Molded body manufacturing method, sintered body manufacturing method, molded body manufacturing device, and sintered body manufacturing device

Abstract

A molded body manufacturing method according to one embodiment comprises a molding step for manufacturing a molded body by pressing a bulk powder containing a metal powder by using a die of a press machine on the basis of molding conditions including a plurality of molding variables, and an estimation step for estimating, on the basis of a molding variable distribution, which is a distribution of the plurality of molding variables, the quality of the molded body to be manufactured. In the estimation step, the quality of the molded body to be manufactured is estimated on the basis of an actual molding variable distribution, which is the actual molding variable distribution during execution of the molding step, and a reference molding variable distribution, which is the molding variable distribution when a non-defective product has been manufactured.

Description

Method for producing molded body, method for producing sintered body, molded body production apparatus and sintered body production apparatus

[0001] The present disclosure relates to a method for producing a molded body, a method for producing a sintered body, a molded body production apparatus, and a sintered body production apparatus. This application claims priority based on Japanese Patent Application No. 2025-053790 filed on March 27, 2025, and incorporates all the content described in the Japanese application by reference.

[0002] There is known a technology for producing a sintered body by pressing a raw material powder containing metal powder in a mold to produce a molded body, and then sintering the produced molded body (see Patent Documents 1 to 4).

[0003] Japanese Unexamined Patent Application Publication No. 2020-085507, Japanese Unexamined Patent Application Publication No. 2001-293356, Japanese Unexamined Patent Application Publication No. 2006-175499, International Publication No. WO 2020 / 217331

[0004] A method for producing a molded body according to one embodiment comprises: a molding step of producing a molded body by pressing a raw material powder containing metal powder with a mold of a press based on molding conditions including a plurality of molding variables; and an estimating step of estimating the quality of the molded body to be produced based on a molding variable distribution which is a distribution of the plurality of molding variables, wherein in the estimating step, the quality of the molded body to be produced is estimated based on an actual molding variable distribution which is an actual molding variable distribution during the implementation of the molding step and a reference molding variable distribution which is the molding variable distribution when a non-defective product is produced.

[0005] Figure 1 is a flowchart of a sintered body manufacturing method including a molded body manufacturing method according to one embodiment. Figure 2 is a schematic diagram of a sintered body manufacturing apparatus for carrying out the sintered body manufacturing method according to this embodiment. Figure 3 is a schematic configuration diagram showing an example of a press machine used in the molding process. Figure 4 is a schematic diagram illustrating an example of a mold. Figure 5 is a schematic diagram illustrating an example of a drive mechanism used to drive the mold. Figure 6 is a schematic diagram of an example of a molded body manufactured when the molding process is carried out using a press machine. Figure 7 is a cross-sectional view along the line VII-VII in Figure 6. Figure 8 is a schematic diagram of an example of a sintered body manufactured using the molded body shown in Figure 6. Figure 9 is a schematic diagram of a molded body manufacturing apparatus focusing on the functions of the molded body manufacturing apparatus. Figure 10 is a flowchart of an example of an estimated process.

[0006] Cracks may occur in molded products due to stress and other factors when pressurizing the raw material powder within the mold. The presence or absence of such cracks could be inspected, for example, by magnetic particle testing. However, due to the weak magnetization of the molded product, it was practically impossible to inspect for cracks at the manufacturing stage. As a result, defects such as cracks caused by these cracks occurred in the sintered products obtained by sintering the molded products, sometimes leading to a decrease in the manufacturing yield of the sintered products.

[0007] One aspect of this disclosure is to provide a molded body manufacturing method, a sintered body manufacturing method, a molded body manufacturing apparatus, and a sintered body manufacturing apparatus that can improve manufacturing yield.

[0008] According to this disclosure, it is possible to provide a molded body manufacturing method, a sintered body manufacturing method, a molded body manufacturing apparatus, and a sintered body manufacturing apparatus that can improve manufacturing yield.

[0009] First, the contents of embodiments of the present disclosure will be listed and explained. (1) A method for manufacturing a molded article according to one aspect of the present disclosure comprises a molding step of manufacturing a molded article by pressurizing raw material powder containing metal powder with a die of a press machine based on molding conditions including a plurality of molding variables, and an estimation step of estimating the quality of the molded article to be manufactured based on a molding variable distribution which is the distribution of the plurality of molding variables, wherein the estimation step estimates the quality of the molded article to be manufactured based on an actual molding variable distribution which is the actual molding variable distribution during the execution of the molding step and a reference molding variable distribution which is the molding variable distribution when a good product is manufactured.

[0010] The molded body manufacturing method described in (1) above includes an estimation step for estimating whether the molded body to be manufactured is a good product or a defective product. Therefore, if it is estimated in the estimation step that a defective product will be manufactured, the manufacturing of the molded body can be stopped. Thus, the manufacturing yield of the molded body is improved. Therefore, when a sintered body is manufactured by sintering the molded body, the manufacturing yield of the sintered body is also improved.

[0011] (2) In the molded article manufacturing method described in (1) above, if the distribution of multiple factor variables for setting the molding conditions is called the factor variable distribution, the estimation step may include a selection step of selecting the molding variable distribution that corresponds to the actual factor variable distribution which is the factor variable distribution during the molding process, from among a plurality of molding variable distributions which correspond to the plurality of factor variable distributions and which produce good molded articles, as the reference molding variable distribution, and a determination step of determining whether the molded article to be manufactured is good or bad by comparing the reference molding variable distribution selected in the selection step with the actual molding variable distribution.

[0012] In the molded article manufacturing method described in (2) above, a reference molding variable distribution is selected according to the distribution of real-factor variables during the manufacturing of the molded article, and the quality of the molded article can be estimated based on the selected reference molding variable distribution. Therefore, it is possible to estimate the quality of the molded article more accurately.

[0013] (3) In the method for manufacturing a molded article described in (1) or (2) above, the mold comprises a first mold and a second mold, the first mold being a first movable mold driven toward the second mold, the molding step pressurizing the raw material powder by driving the first mold toward the second mold, the first mold having a plurality of first punches driven independently of each other, and the plurality of molding variables may include at least the position of each of the plurality of first punches and the driving pressure for driving each of the plurality of first punches.

[0014] In this case, the molding variable distribution includes more molding variables. A molding method that can estimate the quality of a molded product based on the actual molding variable distribution and a reference molding variable distribution is effective when there are many molding variables.

