high
performance properties (e.g., in the interior away from the
abrading surface). The same approach can apply to metal bond
abrasive articles.
[0081] In another aspect, the present disclosure provides a
vitreous bond abrasive article precursor. The vitreous bond
abrasive article precursor comprises abrasive particles bonded
together by a vitreous bond precursor material and an organic
compound, wherein the vitreous bond abrasive article precursor
further comprises at least one of: at least one tortuous cooling
channel extending at least partially through the vitreous bond
abrasive article precursor; or at least one arcuate cooling channel
extending at least partially through the vitreous bond abrasive
article precursor. The abrasive particles often include at least
one of silicon carbide, boron carbide, silicon nitride, or metal
oxide ceramic particles.
[0082] Generally, vitreous bond abrasive articles made in ways
according to the present disclosure have considerable porosity
throughout their volumes. Accordingly, the abrasive article preform
may then be infused with a solution or dispersion of additional
vitreous bond precursor material, or grain growth modifiers.
[0083] In embodiments in which the loose powder particles include
higher melting metal particles and lower melting metal particles,
the abrasive article preform may be heated sufficiently to cause
the lower melting metal particles to soften/melt and bond to at
least a portion of the loose powder particles, and then cooled to
provide the metal bond abrasive article. In embodiments in which
the loose powder particles include higher melting metal particles
and no lower melting metal particles, the abrasive article preform
may be heated sufficiently to cause the higher melting metal
particles to at least sinter and bond to at least a portion of the
loose powder particles, and then cooled to provide the metal bond
abrasive article. Cooling may be accomplished by any means known to
the art; for example cold quenching or air cooling to room
temperature.
[0084] Metal bond abrasive articles and/or abrasive article
preforms made according to the present disclosure may comprise a
porous metal-containing matrix (e.g., which may comprise metal
particles and abrasive particles, and which may be sintered) with
considerable porosity throughout its volume, although this is not a
requirement. For example, the porous metal-containing matrix may
have a void fraction of 1 to 60 volume percent, preferably 5 to 50
volume percent, and more preferably 15 to 50 volume percent, more
preferably 40 to 50 volume percent, although this is not a
requirement. Accordingly, the abrasive article preform may then be
infused with a molten metal that has a temperature below the
melting point(s) of any other metallic components, then cooled.
Examples of suitable metals that can be made molten and infused
into the abrasive article preform include aluminum, indium, brass,
bronze, silver, copper, gold, lead, cobalt, magnesium, nickel,
zinc, tin, iron, chromium, silicon alloys, alloys of the foregoing,
and combinations thereof.
[0085] Further details concerning sintering and then infusing with
molten metal can be found in, for example, U.S. Pat. No. 2,367,404
(Kott) and U.S. Pat. Appln. Publ. No. 2002/095875 (D'Evelyn et
al.).
[0086] Advantageously, methods according to the present disclosure
are suitable for manufacturing various metal bond abrasive articles
that cannot be readily or easily fabricated by other methods. For
example, inclusion of internal voids is possible as long as an
opening to the exterior of the abrasive preform exists for removal
of unbonded loose powder. Accordingly, cooling channels having
tortuous and or arcuate paths can be readily manufactured using
methods of the present disclosure. Cooling channels are open to the
exterior of the metal bond abrasive article. In some embodiments,
they have a single opening, but more typically they have two or
more openings. A cooling medium (e.g., air, water, emulsion, or
oil) circulates through the cooling channel(s) to remove heat
generated during the abrading process.
[0087] Accordingly, in another aspect, the present disclosure
provides a metal bond abrasive article precursor comprising
metallic particles and abrasive particles bonded together by an
organic compound material, wherein the metal bond abrasive article
precursor further comprises at least one of: at least one tortuous
cooling channel extending at least partially through the metal bond
abrasive article precursor; at least one arcuate cooling channel
extending at least partially through the metal bond abrasive
article precursor.
[0088] The abrasive article preform 190 is then heated (step 195 in
FIG. 1A) to remove any organic compound material that may be
present, and sinter the abrasive particles with the metal or
vitreous bond precursor particles (e.g., by burning off the organic
compound material), thereby providing the metal bond or vitreous
bond abrasive article, respectively.
[0089] In certain embodiments, the vitreous bond or metal bond
abrasive article is selected from the group consisting of a unitary
structured abrasive disc, an abrasive grinding bit, abrasive
segments, abrasive rims, shaped abrasive particles (e.g.,
triangular abrasive particles), and an abrasive wheel, as well as
many hitherto unknown vitreous bond or metal bond abrasive
articles. In some preferred embodiments, a metal bond abrasive
article comprises at least a portion of a rotary dental tool (e.g.,
a dental drill bit, a dental bur, or a dental polishing tool).
[0090] Referring now to FIG. 2, an exemplary vitreous bond or metal
bond abrasive wheel 200 has arcuate and tortuous cooling channels
220, respectively.
[0091] FIG. 3 shows another exemplary vitreous bond or metal bond
abrasive wheel 300 that has tortuous cooling channels 320.
