阅读说明：本技术 烧结体的制造系统及制造方法 (Sintered body manufacturing system and manufacturing method ) 是由 野口真 山本达司 林哲也 于 2019-04-24 设计创作，主要内容包括：本发明的一个方式所涉及的制造系统具有：成型装置,其通过对包含金属粉末的原料粉末进行单轴加压,从而制作整体或一部分的相对密度为93％以上的压粉成型体；机器人加工装置,其具有通过对所述压粉成型体进行机械加工而制作加工成型体的多关节机器人；以及感应加热烧结炉,其通过高频感应加热对所述加工成型体进行烧结,由此制作烧结体。(A manufacturing system according to an embodiment of the present invention includes: a molding device that produces a powder compact having a relative density of 93% or more in whole or in part by uniaxially pressing a raw material powder containing a metal powder; a robot processing device having an articulated robot for producing a processed molded body by machining the powder compact; and an induction heating sintering furnace for sintering the molded body by high-frequency induction heating to produce a sintered body.)

1. A system for manufacturing a sintered body, comprising:

a molding device that produces a powder compact having a relative density of 93% or more in whole or in part by uniaxially pressing a raw material powder containing a metal powder;

a robot processing device having an articulated robot for producing a processed molded body by machining the powder compact; and

and an induction heating sintering furnace for sintering the molded body by high-frequency induction heating to produce a sintered body.

2. The manufacturing system of the sintered body according to claim 1,

the apparatus further includes an acquisition unit that acquires 3D data of the object that is a reference of the shape.

3. The manufacturing system of the sintered body according to claim 2,

the inspection apparatus is also provided, and performs at least 1 inspection of the sintered body for dimensional accuracy and defect-free based on the 3D data of the object.

4. The manufacturing system of the sintered body according to claim 2 or 3,

further comprising a computer device for creating a machining program for controlling the operation of the robot machining device based on the 3D data of the object,

the robot processing device produces the processed molded body based on the processing program.

5. The manufacturing system of the sintered body according to any one of claims 1 to 4,

the robot processing apparatus has a plurality of the multi-joint robots,

the plurality of articulated robots include a1 st robot that holds a tool for machining the compact and a 2 nd robot that holds the compact.

6. A system for manufacturing a sintered body, comprising:

a processing device which follows the 3D data of the object to be the standard of the shape and processes the powder compact mechanically to produce a processed compact; and

and a sintering device for sintering the processing forming body to prepare a sintered body.

7. The manufacturing system of the sintered body according to claim 6,

the apparatus further includes a 3D scanner that acquires 3D data of the object in a non-contact manner.

8. The manufacturing system of the sintered body according to claim 6 or 7,

the processing device is a robot processing device with a multi-joint robot,

the sintered body manufacturing system further includes a computer device that creates a machining program for controlling the operation of the robot machining device based on the 3D data of the object.

9. The manufacturing system of a sintered body according to any one of claims 6 to 8,

the inspection apparatus is also provided, and performs at least 1 inspection of the sintered body for dimensional accuracy and defect-free based on the 3D data of the object.

10. The manufacturing system of the sintered body according to any one of claims 6 to 9,

the molding apparatus is also provided for producing the powder compact having a relative density of 93% or more in whole or in part by uniaxially pressing a raw material powder containing a metal powder.

11. The manufacturing system of the sintered body according to any one of claims 6 to 10,

the sintering device is an induction heating sintering furnace for sintering the processing formed body by high-frequency induction heating.

12. The manufacturing system of the sintered body according to claim 6,

there are also mobile devices that can be passed on the road,

the processing device is a robot processing device with a multi-joint robot,

the sintering device is an induction heating sintering furnace for sintering the processing formed body by high-frequency induction heating,

the apparatus mounted on the moving device includes the robot processing apparatus and the induction heating sintering furnace.

13. The manufacturing system of the sintered body according to claim 12,

the device mounted on the mobile device includes a 3D scanner for acquiring 3D data of the object in a non-contact manner.

14. The manufacturing system of a sintered body according to any one of claims 1 to 13,

the relative density of the whole or a part of the compact is 96% or more.

15. A method for producing a sintered body, using the production system according to any one of claims 1 to 14.

Technical Field

The present invention relates to a system and a method for manufacturing a sintered body.

Background

Patent documents 1 and 2 describe a method for producing a sintered body, which includes: a preparation step of preparing a raw material powder containing a metal powder; a molding step of uniaxially pressing a raw material powder using a mold to produce a powder compact; a processing step of machining the powder compact to produce a processed compact; and a sintering step of sintering the molded body to obtain a sintered body.

In patent document 2, in the above-mentioned molding step, it is recommended to set the average relative density of the whole powder compact to 93% or more.

Patent document 1: japanese patent laid-open publication No. 2004-323939

Patent document 2: international publication No. 2017/175772

Disclosure of Invention

A manufacturing system according to an embodiment of the present invention includes: a molding device that produces a powder compact having a relative density of 93% or more in whole or in part by uniaxially pressing a raw material powder containing a metal powder; a robot processing device having an articulated robot for producing a processed molded body by machining the powder compact; and an induction heating sintering furnace for sintering the molded body by high-frequency induction heating to produce a sintered body.

A manufacturing system according to another aspect of the present invention includes: a processing device which follows the 3D data of the object to be the standard of the shape and processes the powder compact mechanically to produce a processed compact; and a sintering device that sinters the molded product to produce a sintered body.

Drawings

Fig. 1 is an explanatory view showing an outline of a method for producing a sintered body.

Fig. 2 is an explanatory diagram showing an example of the apparatus used in step 1 and step 2.

Fig. 3 is an overall configuration diagram showing an example of the manufacturing apparatus used in step 3.

Fig. 4 is a schematic configuration diagram showing an example of a molding apparatus used in a molding process.

Fig. 5 is a schematic configuration diagram showing an example of a processing apparatus used in a processing step.

Fig. 6 is a schematic configuration diagram showing an example of a sintering apparatus used in the sintering step.

Fig. 7 is a schematic configuration diagram showing an example of an inspection apparatus used in an inspection process.

Fig. 8 is an explanatory diagram showing an example of the apparatus used in step 4.

Fig. 9 is a schematic configuration diagram showing an example of a movable manufacturing system.

Detailed Description

The problem to be solved by the present invention

When there is a customer who is studying replacement of a current product with a sintered body, it is preferable that a sintered body that is a current product of a customer be manufactured as soon as possible as a manufacturer of the sintered body, and the manufactured sintered body be presented to the customer as a sample.

However, patent documents 1 and 2 do not assume the delivery date of the sintered body presented to the customer as a sample. In view of the conventional problems, an object of the present invention is to make it possible to shorten the delivery time of a sintered body.

Further, in the case of manufacturing a sintered body which is presented to a customer as a sample, it is desired to make the apparatus compact (small-sized). In view of the conventional problems, an object of the present invention is to make it possible to make a manufacturing apparatus of a sintered body compact.

< effects of the present invention >

According to the present invention, the delivery time of the sintered body can be shortened.

According to the present invention, the manufacturing equipment of the sintered body can be made compact.

< summary of embodiments of the invention >

The following describes an outline of an embodiment of the present invention.

(1) The manufacturing system of the present embodiment includes: a molding device that produces a powder compact having a relative density of 93% or more in whole or in part by uniaxially pressing a raw material powder containing a metal powder; a robot processing device having an articulated robot for producing a processed molded body by machining the powder compact; and an induction heating sintering furnace for sintering the molded body by high-frequency induction heating to produce a sintered body.

According to the manufacturing system of the present embodiment, since the induction heating sintering furnace capable of producing the sintered body in a shorter time than the belt-type continuous sintering furnace is provided, the delivery time of the sintered body can be shortened.

According to the manufacturing system of the present embodiment, since the robot processing device having a smaller installation space than the 5-axis processing center and the induction heating sintering furnace having a smaller installation space than the belt-type continuous sintering furnace are provided, the manufacturing facility of the sintered body can be made compact.

(2) The manufacturing system according to the present embodiment preferably further includes an acquisition unit that acquires 3D data of an object that is a reference of the shape.

According to the manufacturing system of the present embodiment, the acquisition unit acquires 3D data of the object that becomes the reference of the shape, and therefore, as will be described later, inspection of the sintered body based on the acquired 3D data, creation of a machining program, and the like can be executed.

(3) The manufacturing system according to the present embodiment preferably further includes an inspection device that performs at least 1 inspection of the sintered body for dimensional accuracy and presence/absence of defects based on the 3D data of the target product.

According to the manufacturing system of the present embodiment, since the inspection device performs the above-described inspection, a highly accurate sintered body that is not inferior to the target product can be manufactured.

(4) In the manufacturing system according to the present embodiment, it is preferable that the manufacturing system further includes a computer device that creates a machining program for controlling an operation of the robot machining device based on the 3D data of the object, and the robot machining device creates the machined molded body based on the machining program.

According to the manufacturing system of the present embodiment, the computer device creates the above-described machining program, and the robot machining device creates the machined molded body based on the above-described machining program, so that the robot machining device can be controlled so as to machine the powder compact into substantially the same shape as the target product.