[0015] (4) In the method for manufacturing a molded article described in (3) above, the second mold is a second movable mold that is driven toward the first mold, and in the molding step, the raw material powder is pressurized by driving both the first mold and the second mold, and the plurality of molding variables may include the position of the second mold and the driving pressure for driving the second mold.

[0016] In this case, the number of molding variables increases further, making the molded product manufacturing method described in (4) above even more effective.

[0017] (5) The present disclosure also relates to a sintered body manufacturing method, which includes the molded body manufacturing method described in any of (1) to (4) above.

[0018] The sintered body manufacturing method described in (5) above includes the molded body manufacturing method described in any of (1) to (4) above, and therefore has the same effect as the molded body manufacturing method described in any of (1) to (4) above.

[0019] (6) A molded article manufacturing apparatus relating to another aspect of the present disclosure includes a press machine including a mold for pressurizing raw material powder containing metal powder, a control device for controlling the press machine based on molding conditions including a plurality of molding variables, and a data acquisition unit for acquiring data of the plurality of molding variables during the manufacture of a molded article, wherein the control device includes a molding control unit for controlling the press machine to manufacture the molded article by pressurizing the raw material powder based on the molding conditions, and an estimation unit for estimating the quality of the molded article to be manufactured based on a molding variable distribution which is a distribution of the plurality of molding variables, wherein the estimation unit estimates the quality of the molded article to be manufactured based on an actual molding variable distribution which is a distribution of the plurality of molding variables acquired by the data acquisition unit and a reference molding variable distribution which is a distribution of the molding variables when a good product is manufactured.

[0020] The molded body manufacturing apparatus described in (6) above includes a control device equipped with an estimation unit that estimates whether the molded body to be manufactured is a good product or a defective product. Therefore, if the estimation unit estimates that a defective product will be manufactured, the production of the molded body can be stopped. Thus, the production yield of the molded body is improved. Therefore, when the molded body is sintered to produce a sintered body, the production yield of the sintered body is also improved.

[0021] (7) In the molded body manufacturing apparatus described in (6) above, the control device has a storage unit, and if the distribution of a plurality of factor variables for setting the molding conditions is called a factor variable distribution, the data acquisition unit acquires data of some of the factor variables from the plurality of factor variables during the manufacturing of the molded body, the storage unit stores the plurality of factor variable distributions and the plurality of molding variable distributions that correspond to the plurality of factor variable distributions and in which good molded bodies are manufactured, and the estimation unit selects from the plurality of molding variable distributions the molding variable distribution that corresponds to the actual factor variable distribution which is the factor variable distribution that includes the data of some of the factor variables acquired by the data acquisition unit as the reference molding variable distribution, and determines whether the molded body to be manufactured is good or bad by comparing the selected reference molding variable distribution with the actual molding variable distribution.

[0022] In the molded body manufacturing apparatus described in (7) above, a reference molding variable distribution can be selected according to the distribution of real-factor variables during the manufacturing of the molded body, and the quality of the molded body can be estimated based on the selected reference molding variable distribution. Therefore, it is possible to estimate the quality of the molded body more accurately.

[0023] (8) The molded body manufacturing apparatus described in (7) above further comprises a powder supply device that supplies the raw material powder to the mold while applying vibration to the raw material powder, and the some factor variables acquired by the data acquisition unit may include at least one of the temperature, humidity, the transfer time of the raw material powder from the powder supply device to the mold, and the particle size distribution of the raw material powder contained in the powder supply device.

[0024] (9) In the molded body manufacturing apparatus described in any of (6) to (8) above, the mold comprises a first mold and a second mold, the first mold is a first movable mold driven toward the second mold, the press has a first drive mechanism for driving the first movable mold, the first movable mold has a plurality of first punches driven independently of each other, the molding control unit pressurizes the raw material powder by driving the first mold toward the second mold by controlling the first drive mechanism, and the plurality of molding variables may include at least the position of each of the plurality of first punches and the drive pressure for driving each of the plurality of first punches.

[0025] In this case, the molding variable distribution includes more molding variables. The estimation unit automatically estimates the quality of the molded product by comparing the actual molding variable distribution with the reference molding variable distribution. As described in (9) above, this method of manufacturing molded products that can automatically estimate the quality of the molded product is effective when there are many molding variables.

[0026] (10) In the molded body manufacturing apparatus described in (9) above, the second mold is a second movable mold driven toward the first mold, the press has a second drive mechanism for driving the second movable mold, the molding control unit pressurizes the raw material powder by controlling the first drive mechanism to drive the first mold toward the second mold and by controlling the second drive mechanism to drive the second mold toward the first mold, and the plurality of molding variables may include the position of the second mold and the drive pressure for driving the second mold.

[0027] In this case, the number of molding variables increases further, making the molded product manufacturing method described in (10) above even more effective.

[0028] (11) The present disclosure also relates to a sintered body manufacturing apparatus, including a molded body manufacturing apparatus as described in any of (6) to (10) above.

[0029] Since the sintered body manufacturing apparatus described in (11) above includes the molded body manufacturing apparatus described in any of (6) to (10) above, it has the same effect as the molded body manufacturing apparatus described in any of (6) to (10) above.

[0030] [Details of Embodiments of the Disclosure] Specific examples of embodiments of the Disclosure are described below with reference to the drawings. The Disclosure is not limited to these examples, and is intended to include all changes within the meaning and scope of the claims, as indicated by the claims. In the description of the drawings, identical elements are denoted by the same reference numerals, and redundant descriptions are omitted.

[0031] <Sintered Body Manufacturing Method Including Molded Body Manufacturing Method> Figure 1 is a flowchart of a sintered body manufacturing method including a molded body manufacturing method according to one embodiment. An example of a sintered body in this embodiment is a product incorporated into a machine. For example, sintered bodies include sprockets, rotors, gears, rings, flanges, pulleys, vanes, or bearings. Sintered bodies may be products in the automotive field, but are not limited to products in the automotive field. For example, sintered bodies include turbine blades for aircraft, artificial bones and artificial joints used in the medical field, or radiation shielding components used in the nuclear field.

[0032] When manufacturing a sintered body, first, a molded body is manufactured by pressurizing raw material powder containing metal powder (molding step S11). That is, in molding step S11, a molded body is manufactured by press molding the raw material powder. Molding step S11 is a step included in the molded body manufacturing method of this embodiment. The molded body manufacturing method of this embodiment has the above molding step S11 and an estimation step. The estimation step will be described later. The molded body manufactured in molding step S11 may also be called a compacted molded body or a press-molded body.