[0092] FIG. 4 shows an exemplary vitreous bond or metal bond
abrasive segment 400. In typical use, multiple vitreous bond or
metal bond abrasive segments 400 are mounted evenly spaced along
the circumference of a metal disc to form an abrasive wheel.
[0093] FIG. 5 shows a vitreous bond or metal bond abrasive disc 500
has two regions 510, 520. Each region has abrasive particles 530,
540 retained in a vitreous bond or metal bond matrix material 550,
560, respectively.
[0094] FIGS. 6A-6B and 7A-7B, respectively show various unitary
structured abrasive discs with precisely-shaped ceramic abrasive
elements 610, 710 formed integrally with ceramic planar bases 620,
720.
[0095] FIG. 8 shows a rotary abrasive tool 800 (a bit for a
handheld motor driven shaft such as, for example, a Dremel
tool).
[0096] An exemplary dental bur 900 is shown in FIG. 9. Referring
now to FIG. 9, dental bur 900 includes head 930 secured to shank
920. Dental bur 900 comprises abrasive particles 905 secured in
porous metal bond or vitreous bond 910.
[0097] The foregoing abrasive wheels shown in FIGS. 2 and 3 can be
prepared by firing corresponding green bodies (i.e., having the
same general shape features, but comprising a vitreous bond or
metal bond precursor particles held together by a temporary
binder).
[0098] In some embodiments, a (e.g., non-transitory)
machine-readable medium is employed in additive manufacturing of
vitreous bond abrasive articles and/or metal bond abrasive articles
according to at least certain aspects of the present disclosure.
Data is typically stored on the machine-readable medium. The data
represents a three-dimensional model of a vitreous bond abrasive
article or a metal bond abrasive article, which can be accessed by
at least one computer processor interfacing with additive
manufacturing equipment (e.g., a 3D printer, a manufacturing
device, etc.). The data is used to cause the additive manufacturing
equipment to create at least a vitreous bond abrasive article
precursor or preform or a metal bond abrasive article precursor or
preform.
[0099] Data representing a vitreous bond abrasive article or a
metal bond abrasive article may be generated using computer
modeling such as computer aided design (CAD) data. Image data
representing the vitreous bond abrasive article and/or metal bond
abrasive article design can be exported in STL format, or in any
other suitable computer processable format, to the additive
manufacturing equipment. Scanning methods to scan a
three-dimensional object may also be employed to create the data
representing the vitreous bond abrasive article or metal bond
abrasive article. One exemplary technique for acquiring the data is
digital scanning. Any other suitable scanning technique may be used
for scanning an article, including X-ray radiography, laser
scanning, computed tomography (CT), magnetic resonance imaging
(MRI), and ultrasound imaging. Other possible scanning methods are
described, e.g., in U.S. Patent Application Publication No.
2007/0031791 (Cinader, Jr., et al.). The initial digital data set,
which may include both raw data from scanning operations and data
representing articles derived from the raw data, can be processed
to segment an abrasive article design from any surrounding
structures (e.g., a support for the abrasive article).
[0100] Often, machine-readable media are provided as part of a
computing device. The computing device may have one or more
processors, volatile memory (RAM), a device for reading
machine-readable media, and input/output devices, such as a
display, a keyboard, and a pointing device. Further, a computing
device may also include other software, firmware, or combinations
thereof, such as an operating system and other application
software. A computing device may be, for example, a workstation, a
laptop, a personal digital assistant (PDA), a server, a mainframe
or any other general-purpose or application-specific computing
device. A computing device may read executable software
instructions from a computer-readable medium (such as a hard drive,
a CD-ROM, or a computer memory), or may receive instructions from
another source logically connected to computer, such as another
networked computer. Referring to FIG. 10, a computing device 1000
often includes an internal processor 1080, a display 1100 (e.g., a
monitor), and one or more input devices such as a keyboard 1140 and
a mouse 1120. In FIG. 10, a rotary abrasive tool 1130 is shown on
the display 1100.
[0101] Referring to FIG. 11, in certain embodiments, the present
disclosure provides a system 1150. The system 1150 comprises a
display 1160 that displays a 3D model 1155 of a metal bond abrasive
article (e.g., a rotary abrasive tool 1130 as shown on the display
1100 of FIG. 10); and one or more processors 1165 that, in response
to the 3D model 1155 selected by a user, cause a 3D
printer/additive manufacturing device 1175 to create a physical
object of a metal bond abrasive article precursor 1180 of the metal
bond abrasive article. The metal bond abrasive article precursor
1180 comprises metallic particles and abrasive particles bonded
together by an organic compound material. The metal bond abrasive
article precursor 1180 further comprises at least one of at least
one tortuous cooling channel extending at least partially through
the metal bond abrasive article precursor; and at least one arcuate
cooling channel extending at least partially through the metal bond
abrasive article precursor. Similarly, in certain embodiments a
system 1150 comprises a display 1160 that displays a 3D model 1155
of a vitreous bond abrasive article; and one or more processors
1165 that, in response to the 3D model 1155 selected by a user,
cause a 3D printer/additive manufacturing device 1175 to create a
physical object of a vitreous bond abrasive article precursor 1180
of the vitreous bond abrasive article. The vitreous bond abrasive
article precursor 1180 comprises abrasive particles bonded together
by a vitreous bond precursor material and an organic compound. The
vitreous bond abrasive article precursor 1180 further comprises at
least one of at least one tortuous cooling channel extending at
least partially through the vitreous bond abrasive article
precursor; or at least one arcuate cooling channel extending at
least partially through the vitreous bond abrasive article
precursor.