(5) In the manufacturing system according to the present embodiment, it is preferable that the robot processing device includes a plurality of the articulated robots, and the plurality of the articulated robots include a1 st robot that holds a tool for processing the compact and a 2 nd robot that holds the compact.

According to the manufacturing system of the present embodiment, since the relative density of the powder compact is 93% or more, the powder compact is not damaged even if the cutting work is performed on the powder compact held by the 2 nd robot by the cutter held by the 1 st robot. Therefore, the compact can be processed quickly.

In addition, the cutter can be brought into contact with the powder compact at an arbitrary angle, and complicated machining can be performed quickly.

(6) The manufacturing system of the present embodiment includes: a processing device which follows the 3D data of the object to be the standard of the shape and processes the powder compact mechanically to produce a processed compact; and a sintering device that sinters the molded product to produce a sintered body.

According to the manufacturing system of the present embodiment, the processing device processes the green compact mechanically by following the 3D data of the object to produce the processed compact, and the sintering device sinters the processed compact to produce the sintered body, so that the sintered body having substantially the same shape as the object can be produced in a short time. Therefore, the delivery time of the sintered body can be shortened.

(7) The manufacturing system according to the present embodiment preferably further includes a 3D scanner, and the 3D scanner acquires 3D data of the target object in a non-contact manner.

According to the manufacturing system of the present embodiment, since the 3D scanner acquires 3D data of the object in a non-contact manner, even when 3D data of the object does not currently exist, the 3D scanner can acquire 3D data of the object quickly.

(8) In the manufacturing system according to the present embodiment, it is preferable that the manufacturing system further includes a computer device that creates a machining program for controlling the operation of the robot machining device based on the 3D data of the object when the machining device is a robot machining device including an articulated robot.

According to the manufacturing system of the present embodiment, since the robot processing device having a smaller installation space than the 5-axis machining center is provided, the manufacturing facility of the sintered body can be made compact.

According to the manufacturing system of the present embodiment, since the computer device creates the above-described machining program, the robot machining device can be controlled so as to machine the powder compact into substantially the same shape as the target product.

(9) The manufacturing system according to the present embodiment preferably further includes an inspection device that performs at least 1 inspection of the sintered body for dimensional accuracy and presence/absence of defects based on the 3D data of the target product.

According to the manufacturing system of the present embodiment, since the inspection device performs the above-described inspection, a highly accurate sintered body that is not inferior to the target product can be manufactured.

(10) The production system of the present embodiment preferably further includes a molding device that produces the powder compact having a relative density of 93% or more in whole or in part by uniaxially pressing a raw material powder containing a metal powder.

According to the manufacturing system of the present embodiment, the molding device performs uniaxial pressing on the raw material powder including the metal powder to produce the powder compact having the above-described relative density, and thus a high-precision powder compact can be obtained quickly. Therefore, the delivery time of the sintered body can be shortened.

(11) In the manufacturing system of the present embodiment, it is preferable that the sintering device is an induction heating sintering furnace for sintering the molded product by high-frequency induction heating.

In this case, the induction heating sintering furnace can produce a sintered body in a shorter time than the belt-type continuous sintering furnace, and therefore the delivery time of the sintered body can be shortened. Further, since the induction heating sintering furnace is provided in a smaller space than the belt-type continuous sintering furnace, the manufacturing facility of the sintered body can be made compact.

(12) In the manufacturing system according to the present embodiment, it is preferable that the processing apparatus is a robot processing apparatus having an articulated robot, the sintering apparatus is an induction heating sintering furnace for sintering the processed molded product by high-frequency induction heating, and the apparatus mounted on the moving apparatus includes the robot processing apparatus and the induction heating sintering furnace.

According to the manufacturing system of the present embodiment, since the robot processing device and the induction heating sintering furnace are mounted on the moving device, these devices can be transported to a place near the customer site. Therefore, the sintered body can be manufactured at a place near the customer site.

Therefore, it is made possible to deliver the sintered body to the customer in a shorter time as compared with the case where the sintered body is manufactured at a factory remote from the customer site.

(13) In the manufacturing system according to the present embodiment, it is preferable that the device mounted on the mobile device includes a 3D scanner that acquires 3D data of the object in a non-contact manner.

According to the manufacturing system of the present embodiment, since the 3D scanner acquires the 3D data of the object in a non-contact manner, the 3D data of the object can be acquired quickly even when the 3D data of the object is not stored by the customer or a third person.

(14) In the production system of the present embodiment, the relative density of the whole or a part of the powder compact is preferably 96% or more.

When the relative density of the compact is 96% or more, the strength of the sintered body is improved as compared with the case where the relative density is less than the above value, and the compact is not easily damaged when processed by a robot processing apparatus.

(15) The manufacturing method of the present embodiment is a manufacturing method of manufacturing the sintered body by using the manufacturing system described in any one of (1) to (14) above.

Therefore, the production method of the present embodiment has the same operational advantages as the production system described in any one of (1) to (14) above.

< details of the embodiment of the present invention >

The following describes the embodiments of the present invention in detail with reference to the drawings. At least some of the embodiments described below may be arbitrarily combined.

[ outline of the method for producing the sintered body ]

Fig. 1 is an explanatory view showing an outline of a method for producing a sintered body S.

As shown in fig. 1, the customer provides the manufacturer with, for example, an existing component loaded into the product (finished product) of the company, i.e., the current product C. The manufacturer manufactures the sintered body S by following the current product C, and provides the manufactured sintered body S as a sample to the customer.

The method for producing the sintered body S according to the present embodiment includes the steps of step 1 to step 5. The manufacturer manufactures the sintered body S having substantially the same shape as the current product C through steps 1 to 5. The outline of each of steps 1 to 5 will be described below.

A combination of all or a part of the apparatuses used in the manufacturing method shown in fig. 1 is referred to as a "manufacturing system" of the sintered body S.

Step 1: acquisition of 3D data

Step 1 is a step of acquiring 3-dimensional cad (computer Aided design) data of an object (in the present embodiment, a current product C of a customer) which becomes a reference of the shape of the sintered body S. Hereinafter, the 3-dimensional CAD data is referred to as "3D data".

In step 1, a real object of the current product C is read, for example, by the 3D scanner 1, thereby acquiring 3D data. In this case, the 3D scanner serves as a 3D data acquisition unit.

When a customer or a third party (hereinafter, referred to as "customer or the like") has 3D data of the current product C, the 3D data specified by the customer or the like may be directly input to the computer device 2 in 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 not needed or used, and the computer device 2 serves as a 3D data acquisition unit.

Step 2: creation of molded body processing program (setting of production conditions)

Step 2 is a step of creating a molded body machining program (hereinafter, also referred to as "machining program") from the 3D data acquired in step 1.

The machining program is a computer program for controlling the operation of the molded body machining device 32 used in step 3. The creation of the machining program is performed, for example, by the computer device 2 storing CAD/cam (computer aid manufacturing) software.

And step 3: production of sintered bodies by machining of shaped bodies

Step 3 is a step of manufacturing the sintered body S by the manufacturing apparatus 3.

The manufacturing facility 3 used in step 3 includes a step P2 of processing the green compact M before sintering by a compact processing device (hereinafter, also referred to as "processing device") 32. The processing device 32 performs a predetermined process on the powder compact M in accordance with the processing program created in step 2.

And 4, step 4: modification of the processing procedure for molded articles (optimization of production conditions)

Step 4 is a step of correcting the machining program based on the 3D data of the non-defective sintered body S manufactured in step 3.

The modification of the machining program is performed, for example, by a computer device 4 storing CAD/cat (computer Aided testing) software. The result of the correction of the machining program is fed back to the machining device 32 in step 3. The result of the correction of the machining program may be fed back to the computer device 2 that created the machining program (step 2).

And 5: provision of sintered body (sample)

Step 5 is a step of determining 1 or more sintered bodies S manufactured by the correction process of step 4 as samples, and providing the sintered bodies S determined as the samples to the customer.

The customer provided with the sample, i.e., the sintered body S, can perform the performance comparison of the current product C and the sintered body S by, for example, a test apparatus of the present company. If the performance of the sintered body S provided as a sample is equal to or higher than that of the current product C, the customer may replace the current product C with the sintered body S.

In the present embodiment, since the manufacturing facility 3 (see fig. 3) for processing the green compact M is used in step 3, the processing such as cutting is easy and the productivity is excellent. Therefore, the sintered body S can be produced at a lower cost and in a shorter delivery period than, for example, a cast product or a forged product.

Therefore, in the case where the current product C is a cast body or a forged body, the customer replaces the current product C with the sintered body S, thereby expecting to suppress the manufacturing cost and shorten the staging period.

According to the manufacturing method of the present embodiment, for example, the sintered body S such as a sprocket, a rotor, a gear, a link, a flange, a pulley, a vane, or a bearing incorporated in a machine such as an automobile can be manufactured.

