U.S. patent application number 17/603346 was filed with the patent office on 2022-06-09 for manufacturing system and manufacturing method of sintered product.
This patent application is currently assigned to Sumitomo Electric Sintered Alloy, Ltd.. The applicant listed for this patent is Sumitomo Electric Sintered Alloy, Ltd.. Invention is credited to Tetsuya HAYASHI, Shin NOGUCHI, Tatsushi YAMAMOTO.
Application Number | 20220176448 17/603346 |
Document ID | / |
Family ID | 1000006214510 |
Filed Date | 2022-06-09 |
United States Patent
Application |
20220176448 |
Kind Code |
A1 |
NOGUCHI; Shin ; et
al. |
June 9, 2022 |
MANUFACTURING SYSTEM AND MANUFACTURING METHOD OF SINTERED
PRODUCT
Abstract
A manufacturing system according to an aspect of the present
disclosure includes: a molding apparatus configured to uniaxially
press raw material powder containing metal powder to fabricate a
powder compact whose whole or part has a relative density of 93% or
more; a robot processing apparatus including an articulated robot
configured to machine the powder compact to fabricate a processed
molded article; and an induction heating sintering furnace
configured to sinter the processed molded article by high frequency
induction heating to fabricate a sintered product.
Inventors: |
NOGUCHI; Shin;
(Takahashi-shi, Okayama, JP) ; YAMAMOTO; Tatsushi;
(Takahashi-shi, Okayama, JP) ; HAYASHI; Tetsuya;
(Takahashi-shi, Okayama, JP) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Sumitomo Electric Sintered Alloy, Ltd. |
Takahashi-shi, Okayama |
|
JP |
|
|
Assignee: |
Sumitomo Electric Sintered Alloy,
Ltd.
Takahashi-shi, Okayama
JP
|
Family ID: |
1000006214510 |
Appl. No.: |
17/603346 |
Filed: |
April 24, 2019 |
PCT Filed: |
April 24, 2019 |
PCT NO: |
PCT/JP2019/017351 |
371 Date: |
October 13, 2021 |
Current U.S.
Class: |
1/1 |
Current CPC
Class: |
B22F 2301/35 20130101;
B22F 3/162 20130101; B22F 3/003 20130101 |
International
Class: |
B22F 3/00 20060101
B22F003/00; B22F 3/16 20060101 B22F003/16 |
Claims
1. A manufacturing system of a sintered product, comprising: a
molding apparatus configured to uniaxially press raw material
powder containing metal powder to fabricate a powder compact whose
whole or part has a relative density of 93% or more; a robot
processing apparatus including an articulated robot configured to
machine the powder compact to fabricate a processed molded article;
and an induction heating sintering furnace configured to sinter the
processed molded article by high frequency induction heating to
fabricate a sintered product.
2. The manufacturing system of a sintered product according to
claim 1, further comprising an acquisition unit configured to
acquire 3D data of a target product serving as a reference of a
shape.
3. The manufacturing system of a sintered product according to
claim 2, further comprising an inspection apparatus configured to
execute, based on the 3D data of the target product, an inspection
of at least one of dimensional precision of the sintered product
and presence or absence of a defect.
4. The manufacturing system of a sintered product according to
claim 2, further comprising a computer apparatus configured to
create, based on the 3D data of the target product, a processing
program for controlling operation of the robot processing
apparatus, wherein the robot processing apparatus fabricates the
processed molded article based on the processing program.
5. The manufacturing system of a sintered product according to
claim 1, wherein the robot processing apparatus includes a
plurality of the articulated robots, and the plurality of the
articulated robots includes a first robot configured to hold a tool
for processing the powder compact, and a second robot configured to
hold the powder compact.
6. A manufacturing system of a sintered product, comprising: a
processing apparatus configured to machine a powder compact
following 3D data of a target product serving as a reference of a
shape to fabricate a processed molded article; and a sintering
apparatus configured to sinter the processed molded article to
fabricate a sintered product.
7. The manufacturing system of a sintered product according to
claim 6, further comprising a 3D scanner configured to acquire 3D
data of the target product in a non-contact manner.
8. The manufacturing system of a sintered product according to
claim 6, wherein: the processing apparatus is a robot processing
apparatus including an articulated robot; and the manufacturing
system further includes a computer apparatus configured to create,
based on the 3D data of the target product, a processing program
for controlling operation of the robot processing apparatus.
9. The manufacturing system of a sintered product according to
claim 6, further comprising an inspection apparatus configured to
execute, based on the 3D data of the target product, an inspection
of at least one of dimensional precision of the sintered product
and presence or absence of a defect.
10. The manufacturing system of a sintered product according to
claim 6, further comprising a molding apparatus configured to
uniaxially press raw material powder containing metal powder to
fabricate the powder compact whose whole or part has a relative
density of 93% or more.
11. The manufacturing system of a sintered product according to
claim 6, wherein the sintering apparatus is an induction heating
sintering furnace configured to sinter the processed molded article
by high frequency induction heating.
12. The manufacturing system of a sintered product according to
claim 6, further comprising a mobile apparatus capable of traveling
on a road, wherein: the processing apparatus is a robot processing
apparatus including an articulated robot; the sintering apparatus
is an induction heating sintering furnace configured to sinter the
processed molded article by high frequency induction heating; and
apparatuses to be mounted on the mobile apparatus include the robot
processing apparatus and the induction heating sintering
furnace.
13. The manufacturing system of a sintered product according to
claim 12, wherein the apparatuses to be mounted on the mobile
apparatus include a 3D scanner configured to acquire the 3D data of
the target product in a non-contact manner.
14. The manufacturing system of a sintered product according to
claim 1, wherein the whole or part of the powder compact has a
relative density of 96% or more.
15. A manufacturing method of a sintered product, wherein the
sintered product is manufactured by using the manufacturing system
according to claim 1.
16. The manufacturing system of a sintered product according to
claim 6, wherein the whole or part of the powder compact has a
relative density of 96% or more.
17. A manufacturing method of a sintered product, wherein the
sintered product is manufactured by using the manufacturing system
according to claim 6.
Description
TECHNICAL FIELD
[0001] The present invention relates to a manufacturing system and
a manufacturing method of a sintered product.
BACKGROUND ART
[0002] Patent Literatures 1 and 2 describe a manufacturing method
of a sintered product including: a preparation step of preparing
raw material powder containing metal powder; a molding step of
uniaxially pressing the raw material powder using a mold to
fabricate a powder compact; a processing step of machining the
powder compact to fabricate a processed molded article; and a
sintering step of sintering the processed molded article to obtain
a sintered product.
[0003] In Patent Literature 2, it is recommended to set the average
relative density of the whole powder compact to 93% or more in the
molding step described above.
CITATION LIST
Patent Literature
[0004] Patent Literature 1: Japanese Unexamined Patent Publication
No. 2004-323939 [0005] Patent Literature 2: WO 2017/175772 A
SUMMARY OF INVENTION
[0006] A manufacturing system according to one aspect of the
present invention includes: a molding apparatus configured to
uniaxially press raw material powder containing metal powder to
fabricate a powder compact whose whole or part has a relative
density of 93% or more; a robot processing apparatus including an
articulated robot configured to machine the powder compact to
fabricate a processed molded article; and an induction heating
sintering furnace configured to sinter the processed molded article
by high frequency induction heating to fabricate a sintered
product.
[0007] A manufacturing system according to another aspect of the
present invention includes: a processing apparatus configured to
machine a powder compact following 3D data of a target product
serving as a reference of a shape to fabricate a processed molded
article; and a sintering apparatus configured to sinter the
processed molded article to fabricate a sintered product.
BRIEF DESCRIPTION OF DRAWINGS
[0008] FIG. 1 is an explanatory illustration showing an outline of
a manufacturing method of a sintered product.
[0009] FIG. 2 is an explanatory illustration showing an example of
each of apparatuses used in steps 1 and 2.
[0010] FIG. 3 is an overall configuration illustration showing an
example of a manufacturing facility used in step 3.
[0011] FIG. 4 is a schematic configuration illustration showing an
example of a molding apparatus used in a molding step.
[0012] FIG. 5 is a schematic configuration illustration showing an
example of a processing apparatus used in a processing step.
[0013] FIG. 6 is a schematic configuration illustration showing an
example of a sintering apparatus used in a sintering step.
[0014] FIG. 7 is a schematic configuration illustration showing an
example of an inspection apparatus used in an inspection step.
[0015] FIG. 8 is an explanatory illustration showing an example of
an apparatus used in step 4.
[0016] FIG. 9 is a schematic configuration illustration showing an
example of a movable manufacturing system.
DESCRIPTION OF EMBODIMENTS
Technical Problem
[0017] When there is a customer who is considering replacing a
current product with a sintered product, it is preferable for a
manufacturer of sintered products to manufacture a sintered product
following the current product of the customer as early as possible
and present the manufactured sintered product as a sample to the
customer.
[0018] In Patent Literatures 1 and 2, however, delivery date of a
sintered product to be presented to a customer as a sample is not
taken into consideration. In view of such a conventional problem,
an object of the present disclosure is to shorten the delivery date
of a sintered product.
[0019] In addition, it is desired to make a facility for
manufacturing a sintered product to be presented to a customer as a
sample compact (downsizing). In view of such a conventional
problem, an object of the present disclosure is such that a
manufacturing facility of a sintered product can be made
compact.
Advantageous Effects of Present Disclosure
[0020] According to the present disclosure, the delivery date of a
sintered product can be shortened.
[0021] According to the present disclosure, a manufacturing
facility of a sintered product can be made compact.
OUTLINE OF EMBODIMENTS OF PRESENT INVENTION
[0022] Hereinafter, outlines of embodiments of the present
invention will be listed and described.
[0023] (1) A manufacturing system according to the present
embodiment includes: a molding apparatus configured to uniaxially
press raw material powder containing metal powder to fabricate a
powder compact whose whole or part has a relative density of 93% or
more; a robot processing apparatus including an articulated robot
configured to machine the powder compact to fabricate a processed
molded article; and an induction heating sintering furnace
configured to sinter the processed molded article by high frequency
induction heating to fabricate a sintered product.
[0024] According to the manufacturing system of the present
embodiment, the induction heating sintering furnace, capable of
fabricating a sintered product in a shorter time than a belt type
continuous sintering furnace, is provided, so that the delivery
date of a sintered product can be shortened.
[0025] According to the manufacturing system of the present
embodiment, the robot processing apparatus needing an installation
space smaller than that of a five-axis machining center, and the
induction heating sintering furnace needing an installation space
smaller than that of a belt type continuous sintering furnace, are
provided, so that a manufacturing facility of a sintered product
can be made compact.
[0026] (2) The manufacturing system according to the present
embodiment preferably further includes an acquisition unit
configured to acquire 3D data of a target product serving as a
reference of a shape.