[0102] Referring to FIG. 12, a processor 1220 (or more than one
processor) is in communication with each of a machine-readable
medium 1210 (e.g., a non-transitory medium), a 3D printer/additive
manufacturing device 1240, and optionally a display 1230 for
viewing by a user. The 3D printer/additive manufacturing device
1240 is configured to make one or more articles 1250 based on
instructions from the processor 1220 providing data representing a
3D model of the article 1250 from the machine-readable medium
1210.
[0103] Referring to FIG. 13, for example and without limitation, an
additive manufacturing method comprises retrieving 1310, from a
(e.g., non-transitory) machine-readable medium, data representing a
3D model of a vitreous bond abrasive article or a metal bond
abrasive article according to at least one embodiment of the
present disclosure. The method further includes executing 1320, by
one or more processors, an additive manufacturing application
interfacing with a manufacturing device using the data; and
generating 1330, by the manufacturing device, a physical object of
the vitreous bond abrasive article or metal bond abrasive article.
The additive manufacturing equipment can selectively bond the
metallic particles or vitreous bond precursor particles with the
abrasive particles and organic compound material according to a set
of computerized design instructions to create a desired metal bond
abrasive article precursor or preform or vitreous bond abrasive
article precursor or preform, respectively. One or more various
optional post-processing steps 1340 may be undertaken. For
instance, optionally, the metal bond abrasive article precursor or
preform or vitreous bond abrasive article precursor or preform is
heated to form the metal bond abrasive article or the vitreous bond
abrasive article, respectively. Additionally, referring to FIG. 14,
methods of forming a metal bond abrasive article precursor or
preform or a vitreous bond abrasive article precursor or preform
comprise receiving 1410, by a manufacturing device having one or
more processors, a digital object comprising data specifying a
plurality of layers of a metal bond abrasive article or a vitreous
bond abrasive article; and generating 1420, with the manufacturing
device by an additive manufacturing process, the metal bond
abrasive article precursor or preform or vitreous bond abrasive
article precursor or preform, respectively, based on the digital
object. Again, the article may undergo one or more steps of
post-processing 1430.
Select Embodiments of the Present Disclosure
[0104] Embodiment 1 is a method of making a vitreous bond abrasive
article, the method comprising sequential steps:
[0105] a) a subprocess comprising sequentially: [0106] i)
depositing a layer of loose powder particles in a confined region,
wherein the loose powder particles comprise vitreous bond precursor
particles, abrasive particles, and organic compound particles, and
wherein the layer of loose powder particles has substantially
uniform thickness; and [0107] ii) selectively applying heat via
conduction or irradiation, to heat treat an area of the layer of
loose powder particles;
[0108] b) independently carrying out step a) a plurality of times
to generate an abrasive article preform comprising the bonded
powder particles and remaining loose powder particles, wherein in
each step a), the loose powder particles are independently
selected;
[0109] c) separating substantially all of the remaining loose
powder particles from the abrasive article preform; and
[0110] d) heating the abrasive article preform to provide the
vitreous bond abrasive article comprising the abrasive particles
retained in a vitreous bond material.
[0111] Embodiment 2 is the method of embodiment 1, wherein the
abrasive particles include at least one of diamond particles or
cubic boron nitride particles.
[0112] Embodiment 3 is the method of embodiment 1, wherein the
abrasive particles include metal oxide ceramic particles.
[0113] Embodiment 4 is the method of any of embodiments 1 to 3,
wherein the abrasive particles and the vitreous bond material have
the same chemical composition.
[0114] Embodiment 5 is the method of any of embodiments 1 to 4,
wherein the vitreous bond abrasive article includes at least one
cooling channel.
[0115] Embodiment 6 is the method of any of embodiments 1 to 5,
wherein the vitreous bond abrasive article is selected from the
group consisting of a unitary structured abrasive disc, an abrasive
grinding bit, abrasive segments, abrasive rims, and an abrasive
wheel.
[0116] Embodiment 7 is the method of any of embodiments 1 to 6,
wherein the organic compound particles have a melting point between
50 degrees Celsius and 250 degrees Celsius, inclusive.
[0117] Embodiment 8 is the method of any of embodiments 1 to 7,
wherein the organic compound particles have a melting point between
100 degrees Celsius to 180 degrees Celsius, inclusive.
[0118] Embodiment 9 is the method of any of embodiments 1 to 8,
wherein the organic compound particles are selected from waxes,
sugars, dextrins, thermoplastics having a melting point of no
greater than 250 degrees Celsius, acrylates, methacrylates, and
combinations thereof.
[0119] Embodiment 10 is the method of any of embodiments 7 to 9,
wherein the organic compound particles are selected from waxes,
acrylates, methacrylates, polyethyleneterephthalate (PET),
polylactic acid (PLA), and combinations thereof.