The sintered body S is not limited to a product in the automobile field. For example, according to the manufacturing method of the present embodiment, the sintered body S such as a turbine blade of an airplane, an artificial bone and an artificial joint used in the medical field, or a radiation shielding member used in the nuclear energy field can be manufactured, and the application range is wide.

[ apparatus used in step 1 ]

Fig. 2 is an explanatory diagram showing an example of the apparatus used in step 1 and step 2.

As shown in fig. 2, the apparatus used in step 1 is a non-contact 3-dimensional shape measuring machine (hereinafter referred to as a "3D scanner") 1. The non-contact 3D scanner 1 is a device that detects irregularities on a surface (a distance to an arbitrary point on the surface) without contacting an object, converts the detection result into 3-dimensional CAD data, and introduces the data into the computer device 2.

Specifically, the 3D scanner 1 acquires 3-dimensional coordinate data (X, Y, Z) of each point on the surface of the object while irradiating light to the object. The 3D scanner 1 converts the acquired point group data into polygon data to generate a mesh-like stereoscopic image.

The 3D scanner 1 converts point group data constituting a three-dimensional figure into 3-dimensional CAD data in a predetermined file format, and transmits the converted 3-dimensional CAD data to the computer device 2 connected to the scanner itself.

The non-contact type 3D scanner 1 is roughly classified into a "laser type" and a "pattern light type". The laser type is a type in which a laser beam is irradiated to an object and scanned, a light receiving sensor recognizes reflected light from the object, and a distance to the object is measured by a trigonometry method.

The pattern light type is a type in which a pattern light is irradiated to an object and scanned, and a distance from the device to the object is measured by recognizing a line of the pattern in a stripe pattern.

The pattern light type can be measured at a higher speed than the laser type. Therefore, in the example of fig. 2, the pattern light type 3D scanner 1 is adopted. As a commercial product of the pattern light type 3D scanner 1, for example, KEYENCEVL-300 series is available.

The 3D scanner 1 illustrated in fig. 2 is a fixed type, but the 3D scanner 1 may be a portable type scanner that can be held by a hand of a user to perform measurement.

As shown in fig. 2, when the customer has 3-dimensional CAD data of the current product C, a file of the data may be directly read into the computer device 2. In this case, the operation of scanning the current product C of the real object is not required.

The acquisition target of the 3-dimensional CAD data of the current product C may be a third party other than the customer. As a third person, for example, a manufacturer of the current product C, which is requested to be manufactured by a customer, or a practitioner who exclusively decomposes a finished product and reads 3D data of the current product C is conceivable.

[ apparatus used in step 2 ]

As shown in fig. 2, the device used in step 2 is constituted by a computer device 2. The computer device 2 is constituted by, for example, a desktop Personal Computer (PC). The type of the computer device 2 is not particularly limited. The type of the computer device 2 may be, for example, a notebook type or a tablet type.

The computer device 2 includes an information Processing device including a CPU (central Processing unit) and a volatile memory, and a storage device including a nonvolatile memory for storing a computer program executed by the CPU and data necessary for the execution thereof. Also included in the computer device 2 are an input device and a display.

The computer device 2 functions as a predetermined control device by the CPU reading out and executing a computer program in the volatile memory.

The computer device 2 is provided with CAD/CAM software. The CAD/CAM software is software for creating a machining program for operating the molded body machining device 32 in response to an operation input by a User to a gui (graphical User interface) of the computer device 2.

As the CAD/CAM software, for example, software such as "MasterCam" or "robotmtler" (both registered trademarks) can be used. These pieces of software can generate a machining program corresponding to the type of the molded body machining device 32 (for example, articulated robot, 5-axis machining center, or the like). These pieces of software may be capable of generating a machining program described in japanese patent application laid-open No. 2009-226562.

The settings necessary for creating the machining program include setting of the shape of the workpiece (the powder compact M in the present embodiment), setting of the tool used for machining, setting of the tool path, and the like.

The computer 2 creates a molded body processing program, for example, an nc (numerical control) program, based on the 3-dimensional CAD data of the current product C and setting information input by the user. The computer means 2 sends the machining program created by the CAD/CAM software to the molded body machining means 32 used in step 3.

In the present embodiment, in step 3, the molding device 31 (see fig. 3 and 4) produces a green compact M having a simple shape such as a cylinder or a barrel, and the processing device 32 (see fig. 3 and 5) cuts the green compact M to produce a processed compact P having the same shape as the current product C.

Therefore, the machining program created by the computer device 2 is a program for causing the machining device 32 to perform cutting with respect to the powder compact M having a predetermined shape. The 3-dimensional CAD data of the compact M as the workpiece is registered in the computer 2 in advance.

(kind of cutter used)

When the molded body processing apparatus 32 includes articulated robots 201 and 202 (see fig. 5) capable of replacing a tool, the processing program preferably includes a code for designating that a different tool is used for each type of work for the articulated robots 201 and 202.

For example, when it is necessary to cut the surface of the powder compact M relatively finely, the used tool may be an end mill. When the groove portion, the window portion, or the like is cut in the powder compact M, the used cutter may be a side edge cutter.

When the cutting is performed so as to widen the groove portion formed in the powder compact M, the cutting tool may be a T-slot milling cutter. When cutting a through hole in the powder compact M, the used cutter may be a drill.

The drill used for drilling is preferably a round-head drill having an arc-shaped blade at the tip (see, for example, japanese patent laid-open publication No. 2016-. When these drills are used, chipping at the hole outlet of the powder compact M can be suppressed.

(processing conditions of the powder compact)

The preferred rotational speed of the tool used when cutting the powder compact M is, for example, 500 to 50000 rpm. More preferably 1000 to 15000 rpm.

The preferable feed rate of the cutter used when cutting the powder compact M is, for example, 20 to 6000 mm/min. More preferably 200 to 2000 mm/min.

The depth of cut and the position of cut of the powder compact M are calculated based on the 3-dimensional CAD data of the powder compact M input by the user operation in step 2 and the 3-dimensional CAD data of the current product C acquired in step 1.

[ manufacturing facility used in step 3 ]

Fig. 3 is an overall configuration diagram showing an example of the manufacturing apparatus 3 used in step 3.

As shown in fig. 3, the manufacturing facility 3 of the present embodiment is a facility in which apparatuses 31 to 35 for individually performing the steps P1 to P5 are sequentially provided. The manufacturing apparatus 3 is installed in a factory of a manufacturer of the sintered body S.

The manufacturing facility 3 illustrated in fig. 3 is constituted by a line, specifically, the line includes devices 31 to 35 corresponding to the steps P1 to P5, conveyors 36 passing near the devices 31 to 35, and a robot arm 37 for carrying in and out a workpiece (such as a powder compact M) to the devices 31 to 35.

The robot arm 37 carries in the workpiece from the conveyor 36 to each of the devices 32 to 35 and carries out the workpiece from each of the devices 31 to 35 to the conveyor 36 in units of 1.

The respective processes P1 to P5 executed by the manufacturing apparatus 3 are summarized as follows.

P1) molding process: the raw material powder is uniaxially pressed by using a die, thereby producing a powder compact M having a relative density of 93% or more in whole or in part.

P2) processing procedure: the powder compact M is machined to produce a molded product P.

P3) sintering process: the molded body P is sintered to obtain a sintered body S.

P4) finishing process: finishing is performed so that the actual dimension of the sintered body S approaches the design dimension.

P5) inspection process: the sintered body S is inspected for dimensional accuracy and/or the presence or absence of defects.

Preferred specific examples of the steps P1 to P5 are described below.

[ Molding Process P1 ]

(example 1 of raw Material powder)

The metal powder that becomes the raw material of the molding step P1 is the main material constituting the sintered body S. Examples of the metal powder include iron and iron alloy powder containing iron as a main component. As the metal powder, a pure iron powder or an iron alloy powder is typically used.

The "iron alloy containing iron as a main component" means that the iron element is contained in an amount of more than 50 mass%, preferably 80 mass% or more, and more preferably 90 mass% or more as a constituent component. Examples of the iron alloy include an iron alloy containing at least 1 alloying element selected from Cu, Ni, Sn, Cr, Mo, Mn, and C.

The above-mentioned alloying elements contribute to the improvement of the mechanical properties of the iron-based sintered body. The content of Cu, Ni, Sn, Cr, Mn, and Mo in the alloying elements is 0.5 mass% or more and 5.0 mass% or less in total, and is further 1.0 mass% or more and 3.0 mass% or less.

The content of C is set to 0.2 mass% to 2.0 mass%, and further 0.4 mass% to 1.0 mass%. In addition, as the metal powder, iron powder to which the above-described alloying elements are added (alloying powder) may be used.

In this case, the constituent component of the metal powder is iron at the stage of the raw material powder, but the iron is alloyed by the reaction of the iron with the alloying element by sintering in the sintering step P3.

The content of the metal powder (including the alloying powder) in the raw material powder is, for example, 90 mass% or more, and further 95 mass% or more. As the metal powder, for example, powder produced by a water atomization method, a gas atomization method, a carbonyl method, a reduction method, or the like can be used.