[0033] The raw material powder is pressurized using a mold. The mold has a pair of first and second molds. The first mold may have a die and a plurality of first punches positioned inside the die. The second mold may have a plurality of second punches.

[0034] An example of the molding process S11 will be described in detail. In the molding process S11, raw material powder is filled between the first mold and the second mold (filling process). Then, at least one of the first mold and the second mold is driven to uniaxially pressurize the raw material powder in the first mold and the second mold (pressurization process). This yields a molded body. Examples of pressurization pressures include 600 MPa or more, 1000 MPa or more, and more preferably 1500 MPa or more. Increasing the pressurization pressure can increase the relative density of the molded body. After the molding process S11, the molded body is removed by driving at least one of the first mold and the second mold to separate the first mold and the second mold (removal process).

[0035] The shape of the molded body obtained in molding process S11 is determined by the shape of the filling area of ​​the raw material powder in the mold. The molded body produced by the mold is a simple shape. Examples of simple shapes include cylindrical, cylindrical, prismatic, and rectangular tube shapes. A punch with convex and concave portions on its punch surface may also be used. In this case, indentations and protrusions corresponding to the convex and concave portions are formed on the simple-shaped molded body.

[0036] Next, the molded body produced in molding step S11 is processed (processing step S12). In processing step S12, more complex shapes are imparted to the molded body from the sintered body product. Examples of shapes to be formed in processing step S12 include groove shapes, gear shapes, etc. Examples of processing methods include cutting.

[0037] After performing the processing step S12, a sintered body is obtained by sintering the processed molded body (sintering step S13). The sintering of the molded body may be carried out using an induction heating sintering furnace, a belt-type continuous sintering furnace, or the like.

[0038] Subsequently, the sintered body obtained in the sintering process S13 is inspected (inspection process S14). In inspection process S14, the presence or absence of cracks, whether or not it meets the desired dimensions or shape, etc., are checked. The inspection of the sintered body is carried out using inspection equipment appropriate to the inspection content. If multiple inspections are performed, equipment appropriate to each of the multiple inspections is used. The inspection may be carried out, for example, by magnetic particle testing or optically.

[0039] The order of the processing step S12 and the sintering step S13 described above may be reversed. That is, the sintering step S13 may be performed first, and then the desired processing may be applied to the resulting sintered body.

[0040] <Raw Material Powder> The metal powder contained in the raw material powder, which is the material for the molded body and sintered body, is the main material that constitutes the sintered body and molded body, which are the finished products. Examples of metal powder include iron or iron alloy powder with iron as the main component. Examples of metal powder include pure iron powder and iron alloy powder. "Iron alloy with iron as the main component" means that it contains more than 50% by mass of iron element, preferably 80% by mass or more, and more preferably 90% by mass or more as a constituent component.

[0041] Examples of the iron alloy include those containing at least one alloying element selected from copper (Cu), nickel (Ni), tin (Sn), chromium (Cr), molybdenum (Mo), manganese (Mn) and carbon (C). The above-mentioned alloying elements contribute to improving the mechanical properties of the iron-based sintered body.

[0042] Iron powder may be used as the metal powder, and the powder of the above alloying element (alloying powder) may be added thereto. In this case, the constituent component of the metal powder is iron at the raw material powder stage, but sintering in the sintering step S13 causes iron to react with the alloying element and be alloyed.

[0043] The content of the metal powder (including alloying powder) in the raw material powder may be, for example, 90% by mass or more, further 95% by mass or more. For the metal powder, those produced by, for example, a water atomization method, a gas atomization method, a carbonyl method, a reduction method, or the like can be used.

[0044] When the sintering step S13 is performed by high-frequency induction heating, the raw material powder may be a raw material powder containing Fe powder or Fe alloy powder and C powder. This raw material powder is mainly composed of Fe powder or Fe alloy powder.

[0045] The raw material powder may contain an internal lubricant to prevent seizure of the metal powder to the mold. Examples of the internal lubricant include metal soaps such as lithium stearate and zinc stearate. The raw material powder may contain an organic binder in order to reduce the occurrence of cracks, chips, and the like in the compact in the processing step S12. Examples of the organic binder include polyethylene, polypropylene, polyolefin, polymethyl methacrylate, polystyrene, polyvinyl chloride, polyvinylidene chloride, polyamide, polyester, polyether, polyvinyl alcohol, vinyl acetate, paraffin, and various waxes.

[0046] <Sintered Body Manufacturing Apparatus> Figure 2 is a schematic diagram of a sintered body manufacturing apparatus 1 for carrying out the sintered body manufacturing method according to the present embodiment. The sintered body manufacturing apparatus 1 includes a molded body manufacturing apparatus 2 for carrying out a molding step S11, a processing apparatus 3 for carrying out a processing step S12, a sintering apparatus 4 for carrying out a sintering step S13, and an inspection apparatus 5 for carrying out an inspection step S14.

[0047] An example of the molded body manufacturing apparatus 2 according to the present embodiment includes a press 2A for pressing raw material powder, a control device 2C for controlling the press 2A, and a data acquisition unit 64 (see FIG. 9). The molded body manufacturing apparatus 2 may further include a powder supply device 2B that supplies raw material powder to the press 2A. Hereinafter, unless otherwise stated, an embodiment in which the molded body manufacturing apparatus 2 includes the powder supply device 2B will be described. In this case, the control device 2C further controls the powder supply device 2B.

[0048] (Press) The press 2A is an apparatus that obtains a molded body by pressing raw material powder filled in a die.

[0049] (Powder Supply Device) The powder supply device 2B is an apparatus that accommodates raw material powder and supplies an amount of raw material powder required for manufacturing the molded body to the press 2A. The powder supply device 2B may have a vibrating unit that vibrates a conveying path for raw material powder from the powder supply device 2B to the press 2A. Applying such vibration to the conveying path prevents the raw material powder from adhering to the inside of the conveying path, and makes it possible to supply an appropriate amount of raw material powder to the press 2A.

[0050] (Control Device) The control device 2C is an apparatus that controls the press 2A and the powder supply device 2B. The control device 2C is constituted by at least one computer.