[0120] Embodiment 11 is the method of any of embodiments 1 to 10,
wherein the organic compound particles are present in an amount of
2.5 weight percent to 30 weight percent of the loose powder
particles.
[0121] Embodiment 12 is the method of any of embodiments 1 to 11,
wherein the organic compound particles are present in an amount of
5 weight percent to 20 weight percent of the loose powder
particles.
[0122] Embodiment 13 is the method of embodiment 11 or embodiment
12, wherein the inorganic vitreous bond precursor includes a
precursor of alpha alumina.
[0123] Embodiment 14 is the method of any of embodiments 8 to 13,
wherein the loose powder particles include submicron ceramic
particles.
[0124] Embodiment 15 is the method of any of embodiments 1 to 14,
wherein the loose powder particles further include flow agent
particles.
[0125] Embodiment 16 is the method of any of embodiments 1 to 15,
wherein step d) further includes burning out the organic compound
material.
[0126] Embodiment 17 is the method of any of embodiments 1 to 16,
wherein in step ii) the heat is applied using a single heated tip
or a thermal print head.
[0127] Embodiment 18 is the method of claim 17, wherein in step ii)
the single heated tip further applies pressure to the area of the
layer of loose powder particles.
[0128] Embodiment 19 is the method of any of embodiments 1 to 16,
wherein in step ii) the heat is applied using at least one
laser.
[0129] Embodiment 20 is a vitreous bond abrasive article precursor
including abrasive particles bonded together by a vitreous bond
precursor material and an organic compound, wherein the vitreous
bond abrasive article precursor further includes at least one of at
least one tortuous cooling channel extending at least partially
through the vitreous bond abrasive article precursor; or at least
one arcuate cooling channel extending at least partially through
the vitreous bond abrasive article precursor.
[0130] Embodiment 21 is the vitreous bond abrasive precursor of
embodiment 20, wherein the abrasive particles include at least one
of silicon carbide, boron carbide, silicon nitride, or metal oxide
ceramic particles.
[0131] Embodiment 22 is a method of making a metal bond abrasive
article, the method comprising sequential steps:
[0132] a) a subprocess comprising sequentially: [0133] i)
depositing a layer of loose powder particles in a confined region,
wherein the loose powder particles comprise higher melting metal
particles, abrasive particles, and organic compound particles, and
wherein the layer of loose powder particles has substantially
uniform thickness; and [0134] ii) selectively applying heat via
conduction or irradiation, to heat treat an area of the layer of
loose powder particles;
[0135] b) independently carrying out step a) a plurality of times
to generate an abrasive article preform comprising the bonded
powder particles and remaining loose powder particles, wherein in
each step a), the loose powder particles are independently
selected;
[0136] c) separating substantially all of the remaining loose
powder particles from the abrasive article preform;
[0137] d) infusing the abrasive article preform with a molten lower
melting metal, wherein at least some of the higher melting metal
particles do not completely melt when contacted by the molten lower
melting metal; and
[0138] e) solidifying the molten lower melting metal to provide the
metal bond abrasive article.
[0139] Embodiment 23 is the method of embodiment 22, wherein the
loose powder particles further include fluxing agent particles.
[0140] Embodiment 24 is the method of embodiment 22 or embodiment
23, wherein the abrasive particles include at least one of diamond
particles or cubic boron nitride particles.
[0141] Embodiment 25 is the method of embodiment 22 or embodiment
23, wherein the abrasive particles include metal oxide ceramic
particles.
[0142] Embodiment 26 is the method of any of embodiments 22 to 25,
wherein the metal bond abrasive article includes at least one
cooling channel.
[0143] Embodiment 27 is the method of any of embodiments 22 to 26,
wherein the metal bond abrasive article is selected from the group
consisting of an abrasive pad, an abrasive grinding bit, abrasive
segments, and an abrasive wheel.
[0144] Embodiment 28 is the method of any of embodiments 22 to 26,
wherein the metal bond abrasive article comprises at least a
portion of a rotary dental tool.
[0145] Embodiment 29 is the method of any of embodiments 22 to 28,
wherein the organic compound particles have a melting point between
50 degrees Celsius and 250 degrees Celsius, inclusive.
[0146] Embodiment 30 is the method of any of embodiments 22 to 29,
wherein the organic compound particles have a melting point between
100 degrees Celsius to 180 degrees Celsius, inclusive.
[0147] Embodiment 31 is the method of any of embodiments 22 to 30,
wherein the organic compound particles are selected from waxes,
sugars, dextrins, thermoplastics having a melting point of no
greater than 250 degrees Celsius, acrylates, methacrylates, and
combinations thereof.
[0148] Embodiment 32 is the method of any of embodiments 29 to 31,
wherein the organic compound particles are selected from waxes,
acrylates, methacrylates, polyethyleneterephthalate (PET),
polylactic acid (PLA), and combinations thereof.
[0149] Embodiment 33 is the method of any of embodiments 22 to 32,
wherein the organic compound particles are present in an amount of
1.5 weight percent to 25 weight percent of the loose powder
particles.