[0027] According to the manufacturing system of the present
embodiment, the acquisition unit acquires 3D data of a target
product serving as a reference of a shape, so that it becomes
possible to execute, based on the acquired 3D data, an inspection
of the sintered product, creation of a processing program, and the
like, as described later.
[0028] (3) The manufacturing system according to the present
embodiment preferably further includes an inspection apparatus
configured to execute, based on the 3D data of the target product,
an inspection of at least one of dimensional precision of the
sintered product and presence or absence of a defect.
[0029] According to the manufacturing system of the present
embodiment, the inspection apparatus executes the inspection
described above, so that a sintered product with high precision
comparable to a target product can be manufactured.
[0030] (4) The manufacturing system according to the present
embodiment preferably further includes a computer apparatus
configured to create, based on the 3D data of the target product, a
processing program for controlling operation of the robot
processing apparatus such that the robot processing apparatus
fabricates the processed molded article based on the processing
program.
[0031] According to the manufacturing system of the present
embodiment, the computer apparatus creates the processing program
described above, and the robot processing apparatus fabricates a
processed molded article based on the processing program described
above, so that the robot processing apparatus can be controlled to
process a powder compact into substantially the same shape as a
target product.
[0032] (5) In the manufacturing system according to the present
embodiment, the robot processing apparatus preferably includes a
plurality of the articulated robots, in which the plurality of the
articulated robots includes a first robot configured to hold a tool
for processing the powder compact and a second robot configured to
hold the powder compact.
[0033] According to the manufacturing system of the present
embodiment, the relative density of the powder compact is 93% or
more, so that even when cutting work is performed on the powder
compact held by the second robot with the tool held by the first
robot, the powder compact is not broken. Therefore, the powder
compact can be quickly processed.
[0034] In addition, the tool can be brought into contact with the
powder compact at an arbitrary angle, so that complicated
processing can be quickly executed.
[0035] (6) A manufacturing system according to the present
embodiment includes a processing apparatus configured to machine a
powder compact following 3D data of a target product serving as a
reference of a shape to fabricate a processed molded article, and a
sintering apparatus configured to sinter the processed molded
article to fabricate a sintered product.
[0036] According to the manufacturing system of the present
embodiment, the processing apparatus machines a powder compact
following the 3D data of a target product to fabricate a processed
molded article, and the sintering apparatus sinters the processed
molded article to fabricate a sintered product, so that a sintered
product having substantially the same shape as the target product
can be fabricated in a short time. Thus, the delivery date of a
sintered product can be shortened.
[0037] (7) The manufacturing system according to the present
embodiment preferably further includes a 3D scanner configured to
acquire 3D data of the target product in a non-contact manner.
[0038] According to the manufacturing system of the present
embodiment, the 3D scanner acquires the 3D data of a target product
in a non-contact manner, so that even when the 3D data of a target
product does not exist, the 3D data of the target product can be
quickly acquired.
[0039] (8) In the manufacturing system according to the present
embodiment, in a case where the processing apparatus is a robot
processing apparatus including an articulated robot, it is
preferable to further include a computer apparatus configured to
create, based on the 3D data of the target product, a processing
program for controlling operation of the robot processing
apparatus.
[0040] According to the manufacturing system of the present
embodiment, the robot processing apparatus, needing an installation
space smaller than that of a five-axis machining center, is
included, so that a manufacturing facility of sintered products can
be made compact.
[0041] According to the manufacturing system of the present
embodiment, the computer apparatus creates the processing program
described above, so that the robot processing apparatus can be
controlled to process a powder compact into substantially the same
shape as a target product.
[0042] (9) The manufacturing system according to the present
embodiment preferably further includes an inspection apparatus
configured to execute, based on the 3D data of the target product,
an inspection of at least one of dimensional precision of the
sintered product and presence or absence of a defect.
[0043] According to the manufacturing system of the present
embodiment, the inspection apparatus executes the inspection
described above, so that a sintered product with high precision
comparable to a target product can be manufactured.
[0044] (10) The manufacturing system according to the present
embodiment preferably further includes a molding apparatus
configured to uniaxially press raw material powder containing metal
powder to fabricate the powder compact whose whole or part has a
relative density of 93% or more.
[0045] According to the manufacturing system of the present
embodiment, the molding apparatus uniaxially presses raw material
powder containing metal powder to fabricate a powder compact having
the relative density described above, so that a powder compact with
high precision can be quickly obtained. Thus, the delivery date of
a sintered product can be shortened.
[0046] (11) In the manufacturing system according to the present
embodiment, the sintering apparatus is preferably an induction
heating sintering furnace configured to sinter the processed molded
article by high frequency induction heating.
[0047] In this case, the induction heating sintering furnace can
fabricate a sintered product in a shorter time than a belt type
continuous sintering furnace, so that the delivery date of a
sintered product can be shortened. In addition, the induction
heating sintering furnace needs an installation space smaller than
that of a belt type continuous sintering furnace, so that a
manufacturing facility of a sintered product can be made
compact.
[0048] (12) When the manufacturing system according to the present
embodiment further includes a mobile apparatus capable of traveling
on a road, it is preferable that the processing apparatus is a
robot processing apparatus including an articulated robot, the
sintering apparatus is an induction heating sintering furnace
configured to sinter the processed molded article by high frequency
induction heating, and apparatuses to be mounted on the mobile
apparatus include the robot processing apparatus and the induction
heating sintering furnace.
[0049] According to the manufacturing system of the present
embodiment, the robot processing apparatus and the induction
heating sintering furnace are mounted on the mobile apparatus, so
that these apparatuses can be transported to a point near the
location of a customer. Therefore, a sintered product can be
manufactured at a point near the location of a customer.
[0050] Thus, a sintered product can be delivered to a customer in a
shorter time than when the sintered product is manufactured in a
factory far from the location of the customer.
[0051] (13) In the manufacturing system according to the present
embodiment, the apparatuses to be mounted on the mobile apparatus
preferably include a 3D scanner configured to acquire the 3D data
of the target product in a non-contact manner.
[0052] According to the manufacturing system of the present
embodiment, the 3D scanner acquires 3D data of a target product in
a non-contact manner, so that even when a customer or a third party
does not store 3D data of a target product, the 3D data of the
target product can be quickly acquired.
[0053] (14) In the manufacturing system according to the present
embodiment, the whole or part of the powder compact preferably has
a relative density of 96% or more.
[0054] This is because when the relative density of a powder
compact is 96% or more, the strength of a sintered product is
increased to be higher than a case where the relative density is
less than that and the powder compact is less likely to be broken
when processed by a robot processing apparatus.
[0055] (15) The manufacturing method according to the present
embodiment is a manufacturing method of a sintered product, in
which the sintered product is manufactured by using the
manufacturing system according to any one of (1) to (14) described
above.
[0056] Thus, the manufacturing method according to the present
embodiment achieves the similar operation and effect to those of
the manufacturing system according to any one of (1) to (14)
described above.
DETAILS OF EMBODIMENTS OF PRESENT INVENTION
[0057] Hereinafter, embodiments of the present invention will be
described in detail with reference to the drawings. Note that at
least some of the embodiments described below may be arbitrarily
combined.
[0058] [Outline of Manufacturing Method of Sintered Product]
[0059] FIG. 1 is an explanatory illustration showing an outline of
a manufacturing method of a sintered product S.
[0060] As shown in FIG. 1, a customer provides a manufacturer with
a current product C, which is a current part that is incorporated
into, for example, an in-house product (finished product). The
manufacturer manufactures the sintered product S following the
current product C, and provides the customer with the manufactured
sintered product S as a sample.
[0061] The manufacturing method of the sintered product S according
to the present embodiment includes procedures of steps 1 to 5. The
manufacturer manufactures the sintered product S having
substantially the same shape as the current product C through steps
1 to 5. Hereinafter, the outline of each of steps 1 to 5 will be
described.
[0062] Note that a combination of all or some apparatuses used in
the manufacturing method shown in FIG. 1 is referred to as a
"manufacturing system" of the sintered product S.
[0063] Step 1: Acquire 3D Data
[0064] Step 1 is a step of acquiring three-dimensional CAD
(Computer Aided Design) data of a target product (current product C
of a customer in the present embodiment), which serves as a
reference of the shape of the sintered product S. Hereinafter,
three-dimensional CAD data is also referred to as "3D data."
[0065] In step 1, 3D data is acquired by reading, for example, an
actual article of the current product C with a 3D scanner 1. In
this case, the 3D scanner serves as an acquisition unit for the 3D
data.
[0066] When a customer or a third party (hereinafter referred to as
a "customer or the like") has the 3D data of the current product C,
the 3D data designated by the customer or the like may be directly
input to a computer apparatus 2 of step 2 by data transmission by
e-mail, data transfer using a USB memory, or the like. In this
case, the 3D scanner 1 is unnecessary or not used, and the computer
apparatus 2 serves as an acquisition unit for the 3D data.
[0067] Step 2: Create Molded Article Processing Program (Set
Manufacturing Conditions)
[0068] Step 2 is a step of creating a molded article processing
program (hereinafter, also referred to as a "processing program")
from the 3D data acquired in step 1.
[0069] The processing program is a computer program for controlling
operation of a molded article processing apparatus 32 used in step
3. The processing program is created by the computer apparatus 2
storing, for example, CAD/CAM (Computer Aided Manufacturing)
software.
[0070] Step 3: Manufacture Sintered Product by Processing Molded
Article
[0071] Step 3 is a step of manufacturing the sintered product S by
a manufacturing facility 3.
[0072] The manufacturing facility 3 used in step 3 includes a step
P2 in which the molded article processing apparatus (hereinafter,
also referred to as a "processing apparatus") 32 processes a powder
compact M before sintering. The processing apparatus 32 performs
predetermined processing on the powder compact M in accordance with
the processing program created in step 2.
[0073] Step 4: Correct Molded Article Processing Program (Optimize
Manufacturing Conditions)
[0074] Step 4 is a step of correcting the processing program based
on the 3D data of the sintered product S that is an accepted
product manufactured in step 3.
[0075] The processing program is corrected by a computer apparatus
4 storing, for example, CAD/CAT (Computer Aided Testing) software.
A result of correcting the processing program is fed back to the
processing apparatus 32 of step 3. The result of correcting the
processing program may be fed back to the computer apparatus 2
configured to create the processing program (step 2).
[0076] Step 5: Provide Sintered Product (Sample)
[0077] Step 5 is a step of determining one or more of the sintered
products S manufactured by the corrected program of step 4 as a
sample, and providing the sintered product S determined as the
sample to the customer.
[0078] The customer provided with the sintered product S as a
sample can compare the performance of the current product C with
the performance of the sintered product S by, for example, an
in-house test facility. When the performance of the sintered
product S provided as a sample is higher than or equal to the
performance of the current product C, the customer can replace the
current product C with the sintered product S.