[0051] The control device 2C may have components of a computer, such as input / output ports, a processor, and various memory devices. The processor may consist of one or more computing devices such as a CPU (Central Processing Unit) or a GPU (Graphics Processing Unit). The processor realizes various functions of the control device 2C by executing a predetermined program. The various memory devices may include one or more non-volatile memory devices and one or more volatile memory devices. Examples of non-volatile memory devices include flash memory and hard disks. The non-volatile memory device stores, for example, the predetermined program. Examples of volatile memory devices include random access memory. The volatile memory device temporarily stores, for example, a program loaded from the non-volatile memory device.

[0052] The hardware configuration of the control device 2C is not necessarily limited to cases where each functional block is configured by a program. For example, each functional block of the control device 2C may be composed of a dedicated logic circuit or an ASIC (Application Specific Integrated Circuit) that integrates such circuits.

[0053] (Processing device) Processing device 3 is a device for processing the molded body manufactured by the molded body manufacturing device 2. Processing device 3 may be a device that is appropriate for the processing method of the molded body. For example, if the molded body is cut, processing device 3 may be a cutting device equipped with a cutting tool. An example of processing device 3 is a robotic processing device that processes the molded body using an articulated robot. In such a robotic processing device, for example, a first robot of the articulated robot holds the molded body, and a second robot different from the first robot can process the molded body using a cutting tool.

[0054] (Sintering apparatus) The sintering apparatus 4 is an apparatus for sintering a processed molded body. The sintering apparatus 4 is an apparatus that includes, for example, an induction heating sintering furnace that heats the molded body by a high-frequency induction method. Heating by a high-frequency induction method can raise the temperature of the object at high speed, making it possible to raise the molded body to a predetermined temperature in a short time. Therefore, it has the advantage of making it easy to manufacture sintered bodies in a short time and contributes to energy saving. The sintering apparatus 4 may also be an apparatus that has a belt-type continuous sintering furnace.

[0055] (Inspection device) The inspection device 5 can be any device that is appropriate to the inspection content performed in inspection process S14. Examples of inspection devices 5 include non-contact 3D scanners and non-contact non-destructive testing devices. Examples of 3D scanners include laser light type and pattern light type 3D scanners. Examples of non-contact non-destructive testing devices include devices that can perform magnetic particle testing. Using the example inspection device 5, sintered bodies can be inspected automatically and one by one. If different inspections are to be performed in inspection process S14, an inspection device 5 appropriate to each inspection should be used.

[0056] The sintered body manufacturing apparatus 1 may include a first conveying device for conveying molded bodies manufactured by the molded body manufacturing apparatus 2 toward the processing apparatus 3, a second conveying device for conveying molded bodies processed by the processing apparatus 3 toward the sintering apparatus 4, and a third conveying device for conveying sintered bodies manufactured by the sintering apparatus 4 toward the inspection apparatus 5. Examples of the first, second, and third conveying devices include belt conveyors and robots.

[0057] <Press Machine> Next, an example of press machine 2A will be further explained using Figure 3. Figure 3 is a schematic diagram showing an example of press machine 2A used in the molding process.

[0058] In this embodiment, the press machine 2A is a press machine driven using hydraulics. The press machine 2A may be a press machine for performing uniaxial pressing driven by a hydraulic servo system.

[0059] The press machine 2A comprises a base plate 11, a plurality of support columns 12, a frame 13, and a movable plate 14. In the following description, the press machine 2A will be described based on the state in which the base plate 11 is in contact with the floor surface. Therefore, terms indicating directions such as "up" and "down" in the following description are based on the state in which the base plate 11 is in contact with the floor surface.

[0060] The base plate 11 is, for example, rectangular in shape. Above the base plate 11, a first movable mold 21 is provided, whose vertical position (in a predetermined direction) is controlled by a first drive mechanism 15.

[0061] Multiple support columns 12 are provided around the periphery of the base plate 11. For example, multiple support columns 12 are provided at the four corners of the base plate 11. In this case, there are four support columns 12.

[0062] The frame 13 is fixed to the upper end of the support column 12. A hydraulically driven upper cylinder 17 is provided in the center of the frame 13.

[0063] The movable plate 14 is positioned on top of the support column 12 and is supported by the support column 12 so as to be movable along the support column 12. The upper surface of the movable plate 14 and the lower end of the rod of the upper cylinder 17 are connected via a link mechanism 18.

[0064] Below the movable plate 14, a second movable mold 22 is provided, whose vertical position is controlled by a second drive mechanism 16. The second movable mold 22, together with the first movable mold 21, forms a mold 20 for obtaining a molded product.

[0065] In the press machine 2A described above, when the upper cylinder 17 extends, the movable plate 14 descends to the preparation position for the raw material powder. Subsequently, by driving the first drive mechanism 15 and the second drive mechanism 16, the first movable mold 21 and the second movable mold 22 are joined together, and the raw material powder is pressurized.

[0066] <Mold> Figure 4 is a schematic diagram illustrating the mold 20 of the press machine 2A. The mold 20 includes a first movable mold 21 and a second movable mold 22.

[0067] The first movable mold 21 comprises a die 211, a core rod 212, and a first punch set 210. The die 211 is cylindrical. The core rod 212 is positioned along the central axis of the die 211.

[0068] The first punch set 210 has a plurality of first punches 213. The number of first punches 213 is not limited, but in this embodiment, as shown in Figure 4, the first punch set 210 has four first punches 213. When distinguishing between the four first punches 213, they are referred to as first punch 213a, first punch 213b, first punch 213c, and first punch 213d.

[0069] The first punches 213a, 213b, 213c, and 213d are cylindrical and are arranged in the order of first punch 213a, first punch 213b, first punch 213c, and first punch 213d from the die 211 toward the core rod 212.

[0070] Specifically, the first punch 213a is positioned such that its outer circumferential surface is in contact with the inner circumferential surface of the die 211. The first punch 213b is positioned such that its outer circumferential surface is in contact with the inner circumferential surface of the first punch 213a. The first punch 213c is positioned such that its outer circumferential surface is in contact with the inner circumferential surface of the first punch 213b. The first punch 213d is positioned such that its outer circumferential surface is in contact with the inner circumferential surface of the first punch 213c.

[0071] The central axis of each first punch 213 coincides with the central axis of the die 211. The vertical lengths of each first punch 213 may differ. The width of each first punch 213 may be a length corresponding to the molded product to be manufactured. The width of the first punch 213 is the length of the first punch 213 along the direction perpendicular to the extension direction of the first punch 213.