[0150] Embodiment 34 is the method of any of embodiments 22 to 33,
wherein the organic compound particles are present in an amount of
3 weight percent to 20 weight percent of the loose powder
particles.
[0151] Embodiment 35 is the method of any of embodiments 22 to 34,
wherein the higher melting metal particles have a melting point
that is at least 50 degrees Celsius higher than the temperature of
the molten lower melting metal.
[0152] Embodiment 36 is the method of any of embodiments 22 to 35,
further comprising, between steps c) and d), burning off at least a
portion of the organic compound material.
[0153] Embodiment 37 is the method of any of embodiments 22 to 36,
wherein in step ii) the heat is applied using a single heated tip
or a thermal print head.
[0154] Embodiment 38 is the method of embodiment 37, wherein in
step ii) the single heated tip further applies pressure to the area
of the layer of loose powder particles.
[0155] Embodiment 39 is the method of any of embodiments 22 to 36,
wherein in step ii) the heat is applied using at least one
laser.
[0156] Embodiment 40 is a method of making a metal bond abrasive
article, the method comprising sequential steps:
[0157] a) a subprocess comprising sequentially: [0158] i)
depositing a layer of loose powder particles in a confined region,
wherein the loose powder particles comprise metal particles,
abrasive particles, and organic compound particles, and wherein the
layer of loose powder particles has substantially uniform
thickness; [0159] ii) selectively applying heat via conduction or
irradiation, to heat treat an area of the layer of loose powder
particles;
[0160] b) independently carrying out step a) a plurality of times
to generate an abrasive article preform comprising the bonded
powder particles and remaining loose powder particles, wherein the
abrasive article preform has a predetermined shape, and wherein in
each step a), the loose powder particles are independently
selected;
[0161] c) separating substantially all of the remaining loose
powder particles from the abrasive article preform; and
[0162] d) heating the abrasive article preform to provide the metal
bond abrasive article.
[0163] Embodiment 41 is the method of embodiment 40, wherein the
loose powder particles further include fluxing agent particles.
[0164] Embodiment 42 is the method of embodiment 40 or embodiment
41, wherein the abrasive particles include at least one of diamond
particles or cubic boron nitride particles.
[0165] Embodiment 43 is the method of embodiment 40 or embodiment
41, wherein the abrasive particles include metal oxide ceramic
particles.
[0166] Embodiment 44 is the method of any of embodiments 40 to 43,
wherein the metal particles include a combination of higher melting
metal particles and lower melting metal particles, wherein the
higher melting metal particles have a melting point that is at
least 50 degrees Celsius higher than the temperature of the molten
lower temperature metal.
[0167] Embodiment 45 is the method of any of embodiments 40 to 44,
wherein the metal bond abrasive article includes at least one
cooling channel.
[0168] Embodiment 46 is the method of any of embodiments 40 to 45,
wherein the metal bond abrasive article is selected from the group
consisting of an abrasive pad, an abrasive grinding bit, abrasive
segments, and an abrasive wheel.
[0169] Embodiment 47 is the method of any of embodiments 40 to 45,
wherein the metal bond abrasive article includes at least a portion
of a rotary dental tool.
[0170] Embodiment 48 is the method of any of embodiments 40 to 47,
wherein the organic compound particles have a melting point between
50 degrees Celsius and 250 degrees Celsius, inclusive.
[0171] Embodiment 49 is the method of any of embodiments 40 to 48,
wherein the organic compound particles have a melting point between
100 degrees Celsius to 180 degrees Celsius, inclusive.
[0172] Embodiment 50 is the method of any of embodiments 40 to 49,
wherein the organic compound particles are selected from waxes,
sugars, dextrins, thermoplastics having a melting point of no
greater than 250 degrees Celsius, acrylates, methacrylates, and
combinations thereof.
[0173] Embodiment 51 is the method of any of embodiments 48 to 50,
wherein the organic compound particles are selected from waxes,
acrylates, methacrylates, polyethyleneterephthalate (PET),
polylactic acid (PLA), and combinations thereof.
[0174] Embodiment 52 is the method of any of embodiments 40 to 51,
wherein the organic compound particles are present in an amount of
1.5 weight percent to 25 weight percent of the loose powder
particles.
[0175] Embodiment 53 is the method of any of embodiments 40 to 52,
wherein the organic compound particles are present in an amount of
3 weight percent to 20 weight percent of the loose powder
particles.
[0176] Embodiment 54 is the method of any of embodiments 40 to 53,
wherein in step ii) the heat is applied using a single heated tip
or a thermal print head.
[0177] Embodiment 55 is the method of embodiment 54, wherein in
step ii) the single heated tip further applies pressure to the area
of the layer of loose powder particles.
[0178] Embodiment 56 is the method of any of embodiments 40 to 53,
wherein in step ii) the heat is applied using at least one
laser.
[0179] Embodiment 57 is a metal bond abrasive article precursor
including metallic particles and abrasive particles bonded together
by an organic compound material, wherein the metal bond abrasive
article precursor further includes at least one of: at least one
tortuous cooling channel extending at least partially through the
metal bond abrasive article precursor; and at least one arcuate
cooling channel extending at least partially through the metal bond
abrasive article precursor.