[0079] In the present embodiment, the manufacturing facility 3 (see
FIG. 3) for processing the powder compact M that remains to be
sintered is used in step 3, so that processing, such as cutting, is
easily performed and productivity is excellent. Therefore, the
sintered product S can be manufactured at a lower cost and with a
shorter delivery date than, for example, a cast product or a forged
product.
[0080] Thus, when the current product C is a cast article or a
forged article, the customer can expect suppression of the
manufacturing cost and shortening of the procurement period by
replacing the current product C with the sintered product S.
[0081] According to the manufacturing method of the present
embodiment, the sintered products S, such as sprockets, rotors,
gears, rings, flanges, pulleys, vanes, or bearings to be
incorporated into machines such as automobiles, can be
manufactured.
[0082] The sintered products S are not limited to products in the
automotive field. According to the manufacturing method of the
present embodiment, sintered products S, such as turbine blades of
aircrafts, artificial bones and artificial joints to be used in the
medical field, or radiation shielding parts to be used in the
nuclear field, can be manufactured, which can be used in a wide
range of applications.
[0083] [Apparatus Used in Step 1]
[0084] FIG. 2 is an explanatory illustration showing an example of
each of apparatuses used in step 1 and step 2.
[0085] As shown in FIG. 2, the apparatus used in step 1 includes a
non-contact type three-dimensional shape measuring machine
(hereinafter, referred to as a "3D scanner") 1. The non-contact
type 3D scanner 1 is an apparatus configured to sense unevenness of
a surface (distance to an arbitrary point on a surface) without
contacting an object, convert a result of the sensing into
three-dimensional CAD data, and incorporate it into the computer
apparatus 2.
[0086] Specifically, the 3D scanner 1 acquires three-dimensional
coordinate data (X, Y, Z) of each point on the surface of an object
while irradiating the object with light. The 3D scanner 1 converts
the acquired data of a group of points into polygon data to
generate a mesh-like three-dimensional figure.
[0087] The 3D scanner 1 converts the data of a group of points
constituting the three-dimensional figure into three-dimensional
CAD data in a predetermined file format, and transmits the
converted three-dimensional CAD data to the computer apparatus 2
connected to the 3D scanner 1.
[0088] The non-contact type 3D scanner 1 is roughly divided into a
"laser light type" and a "patterned light type." The laser light
type is configured to scan an object while irradiating the object
with laser beams, identify reflected light from the object by a
light receiving sensor, and measure a distance to the object by
trigonometry.
[0089] The patterned light type is configured to scan an object
while irradiating the object with patterned light, identify a line
of a striped pattern, and measure a distance from the scanner to
the object.
[0090] The patterned light type can perform measurement faster than
the laser light type. Therefore, in the example of FIG. 2, a
patterned light 3D scanner 1 is adopted. Examples of commercially
available products of the patterned light 3D scanner 1 include
KEYENCE VL-300 series.
[0091] Although the 3D scanner 1 shown in FIG. 2 is a stationary
type, the 3D scanner 1 may be a handy-type scanner that a user can
hold in a hand for measurement.
[0092] When the customer has the three-dimensional CAD data of the
current product C, a file of the data may be directly read into the
computer apparatus 2, as shown in FIG. 2. In this case, the work of
scanning the actual current product C becomes unnecessary.
[0093] The acquisition source of the three-dimensional CAD data of
the current product C may be a third party other than the customer.
Examples of the third party include a manufacturer of the current
products C to whom the customer has entrusted the manufacture of
the current products, or a company that specializes in
disassembling finished products and reading the 3D data of the
current product C.
[0094] [Apparatus Used in Step 2]
[0095] As shown in FIG. 2, the apparatus used in step 2 includes
the computer apparatus 2. The computer apparatus 2 includes, for
example, a desktop personal computer (PC). The type of the computer
apparatus 2 is not particularly limited. The type of the computer
apparatus 2 may be, for example, a notebook type or a tablet
type.
[0096] The computer apparatus 2 includes: an information processor
including a central processing unit (CPU) and a volatile memory; a
storage device including a nonvolatile memory configured to store a
computer program to be executed by the CPU and data necessary for
the execution; and the like. The computer apparatus 2 also includes
an input device and a display.
[0097] The CPU reads the computer program into the volatile memory
to execute the computer program, whereby the computer apparatus 2
functions as a predetermined controller.
[0098] The computer apparatus 2 has CAD/CAM software installed. The
CAD/CAM software is software that realizes creation of a processing
program for operating the molded article processing apparatus 32 in
accordance with a user's operation input to a graphical user
interface (GUI) of the computer apparatus 2.
[0099] As the CAD/CAM software, for example, software such as
"MasterCam" or "Robotmater" (both registered trademarks) can be
adopted. These pieces of software can generate a processing program
in accordance with the type of the molded article processing
apparatus 32 (e.g., an articulated robot or a five-axis machining
center). In addition, these pieces of software may be capable of
generating the processing program described in Japanese Unexamined
Patent Publication No. 2009-226562.
[0100] Examples of the settings necessary for creating the
processing program include setting of the shape of a workpiece
(powder compact M in the present embodiment), setting of a tool to
be used for processing, and tool path setting.
[0101] The computer apparatus 2 creates a molded article processing
program including, for example, a numerical control (NC) program,
based on the three-dimensional CAD data of the current product C
and the setting information entered by a user. The computer
apparatus 2 transmits the processing program created by the CAD/CAM
software to the molded article processing apparatus 32 used in step
3.
[0102] In the present embodiment, in step 3, a molding apparatus 31
(see FIGS. 3 and 4) manufactures the powder compact M having a
simple shape such as a cylinder or a hollow cylinder, and the
processing apparatus 32 (see FIGS. 3 and 5) cuts the powder compact
M to fabricate a processed molded article P having the same shape
as the current product C.
[0103] Thus, the processing program created by the computer
apparatus 2 includes a program that makes the processing apparatus
32 perform cutting on the powder compact M having a predetermined
shape. The three-dimensional CAD data of the powder compact M as
the workpiece is registered in advance in the computer apparatus
2.
[0104] (Types of Tools to be Used)
[0105] When the molded article processing apparatus 32 includes
articulated robots 201, 202 (see FIG. 5) capable of replacing
tools, the processing program preferably includes a code that
commands the articulated robots 201, 202 to use a different tool
for each type of work.
[0106] For example, when relatively fine cutting is required for
the surface of the powder compact M, the tool to be used may be an
end mill. When a groove portion, a window portion, or the like is
cut in the powder compact M, the tool to be used may be a side
cutter.
[0107] When cutting is performed to widen the middle of a groove
portion formed in the powder compact M, the tool to be used may be
a T-slot cutter. When a through hole is cut in the powder compact
M, the tool to be used may be a drill.
[0108] The drill to be used for drilling is preferably a round tip
drill having an arc-shaped cutting edge at the tip portion (see,
e.g., Japanese Unexamined Patent Publication No. 2016-113657) or a
candle-type drill (see, e.g., Japanese Unexamined Patent
Publication No. 2016-113658). By adopting these drills, occurrence
of edge chipping at the hole exit of the powder compact M can be
suppressed.
[0109] (Processing Conditions of Powder Compact)
[0110] A rotation speed of the tool used for cutting the powder
compact M is preferably, for example, 500 to 50000 rpm. The
rotation speed is more preferably 1000 to 15000 rpm.
[0111] A feed speed of the tool used for cutting the powder compact
M is preferably, for example, 20 to 6000 mm/min. The feed speed is
more preferably 200 to 2000 mm/min.
[0112] The cutting depth and cutting position of the powder compact
M are calculated based on the three-dimensional CAD data of the
powder compact M entered by the user in step 2 and the
three-dimensional CAD data of the current product C acquired in
step 1.
[0113] [Manufacturing Facility Used in Step 3]
[0114] FIG. 3 is an overall configuration illustration showing an
example of the manufacturing facility 3 used in step 3.
[0115] As shown in FIG. 3, the manufacturing facility 3 according
to the present embodiment is a facility in which apparatuses 31 to
35 that each individually execute steps P1 to P5 are installed in
order. The manufacturing facility 3 is installed in a factory of
the manufacturer of the sintered product S.
[0116] Specifically, the manufacturing facility 3 shown in FIG. 3
includes a production line including: the apparatuses 31 to 35
corresponding to the steps P1 to P5, respectively; a conveyor 36
passing through the vicinity of each of the apparatuses 31 to 35;
and robot arms 37 that each carry a workpiece (powder compact M or
the like) in and out for each of the apparatuses 31 to 35.
[0117] The robot arms 37 each carry the workpiece in from the
conveyor 36 to each of the apparatuses 32 to 35 and carry the
workpiece out from each off the apparatuses 31 to 35 to the
conveyor 36 on a one-by-one basis.
[0118] The outline of each of the steps P1 to P5 to be executed in
the manufacturing facility 3 is as follows:
[0119] P1) Molding Step: Raw material powder is uniaxially pressed
using a mold to fabricate the powder compact M whose whole or part
has a relative density of 93% or more.
[0120] P2) Processing Step: The powder compact M is machined to
fabricate the processed molded article P.
[0121] P3) Sintering Step: The processed molded article P is
sintered to obtain the sintered product S.
[0122] P4) Finishing Step: Finishing processing is performed to
bring the actual dimension of the sintered product S close to the
design dimension.
[0123] P5) Inspection Step: The dimensional precision of the
sintered product S and/or presence or absence of a defect, and the
like are inspected.
[0124] Hereinafter, preferred specific examples of steps P1 to P5
will be described.
[0125] [Molding Step P1]
[0126] (Example 1 of Raw Material Powder) Metal powder serving as a
raw material in a molding step P1 is a main material constituting
the sintered product S. An example of the metal powder includes
iron powder or iron alloy powder containing iron as a main
component. Typical examples of the metal powder include pure iron
powder and iron alloy powder.
[0127] The "iron alloy containing iron as a main component" means
that an iron element is contained, as a constituent component, in
an amount of more than 50 mass %, preferably 80 mass % or more, and
further 90 mass % or more. Examples of the iron alloy include those
containing at least one alloying element selected from Cu, Ni, Sn,
Cr, Mo, Mn, and C.
[0128] The alloying elements described above contribute to an
improvement in the mechanical characteristics of an iron-based
sintered product. The total content of Cu, Ni, Sn, Cr, Mn, and Mo,
among the alloying elements, may be set to 0.5 mass % or more and
5.0 mass % or less, and further to 1.0 mass % or more and 3.0 mass
% or less.
[0129] The content of C may be set to 0.2 mass % or more and 2.0
mass % or less, and further to 0.4 mass % or more and 1.0 mass or
less. In addition, iron powder may be used as the metal powder, and
thereto powder of the above-described alloying element (alloyed
powder) may be added.