[0072] A lower ram 214 is connected to each die 211 and each first punch 213. The lower ram 214 may be connected to the lower surface of each die 211 and each first punch 213. The lower ram 214 is connected to the first drive mechanism 15.

[0073] In the first movable mold 21, a filling region is formed between the inner circumferential surface of the die 211 and the outer circumferential surface of the core rod 212, where the raw material powder is filled. Specifically, the filling region is formed by the portion formed by the inner circumferential surface of the die 211 and the outer circumferential surface of the core rod 212, and the upper surface of the first punch set 210, that is, the upper surface of each first punch 213. Hereinafter, as shown in Figure 4, the raw material powder will be referred to as "raw material powder 30".

[0074] The second movable die 22 includes a second punch set 220. The second punch set 220 has a plurality of second punches 221. The number of second punches 221 is not limited, but in this embodiment, as shown in Figure 4, the second punch set 220 has two second punches 221. When describing the two second punches 221 separately, they will be referred to as second punch 221a and second punch 221b.

[0075] The second punches 221a and 221b are cylindrical. The central axes of the second punches 221a and 221b coincide with the central axis of the die 211.

[0076] The second punch 221a is positioned such that its outer circumferential surface contacts the inner circumferential surface of the die 211 when one of the first movable mold 21 and the second movable mold 22 moves toward the other. The second punch 221b is positioned such that its outer circumferential surface contacts the inner circumferential surface of the second punch 221a. The hole in the cylindrical second punch 221b is formed such that its inner circumferential surface contacts the outer circumferential surface of the core rod 212 when one of the first movable mold 21 and the second movable mold 22 moves toward the other. The hole in the second punch 221b functions as a passage hole for the core rod 212.

[0077] The vertical lengths of each second punch 221 may be different. The width of each second punch 221 may be a length corresponding to the molded product to be manufactured. The width of the second punch 221 is the length of the second punch 221 along the direction perpendicular to the extension direction of the second punch 221.

[0078] The upper surfaces of the second punches 221a and 221b are fixed to the upper ram 222. The upper ram 222 is connected to the second drive mechanism 16. The upper ram 222 may have a hole 222a through which the core rod 212 passes.

[0079] (Drive Mechanism) Figure 5 is a schematic diagram illustrating an example of a first drive mechanism 15 that drives the first movable mold 21. The first drive mechanism 15 independently drives the die 211 and each first punch 213 of the first movable mold 21. That is, the die 211 and each first punch 213 are the objects to be driven by the first drive mechanism 15. In Figure 5, the die 211 and each first punch 213 are represented as the objects to be driven A.

[0080] The first drive mechanism 15 has a hydraulic cylinder 41. The hydraulic cylinder 41 is housed in a housing 42. The hydraulic cylinder 41 has a cylinder rod 411, a cylinder head 412, and a cylinder container 413. The hydraulic cylinder 41 is arranged so that the cylinder rod 411 moves forward or backward along the direction of the central axis of the die 211. In the first drive mechanism 15, the forward direction of the cylinder rod 411 is the direction in which the cylinder rod 411 moves vertically upward, and the backward direction of the cylinder rod 411 is the direction in which the cylinder rod 411 moves vertically downward.

[0081] One end of the cylinder rod 411 is connected to the lower ram 214. The other end of the cylinder rod 411 is connected to the cylinder head 412. The cylinder rod 411 and the cylinder head 412 are integrated into a single unit.

[0082] The cylinder container 413 is a container for holding hydraulic fluid to drive the cylinder rod 411. The cylinder container 413 may be a cylindrical container. The cylinder head 412 is located inside the cylinder container 413, dividing the space inside the cylinder container 413 into a first space 413a and a second space 413b. The second space 413b is the space in which at least a part of the cylinder rod 411 connected to the cylinder head 412 is located.

[0083] The first drive mechanism 15 supplies hydraulic fluid from a hydraulic fluid supply source 43 to the first space 413a and the second space 413b, respectively. The hydraulic fluid supply source 43 may also be a component of the first drive mechanism 15.

[0084] The first drive mechanism 15 has a valve 44 for supplying hydraulic fluid from a hydraulic fluid supply source 43 to the first space 413a and the second space 413b. The valve 44 distributes the hydraulic fluid from the hydraulic fluid supply source 43 to the first space 413a and the second space 413b while adjusting the pressure and flow rate. The valve 44 is not limited to valves that can adjust the pressure and flow rate. An example of the valve 44 is a servo valve. The valve 44 is controlled based on instructions from the control device 2C.

[0085] A pressure sensor 45a is provided in the hydraulic fluid flow path from valve 44 to the first space 413a to measure the pressure of the hydraulic fluid supplied to the first space 413a, and a pressure sensor 45b is provided in the hydraulic fluid flow path from valve 44 to the second space 413b to measure the pressure of the hydraulic fluid supplied to the second space 413b. The measurement results from pressure sensors 45a and 45b are input to the control device 2C. Pressure sensors 45a and 45b are not limited to sensors capable of detecting the pressure of hydraulic fluid.

[0086] In the first drive mechanism 15, the pressure difference of the hydraulic fluid in the first space 413a and the second space 413b causes the cylinder rod 411 connected to the cylinder head 412 to move forward or backward. Therefore, the difference in the detection results of the pressure sensors 45a and 45b is the drive pressure that drives the cylinder head 412 and the cylinder rod 411. Since the drive target A is driven by the cylinder rod 411, the difference in the detection results of the pressure sensors 45a and 45b corresponds to the drive pressure of the drive target A.

[0087] The first drive mechanism 15 has a position sensor 46 for measuring the position of the drive target A. The position sensor 46 is connected to the lower ram 214 to measure the position of the lower ram 214. The position sensor 46 is supported so as to be movable along a support rod 47 extending from the housing 42. An example of the position sensor 46 is an encoder. The measurement result of the position sensor 46 is input to the control device 2C. The position sensor 46 may also be an optical sensor.

[0088] As described above, the first drive mechanism 15 was described with the die 211 and each first punch 213 as the drive targets A. The first drive mechanism 15 has a hydraulic cylinder 41, a position sensor 46, etc., corresponding to the die 211 and each first punch 213. Therefore, the die 211 and each first punch 213 are driven independently by the first drive mechanism 15. The housing 42 of the first drive mechanism 15 may be a common component for the die 211 and each first punch 213.