[0180] Embodiment 58 is a non-transitory machine readable medium
having data representing a three-dimensional model of a vitreous
bond abrasive article, when accessed by one or more processors
interfacing with a 3D printer, causes the 3D printer to create a
vitreous bond abrasive article precursor of the vitreous bond
abrasive article. The vitreous bond abrasive article precursor
includes abrasive particles bonded together by a vitreous bond
precursor material and an organic compound. The vitreous bond
abrasive article precursor further includes at least one of at
least one tortuous cooling channel extending at least partially
through the vitreous bond abrasive article precursor; or at least
one arcuate cooling channel extending at least partially through
the vitreous bond abrasive article precursor.
[0181] Embodiment 59 is a method including retrieving, from a
(e.g., non-transitory) machine readable medium, data representing a
3D model of a vitreous bond abrasive article. A vitreous bond
abrasive article precursor of the vitreous bond abrasive article
preform includes abrasive particles bonded together by a vitreous
bond precursor material and an organic compound. The vitreous bond
abrasive article precursor further includes at least one of at
least one tortuous cooling channel extending at least partially
through the vitreous bond abrasive article precursor; or at least
one arcuate cooling channel extending at least partially through
the vitreous bond abrasive article precursor. The method further
includes executing, by one or more processors, a 3D printing
application interfacing with a manufacturing device using the data;
and generating, by the manufacturing device, a physical object of
the vitreous bond abrasive article precursor.
[0182] Embodiment 60 is a vitreous bond abrasive article precursor
generated using the method of embodiment 59.
[0183] Embodiment 61 is a method including receiving, by a
manufacturing device having one or more processors, a digital
object comprising data specifying a plurality of layers of a
vitreous bond abrasive article precursor. The vitreous bond
abrasive article precursor includes abrasive particles bonded
together by a vitreous bond precursor material and an organic
compound. The vitreous bond abrasive article precursor further
includes at least one of at least one tortuous cooling channel
extending at least partially through the vitreous bond abrasive
article precursor; or at least one arcuate cooling channel
extending at least partially through the vitreous bond abrasive
article precursor. The method further includes generating, with the
manufacturing device by an additive manufacturing process, the
vitreous bond abrasive article precursor based on the digital
object.
[0184] Embodiment 62 is the method of embodiment 61, further
including separating loose powder particles from the vitreous bond
abrasive article precursor; and heating the abrasive article
precursor to provide the vitreous bond abrasive article including
the abrasive particles retained in a vitreous bond material.
[0185] Embodiment 63 is the method of embodiment 62, further
including burning out the organic compound material.
[0186] Embodiment 64 is a system including a display that displays
a 3D model of a vitreous bond abrasive article; and one or more
processors that, in response to the 3D model selected by a user,
cause a 3D printer to create a physical object of a vitreous bond
abrasive article precursor of the vitreous bond abrasive article.
The vitreous bond abrasive article precursor includes abrasive
particles bonded together by a vitreous bond precursor material and
an organic compound. The vitreous bond abrasive article precursor
further includes at least one of at least one tortuous cooling
channel extending at least partially through the vitreous bond
abrasive article precursor; or at least one arcuate cooling channel
extending at least partially through the vitreous bond abrasive
article precursor.
[0187] Embodiment 65 is a non-transitory machine readable medium
having data representing a three-dimensional model of a metal bond
abrasive article, when accessed by one or more processors
interfacing with a 3D printer, causes the 3D printer to create the
metal bond abrasive article precursor of the metal bond abrasive
article. The metal bond abrasive article precursor includes
metallic particles and abrasive particles bonded together by an
organic compound material. The metal bond abrasive article
precursor further includes at least one of at least one tortuous
cooling channel extending at least partially through the metal bond
abrasive article precursor; and at least one arcuate cooling
channel extending at least partially through the metal bond
abrasive article precursor.
[0188] Embodiment 66 is a method including retrieving, from a
non-transitory machine readable medium, data representing a 3D
model of a metal bond abrasive article precursor. The metal bond
abrasive article precursor includes metallic particles and abrasive
particles bonded together by an organic compound material. The
metal bond abrasive article precursor further includes at least one
of at least one tortuous cooling channel extending at least
partially through the metal bond abrasive article precursor; and at
least one arcuate cooling channel extending at least partially
through the metal bond abrasive article precursor. The method
further includes executing, by one or more processors, a 3D
printing application interfacing with a manufacturing device using
the data; and generating, by the manufacturing device, a physical
object of the metal bond abrasive article precursor.
[0189] Embodiment 67 is a metal bond abrasive article precursor
generated using the method of embodiment 66.
[0190] Embodiment 68 is a method including receiving, by a
manufacturing device having one or more processors, a digital
object comprising data specifying a plurality of layers of a metal
bond abrasive article precursor. The metal bond abrasive article
precursor includes metallic particles and abrasive particles bonded
together by an organic compound material. The metal bond abrasive
article precursor further includes at least one of at least one
tortuous cooling channel extending at least partially through the
metal bond abrasive article precursor; and at least one arcuate
cooling channel extending at least partially through the metal bond
abrasive article precursor. The method further includes generating,
with the manufacturing device by an additive manufacturing process,
the metal bond abrasive article precursor based on the digital
object.