[0130] In this case, the constituent component of the metal powder
is iron in the stage of raw material powder, but the iron reacts
with the alloying element to be alloyed by sintering in a sintering
step P3.
[0131] The content of the metal powder (including alloyed powder)
in the raw material powder may be set to, for example, 90 mass % or
more, and further 95 mass % or more. As the metal powder, those
fabricated by, for example, a water atomization method, a gas
atomization method, a carbonyl method, or a reduction method can be
used.
[0132] The average particle size of the metal powder may be set to,
for example, 20 .mu.m or more and 200 .mu.m or less, and further 50
.mu.m or more and 150 .mu.m or less. By setting the average
particle size of the metal powder within the above range, the metal
powder is easy to handle and easy to perform pressure molding on.
Furthermore, by setting the average particle size of the metal
powder to 20 .mu.m or more, the fluidity of the raw material powder
can be easily secured. By setting the average particle size of the
metal powder to 200 .mu.m or less, the sintered product S having a
dense structure can be easily obtained.
[0133] The average particle size of the metal powder means an
average particle size of particles constituting the metal powder.
The average particle size of the particles is, for example, a
particle size (D50) at which a cumulative volume in a volume
particle size distribution measured by a laser diffraction particle
size distribution measuring device is 50%. By using fine metal
powder, the surface roughness of the sintered product S can be
reduced, and the corner edge can be sharpened.
[0134] (Example 2 of Raw Material Powder: Case of Induction
Heating)
[0135] When the sintering step P3 is performed by high frequency
induction heating, the raw material powder preferably contains Fe
powder or Fe alloy powder, and C powder. This raw material powder
mainly contains Fe powder or Fe alloy powder. Hereinafter, Fe
powder and Fe alloy powder may be collectively referred to as
Fe-based powder.
[0136] Fe Powder, Fe Alloy Powder:
[0137] The Fe powder is pure iron powder. The Fe alloy powder
contains iron as a main component, and has a plurality of Fe alloy
particles containing one or more additive elements selected from,
for example, Ni and Mo. The Fe alloy is allowed to contain
inevitable impurities.
[0138] Specific examples of the Fe alloy include Fe--Ni--Mo-based
alloys. As the Fe-based powder, for example, water atomized powder,
gas atomized powder, carbonyl powder, or reduced powder can be
used. The content of the Fe-based powder in the raw material powder
may be, for example, 90 mass % or more, and further 95 mass % or
more, based on 100 mass % of the raw material powder. The content
of Fe in the Fe alloy may be 90 mass % or more, and further 95 mass
% or more, based on 100 mass % of the Fe alloy. The total content
of the additive elements in the Fe alloy may be more than 0 mass %
and 10.0 mass % or less, and further 0.1 mass % or more and 5.0
mass % or less.
[0139] The average particle size of the Fe-based powder may be, for
example, 50 .mu.m or more and 150 .mu.m or less. By setting the
average particle size of the Fe-based powder within the above
range, the Fe-based powder is easy to handle and easy to perform
pressure molding on. By setting the average particle size of the
Fe-based powder to 50 .mu.m or more, fluidity can be easily
secured. By setting the average particle size of the Fe-based
powder to 150 .mu.m or less, the sintered product S having a dense
structure can be easily obtained. The average particle size of the
Fe-based powder may be further 55 .mu.m or more and 100 .mu.m or
less.
[0140] The "average particle size" means a particle size (D50) at
which a cumulative volume in a volume particle size distribution
measured by a laser diffraction particle size distribution
measuring device is 50%. The same applies to the average particle
sizes of the C powder and Cu powder described later.
[0141] C Powder:
[0142] The C powder becomes a liquid phase of Fe--C when the
temperature is raised, which makes the corners of the pores in the
sintered product S round to improve the strength (radial crushing
strength) of the sintered product S. The content of the C powder in
the raw material powder may be 0.2 mass % or more and 1.2 mass % or
less based on 100 mass % of the raw material powder.
[0143] By setting the content of the C powder to 0.2 mass % or
more, a liquid phase of Fe--C sufficiently appears, which is likely
to make the corners of the pores effectively round to improve the
strength. By setting the content of the C powder to 1.2 mass % or
less, the liquid phase of Fe--C is easily suppressed from being
excessively generated, by which the sintered product S with high
dimensional precision can be easily fabricated.
[0144] The content of the C powder is further preferably 0.4 mass %
or more and 1.0 mass % or less, and particularly preferably 0.6
mass % or more and 0.8 mass % or less. The average particle size of
the C powder is preferably smaller than the average particle size
of the Fe powder. This makes it easy to uniformly disperse the C
particles between the Fe particles, so that the alloying easily
proceeds.
[0145] The average particle size of the C powder may be, for
example, 1 .mu.m or more and 30 .mu.m or less, and further 10 .mu.m
or more and 25 .mu.m or less. From the viewpoint of generating the
liquid phase of Fe--C, it is preferable that the average particle
size of the C powder is large, but if the average particle size is
too large, the time when the liquid phase appears becomes so long
that the pores become too large, which may cause a defect. Note
that if the raw material powder contains the pure iron powder but
does not contain C, the strength of the sintered product S is lower
than that of the sintered product S fabricated using a belt type
continuous sintering furnace.
[0146] Cu Powder:
[0147] The raw material powder preferably further contains Cu
powder. Cu powder contributes to generating the liquid phase of
Fe--C when the temperature is raised in the sintering step
described later. Moreover, Cu has a function of increasing the
strength by forming a solid solution in Fe. By containing Cu
powder, the sintered product S with high strength can be
fabricated.
[0148] The content of the Cu powder in the raw material powder is
0.1 mass % or more and 3.0 mass % or less based on 100 mass % of
the raw material powder. By setting the content of the Cu powder to
0.1 mass % or more, Cu is diffused into Fe while the temperature is
raised (sintering) to easily suppress the diffusion of C into Fe,
by which the liquid phase of Fe--C can be easily generated.
[0149] By setting the content of the Cu powder to 3.0 mass % or
less, Cu diffuses into Fe while the temperature is raised
(sintered), so that the Fe particles expand and act to offset the
shrinkage during the sintering. Thereby, the sintered product S
with high dimensional precision can be easily fabricated.
[0150] The content of the Cu powder may be further 1.5 mass % or
more and 2.5 mass % or less. The average particle size of the Cu
powder is preferably made smaller than the average particle size of
the Fe powder, similarly to the C powder. This makes it easy to
uniformly disperse the Cu particles between the Fe particles, so
that it is easy for the alloying to proceed. The average particle
size of the Cu powder may be, for example, 1 .mu.m or more and 30
.mu.m or less, and further 10 .mu.m or more and 25 .mu.m or
less.
[0151] (Internal Lubricant)
[0152] In the press molding using a mold, raw material powder
obtained by mixing metal powder and an internal lubricant is
commonly used to prevent seizure of the metal powder on the mold.
In the present embodiment, however, it is preferable that an
internal lubricant is not contained in the raw material powder or
contained in an amount of 0.2 mass % or less based on the whole raw
material powder. This is because a decrease in the ratio of the
metal powder to the raw material powder is suppressed to obtain the
powder compact M having a relative density of 93% or more.
[0153] However, it is allowed to contain a small amount of an
internal lubricant in the raw material powder within a range where
the powder compact having a relative density of 93% or more can be
fabricated. As the internal lubricant, a metal soap, such as
lithium stearate or zinc stearate, can be used.
[0154] (Organic Binder)
[0155] It is acceptable even to add an organic binder to the raw
material powder in the subsequent processing step P2, in order to
suppress occurrence of a crack or a chip in the powder compact
M.
[0156] Examples of the organic binder include polyethylene,
polypropylene, polyolefin, polymethyl methacrylate, polystyrene,
polyvinyl chloride, polyvinylidene chloride, polyamide, polyester,
polyether, polyvinyl alcohol, vinyl acetate, paraffin, and various
waxes. The organic binder may be added as necessary, or may not be
added. When an organic binder is added, it is necessary to set the
addition amount to such an extent that the powder compact M having
a relative density of 93% or more can be fabricated in the molding
step P1.
[0157] (Pressing Method of Powder Compact)
[0158] In the molding step P1, the raw material powder is
uniaxially pressed using a mold to fabricate the powder compact M.
The mold to be used for the uniaxial pressing is a mold including a
die and a pair of punches fitted into upper and lower openings of
the die. The powder compact M is fabricated by compressing, with
the upper punch and the lower punch, the raw material powder filled
in the cavity of the die.
[0159] The powder compact M that can be molded by the mold has a
simple shape. Examples of the simple shape include a cylindrical
shape, a hollow cylindrical shape, a prismatic shape, and a hollow
prismatic shape.
[0160] A punch having convex portions or concave portions on the
punch surface may be used. In this case, recesses or protrusions
corresponding to the convex portions or the concave portions are
formed in the powder compact M having a simple shape. The powder
compact having such recesses or protrusions is also included in the
powder compact M having a simple shape.
[0161] The pressure (surface pressure) of the uniaxial pressing may
be 600 MPa or more. By increasing the surface pressure, the
relative density of the powder compact M can be increased. The
surface pressure is preferably 1000 MPa or more, and more
preferably 1500 MPa or more. The upper limit of the surface
pressure is not particularly limited.
[0162] (External Lubricant)
[0163] In the uniaxial pressing, it is preferable to apply an
external lubricant to the inner peripheral surface of the mold (the
inner peripheral surface of the die and the pressing surface of the
punch) in order to prevent seizure of the metal powder on the
mold.
[0164] As the external lubricant, a metal soap, such as lithium
stearate or zinc stearate, can be used. Other than them, fatty acid
amide, such as lauric acid amide, stearic acid amide, or palmitic
acid amide, or higher fatty acid amide, such as ethylene
bis-stearic acid amide, can also be used as the external
lubricant.
[0165] (Relative Density of Powder Compact)
[0166] The average relative density of the whole powder compact M
obtained by the uniaxial pressing is preferably 93% or more. The
average relative density is preferably 94% or more or 95% or more,
more preferably 96% or more, still more preferably 97% or more, and
yet still more preferably 99.8% or more.
[0167] The dense portion having an average relative density of 93%
or more may be the whole or a part of the powder compact M.
However, when the powder compact M is gripped by the articulated
robot 202 (see FIG. 5) in the processing step P2 described later,
the average relative density of the whole is preferably 93% or
more. This is because, when the whole is dense, it is difficult to
chip no matter which portion of the powder compact M is
gripped.
[0168] As described above, according to the manufacturing facility
3 of the present embodiment, the sintered product S whose whole has
an average relative density of 93% or more can be obtained.