[0089] In the following description, unless otherwise specified, the first drive mechanism 15 driving the first movable mold 21 means that the die 211 and each of the first punches 213 are driven independently. Therefore, the position of the first movable mold 21 controlled by the first drive mechanism 15 means the position of the die 211 and each of the first punches 213, and the drive pressure for controlling the first movable mold 21 by the first drive mechanism 15 means the drive pressure for driving the die 211 and each of the first punches 213.

[0090] Although the first drive mechanism 15 for the first movable mold 21 has been described, the second drive mechanism 16 for the second movable mold 22 may have the same configuration. That is, the second drive mechanism 16 may also have components that correspond to the components of the first drive mechanism 15. For the convenience of the following description, the components of the second drive mechanism 16, such as the hydraulic cylinder, will be given the same reference numerals as the components of the first drive mechanism 15 that correspond to them. That is, the second drive mechanism 16 also has a hydraulic cylinder 41, a housing 42, a hydraulic fluid supply source 43, a valve 44, a pressure sensor 45a, a pressure sensor 45b, a position sensor 46, and a support rod 47. In the second drive mechanism 16, the forward direction of the cylinder rod 411 of the second drive mechanism 16 is the direction in which the cylinder rod 411 moves vertically downward, and the backward direction of the cylinder rod 411 is the direction in which the cylinder rod 411 moves vertically upward.

[0091] In this embodiment, the second punches 221a and 221b are fixed to a common upper ram 222. Therefore, the second drive mechanism 16 drives the second punches 221a and 221b integrally. In the following description, the driving of the second movable die 22 by the second drive mechanism 16 means that the second punches 221a and 221b are driven integrally.

[0092] In the second drive mechanism 16, the pressure difference of the hydraulic fluid in the first space 413a and the second space 413b of the hydraulic cylinder 41 of the second drive mechanism 16 causes the cylinder rod 411 connected to the cylinder head 412 of the second drive mechanism 16 to move forward or backward. Therefore, the difference in the detection results of the pressure sensor 45a and the pressure sensor 45b is the driving pressure that drives the cylinder head 412 and the cylinder rod 411. Since the second punch 221a and the second punch 221b are driven by the cylinder rod 411 of the second drive mechanism 16, the difference in the detection results of the pressure sensor 45a and the pressure sensor 45b of the second drive mechanism 16 corresponds to the driving pressure of the second punch 221a and the second punch 221b.

[0093] When manufacturing a molded body using the press machine 2A described above, the upper surface of the core rod 212 is made to protrude from the upper surface of the die 211, and the first punches 213a, 213b, 213c, and 213d are set to be deeper than the upper surface of the die 211, and arranged in a manner corresponding to the shape of the molded body and sintered body to be manufactured. In this state, raw material powder 30 is filled into the filling area from the powder supply device 2B. Uniaxial pressing is performed by raising each of the first punches 213a, 213b, 213c, and 213d while lowering the second movable mold 22.

[0094] The position and movement speed of each first punch 213 are controlled by the control device 2C, which controls the valve 44 based on the measurement results of the position sensor 46, pressure sensor 45a, and pressure sensor 45b of the first drive mechanism 15. The position and movement speed of the second movable mold 22 are also controlled by the control device 44 based on the measurement results of the position sensor 46, pressure sensor 45a, and pressure sensor 45b of the second drive mechanism 16.

[0095] <Examples of Molded and Sintered Body> Figure 6 is a schematic diagram of an example of a molded body produced when the molding process is carried out using press machine 2A. Figure 7 is a cross-sectional view along line VII-VII in Figure 6. Hereinafter, the molded body will be referred to as "molded body 51".

[0096] The press machine 2A described using Figures 3 and 4 has a core rod 212. Therefore, the molded body 51 has a hole 51a corresponding to the core rod 212. As shown in Figures 6 and 7, the molded body 51 has a step 51b on its outer surface formed by the difference in the lower surface positions of the second punch 221a and the second punch 221b. The molded body 51 has a step 51c inside, formed by the difference in the upper surface positions of the first punch 213a, the first punch 213b, the first punch 213c and the first punch 213d.

[0097] As explained using Figure 1, the molding process S11 is followed by the processing process S12 and the sintering process S13. Therefore, for example, in the processing process S12, a gear portion is added to a part of the outer surface of the molded body 51, and a lateral groove is formed, and then the molded body 51 is sintered in the sintering process S13 to obtain a sintered body having the gear portion 52a and lateral groove 52b shown in Figure 8. Figure 8 is a schematic diagram of an example of a sintered body manufactured using the molded body 51 shown in Figure 6. Hereinafter, the sintered body will be referred to as "sintered body 52" as shown in Figure 8.

[0098] In the molding process S11, when the raw material powder 30 is uniaxially pressed, there is a risk that cracks may occur in the molded body due to the effects of stress. Such cracks are likely to cause fractures in the sintered body. Theoretically, cracks can be inspected by magnetic particle testing. However, proper inspection is difficult at the stage when the molded body is manufactured because the magnetization of the molded body is weak. Therefore, it is conceivable to inspect for cracks caused by cracks in the molded body from the sintering process S13 onward to check whether or not cracks have occurred. Since the sintering process S13 is a process that has already been carried out in the molding process S11 and the processing process S12, if inspection is performed after the sintering process S13, the manufacturing yield is likely to decrease.

[0099] <Molded Body Manufacturing Apparatus> Therefore, the molded body manufacturing apparatus 2 of this embodiment is configured to be able to estimate whether or not defective products due to cracks will occur in the molding process S11. Figure 9 is a schematic diagram illustrating the general configuration of the molded body manufacturing apparatus 2, focusing on its functions.

[0100] The molded body manufacturing apparatus 2 has a data acquisition unit 64 in addition to the various functions realized by the control device 2C. The molded body manufacturing apparatus 2 may have at least one of the following: a powder supply amount adjustment unit 61, a vibration generation unit 62, and a hydraulic fluid supply control unit 63. In the following, unless otherwise specified, the description will be of a configuration in which the molded body manufacturing apparatus 2 has a powder supply amount adjustment unit 61, a vibration generation unit 62, and a hydraulic fluid supply control unit 63.