[0191] Embodiment 69 is the method of embodiment 68, further
including separating loose powder particles from the metal bond
abrasive article preform; infusing the abrasive article preform
with a molten lower melting metal, wherein at least some of the
metallic particles do not completely melt when contacted by the
molten lower melting metal; and solidifying the molten lower
melting metal to provide the metal bond abrasive article.
[0192] Embodiment 70 is a system including a display that displays
a 3D model of a metal bond abrasive article; and one or more
processors that, in response to the 3D model selected by a user,
cause a 3D printer to create a physical object of a metal bond
abrasive article precursor of the metal bond abrasive article. The
metal bond abrasive article precursor includes metallic particles
and abrasive particles bonded together by an organic compound
material. The metal bond abrasive article precursor further
includes at least one of at least one tortuous cooling channel
extending at least partially through the metal bond abrasive
article precursor; and at least one arcuate cooling channel
extending at least partially through the metal bond abrasive
article precursor.
EXAMPLES
[0193] Unless otherwise noted, all parts, percentages, ratios, etc.
in the Examples and the rest of the specification are by
weight.
TABLE-US-00001 TABLE 1 ABBREVIATION DESCRIPTION PDR1 ALODUR BFRPL
aluminium oxide particles, grade P320, from Treibacher
Schleifmittel AG (Villach, Austria) PDR2 A mix of 98.5% vitrified
bond VO82069 from Reimbold & Strick, Cologne, Germany and 1.5%
color stain for glazes K90084 from Reimbold & Strick (Cologne,
Germany) PDR3 MicroKlear 116, a micronized blend of polyethylene
and carnauba wax, particle size of 4.5 to 5.5 micron, maximum
particle size 15.6 micron, melting point 248-257 degree F., from
Micro Powders, Inc. (Tarrytown, New York) PDR4 MicroPro 400, a
micronized polypropylene wax, particle size of 5.0 to 7.0 micron,
maximum particle size 22 micron, melting point 284-289 degrees
Fahrenheit (140-143 degrees Celsius), from Micro Powders, Inc.
(Tarrytown, New York)
Example 1
[0194] A print material P1 was prepared by mixing, based on the
mixture weight, 77.3 wt. % of PDR1, 13.6 wt. % of PDR2, and 9.1 wt.
% of PDR3. The powder mixture was put in glass jar and rotated on a
rolling bank mixer at about 50 rpm for 15 minutes. The print
material was spread on a piece of paper using a straight metal
blade, and one sheet of paper was used as a shim and the thickness
of the resulting first powder layer was approximately 100 microns.
It was covered with a 2 mil (50.8 micrometers) thick PET film. A
soldering iron was heated to approximately 425.degree. F.
(.about.218.degree. C.), and the hot tip was slowly moved over a
predetermined approximately 1 centimeter (cm).times.1 cm area. Only
slight pressure was applied and the PET film was barely deformed.
Then the PET film was removed, and it was observed that the print
material P1 had turned from slightly grey to dark grey in the area
where the heated tip had touched the PET film. Using a second layer
of paper as a shim, a second 0.1 millimeter (mm) thick layer of
print material was spread on top of the first layer of print
material. It was again covered with the PET film, and the same 1
cm.times.1 cm area was heated with the tip of the soldering iron
again. The procedure then was repeated for a third layer. After the
PET film was removed, a solid object was extracted from the loose
powder. It was observed that the three layers had melted together
to form a green body. The green body then was placed into a furnace
and burned out at 400.degree. C. for 2 hours, followed by sintering
at 700.degree. C. for 4 hours, resulting in an abrasive square that
measured approximately 1 cm.times.1 cm and 0.3 mm in thickness.
Example 2
[0195] Experimental Apparatus and Preparations
[0196] A laser marking device was assembled, consisting of a CO2
laser, Model E-400, available from Coherent, Santa Clara, Calif.,
and a 3-Axis Modular Scanner, Model HPLK 1330-17, CO2 30MM,
available from GSI Group, Inc, Billerica, Mass. The device was
controlled by a computer running the WaveRunner Advanced Laser
Scanning Software, Version 3.3.5 build-0200, by Nutfield
Technology, Hudson, N.H.
[0197] In the WaveRunner scanning software program, a 1.5 cm square
shape was drawn in the approximate center of the scanning field.
The "Hatch" function was enabled within the program and used to
cross-hatch the square. The first hatch pattern was at an angle of
0 degrees, and the second hatch pattern was at an angle of 90
degrees. In both hatch patterns, the lines were set at a distance
of 0.5 mm apart. Only the hatch patterns were marked; the contour
of the shape was not.
[0198] The laser scanning conditions were set in WaveRunner as
follows: Speed 2000 mm/second, Power: 8%, Frequency 20 kHz. A power
setting of 8% equals a laser beam power of 27.8 Watts.