[0169] The average relative density of the whole sintered compact S
is substantially equal to the average relative density of the whole
powder compact M before sintering. The average relative density of
the sintered product S is preferably 95% or more, more preferably
96% or more, and still more preferably 97% or more. The higher the
average relative density, the higher the strength of the sintered
product S.
[0170] The average relative density of the whole powder compact M
can be determined by taking cross sections (preferably orthogonal
cross sections) of the powder compact M, respectively intersecting
with the pressing axis direction at positions near the center, near
one end side, and near the other end side in the pressing axis
direction, and by performing image analysis on each cross
section.
[0171] More specifically, a plurality of images of field of view in
each cross section, for example, 10 or more images of field of
view, each having an area of 500 .mu.m.times.600 .mu.m=300,000
.mu.m.sup.2, are first acquired in each cross section. The
respective images of field of view are preferably acquired from
positions distributed as evenly as possible in the cross
section.
[0172] Next, each of the acquired images of field of view is
binarized to determine the area ratio of the metal particles to the
field of view, and the area ratio is regarded as a relative density
for the field of view.
[0173] Then, the average relative densities determined from the
respective fields of view are averaged to calculate the average
relative density of the whole powder compact. Here, the portion
near one end side (the portion near the other end side) may be a
position, for example, within 3 mm from the surface of the powder
compact M.
[0174] [Processing Step P2]
[0175] In the processing step P2, the powder compact M fabricated
by the uniaxial pressing is machined without being sintered.
[0176] The machining is typically cutting. In this case, the powder
compact M is processed to have a predetermined shape using a
cutting tool. Examples of the cutting include rolling and turning,
and the rolling includes drilling. Examples of the cutting tool
include a drill or a reamer to be used in drilling, a milling
cutter or an end mill to be used in rolling, and a turning tool and
an interchangeable cutting tip to be used in turning. Cutting may
be performed using a hob, a broach, a pinion cutter, or the like,
other than those described above.
[0177] In the case of the powder compact M in which the metal
particles are pressed and hardened, machining is performed so that
the metal particles are peeled off from the surface of the powder
compact M by a cutting tool.
[0178] Therefore, the friction on the cutting tool is much smaller
than when, for example, a cast article or a pre-sintered article is
cut, which can greatly shorten the life of the tool. In addition,
the processing waste generated by the machining is composed of
metal powder separated from the individual metal particles
constituting the powder compact M. The powdery processing waste can
be reused without being dissolved.
[Sintering Step P3] In the sintering step P3, the processed molded
article P obtained by machining the powder compact M is sintered.
By sintering the processed molded article P, the sintered product S
in which the particles of the metal powder are brought into contact
with each other and bonded is obtained. In the sintering step P3,
predetermined conditions in accordance with the composition of the
metal powder can be applied.
[0179] When the metal powder is iron powder or iron alloy powder,
the sintering temperature may be, for example, 1100.degree. C. or
higher and 1400.degree. C. or lower, and further 1200.degree. C. or
higher and 1300.degree. C. or lower. The sintering time may be, for
example, 15 minutes or longer and 150 minutes or shorter, and
further 20 minutes or longer and 60 minutes or shorter.
[0180] The degree of processing in the processing step P2 may be
adjusted based on the difference between the actual dimension and
the design dimension of the sintered product S. The processed
molded article P obtained by processing the dense powder compact M
having a relative density of 93% or more shrinks substantially
uniformly during sintering.
[0181] Therefore, by adjusting the degree of processing in the
processing step P2 based on the difference between the actual
dimension after sintering and the design dimension, the actual
dimension of the sintered product S can be brought close to the
design dimension. As a result, the efforts and time of the next
finishing step P4 can be reduced. When machining is performed by
the articulated robots 201, 202 or a machining center, the degree
of processing can be easily adjusted.
[0182] [Finishing Step P4]
[0183] In the finishing step P4, the surface of the sintered
product S is polished and the like to reduce the surface roughness
of the sintered product S, and the dimension of the sintered
product S is matched to the design dimension (dimension of the
current product C).
[0184] The polishing finish is performed by a not-shown polishing
apparatus. The three-dimensional CAD data of the current product C,
acquired in step 1, is input to the polishing apparatus. The
polishing apparatus calculates the design dimension of the sintered
product S from the input data, and polishes each portion of the
sintered product S so as to have the calculated design dimension.
For example, when the sintered product S includes a gear, the tooth
surface of the gear is polished.
[0185] [Inspection Step P5]
[0186] In an inspection step P5, at least one of whether the
sintered product S conforms to the design dimension (dimension of
the current product C) and whether there is no defect such as a
crack is inspected.
[0187] These inspections are preferably performed by a non-contact
type 3D scanner (e.g., 3D scanner of laser light type or of
patterned light type) or a non-contact, non-destructive inspection
apparatus. By using these inspection apparatuses, the sintered
products S can be automatically inspected one by one.
[0188] [Apparatus Used in Molding Step P1]
[0189] FIG. 4 is a schematic configuration illustration showing an
example of the molding apparatus 31 used in the molding step
P1.
[0190] As shown in FIG. 4, the molding apparatus 31 used in the
molding step P1 includes, for example, a uniaxial pressing press
molding apparatus driven by a hydraulic servo method.
[0191] The press molding apparatus 31 includes a base plate 101
having a rectangular shape, pillars 102 provided at four corners of
the base plate 101, a ceiling frame 103 fixed to upper ends of the
pillars 102, and an upper plate 104 vertically movably supported by
the upper portions of the pillars 102.
[0192] A punch set 106 whose vertical position is controlled by a
hydraulic cylinder mechanism 105 is provided above the base plate
101, and a punch set 108 whose vertical position is controlled by a
hydraulic cylinder mechanism 107 is provided below the upper plate
104.
[0193] A hydraulically-driven upper cylinder 109 is provided in a
central portion of the ceiling frame 103. The lower end of the rod
of the upper cylinder 109 and the upper surface of the upper plate
104 are connected via a link mechanism 110.
[0194] Thus, when the upper cylinder 109 extends, the upper plate
104 descends to a position where raw material powder 116 is
prepared. Thereafter, the punch set 106 and the punch set 108 are
joined by driving the upper and lower hydraulic cylinder mechanisms
105, 107, so that the raw material powder 116 is pressed.
[0195] The upper and lower hydraulic cylinder mechanisms 105,107
have a structure in which a plurality of hydraulic cylinders are
coaxially multilayered, and the axial center of each hydraulic
cylinder is at the center position of the base plate 101.
[0196] Thus, the press molding apparatus 31 has a slim structure
without any member protruding outside the base plate 101, and can
be installed without a pit. Therefore, the press molding apparatus
31 has advantages that the installation area and the installation
cost are small.
[0197] As shown in FIG. 4, the lower punch set 106 includes a
hollow cylindrical die 111, a core rod 112, an outer punch 113, and
an inner punch 114. A cavity is formed by the inner peripheral
surface of the die 111 and the outer peripheral surface of the core
rod 112.
[0198] The upper punch set 108 includes an upper punch 115. The
upper punch 115 has a hollow cylindrical shape having a passage
hole for the core rod 112.
[0199] In the stage before pressing, the upper end surface of the
core rod 112 is made to protrude from the upper end surface of the
die 111, and the outer punch 113 is set at a deeper position than
the inner punch 114. In this state, the cavity is filled with the
raw material powder 116.
[0200] In the pressing, the upper punch 115 is lowered while the
outer punch 113 and the lower punch 114 are being raised together.
At this time, the rising speed is controlled so that the outer
punch 113 and the inner punch 114 simultaneously reach the top dead
center at the same position.
[0201] By the compression molding described above, an outer
peripheral portion that is filled with a larger amount of the raw
material powder 116 is compressed at a higher pressure than an
inner peripheral portion that is filled with a smaller amount
thereof. In addition, in the example of FIG. 4, the powder compact
M having a uniform thickness is molded. Thus, the powder compact M
becomes a substantially donut-shaped tablet having a high-density
region M1 in the outer peripheral portion and a low-density region
M2 in the inner peripheral portion.
[0202] The molding method described above is suitable for
manufacturing the sintered product S having a sliding portion
continuous along the outer peripheral edge, such as an external
teeth gear or a sprocket. For example, in the case of an external
teeth gear, external teeth having high rigidity and excellent wear
resistance can be obtained by defining the outer peripheral side of
the powder compact M as the high-density region M1.
[0203] Contrary to the case of FIG. 4, when the raw material powder
116 is press-molded by setting the inner punch 114 at a deeper
position than the outer punch 113, the powder compact M is obtained
in which the inner peripheral portion is the high-density region M1
and the outer peripheral portion is the low-density region M2.
[0204] The molding method described above is suitable for
manufacturing the sintered product S having a sliding portion
continuous along the inner peripheral edge, like an internal teeth
gear. For example, in the case of an internal teeth gear, internal
teeth having high rigidity and excellent wear resistance can be
obtained by defining the inner peripheral side of the powder
compact M as the high-density region M1.
[0205] In the case of the powder compact M having the regions M1,
M2 having different relative densities, as described above, the
relative density of the high-density region M1 may be set to 93% or
more, and the relative density of the low-density region M2 may be
less than 93%.
[0206] Note that when the raw material powder 116 is press-molded
by setting the outer punch 113 and the inner punch 114 at the same
depth position, the powder compact M whose whole has an average
relative density of 93% or more can also be molded using the press
molding apparatus 31.
[Apparatus Used in Processing Step P2] FIG. 5 is a schematic
configuration illustration showing an example of the processing
apparatus 32 used in the processing step P2.
[0207] As shown in FIG. 5, the processing apparatus 32 used in the
processing step P2 includes, for example, a robot processing
apparatus configured to process the powder compact M using the
articulated robots 201, 202.
[0208] Since such a robot processing apparatus 32 needs an
installation space smaller than, for example, a five-axis machining
center, it contributes to making the manufacturing facility 3 of
the sintered product S compact.
[0209] The robot processing apparatus 32 according to the present
embodiment includes two articulated robots 201, 202 and a
controller 203 configured to control operation of both the
articulated robots 201, 202.
[0210] Of the two articulated robots 201, 202, a first robot 201 of
one side is a robot configured to hold a tool 204 such as a drill.
A second robot 202 of the other side is a robot configured to hold
the powder compact M.
[0211] The first robot 201 has a grip unit 205 for the tool 204 at
the arm tip. In accordance with a command from the controller 203,
the first robot 201 can grip different types of tools 204 with the
grip unit 205.
[0212] The second robot 202 has a grip unit 206 for the powder
compact M at the arm tip. The second robot 202 can grip the powder
compact M being conveyed on the conveyor 36 with the grip unit 206.
The second robot 202 can also return the processed molded article P
to the conveyor 36.
[0213] The controller 203 includes a first communication unit 207,
a second communication unit 208, a control unit 209, and a storage
unit 210.