The average particle diameter of the metal powder is, for example, 20 μm to 200 μm, and further 50 μm to 150 μm. When the average particle diameter of the metal powder is within the above range, handling is easy and press molding is easy. Further, by setting the average particle diameter of the metal powder to 20 μm or more, the fluidity of the raw material powder is easily ensured. By setting the average particle diameter of the metal powder to 200 μm or less, the sintered body S having a dense structure can be easily obtained.

The average particle diameter of the metal powder is the average particle diameter of the particles constituting the metal powder. The average particle diameter of the particles is, for example, a particle diameter (D50) in which the cumulative volume of the volume particle size distribution measured by a laser diffraction particle size distribution measuring apparatus is 50%. By using the fine-grained metal powder, it is possible to reduce the surface roughness of the sintered body S or sharpen the corner edges.

(example 2 of raw material powder: case of Induction heating)

In the case where the sintering step P3 is performed by high-frequency induction heating, it is preferable to use raw material powder including Fe powder or Fe alloy powder and C powder. The raw material powder mainly contains Fe powder or Fe alloy powder. Hereinafter, the Fe powder and the Fe alloy powder are collectively referred to as Fe-based powder in some cases.

Fe powder, Fe alloy powder:

the Fe powder is pure iron powder. The Fe alloy powder contains iron as a main component, and has, for example, a plurality of Fe alloy particles containing 1 or more kinds of additive elements selected from Ni and Mo. The Fe alloy is allowed to contain inevitable impurities.

Specific examples of the Fe alloy include Fe-Ni-Mo alloys. Examples of the Fe-based powder include water atomized powder, gas atomized powder, carbonyl powder, and reducing powder. The content of the Fe-based powder in the raw material powder is, for example, 90 mass% or more, and more preferably 95 mass% or more, when the raw material powder is 100 mass%. The content of Fe in the Fe alloy is 90 mass% or more, and more preferably 95 mass% or more, based on 100 mass% of the Fe alloy. The content of the additive elements in the Fe alloy is more than 0 mass% and 10.0 mass% or less in total, and is further 0.1 mass% or more and 5.0 mass% or less.

The average particle diameter of the Fe-based powder is, for example, 50 μm or more and 150 μm or less. When the average particle diameter of the Fe-based powder is within the above range, handling and press molding are easy. By setting the average particle diameter of the Fe-based powder to 50 μm or more, the fluidity can be easily ensured. By setting the average particle diameter of the Fe-based powder to 150 μm or less, the sintered body S having a dense structure can be easily obtained. The average particle diameter of the Fe-based powder is more preferably 55 μm or more and 100 μm or less.

The "average particle diameter" is a particle diameter (D50) at which the cumulative volume of the volume particle size distribution measured by a laser diffraction particle size distribution measuring apparatus is 50%. This is the same for the average particle diameters of the C powder and the Cu powder described later.

C, powder:

the C powder becomes a liquid phase of Fe — C at the time of temperature rise, and the corners of the pores in the sintered body S are rounded, thereby improving the strength (radial compressive strength) of the sintered body S. The content of the C powder in the raw material powder is 0.2 mass% to 1.2 mass% when the raw material powder is 100 mass%.

By setting the content of the C powder to 0.2 mass% or more, the liquid phase of Fe — C is sufficiently developed, and the corners of the pores are effectively rounded, thereby facilitating the improvement of strength. By setting the content of the C powder to 1.2 mass% or less, excessive formation of a liquid phase of Fe — C is easily suppressed, and a sintered body S with high dimensional accuracy is easily produced.

The content of the C powder is more preferably 0.4 to 1.0 mass%, and particularly preferably 0.6 to 0.8 mass%. The average particle diameter of the C powder is preferably smaller than that of the Fe powder. In this case, the C particles are easily dispersed uniformly among the Fe particles, and thus the alloying is easily advanced.

The average particle diameter of the C powder is, for example, 1 to 30 μm, and more preferably 10 to 25 μm. From the viewpoint of producing a liquid phase of Fe-C, it is preferable that the average particle diameter of the C powder is large, but if it is too large, the time for the liquid phase to appear becomes long, and the pores become too large and become defects. In addition, in the case where the raw material powder contains pure iron powder but does not contain C, the strength of the sintered body S is lower than that of the sintered body S produced using the belt-type continuous sintering furnace.

Cu powder:

the raw material powder further preferably contains Cu powder. The Cu powder contributes to the liquid phase of Fe-C at the time of temperature rise in the sintering step described later. Cu has a function of improving strength by being dissolved in Fe, and a high-strength sintered body S can be produced by containing Cu powder.

The content of the Cu powder in the raw material powder is 0.1 mass% to 3.0 mass% when the raw material powder is 100 mass%. By setting the content of the Cu powder to 0.1 mass% or more, Cu diffuses in Fe at the time of temperature rise (sintering), so that diffusion of C into Fe is easily suppressed, and a liquid phase of Fe — C is easily generated.

By setting the content of the Cu powder to 3.0 mass% or less, Cu acts to diffuse in Fe at the time of temperature rise (sintering), so that Fe particles expand and the shrinkage at the time of sintering is offset, and therefore, a sintered body S with high dimensional accuracy can be easily produced.

The content of the Cu powder is further 1.5 mass% or more and 2.5 mass% or less. The average particle diameter of the Cu powder is preferably smaller than that of the Fe powder, similarly to the C powder. In this case, the Cu particles are easily dispersed uniformly among the Fe particles, and thus the alloying is easily advanced. The average particle diameter of the Cu powder is, for example, 1 μm to 30 μm, and more preferably 10 μm to 25 μm.

(internal Lubricant)

In press molding using a die, in order to prevent the metal powder from being fused to the die, a raw material powder obtained by mixing the metal powder with an internal lubricant is generally used. However, in the present embodiment, the raw material powder preferably contains no internal lubricant or, if contained, 0.2 mass% or less of the whole raw material powder. The purpose is to obtain a powder compact M having a relative density of 93% or more by suppressing a decrease in the proportion of metal powder in a raw material powder.

However, it is permissible to include a small amount of the internal lubricant in the raw material powder in a range where a powder compact having a relative density of 93% or more can be produced. As the internal lubricant, a metal soap such as lithium stearate or zinc stearate can be used.

(organic Binder)

In the subsequent processing step P2, an organic binder may be added to the raw material powder in order to suppress the occurrence of cracks or chips in the powder compact M.

Examples of the organic binder include polyethylene, polypropylene, polyolefin, polymethyl methacrylate, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyamide, polyester, polyether, polyvinyl alcohol, vinyl acetate, paraffin wax, and various waxes. The organic binder may be added as needed, or may not be added. When the organic binder is added, the amount of the organic binder needs to be such that the powder compact M having a relative density of 93% or more can be produced in the molding step P1.

(pressing method of powder compact)

In the molding step P1, the raw material powder is uniaxially pressed by using a die to produce a powder compact M. The die for uniaxial pressing is a die having a die and a pair of punches fitted into upper and lower openings thereof. The raw powder filled in the cavity of the die is compressed by an upper punch and a lower punch, thereby producing a powder compact M.

The powder compact M that can be molded by the above-described mold has a simple shape. Examples of the simple shape include a cylindrical shape, a square cylindrical shape, and a square cylindrical shape.

A punch having a convex portion or a concave portion on a punch surface may be used. In this case, a depression or protrusion corresponding to the projection or recess is formed in the simply-shaped powder compact M. The powder compact M having the above-described depressions or protrusions is also included in the powder compact M having a simple shape.

The uniaxial pressing pressure (surface pressure) is set to 600MPa or more. By increasing the surface pressure, the relative density of the powder compact M can be increased. The surface pressure is preferably 1000MPa or more, and more preferably 1500MPa or more. The upper limit of the face pressure is not particularly limited.

(external lubricant)

In the uniaxial pressing, in order to prevent the metal powder from being fused to the die, it is preferable to apply an external lubricant to the inner peripheral surface of the die (the inner peripheral surface of the die, the pressing surface of the punch).

As the external lubricant, for example, a metal soap such as lithium stearate or zinc stearate can be used. In addition, fatty acid amides such as lauramide, stearic acid amide, palmitic acid amide and the like, and higher fatty acid amides such as ethylenebisstearic acid amide and the like can be used as the external lubricant.

(relative Density of powder compact)

The average relative density of the whole of the powder compact M obtained by 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 most preferably 99.8% or more.

The high-density portion having an average relative density of 93% or more may be the whole of the powder compact M or a part thereof. However, in the processing step P2 described later, when the powder compact M is gripped by the articulated robot 202 (see fig. 5), the average relative density of the whole is preferably 93% or more. This is because if the density is high as a whole, the chips are not easily generated regardless of the gripping position.

As described above, according to the manufacturing apparatus 3 of the present embodiment, the sintered body S having the average relative density of 93% or more as a whole can be obtained.

The average relative density of the sintered body S as a whole is substantially equal to the average relative density of the green compact M before sintering. The average relative density of the sintered body S is preferably 95% or more, more preferably 96% or more, and still more preferably 97% or more, and the higher the average relative density is, the higher the strength of the sintered body S becomes.