[0199] Experimental Procedure
[0200] Two sheets of paper were put down in the laser scanning area
of the laser marking device. On top of the paper, the print
material P1 was spread using a straight metal blade, and two sheets
of paper, layered on top of each other, were used as a shim and the
thickness of the resulting first powder layer was approximately 200
microns. This first powder layer then was marked with the laser
scanner, using the conditions described above. It was observed that
the print material P1 had turned from slightly grey to dark grey in
the area where the laser had marked the layer. A second and a third
layer of print material P1, each 200 micron in thickness, were
subsequently put down and marked the same way. Finally, a fourth
layer was put down on the previous three layers, and this final
layer was marked with two passes of the laser.
[0201] A solid object was extracted from the loose powder. It was
observed that the four layers had melted together and formed a
green body that could be safely handled without breaking apart.
The green body then was placed into a furnace and burned out at
400.degree. C. for 2 hours, followed by sintering at 700.degree. C.
for 4 hours, resulting in an abrasive square that measured
approximately 1.5 cm.times.1.5 cm and 0.8 mm in thickness.
Example 3
[0202] Experimental Apparatus and Preparations
[0203] An apparatus for 3D printing with powders was constructed as
generally depicted in FIG. 1. Two adjacent chambers, each measuring
about 3 inches.times.2 inches (7.62 cm.times.5.08 cm) in the xy
plane and 2 inches (5.08 cm) in the z-direction, were milled into a
2 inch (5.08 cm) thick aluminum block. Two tightly fitting square
pistons made from aluminum were inserted into the chambers and
connected to stepper motor linear actuators, VersaDrive 17, Model
USV17-110-AB-0506, with a 6 inch (15.24) long lead screw, available
from USAutomation, Mission Viejo, Calif. One chamber and piston was
designated the powder supply, the other was designated the build
chamber. The linear actuators allow the pistons to be moved up and
down in z-direction. A rotating aluminum roller, driven by a motor,
was mounted in the plane about 1 mm above the chambers. This roller
was actuated in x-direction using a stepper motor linear actuator,
VersaDrive 17, Model USV17-110-AB-2512, with a 12 inch (30.48 cm)
long lead screw, available from USAutomation, Mission Viejo, Calif.
This actuated roller allows movement of powder from the powder
supply chamber to the build chamber.
[0204] The motors were connected to a motion controller board,
model EZ4AXIS, available from AllMotion, Union City, Calif. The
motion controller was programmed to run the following sequence:
First, lower the build piston by 0.10 mm, then raise the powder
supply piston by 0.16 mm, then switch on the roller motor, actuate
the roller to move powder from the powder supply chamber to the
build chamber, stop the roller motor, and return the roller to the
origin. This procedure produces a uniform, 0.1 mm thick layer of
powder in the build area. Above the two chamber assembly, a
motorized xy positioning stage was mounted, and a 500 mW, 405 nm
diode laser, model M-33A405-500-G, available from TEM-Laser, Wuhan,
Hubei, China, was attached. The xy table contained a Grbl
controller board for laser engravers and was able to be controlled
by Grbl 0.9, an open source software for controlling the motion of
machines. The graphics were loaded into Inkscape 0.48 with a laser
engraver plug-in, an open source graphics software. This software
generated the xy motion control and the laser power code from a
drawing, and transferred it to the Grbl 0.9 software.
[0205] A print material P2 was prepared by mixing, based on the
mixture weight, 77.3 wt. % of PDR1, 13.6 wt. % of PDR2 and 9.1 wt.
% of PDR4. The powder mixture was put in a glass jar and rotated on
a rolling bank mixer at about 50 rpm for 15 minutes. The powder
supply piston was lowered to the bottom, and the chamber was filled
with the print material P2. The build piston was raised to the top.
Then the powder spreading procedure was executed 10 times to form a
uniform powder base in the build area.
[0206] In the Inkscape software, the font Arial, font size 14 pt,
was selected, and the word "Test" was written. Then the laser
engraver plug-in was selected. The laser was set to 100% output,
and a motion speed of 10 mm/second was selected, and the Grbl code
was generated and transferred to the Grbl 0.9 software. Then a
first 0.1 mm thick layer of print material P2 was spread. Next, the
Grbl code was executed. It was observed that the laser turned on
and moved in the shape of the word "Test", and the powder turned
from a light grey to a dark grey in the shape of the word
"Test".
[0207] A second layer, also 0.1 mm thick, of print material P2 was
spread, and the Grbl code was executed a second time. This sequence
was repeated until a total of 20 layers had been spread and exposed
to the laser.
[0208] Then a spatula was used to remove the object from the
surrounding powder. Loose powder was removed and an object in the
shape of the word "Test", 2.05 mm in thickness, was recovered.
[0209] It was observed that the 20 layers had melted together and
formed a green body that could be safely handled without breaking
apart. The green body was placed into a furnace and burned out at
400.degree. C. for 2 hours, followed by sintering at 700.degree. C.
for 4 hours, resulting in an abrasive article in the shape of the
word "Test". The article was rubbed against a block of aluminum,
and an abrasion pattern was observed.
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