[0214] The first communication unit 207 includes a communication
interface configured to communicate with an external device
according to a predetermined communication standard such as
Ethernet (registered trademark). The second communication unit 208
includes a communication interface communicably connected to the
first and second arms 201, 202.
[0215] The control unit 209 includes an information processor
including a CPU, a volatile memory, and the like. The storage unit
210 includes a storage device including a recording medium such as
a hard disk drive (HDD) or a solid state drive (SSD).
[0216] When receiving the processing program from the computer
apparatus 2 of step 2, the first communication unit 207 provides
the received program to the control unit 209. The control unit 209
extracts an operation code (e.g., a G code or an M code) from the
received processing program.
[0217] The control unit 209 sequentially outputs the respective
operation codes extracted to the second communication unit 208 to
make the second communication unit 208 transmit the operation codes
to the articulated robots 201, 202. The articulated robots 201, 202
execute predetermined work in accordance with the received
operation codes.
[0218] As a result, the articulated robots 201, 202 perform
predetermined processing on the powder compact M in accordance with
a command from the controller 203.
[0219] In order to enable both the positions and postures of work
objects (the tool 204 and the powder compact M) to be adjusted
three-dimensionally, it is preferable that the first and second
robots 201, 202 each have an arm structure with at least six
degrees of freedom.
[0220] For the powder compact M, however, the second robot 202
having a degree of freedom of less than 6 may be adopted when the
position and posture of the powder compact M are not required to be
adjusted with a high degree of freedom, such as being held at the
same position while being processed.
[0221] In the manufacturing facility 3 according to the present
embodiment, the relative density of the powder compact M is 93% or
more, so that the powder compact M is not broken even when cutting
is performed on the powder compact M held by the second robot 202
with the tool 204 of the first robot 201. Therefore, the powder
compact M can be quickly processed.
[0222] In addition, at least the first robot 201 has six degrees of
freedom, so that the tool 204 can be brought into contact with the
powder compact M at an arbitrary angle, by which complicated
processing can be quickly executed.
[0223] [Apparatus Used in Sintering Step P3]
[0224] FIG. 6 is a schematic configuration illustration showing an
example of a sintering apparatus 33 used in the sintering step
P3.
[0225] As shown in FIG. 6, the sintering apparatus 33 used in the
sintering step P3 includes, for example, an induction heating
sintering furnace configured to heat the processed powder compact M
(processed molded article P) by a high frequency induction
method.
[0226] Since the temperature of an object can be raised at a high
rate by the heating using a high frequency induction method, the
processed molded article P can be heated to a predetermined
temperature in a short time. Therefore, the sintered product S can
be easily manufactured in a short time.
[0227] As shown in FIG. 6, the induction heating sintering furnace
33 includes a chamber 301 that is vertically long, a hollow
cylindrical heating container 302 housed in the chamber 301, a
cooling container 303 arranged below the heating container 302, and
a lifting table 304 arranged below the heating container 302.
[0228] An induction coil 305 is wound around the outer peripheral
surface of the heating container 302, and the inside of the heating
container 302 and the inside of the cooling container 303
communicate with each other in the vertical direction. The lifting
table 304 can lift or lower the processed molded article P to the
height of either the inside of the heating container 302 or the
inside of the cooling container 303.
[0229] The induction heating sintering furnace 33 also includes a
power supply (not shown) capable of adjusting an output value
(e.g., a power value) and a frequency for the induction coil
305.
[0230] The processed molded article P is placed on the lifting
table 304 by the robot arm 37. When the processed molded article P
is heated, the lifting table 304 positions the processed molded
article P inside the heating container 302. When the processed
molded article P after sintering (sintered product S) is cooled,
the lifting table 304 positions the processed molded article P
after sintering inside the cooling container 303.
[0231] The induction heating sintering furnace 33 preferably
includes a gas supply path for supplying an inert gas into the
heating container 302 and a gas discharge path for discharging a
gas to the outside of the heating container 302. In this case, the
processed molded article P can be sintered under a non-oxidizing
gas atmosphere. Examples of the inert gas include nitrogen gas and
argon gas.
[0232] The induction heating sintering furnace 33 can raise the
temperature of an object at a high rate, and can raise the
temperature of the processed molded article P to a predetermined
temperature in a short time. Thus, there is an advantage that the
sintered product S can be manufactured in a shorter time than, for
example, a belt type continuous sintering furnace.
[0233] Since the induction heating sintering furnace 33 has a high
heating rate, there is also an advantage that a smaller
installation space is sufficient than, for example, a belt type
continuous sintering furnace. In the case of the induction heating
sintering furnace 33, for example, a relatively small chamber 301
(e.g., 1.5 m.times.1.5 m) can be adopted.
[0234] The induction heating sintering furnace 33 takes a short
time to sinter the processed molded article P, and it is not
necessary to keep the temperature of the sintering furnace 33 while
the processed molded article P is not sintered. Thus, there is also
an advantage that more energy can be saved than, for example, a
belt type continuous sintering furnace.
[0235] In the sintering step P3, a heating process, a sintering
process, and a cooling process are passed in sequence. Hereinafter,
a temperature course preferable when the induction heating
sintering furnace 33 is used will be described.
[0236] (Heating Process)
[0237] In the heating process, the temperature of the processed
molded article P is controlled to satisfy all of the following
conditions (I) to (III). A point A1 is about 738.degree. C., and a
point A3 is about 910.degree. C.
[0238] (I) The temperature is raised without being kept in a
temperature range from the point A1 or higher to lower than the
sintering temperature of the processed molded article P in an Fe--C
system phase diagram.
[0239] (II) The heating rate in the temperature range from the
point A1 to the point A3 in the Fe--C system phase diagram is set
to 12.degree. C./sec or more.
[0240] (III) The heating rate from the point A3 to the sintering
temperature of the processed molded article P in the Fe--C system
phase diagram is set to 4.degree. C./sec or more.
[0241] When the temperature is controlled to satisfy the conditions
(I) to (III), the following conditions (i) to (iii) are satisfied.
This is because there is a substantial correlation between the
conditions (I) to (III) and the conditions (i) to (iii).
[0242] That is, when the conditions (i) to (iii) are satisfied, the
temperature is controlled to satisfy the conditions (I) to
(III).
[0243] An atmospheric temperature is raised without being kept in
an atmospheric temperature range corresponding to from the point A1
or higher to lower than the sintering temperature of the processed
molded article P in the Fe--C system phase diagram.
[0244] (ii) The heating rate in an atmospheric temperature range
corresponding to from the point A1 to the point A3 in the Fe--C
system phase diagram is set to 12.degree. C./sec or more.
[0245] (iii) The heating rate in an atmospheric temperature range
corresponding to from the point A3 to the sintering temperature of
the processed molded article P in the Fe--C system phase diagram is
set to 4.degree. C./sec or more.
[0246] The atmospheric temperature is an atmospheric temperature in
the heating container 302, and is a temperature measured with a
thermocouple (diameter y 3.5 mm) arranged within 8.5 mm from the
processed molded article P.
[0247] Since the atmosphere in the heating container 302 is heated
by the heat of the processed molded article P that has been
induction-heated, the atmospheric temperature is often slightly
lower than the temperature of the processed molded article P itself
that has been induction-heated. For example, the atmospheric
temperature corresponding to the point A1 is the temperature of the
atmosphere when the temperature of the processed molded article P
reaches the point A1, and is often a temperature lower than or
equal to the point A1. The same applies to the atmospheric
temperature corresponding to the point A3 and the atmospheric
temperature corresponding to the sintering temperature of the
processed molded article P.
[0248] By satisfying all of the conditions (I) to (III) (i.e., all
of the conditions (i) to (iii)), the sintered product S with high
strength can be manufactured. The reason is considered as
follows:
[0249] Although C is likely to diffuse into Fe in the temperature
range of the condition (I), the diffusion of C into Fe is
suppressed when the temperature is not kept in this temperature
range and the heating rate is set to a high rate as in the
conditions (II) and (III).
[0250] Then, for example, C particles adjacent to Fe particles
remain as a solid phase, and adjacent interfaces between the Fe
particles and the C particles, and the like become a C-rich phase
(sometimes only C is present).
[0251] When a C-rich phase remains on the surface of Fe, a liquid
phase of Fe--C is generated at the sintering temperature. As is
apparent from the Fe--C system phase diagram, when C is about 0.2
mass % or more, the Fe--C system material becomes a liquid phase at
1153.degree. C. or higher. Therefore, when the processed molded
article P is sintered at a temperature higher than or equal to
1153.degree. C., the C-rich phase becomes a liquid phase.
[0252] That is, when the temperature is raised at a high rate
without being kept in a temperature range where C is likely to
diffuse into Fe, a liquid phase of Fe--C is likely to be generated.
The liquid phase of Fe--C makes the corners of pores formed between
particles round, and reduces acute angle portions of the pores that
cause a decrease in strength (starting points of breaking). As a
result, the strength of the sintered product S, especially the
radial crushing strength, can be increased.
[0253] The heating rate can be adjusted by adjusting the output or
frequency of the power supply of the induction heating sintering
furnace 33. Examples of the setting of the output or the frequency
include setting of the output or the frequency satisfying the
heating rate of the condition (II).
[0254] The setting of the output or the frequency may be made
constant from the temperature range of the condition (II) to the
temperature range of the condition (III), or may be changed when
the temperature range of the condition (II) is shifted to the
temperature range of the condition (III).
[0255] When the setting of the output or the frequency is made
constant from the temperature range of the condition (II) to the
temperature range of the condition (III), the heating rate of the
condition (III) can be satisfied.
[0256] However, if the output or the frequency is made constant,
the heating rate of the condition (III) is smaller than the heating
rate of the condition (II). By changing the setting of the output
or the frequency when the temperature range of the condition (II)
is shifted to the temperature range of the condition (III), the
heating rate of the condition (III) can be further increased, and
eventually the heating rate can be made approximately equal to the
heating rate of the condition (II).
[0257] The heating rate of the condition (II) is preferably as high
as possible, and more preferably, for example, 12.5.degree. C./sec
or more. The upper limit of the heating rate of the condition (II)
may be, for example, 50.degree. C./sec or less, and more preferably
15.degree. C./sec or less.
[0258] The heating rate of the condition (III) is preferably as
high as possible, similarly to the condition (II). It is
preferably, for example, 5.degree. C./sec or more, and more
preferably 10.degree. C./sec or more. The upper limit of the
heating rate of the condition (III) may be, for example, 50.degree.
C./sec or less, and more preferably 15.degree. C./sec or less.
[0259] In the heating process, the temperature of the processed
molded article P is further preferably controlled to satisfy either
a condition (IV) or a condition (V).
[0260] (IV) A temperature is not kept in a temperature range where
the temperature of the processed molded article P is 410.degree. C.
or higher and lower than the point A1 in the Fe--C system phase
diagram, and the heating rate in this temperature range is set to
12.degree. C./sec or more.