The average relative density of the entire powder compact M can be obtained by taking cross sections (preferably orthogonal cross sections) intersecting the pressing axis direction at positions near the center, near one end side, and near the other end side of the powder compact M in the pressing axis direction, and analyzing the images of the cross sections.

More specifically, first, images of a plurality of observation fields are acquired at each cross section, and for example, 10 or more images having a size of 500 μm × 600 μm (300000 μm) are acquired at each cross section²An image of the observation field of view of the area of (a). The images of the respective observation fields are preferably acquired from positions dispersed as evenly as possible in the cross section.

Next, the obtained images of the respective observation fields are binarized to determine the area ratio of the metal particles in the observation fields, and the area ratio is regarded as the relative density of the observation fields.

Then, the relative densities obtained from the respective observation fields were averaged, and the average relative density of the whole compact was calculated. Here, the vicinity of the one end (the vicinity of the other end) is, for example, a position within 3mm from the surface of the powder compact M.

[ working procedure P2 ]

In the processing step P2, the green compact M produced by uniaxial pressing is machined without sintering.

Machining is typically cutting. In this case, a powder compact M having a predetermined shape is machined by using a cutting tool. Examples of the cutting process include a milling process and a turning process, and the milling process includes a drilling process. Examples of the cutting tool include a drill and a reamer used for drilling, a milling cutter and an end mill used for milling, and a turning tool and an edge-replaceable cutting insert used for turning. Alternatively, cutting may be performed using a hob, a broach, a slotting cutter, or the like.

In the case of a powder compact M in which metal particles are compacted, machining is performed so that the metal particles are peeled off from the surface of the powder compact M by a cutting tool.

Therefore, the friction of the cutting tool is extremely reduced as compared with the case of cutting a cast body, a temporarily fired body, or the like, for example, and the life of the tool can be significantly shortened. Further, the machining chips generated by the machining are composed of metal powder separated from each metal particle constituting the powder compact M. The powdery processing chips can be reused without dissolution.

[ sintering Process P3 ]

In the sintering step P3, the processed compact P obtained by machining the powder compact M is sintered. The work compact P is sintered to obtain a sintered body S in which particles of the metal powder are bonded to each other in contact with each other. In the sintering step P3, predetermined conditions corresponding to the composition of the metal powder can be applied.

When the metal powder is an iron powder or an iron alloy powder, the sintering temperature is, for example, 1100 ℃ to 1400 ℃ inclusive, and further 1200 ℃ to 1300 ℃ inclusive. The sintering time is, for example, 15 minutes to 150 minutes, and more preferably 20 minutes to 60 minutes.

The degree of machining in the machining step P2 can be adjusted based on the difference between the actual dimension and the design dimension of the sintered body S. A processed compact P obtained by processing a high-density green compact M having a relative density of 93% or more shrinks substantially uniformly during sintering.

Therefore, the actual size of the sintered body S can be made close to the design size by adjusting the degree of machining in the machining step P2 based on the difference between the actual size and the design size after sintering. As a result, the workload and time of the subsequent finishing process P4 can be reduced. When machining is performed by the articulated robots 201 and 202 or the machining center, the degree of machining can be easily adjusted.

[ finishing procedure P4 ]

In the finishing process P4, the surface of the sintered body S is polished or the like to reduce the surface roughness of the sintered body S and to make the size of the sintered body S coincide with the design size (the size of the current product C).

The polishing finishing is performed by a polishing device not shown. The 3-dimensional CAD data of the current product C obtained in step 1 is input to the grinding device. The polishing device calculates the design dimensions of the sintered body S from the input data, and polishes each portion of the sintered body S so as to be the calculated design dimensions. For example, when the sintered body S is made of a gear, the tooth surface of the gear is polished.

[ inspection procedure P5 ]

In the inspection step P5, it is inspected whether or not the sintered body S conforms to the design size (the size of the current product C) and whether or not there are at least 1 of defects such as cracks.

These inspections are preferably performed by a non-contact type 3D scanner (for example, a laser type or a pattern light type 3D scanner), a non-contact type nondestructive inspection apparatus. If these inspection devices are used, the sintered bodies S can be automatically and one by one inspected.

[ device used in Molding Process P1 ]

Fig. 4 is a schematic configuration diagram showing an example of the molding apparatus 31 used in the molding step P1.

As shown in fig. 4, the forming device 31 used in the forming step P1 is, for example, a single-shaft press forming device driven by a hydraulic servo system.

The press-molding device 31 includes: a rectangular base plate 101; support columns 102 provided at four corners of the base plate 101; a ceiling frame 103 fixed to an upper end of the pillar 102; and an upper plate 104 supported on the upper part of the column 102 so as to be freely movable up and down.

A punch group 106 for controlling the vertical position by a hydraulic cylinder mechanism 105 is provided above the base plate 101, and a punch group 108 for controlling the vertical position by a hydraulic cylinder mechanism 107 is provided below the upper plate 104.

A hydraulically driven upper cylinder 109 is provided at the center 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 coupled via a link mechanism 110.

Therefore, if the upper cylinder 109 is extended, the upper plate 104 is lowered to the ready position of the raw material powder 116. Then, the upper and lower hydraulic cylinder mechanisms 105 and 107 are driven, whereby the punch group 106 and the punch group 108 are joined to each other, and the raw material powder 116 is pressurized.

The upper and lower cylinder mechanisms 105 and 107 have a structure in which a plurality of cylinders are arranged in a concentric manner in a plurality of stages, and the axis of each cylinder is located at the center of the base plate 101.

Therefore, the press-molding device 31 has a slender structure in which there is no member protruding outward from the base plate 101, and can be provided without a dent. Therefore, the press-molding device 31 has an advantage of being small in installation area and installation cost.

As shown in fig. 4, the lower punch set 106 includes a 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.

The upper punch set 108 has an upper punch 115. The upper punch 115 is cylindrical with a through hole of the core rod 112.

In the stage before the press, the upper end surface of the core rod 112 is protruded from the upper end surface of the die 111, and the outer punch 113 is provided at a position deeper than the inner punch 114. In this state, the cavity is filled with the raw material powder 116.

At the time of punching, the outer punch 113 is raised together with the lower punch 114, and the upper punch 115 is lowered. At this time, the rising speed is controlled so that the outer punch 113 and the inner punch 114 reach the top dead center at the same position simultaneously.

By the compression molding, the outer peripheral portion having a larger filling amount of the raw material powder 116 is compressed at a higher pressure than the inner peripheral portion having a smaller filling amount. In the example of fig. 4, a powder compact M having a uniform thickness is formed. Therefore, the powder compact M is a flat plate having a substantially annular shape and having the high density region M1 in the outer peripheral portion and the low density region M2 in the inner peripheral portion.

The above molding method is suitable for manufacturing a sintered body S in which sliding portions are continuous at the outer peripheral edge, such as an external gear and a sprocket. For example, in the case of an external gear, the outer teeth having high rigidity and excellent wear resistance are obtained by setting the outer peripheral side of the powder compact M to be the high density region M1.

In contrast to the case of fig. 4, if the raw material powder 116 is press-molded by providing the inner punch 114 at a position deeper than the outer punch 113, a powder compact M having a high density region M1 in the inner peripheral portion and a low density region M2 in the outer peripheral portion is obtained.

The molding method described above is suitable for the production of a sintered body S in which the sliding portion is continuous at the inner peripheral edge, such as an internal gear. For example, in the case of an internal gear, internal teeth having high rigidity and excellent wear resistance are obtained by setting the inner peripheral side of the powder compact M to be the high density region M1.

As described above, in the case of the powder compact M having the regions M1 and M2 having different relative densities, the relative density of the high-density region M1 may be 93% or more, and the relative density of the low-density region M2 may be less than 93%.

Further, if the raw material powder 116 is press-molded by providing the outer punch 113 and the inner punch 114 at the same depth position, the press-molding device 31 can be used to mold the powder compact M having an average relative density of 93% or more as a whole.

[ apparatus used in working procedure P2 ]

Fig. 5 is a schematic configuration diagram showing an example of the processing apparatus 32 used in the processing step P2.

As shown in fig. 5, the processing apparatus 32 used in the processing step P2 is, for example, a robot processing apparatus that processes the powder compact M using articulated robots 201 and 202.

The robot processing device 32 is provided in a smaller space than a 5-axis processing center, for example, and therefore contributes to the compactness of the manufacturing facility 3 of the sintered body S.

The robot machining device 32 of the present embodiment includes: 2 multi-joint robots 201, 202; and a control device 203 that controls the operation of the 2 multi-joint robots 201 and 202.

One 1 st robot 201 among the 2 multi-joint robots 201, 202 is a robot that holds a tool 204 such as a drill. The other 2 nd robot 202 is a robot that holds the powder compact M.

The 1 st robot 201 has a gripper 205 for a tool 204 at the tip of the arm. The 1 st robot 201 can grip different types of tools 204 by the gripping unit 205 in accordance with a command from the control device 203.