[0101] The powder supply amount adjustment unit 61 is a function implemented in the powder supply device 2B. Based on instructions from the control device 2C, the powder supply amount adjustment unit 61 weighs a predetermined amount of raw material powder 30 from the raw material powder 30 contained in the powder supply device 2B and delivers it to the press machine 2A. For example, when supplying the raw material powder 30 from a storage unit such as a hopper containing the raw material powder 30 to a transport path, the powder supply amount adjustment unit 61 may weigh the amount of raw material powder 30 to be supplied to the press machine 2A by detecting changes in the weight of the raw material powder 30 in the storage unit.

[0102] The vibration generating unit 62 applies vibration to the transport path of the raw material powder 30 from the powder supply device 2B to the press machine 2A. Applying vibration to the transport path in this manner is sometimes referred to as applying vibration to the raw material powder 30. The vibration generating unit 62 can be implemented, for example, by a vibrator that generates vibrations.

[0103] The hydraulic fluid supply control unit 63 controls the supply state of hydraulic fluid to the hydraulic cylinders 41 of the first drive mechanism 15 and the second drive mechanism 16 so that the positions of the first movable mold 21 and the second movable mold 22 are at desired positions. The hydraulic fluid supply control unit 63 is realized by valves 44 of the first drive mechanism 15 and the second drive mechanism 16, respectively.

[0104] The data acquisition unit 64 acquires actual data during the manufacturing of the molded body 51. The data acquisition unit 64 may include a vibration detection unit 641, a movement time detection unit 642, a drive pressure detection unit 643, a position detection unit 644, a mold temperature detection unit 645, a powder remaining amount detection unit 646, an environmental condition detection unit 647, and a particle size detection unit 648.

[0105] The vibration detection unit 641 detects the vibration state when the vibration generating unit 62 applies vibration to the transport path of the raw material powder 30 to the press machine 2A. The vibration detection unit 641 can be implemented, for example, by a vibration sensor. The detected vibration state may be the vibration frequency (or vibration period).

[0106] The movement time detection unit 642 detects the movement time of the raw material powder 30 when it is supplied from the powder supply device 2B to the press machine 2A. The movement time detection unit 642 can be implemented, for example, by measuring the time it takes for a specified weight of raw material powder 30 to fill the filling area in the mold 20 using a weighing scale. The weighing scale only needs to be installed in the mold 20.

[0107] The drive pressure detection unit 643 detects the drive pressure applied to the cylinder rods 411 of the first drive mechanism 15 and the second drive mechanism 16, respectively. The drive pressure detection unit 643 is realized by pressure sensors 45a and 45b, respectively, of the first drive mechanism 15 and the second drive mechanism 16. Specifically, the drive pressure applied to the cylinder head 412 corresponding to pressure sensors 45a and 45b is obtained by the difference in the detection results of pressure sensors 45a and 45b. The drive pressure applied to the cylinder head 412 corresponds to the drive pressure of the cylinder rods 411 connected to the cylinder head 412.

[0108] The position detection unit 644 detects the position of the first movable mold 21 and the position of the second movable mold 22. Detecting the position of the first movable mold 21 means detecting the positions of the die 211 and each of the first punches 213 that are independently driven and located within the first movable mold 21. The position detection unit 644 is realized by position sensors 46 located within the first drive mechanism 15 and the second drive mechanism 16, respectively.

[0109] The mold temperature detection unit 645 detects the temperatures of the first movable mold 21 and the second movable mold 22. The mold temperature detection unit 645 may detect the temperatures of the die 211 and each first punch 213 of the first movable mold 21, as well as the temperatures of each second punch 221 of the second movable mold 22. The mold temperature detection unit 645 may be implemented by a contact-type or non-contact-type temperature sensor.

[0110] The powder remaining amount detection unit 646 detects the remaining amount of raw material powder 30 in the powder supply device 2B. The powder remaining amount detection unit 646 may be a weighing scale (or mass scale) that measures the weight of the container that holds the raw material powder 30.

[0111] The environmental condition detection unit 647 detects the temperature and humidity of the surrounding environment of the molded body manufacturing apparatus 2. The environmental condition detection unit 647 may include, for example, a thermometer and a hygrometer.

[0112] The particle size detection unit 648 detects the particle size distribution of the raw material powder 30 contained in the powder supply device 2B. The particle size detection unit 648 may, for example, have a particle size distribution meter. Any type of particle size distribution meter may be used, for example, a laser diffraction / scattering type or a dynamic light scattering type.

[0113] The control device 2C has a molding control unit 72 and an estimation unit 73 as functional blocks. The control device 2C may have a storage unit 71. Unless otherwise specified, the following description will describe a configuration having a storage unit 71.

[0114] The functions of the storage unit 71 are realized by non-volatile memory devices and volatile memory devices included in the hardware of the control device 2C. The storage unit 71 stores data necessary for the molding control unit 72 and estimation unit 73 to function, along with programs for realizing the functions of the molding control unit 72 and estimation unit 73. The data stored in the storage unit 71 also includes data acquired by the data acquisition unit 64. The storage unit 71 may also store structural parameters of each component constituting the molded body manufacturing apparatus 2, such as the sizes of the first punch 213 and the second punch 221 (length, size of the surface in contact with the raw material powder 30, etc.) and the sizes of each component of the hydraulic cylinder 41.

[0115] The functions of the molding control unit 72 are realized by the control device 2C executing a program corresponding to the molding control unit 72 that is stored in the memory unit 71. In order to manufacture the molded body 51, the molding control unit 72 controls the supply of raw material powder 30 from the powder supply device 2B and also controls the hydraulic fluid supply control unit 63, that is, the valves 44 of the first drive mechanism 15 and the second drive mechanism 16, respectively.

[0116] For example, the molding control unit 72 inputs powder supply conditions as operation instructions to the powder supply device 2B. These powder supply conditions include vibration conditions such as vibration frequency, the travel time of the raw material powder 30, and the remaining amount of raw material powder 30 in the powder supply device 2B. As a result, the raw material powder 30, adjusted to the desired amount by the powder supply amount adjustment unit 61 based on the powder supply conditions, is supplied from the powder supply device 2B to the press machine 2A through a conveyor path to which vibration is applied by the vibration generating unit 62.