[0261] (V) The temperature in the temperature range where the
temperature of the processed molded article P is 410.degree. C. or
higher and lower than the point A1 in the Fe--C system phase
diagram is kept for 30 seconds or longer and 90 seconds or
shorter.
[0262] By controlling the temperature to satisfy either the
condition (IV) or the condition (V), either one of the following
conditions (iv) and (v) is satisfied. This is because there is a
substantial correlation between the conditions (IV) and (V) and the
conditions (iv) and (v).
[0263] That is, when either one of the conditions (iv) and (v) is
satisfied, the temperature is controlled to satisfy either one of
the conditions (IV) and (V).
[0264] (iv) An atmospheric temperature of 400.degree. C. or higher
and lower than 700.degree. C. is not kept, and the heating rate in
this atmospheric temperature range is set to 12.degree. C./sec or
more.
[0265] (v) An atmospheric temperature of 400.degree. C. or higher
and lower than 700.degree. C. is kept for 30 seconds or longer and
90 seconds or shorter.
[0266] When the conditions (IV) and (iv) are satisfied, the
sintered product S with high strength can be manufactured in a
shorter time than when the conditions (V) and (v) are satisfied.
The heating rate of the conditions (IV) and (iv) can be achieved
by, for example, setting the output or the frequency to be the same
as the output or the frequency that satisfies the heating rate of
the conditions (II) and (ii).
[0267] In this case, it can be mentioned that the setting of the
output or frequency of the power supply of the induction heating
sintering furnace 33 is always made constant from the start of the
heating to the time of sintering, and an atmospheric temperature
from the atmospheric temperature at the start of the heating to the
atmospheric temperature during the sintering is not kept. Since an
atmospheric temperature lower than the atmospheric temperature
during the sintering is not kept, the sintered product S can be
manufactured in a short time. The heating rate at the atmospheric
temperature of the conditions (IV) and (iv) is further preferably
15.degree. C./sec or more, and particularly preferably 20.degree.
C./sec or more.
[0268] When the conditions (V) and (v) are satisfied, the processed
molded article P can be heated more uniformly than when the
conditions (IV) and (iv) are satisfied. That is, the conditions (V)
and (v) are particularly suitable when the processed molded article
P having a complicated shape is sintered.
[0269] In addition, even when the conditions (V) and (v) are
satisfied, the sintered product S with high strength can be
obtained. The temperature range of the condition (V) is further
preferably 735.degree. C. or lower, and particularly preferably
700.degree. C. or lower. The atmospheric temperature of the
condition (v) is further preferably 600.degree. C. or lower, and
particularly preferably 500.degree. C. or lower.
[0270] The keeping time for keeping the atmospheric temperature of
the conditions (V) and (v) is further preferably 45 seconds or
longer and 75 seconds or shorter. The heating rates, after the
temperature of the condition (V) or the atmospheric temperature of
the condition (v) is kept, are set to the heating rates of the
conditions (II), the conditions (ii) and (III), and the condition
(iii).
[0271] (Sintering Process)
[0272] The holding time of the processed molded article P at the
atmospheric temperature during the sintering (sintering
temperature) depends on the atmospheric temperature (sintering
temperature) and the size of the molded article, but it is
preferably, for example, 30 seconds or longer and 90 seconds or
shorter.
[0273] When the holding time is set to 30 seconds or longer, the
processed molded article P can be sufficiently heated, so that the
sintered product S with high strength can be easily manufactured.
When the holding time is set to 90 seconds or shorter, the holding
time is short, so that the sintered product S can be manufactured
in a short time. The holding time is further preferably 90 seconds
or shorter, and particularly preferably 60 seconds or shorter. Note
that in the case of the processed molded article P having a large
size, or the like, it may be effective to set the holding time to
90 seconds or longer.
[0274] The sintering temperature of the processed molded article P
may be higher than or equal to a temperature at which the liquid
phase of Fe--C is generated, and may be 1153.degree. C. or higher.
When the sintering temperature is set to 1153.degree. C. or higher,
the liquid phase is generated and the corners of the pores can be
easily rounded, so that the sintered product S with high strength
can be easily manufactured.
[0275] The sintering temperature is preferably, for example,
1250.degree. C. or lower. In this case, the temperature is not too
high and the liquid phase can be suppressed form being excessively
generated, so that the sintered product S with high dimensional
precision can be easily manufactured. The sintering temperature is
further preferably 1153.degree. C. or higher and 1200.degree. C. or
lower, and particularly preferably 1155.degree. C. or higher and
1185.degree. C. or lower.
[0276] The atmospheric temperature during the sintering of the
processed molded article P is preferably 1135.degree. C. or higher
and lower than 1250.degree. C. When the sintering temperature of
the processed molded article P satisfies 1153.degree. C. or higher,
the atmospheric temperature during the sintering of the processed
molded article P satisfies 1135.degree. C. or higher.
[0277] Similarly, when the sintering temperature of the processed
molded article P satisfies 1250.degree. C. or lower, the
atmospheric temperature during the sintering of the processed
molded article P satisfies lower than 1250.degree. C. The
atmospheric temperature during the sintering is further preferably
1135.degree. C. or higher and 1185.degree. C. or lower, and
particularly preferably 1135.degree. C. or higher and lower than
1185.degree. C.
[0278] (Cooling Process)
[0279] A cooling rate in the cooling process of the sintering step
P3 is preferably increased. By increasing the cooling rate, a
bainite structure is easily formed, and furthermore a martensite
structure is easily formed, so that the strength of the sintered
product S is easily increased.
[0280] The cooling rate is preferably 1.degree. C./sec or more. As
a result, the processed molded article P can be quickly cooled. The
cooling rate is further preferably 2.degree. C./sec or more, and
particularly preferably 5.degree. C./sec or more. The cooling rate
may be, for example, 200.degree. C./sec or less, further
100.degree. C./sec or less, and particularly 50.degree. C./sec or
less.
[0281] A temperature range where the processed molded article P is
cooled at this cooling rate may be set to a temperature range from
the start of the cooling (the sintering temperature of the
processed molded article P) to the completion of the cooling (e.g.,
about 200.degree. C.). The temperature range is particularly
preferably set to a temperature range (atmospheric temperature
range) from the temperature of the processed molded article P
(atmospheric temperature) of 750.degree. C. (700.degree. C.) to
230.degree. C. (200.degree. C.).
[0282] Examples of the cooling method include spraying a cooling
gas onto the sintered product S. Examples of the type of the
cooling gas include inert gases such as nitrogen gas and argon gas.
Due to the rapid cooling, the subsequent heat treatment step can be
omitted.
[Apparatus Used in Inspection Step P5] FIG. 7 is a schematic
configuration illustration showing an example of an inspection
apparatus 35 used in the inspection step P5.
[0283] As shown in FIG. 7, the inspection apparatus 35 used in the
inspection step P5 includes first and second sensor apparatuses
501, 502 and a computer apparatus 503 communicably connected to
each of the sensor apparatuses 501, 502.
[0284] The computer apparatus 503 includes, for example, a desktop
personal computer (PC). The type of the computer apparatus 503 is
not particularly limited. The type of the computer apparatus 503
may be, for example, a notebook type or a tablet type.
[0285] The computer apparatus 503 includes: an information
processor including a CPU and a volatile memory; a storage device
including a nonvolatile memory configured to store a computer
program to be executed by the CPU and data necessary for the
execution; and the like. The computer apparatus 2 also includes an
input device and a display.
[0286] The CPU reads the computer program into the volatile memory
to execute the computer program, whereby the computer apparatus 503
functions as a predetermined controller.
[0287] The first sensor apparatus 501 includes, for example, a
non-contact type 3D scanner. The 3D scanner may be the
afore-mentioned patterned light 3D scanner 1 (see FIG. 2), or may
be a laser light 3D scanner.
[0288] The first sensor apparatus 501 scans the sintered products S
subjected to the finishing step P4 one by one to generate
three-dimensional CAD data, and transmits the generated data to the
computer apparatus 503.
[0289] The second sensor apparatus 502 includes, for example, a
digital camera capable of acquiring a digital image. The second
sensor apparatus 502 photographs the sintered products S subjected
to the finishing step P4 one by one to generate image data, and
transmits the generated image data to the computer apparatus
503.
[0290] The computer apparatus 503 stores three-dimensional CAD data
of the current product C. This data is, for example, the data
received from the computer apparatus 2 of step 2, or the data
stored in the computer apparatus 503 via a recording medium such as
a USB memory.
[0291] The computer apparatus 503 calculates a dimensional error
between the sintered product S and the current product C, based on
the three-dimensional CAD data of the sintered product S and the
three-dimensional CAD data of the current product C. Based on the
calculated dimensional error, the computer apparatus 503 determines
whether the sintered product S passes or fails. Specifically, the
sintered product S having a dimensional error of a predetermined
value or less is determined to be acceptable, and the sintered
product S having a dimensional error exceeding the predetermined
value is determined to be unacceptable (defective).
[0292] In addition, the computer apparatus 503 transmits the
three-dimensional CAD data of the sintered product S determined to
be acceptable to the computer apparatus 4 used in step 4.
[0293] The computer apparatus 503 determines the presence or
absence of a crack or a scratch on the surface based on the image
data acquired from the second sensor apparatus 502, and determines
the sintered product S having a crack or a scratch to be
unacceptable (defective). The sintered product S having a crack or
a scratch is excluded as a defective product.
[0294] The determination processing can be performed, for example,
by determining whether or not a partial image obtained by dividing
the image data into a grid pattern includes something that is
included in the target events, such as a scratch, that are included
in the classification models obtained by machine learning (see
Japanese Unexamined Patent Publication No. 2018-81629).
[0295] [Effects of Manufacturing Facility of Present
Embodiment]
[0296] According to the manufacturing facility 3 of the present
embodiment, the powder compact M having a simple shape and a high
density is fabricated by uniaxial pressing, the powder compact M is
processed by the robot processing apparatus 32 having a high degree
of freedom in processing to fabricate the processed molded article
P, and the processed molded article P is sintered to manufacture
the sintered product S.
[0297] Thus, the sintered product S with high precision can be
manufactured without using a mold having a complicated shape that
takes several months to manufacture. Thus, the delivery date of the
sintered product S can be shortened.
[0298] According to the manufacturing facility 3 of the present
embodiment, the induction heating sintering furnace 33, capable of
manufacturing the sintered product S in a shorter time than a belt
type continuous sintering furnace, is adopted, so that the delivery
date of the sintered product S can be shortened also in this
respect.
[0299] According to the manufacturing system of the present
embodiment, the robot processing apparatus 32, needing an
installation space smaller than a five-axis machining center, and
the induction heating sintering furnace 33, needing an installation
space smaller than a belt type continuous sintering furnace, are
adopted, so that there is also an advantage that the manufacturing
facility 3 can be made compact.