The 2 nd robot 202 has a grip 206 for the powder compact M at the tip of the arm. The 2 nd robot 202 can grip the powder compact M being conveyed by the conveyor 36 by the gripping unit 206. The 2 nd robot 202 can also return the molded product P to the conveyor 36.

The control device 203 includes a1 st communication unit 207, a 2 nd communication unit 208, a control unit 209, and a storage unit 210.

The 1 st communication unit 207 is a communication interface for communicating with an external device according to a communication standard such as ethernet (registered trademark). The 2 nd communication unit 208 is configured by a communication interface communicably connected to the 1 st and 2 nd arms 201 and 202.

The control unit 209 is constituted by an information processing device including a CPU, a volatile memory, and the like. The storage unit 210 is configured by a storage device including a recording medium such as an hdd (hard Disk drive) or ssd (solid State drive).

The 1 st communication unit 207, upon receiving the machining program from the computer device 2 in step 2, supplies the received program to the control unit 209. The control unit 209 extracts an operation code (for example, G code or M code) from the received machining program.

The control unit 209 sequentially outputs the extracted operation codes to the 2 nd communication unit 208, and transmits the operation codes to the articulated robots 201 and 202. The articulated robots 201 and 202 execute a predetermined operation in accordance with the received operation code.

Accordingly, the articulated robots 201 and 202 perform predetermined processing on the powder compact M in accordance with a command from the control device 203.

Since both the position and the posture of the work object (the tool 204 and the powder compact M) can be adjusted in 3-dimensions, the 1 st and 2 nd robots 201 and 202 preferably have an arm structure with at least 6 degrees of freedom.

However, the 2 nd robot 202 having a degree of freedom smaller than 6 may be used in the case where the powder compact M is held at the same position during processing and the like, and adjustment of the position and posture with a high degree of freedom is not required.

In the manufacturing apparatus 3 of the present embodiment, since the relative density of the powder compact M is 93% or more, the powder compact M held by the 2 nd robot 202 is not damaged even if the cutting work is performed on the powder compact M by the cutter 204 of the 1 st robot 201. Therefore, the powder compact M can be processed quickly.

Further, since at least the 1 st robot 201 has 6 degrees of freedom, the cutter 204 can be brought into contact with the powder compact M at an arbitrary angle, and complicated machining can be performed quickly.

[ apparatus used in sintering Process P3 ]

Fig. 6 is a schematic configuration diagram showing an example of the sintering apparatus 33 used in the sintering step P3.

As shown in fig. 6, the sintering apparatus 33 used in the sintering step P3 is constituted by, for example, an induction heating sintering furnace that heats the processed powder compact M (processed compact P) by a high-frequency induction method.

Since the temperature of the object can be raised at a high speed by heating by the high-frequency induction method, the temperature of the molded product P can be raised to a predetermined temperature in a short time. Therefore, the sintered body S can be easily produced in a short time.

As shown in fig. 6, the induction heating sintering furnace 33 includes: an elongated chamber 301; a cylindrical heating container 302 housed in the chamber 301; a cooling container 303 disposed below the heating container 302; and an elevating platform 304 disposed below the heating container 302.

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 the molded product P to any height inside the heating container 302 and inside the cooling container 303.

The induction heating sintering furnace 33 also has a power supply (not shown) capable of adjusting an output value (for example, a power value) and a frequency to the induction coil 305.

The molded product P is placed on the lift table 304 by the robot arm 37. When the molded product P is heated, the lifting/lowering table 304 positions the molded product P inside the heating container 302. When the sintered molded product P (sintered body S) is cooled, the lifting/lowering table 304 positions the sintered molded product P inside the cooling container 303.

The induction heating sintering furnace 33 preferably has: a gas supply path for supplying an inert gas into the heating container 302; and a gas discharge passage for discharging gas to the outside of the heating container 302. In this case, the work compact P can be sintered in a non-oxidizing gas atmosphere. Examples of the inert gas include nitrogen and argon.

The induction heating sintering furnace 33 can raise the temperature of the object at a high speed and can raise the temperature of the molded article P to a predetermined temperature in a short time. Therefore, for example, compared to a belt-type continuous sintering furnace, there is an advantage that the sintered body S can be produced in a short time.

Since the temperature rise rate of the induction heating sintering furnace 33 is high, there is an advantage that the induction heating sintering furnace can be installed in a smaller installation space 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., 1.5m × 1.5m) can be used.

The induction heating sintering furnace 33 can be completed in a short time when sintering the molded product P, and it is not necessary to maintain the temperature of the sintering furnace 33 during a period when sintering the molded product P is not performed. Therefore, for example, compared to a continuous strand sintering furnace, there is an advantage that energy saving is achieved.

In the sintering step P3, the temperature rise process, the sintering process, and the cooling process are sequentially performed. Next, a preferable temperature history in the case of using the induction heating sintering furnace 33 will be described.

(temperature raising Process)

During the temperature increase, the temperature of the formed body P is controlled so as to satisfy all of the following conditions (I) to (III). The A1 point is about 738 deg.C, and the A3 point is about 910 deg.C.

(I) In the temperature region of the Fe-C state diagram, which is equal to or higher than the point A1 and is lower than the sintering temperature of the formed article P, the temperature is not maintained but increased.

(II) the temperature increase rate in the temperature range from point A1 to point A3 of the Fe-C state diagram is set to 12 ℃/sec or more.

(III) the rate of temperature increase from the point A3 of the Fe-C state diagram to the sintering temperature of the formed body P is set to 4 ℃/sec or more.

If the temperature control is performed so that the conditions (I) to (III) are satisfied, the following conditions (I) to (III) are satisfied. The reason for this is that the conditions (I) to (III) and the conditions (I) to (III) substantially have a correlation.

That is, the temperature control is performed so that the conditions (I) to (III) are satisfied if the conditions (I) to (III) are satisfied.

(i) In the atmospheric temperature region corresponding to the temperature of not less than point A1 of the Fe-C state diagram and less than the sintering temperature of the formed body P, the atmospheric temperature is not maintained but increased.

(ii) The temperature increase rate of the atmosphere temperature region corresponding to the point A1 to the point A3 of the Fe-C state diagram is set to 12 ℃/sec or more.

(iii) The temperature increase rate in the atmosphere temperature region from the point A3 of the Fe-C state diagram to the sintering temperature of the formed body P is set to 4 ℃/sec or more.

The atmospheric temperature is the atmospheric temperature in the heating vessel 302 and is measured by a thermocouple (diameter. phi.3.5 mm) disposed within 8.5mm from the molded article P.

Since the atmosphere in the heating container 302 is heated by the heat of the induction-heated molded article P, the temperature of the atmosphere is often slightly lower than the temperature of the induction-heated molded article P itself. For example, the atmospheric temperature corresponding to the point a1 is the atmospheric temperature when the temperature of the molded article P is the point a1, and is often equal to or lower than the point a 1. The same applies to the atmospheric temperature corresponding to the point a3 and the atmospheric temperature corresponding to the sintering temperature of the molded article P.

By satisfying all of the conditions (I) to (III) (i.e., all of the conditions (I) to (III)), the sintered body S having high strength can be manufactured. The reason for this is as follows.

In the temperature range of the condition (I), C is likely to diffuse into Fe, but diffusion of C into Fe is suppressed by keeping the temperature in this temperature range at a high temperature increase rate as in the conditions (II) and (III) without maintaining the temperature.

Then, for example, C particles adjacent to the Fe particles remain as solid phases, and the adjacent interfaces between the Fe particles and the C particles, etc., become C-rich phases (sometimes, only C).

If a C-rich phase remains on the surface of Fe, the phase becomes a liquid phase of Fe-C at the sintering temperature. As is clear from the Fe-C state diagram, if C is about 0.2 mass% or more, the Fe-C material becomes a liquid phase at 1153 ℃ or more. Therefore, if the molded article P is sintered at a temperature of 1153 ℃ or higher, the C-rich phase becomes a liquid phase.

That is, if the temperature is increased at a high rate without maintaining the temperature in a temperature region where C is easily diffused into Fe, a liquid phase of Fe-C is easily generated. The Fe-C liquid phase rounds the corners of the pores formed between the particles, and reduces the acute corners of the pores, which cause a decrease in strength (starting point of fracture). As a result, the strength, particularly the radial compressive strength, of the sintered body S is improved.

The temperature increase rate can be adjusted by adjusting the output and frequency of the power supply of the induction heating sintering furnace 33. The setting of the output and the frequency includes, for example, setting of the output and the frequency to satisfy the temperature increase rate of the condition (II).

The setting of the output and the frequency may be constant over 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 changed to the temperature range of the condition (III).

If the output and the frequency are set to be constant in the temperature range from the condition (II) to the condition (III), the temperature increase rate of the condition (III) can be satisfied.

However, if the output and the frequency are constant, the temperature increase rate under the condition (III) is slower than the temperature increase rate under the condition (II). If the output and frequency settings are changed when switching from the temperature range of condition (II) to the temperature range of condition (III), the temperature increase rate of condition (III) can be further increased, and can be set to be about the same as the temperature increase rate of condition (II).

The temperature increase rate in the condition (II) is preferably as high as possible, and for example, more preferably 12.5 ℃/sec or more. The upper limit of the temperature increase rate in the condition (II) is, for example, 50 ℃/sec or less, and more preferably 15 ℃/sec or less.

The temperature increase rate in the condition (III) is preferably as high as possible, for example, preferably 5 ℃/sec or more, and more preferably 10 ℃/sec or more, as in the above-mentioned condition (II). The upper limit of the temperature increase rate in the condition (III) is, for example, 50 ℃/sec or less, and more preferably 15 ℃/sec or less.

In the temperature raising process, it is further preferable to control the temperature of the molded article P so as to satisfy either of the condition (IV) and the condition (V).

(IV) in the temperature region where the molded article P is 410 ℃ or higher and less than A1 point in the Fe-C based state diagram, the temperature is not maintained, and the temperature rise rate in the temperature region is set to 12 ℃/sec or higher.

(V) the temperature of the molded article P is maintained in a temperature range of 410 ℃ or higher and less than point A1 in the Fe-C system diagram for 30 seconds to 90 seconds.

If the temperature control is performed so that either of the condition (IV) and the condition (V) is satisfied, either of the following condition (IV) and the condition (V) is satisfied. The reason for this is that the conditions (IV) and (V) substantially have a correlation with each other.

That is, the temperature is controlled so that if either of the condition (IV) and the condition (V) is satisfied, either of the condition (IV) and the condition (V) is satisfied.

(iv) The temperature rise rate in the atmosphere temperature region is set to 12 ℃/sec or more without maintaining the atmosphere temperature of 400 ℃ or more and less than 700 ℃.

(v) The temperature of the atmosphere is maintained at 400 ℃ or higher and less than 700 ℃ for 30 seconds or longer and 90 seconds or shorter.

If the conditions (IV) and (IV) are satisfied, a sintered body S having a high strength can be produced in a shorter time than when the conditions (V) and (V) are satisfied. The temperature increase rates of the conditions (IV) and (IV) can be realized by setting the output and the frequency to the same setting as the output and the frequency of the temperature increase rate satisfying the conditions (II) and (II), for example.

In this case, the output of the power source of the induction heating sintering furnace 33 and the frequency are set to be constant from the start of temperature rise to the time of sintering, and the atmospheric temperature from the atmospheric temperature at the start of temperature rise to the atmospheric temperature at the time of sintering is not maintained. Since the atmosphere temperature is not maintained at a temperature lower than the atmosphere temperature at the time of sintering, the sintered body S can be produced in a short time. The temperature increase rate of the atmosphere temperature in the conditions (IV) and (IV) is more preferably 15 ℃/sec or more, and particularly preferably 20 ℃/sec or more.

If the conditions (V) and (V) are satisfied, the molded product P can be uniformly heated more easily than if the conditions (IV) and (IV) are satisfied. That is, the conditions (V) and (V) are particularly preferable when the molded product P having a complicated shape is sintered.

Further, a sintered body S having high strength can be obtained by satisfying the conditions (V) and (V). The temperature range of the condition (V) is more preferably 735 ℃ or less, and particularly preferably 700 ℃ or less. The atmosphere temperature of the condition (v) is more preferably 600 ℃ or less, and particularly preferably 500 ℃ or less.

The holding time for holding the ambient temperature under the conditions (V) and (V) is more preferably 45 seconds to 75 seconds. The temperature increase rates after the temperature under the condition (V) and the atmospheric temperature under the condition (V) were set to the temperature increase rates under the conditions (II), (III), and (III).

(sintering Process)

The holding time of the atmosphere temperature (sintering temperature) at the time of sintering the work compact P is determined depending on the atmosphere temperature (sintering temperature) and the compact size, but is preferably 30 seconds to 90 seconds, for example.

If the holding time is 30 seconds or more, the molded body P can be sufficiently heated, and a high-strength sintered body S can be easily produced. If the holding time is 90 seconds or less, the holding time is short, and therefore the sintered body S can be produced in a short time. The holding time is more preferably less than 90 seconds, and particularly preferably 60 seconds or less. In the case of a large-sized molded article P or the like, it may be effective to set the holding time to 90 seconds or more.

The sintering temperature of the heated compact P is not less than the temperature at which a liquid phase of Fe-C is formed, and is not less than 1153 ℃. When the sintering temperature is 1153 ℃ or higher, a liquid phase is generated, and the corners of the pores are easily rounded, and a high-strength sintered body S can be easily produced.

The sintering temperature is preferably 1250 ℃ or lower, for example. In this case, the temperature is not excessively high, and excessive generation of a liquid phase can be suppressed, so that the sintered body S with high dimensional accuracy can be easily produced. The sintering temperature is more preferably 1153 ℃ to 1200 ℃ and even more preferably 1155 ℃ to 1185 ℃.

The atmosphere temperature at the time of sintering of the formed body P is preferably 1135 ℃ or more and less than 1250 ℃. If the sintering temperature of the work-forming body P is 1153 ℃ or higher, the atmosphere temperature during sintering of the work-forming body P is 1135 ℃ or higher.

Likewise, if the sintering temperature of the work-formed body P satisfies 1250 ℃ or less, the atmosphere temperature at the time of sintering the work-formed body P satisfies less than 1250 ℃. The atmosphere temperature during sintering is more preferably 1135 ℃ to 1185 ℃, and particularly preferably 1135 ℃ to 1185 ℃.

(Cooling Process)

The cooling rate in the cooling process in the sintering process P3 is preferably set to be high. By increasing the cooling rate, the bainite structure is easily formed, and the martensite structure is more easily formed, so that the strength of the sintered body S is easily increased.

The cooling rate is preferably 1 ℃/sec or more. Thereby, rapid cooling is enabled. The cooling rate is more preferably 2 ℃/sec or more, and particularly preferably 5 ℃/sec or more. The cooling rate is, for example, 200 ℃/sec or less, further 100 ℃/sec or less, and particularly 50 ℃/sec or less.

The temperature range in which cooling is performed at the cooling rate may be a temperature range from the start of cooling (sintering temperature of the molded product P) to the completion of cooling (e.g., about 200 ℃). In particular, the temperature of the formed product P (atmosphere temperature) is preferably in a temperature range of 750 ℃ (700 ℃) to 230 ℃ (200 ℃ (atmosphere temperature range).

As a cooling method, a method of blowing a cooling gas to the sintered body S is exemplified. The cooling gas may be an inert gas such as nitrogen or argon. The rapid temperature reduction can eliminate the heat treatment step in the subsequent step.

[ device used in inspection Process P5 ]

Fig. 7 is a schematic configuration diagram showing an example of the inspection apparatus 35 used in the inspection process P5.

As shown in fig. 7, the inspection apparatus 35 used in the inspection process P5 includes the 1 st and 2 nd sensor apparatuses 501 and 502, and a computer apparatus 503 communicably connected to the sensor apparatuses 501 and 502.

The computer device 503 is constituted by, for example, a desktop Personal Computer (PC). The type of the computer device 503 is not particularly limited. The type of the computer device 503 may be, for example, a notebook type or a tablet type.

The computer device 503 is configured by an information processing device including a CPU and a volatile memory, and a storage device including a nonvolatile memory for storing a computer program executed by the CPU and data necessary for the execution thereof. Also included in the computer device 2 are an input device and a display.

The computer device 503 functions as a predetermined control device by the CPU reading out and executing a computer program in the volatile memory.

The 1 st sensor device 501 is constituted by a non-contact 3D scanner, for example. The 3D scanner may be the aforementioned pattern light type 3D scanner 1 (see fig. 2) or may be a laser type 3D scanner.

The 1 st sensor device 501 scans the sintered bodies S having undergone the finishing process P4 one by one to generate 3-dimensional CAD data, and transmits the generated data to the computer device 503.

The 2 nd sensor device 502 is constituted by, for example, a digital camera capable of acquiring a digital image. The 2 nd sensor device 502 images the sintered bodies S having undergone the finishing process P4 one by one to generate image data, and transmits the generated image data to the computer device 503.

The computer means 503 stores 3-dimensional CAD data of the current product C. This data is, for example, data received from the computer device 2 in step 2 or data stored in the computer device 503 via a recording medium such as a USB memory.

The computer device 503 calculates the dimensional errors of the sintered body S and the current product C based on the 3-dimensional CAD data of the sintered body S and the 3-dimensional CAD data of the product C, and determines whether or not the sintered body S is acceptable based on the calculated dimensional errors. Specifically, the sintered body S having a dimensional error of a predetermined value or less is regarded as a pass, and the sintered body S exceeding the predetermined value is regarded as a fail.

Further, the computer device 503 transmits the 3-dimensional CAD data of the sintered body S determined to be acceptable to the computer device 4 used in step 4.

The computer device 503 determines the presence or absence of cracks and damages on the surface based on the image data acquired from the 2 nd sensor device 502, and determines that the sintered body S having cracks and damages is defective. The sintered body S having cracks or damages was excluded as a defective product.