[0300] [Apparatus Used in Step 4]
[0301] FIG. 8 is an explanatory illustration showing an example of
an apparatus used in step 4.
[0302] As shown in FIG. 8, the apparatus used in step 4 includes
the computer apparatus 4. The computer apparatus 2 includes, for
example, a desktop personal computer (PC). The type of the computer
apparatus 2 is not particularly limited. The type of the computer
apparatus 2 may be, for example, a notebook type or a tablet
type.
[0303] The computer apparatus 4 includes: an information processor
including a CPU and a volatile memory; a storage device including a
nonvolatile memory configured to store a computer program to be
executed by the CPU and data necessary for the execution; and the
like. The computer apparatus 2 also includes an input device and a
display.
[0304] The CPU reads the computer program into the volatile memory
to execute the computer program, whereby the computer apparatus 4
functions as a predetermined controller.
[0305] CAD/CAT software is installed in the computer apparatus 4.
The CAD/CAT software is software that realizes comparison
processing between the three-dimensional CAD data of a
determination target (here, the sintered product S that has passed
the inspection in the inspection step P5) and the design data
(three-dimensional CAD data of the current product C) serving as a
reference of the shape of the sintered product S, in accordance
with a user's operation input to the GUI of the computer apparatus
4.
[0306] The computer apparatus 4 receives the three-dimensional CAD
data of a plurality of the sintered products S from the computer
apparatus 503 of the inspection step P5.
[0307] The computer apparatus 4 stores the three-dimensional CAD
data of the current product C. This data is, for example, the data
received from the computer apparatus 2 of step 2, the data received
from the computer apparatus 503 of the inspection step P5, or the
data stored in the computer apparatus 4 via a recording medium such
as a USB memory.
[0308] Based on the result of comparing the 3D data of a plurality
of the sintered products C with the 3D data of the current product
C, the computer apparatus 4 determines whether or not a
statistically dominant number of excessively cut or insufficiently
cut portions have been detected.
[0309] When detecting the excessively cut or insufficiently cut
portions, the computer apparatus 4 generates a corrected program
(e.g., an NC program) of the processing program. The corrected
program includes, for example, an operation code for increasing the
cutting depth of an excessively cut portion or an operation code
for increasing the cutting depth of an insufficiently cut
portion.
[0310] The computer apparatus 4 transmits the generated corrected
program to the processing apparatus 32 used in the processing step
P2 of step 3. As a result, the molded article processing apparatus
32 that has received the corrected program processes the powder
compact M at the corrected cutting depth.
[0311] Note that the computer apparatus 4 may transmit the
corrected program to the computer apparatus 2 of step 2 (see FIG.
2). In this case, the computer apparatus 2 of step 2 may forward
the received corrected program to the processing apparatus 32.
[0312] [First Modification: Variation of Apparatus Used in Step
3]
[0313] The molding apparatus 31 used in the molding step P1 of step
3 may be a press molding apparatus configured to mold the powder
compact M whose whole has an average relative density of less than
93%.
[0314] The processing apparatus 32 used in the processing step P2
of step 3 may be a robot processing apparatus including only the
first robot 201. In this case, the first robot 201 performs
predetermined processing on the powder compact M set on a fixing
table.
[0315] The processing apparatus 32 used in the processing step P2
of step 3 may be a robot processing apparatus including a plurality
of at least one of the first and second robots 201, 202. That is,
the number of the first and second robots 201, 202 may be
plural.
[0316] The processing apparatus 32 used in the processing step P2
of step 3 may be a processing apparatus adopting a five-axis
machining center instead of the articulated robots 201, 202.
[0317] The sintering apparatus 33 used in the sintering step P3 of
step 3 may be a belt type continuous sintering furnace instead of
the induction heating sintering furnace.
[0318] The inspection step P5 of step 3 is not limited to a case
where the inspection is performed fully automatically using the
inspection apparatus 35, and the inspection work may be performed
wholly or partially by a human.
[0319] The inspection step P5 of step 3 may include correction of
the processing program in step 4. That is, the arithmetic
processing and the communication processing to be executed by the
computer apparatus 4 of step 4 may be executed by the computer
apparatus 503 of the inspection step P5. In this case, the computer
apparatus 4 of step 4 is unnecessary.
[0320] [Second Modification: Movable Manufacturing System]
[0321] FIG. 9 is a schematic configuration illustration showing an
example of a movable manufacturing system.
[0322] As shown in FIG. 9, a manufacturing system according to a
second modification includes a mobile apparatus 601 capable of
traveling on a road, and predetermined storage elements to be
stored in a storage 602 of the mobile apparatus 601. The
predetermined storage elements mean constituent elements necessary
for manufacturing the sintered product S.
[0323] As shown in FIG. 9, the mobile apparatus 601 includes, for
example, a large truck, and the storage 602 includes a container
fixed to the cargo bed of the large truck.
[0324] In the manufacturing system shown in FIG. 9, the
predetermined storage elements include the 3D scanner 1 used in
step 1, the computer apparatus 2 used in step 2, the robot
processing apparatus 32 used in the processing step P2 of step 3,
and the induction heating sintering furnace 33 used in the
sintering step P3 of step 3.
[0325] According to the second modification, the predetermined
storage elements are placed in the storage 602 of the mobile
apparatus 601, so that the sintered product S can be manufactured
by the following procedures. Thus, the sintered product S (sample)
following the current product C can be provided to the customer in
a short time (e.g., several hours).
[0326] Procedure 1: Drive the mobile apparatus 601 to a point near
the location of the customer in order to transport the
predetermined storage elements placed in the storage 602 to the
nearby point.
[0327] Procedure 2: Receive the current product C that is lent from
the customers.
[0328] Procedure 3: Execute steps 1 to 3 to manufacture the
sintered product S following the current product C on site.
[0329] Procedure 4: Provide the manufactured sintered product S
(sample) to the customer.
[0330] Note that in the manufacture of the sintered product C in
procedure 3, the powder compact M to be processed by the robot
processing apparatus 32 may be fabricated in advance in the
manufacturer's own factory and loaded on the mobile apparatus
601.
[0331] In the second modification, the 3D scanner 1 may be excluded
from the predetermined storage elements. In this case, the 3D data
generated by the 3D scanner 1 outside the vehicle may be
transmitted to the computer apparatus 2 inside the vehicle. The 3D
data of the current product C, acquired from the customer or the
like, may be transmitted to the computer apparatus 2 inside the
vehicle.
[0332] In the second modification, the computer apparatus 2 may be
excluded from the predetermined storage elements. In this case, the
computer apparatus 2 outside the vehicle may generate the molded
article processing program from the 3D data of the current product
C, and transmit the generated program to the robot processing
apparatus 32 inside the vehicle.
[0333] In the second modification, the molding apparatus 31 used in
the molding step P1 of step 3 may be included in the predetermined
storage elements. In this case, the powder compact M can also be
molded on site.
[0334] In the second modification, the apparatus (polishing
apparatus or the like) used in the finishing step P4 of step 3 may
be included in the predetermined storage elements. In this case,
the sintered product S can also be finished on site.
[0335] In the second modification, the inspection apparatus 35 used
in the inspection step P5 of step 3 may be included in the
predetermined storage elements. In this case, inspections, such as
determination on whether the sintered product S passes or fails,
can also be performed on site.
[0336] In the second modification, the apparatus used in step 4
(computer apparatus 4) may be included in the predetermined storage
elements. In this case, the correction of the processing program in
step 4 can also be performed on site.
OTHERS
[0337] The embodiments (modifications are included) described above
are to be construed in all respects as illustrative and not
restrictive. The scope of the present invention is defined by the
claims, not by the above description, and is intended to include
all modifications within the meaning and scope equivalent to the
claims.
[0338] For example, in the embodiments (modifications are included)
described above, the target product serving as a reference of the
shape of the sintered product S is not limited to the existing
current product C, and may be an article under planning that has
not yet been commercialized.
REFERENCE SIGNS LIST
[0339] 1: THREE-DIMENSIONAL SHAPE MEASURING MACHINE (3D SCANNER,
ACQUISITION UNIT) [0340] 2: COMPUTER APPARATUS (ACQUISITION UNIT)
[0341] 3: MANUFACTURING FACILITY (PRODUCTION LINE) [0342] 4:
COMPUTER APPARATUS [0343] 31: MOLDING APPARATUS (MOLDING APPARATUS)
[0344] 32: PROCESSING APPARATUS (MOLDED ARTICLE PROCESSING
APPARATUS, ROBOT PROCESSING APPARATUS) [0345] 33: SINTERING
APPARATUS (INDUCTION HEATING SINTERING FURNACE) [0346] 35:
INSPECTION APPARATUS [0347] 36: CONVEYOR [0348] 37: ROBOT ARM
[0349] 101: BASE PLATE [0350] 102: PILLAR [0351] 103: CEILING FRAME
[0352] 104: UPPER PLATE [0353] 105: HYDRAULIC CYLINDER MECHANISM
(LOWER SIDE) [0354] 106: PUNCH SET (LOWER SIDE) [0355] 107:
HYDRAULIC CYLINDER MECHANISM (UPPER SIDE) [0356] 108: PUNCH SET
(UPPER SIDE) [0357] 109: UPPER CYLINDER [0358] 110: LINK MECHANISM
[0359] 111: DIE [0360] 112: CORE ROD [0361] 113: OUTER PUNCH [0362]
114: INNER PUNCH [0363] 114: LOWER PUNCH [0364] 115: UPPER PUNCH
[0365] 116: RAW MATERIAL POWDER [0366] 201: ARTICULATED ROBOT
(FIRST ROBOT) [0367] 201: ARTICULATED ROBOT (SECOND ROBOT) [0368]
203: CONTROLLER [0369] 204: TOOL [0370] 205: GRIP UNIT [0371] 206:
GRIP UNIT [0372] 207: FIRST COMMUNICATION UNIT [0373] 208: SECOND
COMMUNICATION UNIT [0374] 209: CONTROL UNIT [0375] 210: STORAGE
UNIT [0376] 301: CHAMBER [0377] 302: HEATING CONTAINER [0378] 303:
COOLING CONTAINER [0379] 304: LIFTING TABLE [0380] 305: INDUCTION
COIL [0381] 501: FIRST SENSOR APPARATUS (3D SCANNER) [0382] 502:
SECOND SENSOR APPARATUS (DIGITAL CAMERA) [0383] 503: COMPUTER
APPARATUS [0384] 601: MOBILE APPARATUS [0385] 602: STORAGE [0386]
C: CURRENT PRODUCT (TARGET PRODUCT) [0387] M: POWDER COMPACT [0388]
P: PROCESSED MOLDED ARTICLE [0389] S: SINTERED PRODUCT
* * * * *