The determination process can be performed, for example, by determining whether or not a target event such as a damage included in the classification model obtained by machine learning is included in the partial image obtained by dividing the image data into a grid shape (see japanese patent application laid-open No. 2018-81629).

[ Effect of the manufacturing facility of the present embodiment ]

According to the manufacturing facility 3 of the present embodiment, the green compact M having a simple shape and a high density is manufactured by uniaxial pressing, the green compact M is processed by the robot processing apparatus 32 having a high degree of freedom in processing to produce the green compact P, and the green compact P is sintered to produce the sintered body S.

Therefore, a highly accurate sintered body S can be produced without using a die having a complicated shape which requires several months. Therefore, the delivery time of the sintered body S can be shortened.

According to the manufacturing facility 3 of the present embodiment, the induction heating sintering furnace 33 capable of producing the sintered body S in a shorter time than the continuous strand sintering furnace is used, and therefore the delivery date of the sintered body S can be shortened even in this point.

According to the manufacturing system of the present embodiment, since the robot processing device 32 having a smaller installation space than the 5-axis processing center and the induction heating sintering furnace 33 having a smaller installation space than the belt-type continuous sintering furnace are used, there is an advantage that the manufacturing facility 3 can be made compact.

[ apparatus used in step 4 ]

Fig. 8 is an explanatory diagram showing an example of the apparatus used in step 4.

As shown in fig. 8, the device used in step 4 is constituted by the computer device 4. The computer device 2 is constituted by, for example, a desktop Personal Computer (PC). The type of the computer device 2 is not particularly limited. The type of the computer device 2 may be, for example, a notebook type or a tablet type.

The computer device 4 is configured by an information processing device including a CPU and a volatile memory, a storage device including a nonvolatile memory for storing a computer program executed by the CPU and data necessary for the execution thereof, and the like. Also included in the computer device 2 are an input device and a display.

The computer device 4 functions as a predetermined control device by the CPU reading out and executing a computer program in the volatile memory.

The computer device 4 is provided with CAD/CAT software. The CAD/CAT software is software for realizing a comparison process between 3-dimensional CAD data of a determination target (in this case, the sintered body S that is qualified for inspection in the inspection step P5) and design data (3-dimensional CAD data of the current product C) that serves as a reference of the shape of the sintered body S in accordance with an operation input by a user to the GUI of the computer device 4.

The computer device 4 receives the 3-dimensional CAD data of the plurality of sintered bodies S from the computer device 503 of the inspection step P5.

The computer means 4 stores 3-dimensional CAD data of the current product C. The data is, for example, data received from the computer device 2 in step 2, data received from the computer device 503 in the inspection step P5, or data stored in the computer device 4 via a recording medium such as a USB memory.

The computer device 4 determines whether or not the over-cut or under-cut portion is detected in a statistically significant amount based on the comparison result between the 3D data of the plurality of sintered bodies C and the 3D data of the current product C.

When the computer device 4 detects a region that is cut excessively or cut insufficiently, it generates a correction program (for example, an NC program) of the machining program. The correction program includes, for example, an operation code for increasing the depth of cut of an excessive-cut portion or an operation code for increasing the depth of cut of an insufficient-cut portion.

The computer device 4 transmits the generated correction program to the machining device 32 used in the machining process P2 of step 3. Thus, the compact processing apparatus 32 having received the correction program processes the powder compact M at the corrected depth of cut.

Further, the computer device 4 may transmit the correction program to the computer device 2 (see fig. 2) in step 2. In this case, the computer device 2 in step 2 may transfer the received correction program to the processing device 32.

[ modification 1: variations of the apparatus used in step 3 ]

The molding device 31 used in the molding step P1 of step 3 may be a press molding device for molding the powder compact M having an average relative density of less than 93% as a whole.

The machining device 32 used in the machining process P2 in step 3 may be a robot machining device including only the 1 st robot 201. In this case, the 1 st robot 201 performs a predetermined process on the powder compact M provided on the fixed stand.

The machining device 32 used in the machining step P2 in step 3 may be a robot machining device having at least 1 of the plurality of 1 st and 2 nd robots 201 and 202. That is, the number of the 1 st and 2 nd robots 201 and 202 may be plural.

The machining device 32 used in the machining process P2 of step 3 may be a machining device that employs a 5-axis machining center instead of the articulated robots 201 and 202.

The sintering apparatus 33 used in the sintering process P3 of step 3 may be a belt-type continuous sintering furnace instead of the induction heating sintering furnace.

The inspection process P5 of step 3 is not limited to being performed fully automatically using the inspection apparatus 35, and may be performed entirely or partially by a human.

The inspection process P5 of step 3 may include the modification of the machining program of step 4. That is, the calculation processing and the communication processing performed by the computer device 4 in step 4 may be executed by the computer device 503 in the inspection step P5. In this case, the computer device 4 of step 4 is not required.

[ modification example 2: manufacturing System capable of moving

Fig. 9 is a schematic configuration diagram showing an example of a movable manufacturing system.

As shown in fig. 9, the manufacturing system according to modification 2 includes a moving device 601 that can pass through a road, and a predetermined storage element stored in a storage 602 of the moving device 601. The predetermined storage element is a component necessary for producing the sintered body S.

As shown in fig. 9, the moving device 601 is constituted by, for example, a large truck, and the storage 602 is constituted by a container fixed to a loading platform of the large truck.

The manufacturing system shown in fig. 9 includes, as predetermined housing elements, the 3D scanner 1 used in step 1, the computer device 2 used in step 2, the robot processing device 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.

According to the modification 2, since a predetermined storage element is mounted on the storage box 602 of the mobile device 601, the sintered body S can be manufactured in the following procedure. Therefore, the sintered body S (sample) that is a replica of the current product C can be provided to a customer in a short time (for example, several hours).

Sequence 1: the moving device 601 is moved to a place adjacent to the customer site, and predetermined storage elements loaded in the storage 602 are transported to the adjacent place.

Sequence 2: the current product C is borrowed from the customer.

Sequence 3: the steps 1 to 3 are executed to manufacture a sintered body S which is a replica of the current product C on site.

Sequence 4: the sintered body S (sample) thus produced was supplied to a customer.

In the production of the sintered body C according to the procedure 3, the powder compact M processed by the robot processing device 32 may be previously produced by the manufacturer in the factory of the company and loaded into the transfer device 601.

In modification 2, the 3D scanner 1 may be excluded from predetermined storage elements. In this case, the 3D data generated by the 3D scanner 1 outside the vehicle may be transmitted to the computer device 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 device 2 in the vehicle.

In modification 2, the computer device 2 may be excluded from the predetermined storage elements. In this case, the computer device 2 outside the vehicle may generate a molded body processing program from the 3D data of the current product C, and transmit the generated program to the robot processing device 32 inside the vehicle.

In modification 2, the molding device 31 used in the molding step P1 of step 3 may be included in a predetermined storage element. In this case, the molding of the powder compact M can also be performed on site.

In modification 2, the device (such as a polishing device) used in the finishing step P4 of step 3 may be included in a predetermined housing element. In this case, the sintered body S can be finished in situ.

In modification 2, the inspection device 35 used in the inspection step P5 of step 3 may be included in a predetermined storage element. In this case, the inspection such as the determination of the acceptability of the sintered body S can be performed on site.

In modification 2, the device (computer device 4) used in step 4 may be included in a predetermined storage element. In this case, the machining program in step 4 can be corrected on site.

[ others ]

The above-described embodiments (including the modifications) are to be considered in all respects as illustrative and not restrictive. The scope of the present invention is indicated by the claims, rather than the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are intended to be embraced therein.

For example, in the above-described embodiments (including the modifications), the target product to be the reference of the shape of the sintered product S is not limited to the current product C, and may be a planned product that has not yet been produced.

Description of the reference numerals

13D shape measuring machine (3D scanner, acquisition part)

2 computer device (acquisition unit)

3 manufacturing equipment (production line)

4 computer device

31 molding device (molding device)

32 processing device (forming body processing device, robot processing device)

33 sintering equipment (Induction heating sintering furnace)

35 inspection device

36 conveyer

37 robot arm

101 base plate

102 support post

103 canopy frame

104 upper plate

105 Hydraulic cylinder mechanism (lower side)

106 punch set (lower side)

107 hydraulic cylinder mechanism (upside)

108 punch set (upside)

109 upper cylinder

110 link mechanism

111 punch die

112 core rod

113 outer punch

114 inner punch

114 lower punch

115 upper punch

116 raw material powder

201 Multi-joint robot (the 1 st robot)

201 Multi-joint robot (2 nd robot)

203 control device

204 cutting tool

205 grip portion

206 gripping part

207 1 st communication unit

208 2 nd communication unit

209 control unit

210 storage unit

301 chamber

302 heating container

303 cooling container

304 elevating platform

305 induction coil

501 sensor device 1 (3D scanner)

502 nd 2 sensor device (digital camera)

503 computer device

601 moving device

602 storage warehouse

C Current product (object)

M pressed powder molded body

P-shaped formed body

S sintered body