[0117] For example, the molding control unit 72 inputs hydraulic fluid supply conditions to the hydraulic fluid supply control unit 63, specifically to the valves 44 of the first drive mechanism 15 and the second drive mechanism 16, respectively. The hydraulic fluid supply conditions include the amount of hydraulic fluid to be supplied to the first space 413a and the second space 413b in the hydraulic cylinder 41, respectively, so that the first movable mold 21 and the second movable mold 22 are in predetermined positions for the manufacture of the molded body 51. The hydraulic fluid supply conditions may be stored in advance in the storage unit 71. The hydraulic fluid supply conditions may be changed according to the detection results of the drive pressure detection unit 643 and the position detection unit 644 of the data acquisition unit 64. Such changes to the hydraulic fluid supply conditions correspond to feedback control of the hydraulic fluid supply control unit 63.

[0118] The estimation unit 73 estimates the quality of the molded body 51 to be manufactured. The estimation of the quality of the molded body 51 is an estimation of whether or not defects due to cracks occur in the molded body 51. In this embodiment, the estimation unit 73 estimates the quality of the molded body 51 based on the amount of deviation of the actual molding variable distribution from the reference molding variable distribution.

[0119] The molding variable distribution is the distribution of each element included in the molding conditions (or control conditions) used to control the press machine 2A, where each element is considered a variable (molding variable). Examples of molding variables (each element included in the molding conditions) are the drive pressure used to control the first drive mechanism 15 and the second drive mechanism 16, and the positions of the first movable die 21 and the second movable die 22, respectively.

[0120] In this embodiment, the first movable mold has a plurality of first punches 213 and dies 211, and each of the plurality of first punches 213 and dies 211 is driven independently. Therefore, the drive pressure used to control the first drive mechanism 15 corresponds to the pressure acting on each of the plurality of first punches 213 and dies 211. The position of the first movable mold 21 having the plurality of first punches 213 and dies 211 refers to the position of each of the plurality of first punches 213 and dies 211.

[0121] In this embodiment, the second movable mold 22 has a plurality of second punches 221, which are connected to a common upper ram 222. Therefore, the plurality of second punches 221 are driven together. Consequently, the drive pressure used to control the second drive mechanism 16 is common to the plurality of second punches 221.

[0122] The standard molding variable distribution is the molding variable distribution when a good product is manufactured. The actual molding variable distribution is the molding variable distribution based on data acquired by the data acquisition unit 64 during the manufacturing of the molded body 51. For example, if the molding variable distribution includes the drive pressure and position, the actual molding variable distribution is the molding variable distribution based on data detected by the drive pressure detection unit 643 and the position detection unit 644.

[0123] Each molding variable included in the above molding conditions is set according to the characteristics of the raw material powder 30 that constitutes the molded body 51. The distribution of multiple factors (factor variables) used to set the multiple molding variables included in the molding conditions is called the factor variable distribution.

[0124] Examples of factor variables include (a) to (d) below. (a) Temperature and humidity around the molded body manufacturing apparatus 2 (specifically, the press machine 2A). The temperature and humidity around the molded body manufacturing apparatus 2 may be measured data detected by the thermometer and hygrometer of the environmental condition detection unit 647 during the manufacturing of the molded body 51. The above temperature and humidity may be values ​​that have been measured in advance before the manufacturing of the molded body 51 and stored in the storage unit 71.

[0125] (b) Characteristics and blending conditions of the raw material powder 30 Examples of characteristics of the raw material powder 30 include the particle size distribution and shape of the various components contained in the raw material powder 30. Examples of blending conditions for the raw material powder 30 include the blending ratio of the various components contained in the raw material powder 30 and the blending time. The characteristics and blending conditions of the raw material powder 30 may be stored in the storage unit 71 in advance. The particle size distribution of the various components contained in the raw material powder 30 may also be detected in real time by the particle size detection unit 648 described above. (c) Powder supply conditions Examples of powder supply conditions include the vibration state (vibration frequency, etc.), the movement time of the raw material powder 30, and the remaining amount of raw material powder 30 in the powder supply device 2B. For the vibration state (vibration frequency, etc.) etc. exemplified in the powder supply conditions, actual measurement data during the manufacture of the molded body 51 may be used.

[0126] For example, the vibration frequency, which is an example of a vibration state, may be measured data detected by the vibration detection unit 641. The movement time of the raw material powder 30 may be measured data detected by the movement time detection unit 642. The remaining amount of raw material powder 30 may be measured data detected in real time by the powder remaining amount detection unit 646. Alternatively, the remaining amount of raw material powder 30 may be calculated based on the total amount of raw material powder 30 contained in the powder supply device 2B at the start of operation of the molded body manufacturing apparatus 2, and the amount of raw material powder 30 used to manufacture the molded body 51 after the molded body manufacturing apparatus 2 has been put into operation.

[0127] (d) Mold characteristics Examples of mold characteristics include the temperature, dimensions, and service life of the mold 20. The temperature of the mold 20 may be the temperatures of the components of the first movable mold 21 and the second movable mold 22, respectively (for example, a plurality of first punches 213 and a plurality of second punches 221). The temperature of the mold 20 may be the actual measurement data of the molded body 51 during manufacturing detected by the mold temperature detection unit 645. The dimensions and service life of the mold 20 may be stored in advance in the storage unit 71.

[0128] Hereinafter, the distribution of factor variables obtained when actual measured values ​​are used during the manufacturing of the molded body 51 will be referred to as the real factor variable distribution.

[0129] Since molding conditions are defined according to the factor variables, if the distribution of factor variables differs, the distribution of molding variables will also differ accordingly. In other words, there are different distributions of molding variables that allow for the production of good products for each of the multiple distributions of factor variables.

[0130] The estimation unit 73 selects a reference molding variable distribution from among a plurality of molding variable distributions based on the actual factor variable distribution during the manufacturing of the molded body 51, and automatically estimates the quality of the manufactured molded body 51 by comparing the reference molding variable distribution with the actual molding variable distribution.

[0131] Specifically, if the deviation of the actual molding variable distribution from the reference molding variable distribution exceeds a preset judgment threshold (or judgment criterion), the molded body 51 to be manufactured is estimated to be defective. If the deviation is less than or equal to the judgment threshold, the molded body 51 to be manufactured is estimated to be good. The judgment of quality based on the comparison between the reference molding variable distribution and the actual molding variable distribution performed by the estimation unit 73 may be carried out in accordance with the MT method (Mahalanobis-Taguchi system). Alternatively, the judgment of quality may be carried out using machine learning.

[0132] A molding variable distribution that corresponds to each of the multiple factor variable distributions and is capable of producing good products may be prepared in advance by repeating experiments, for example, or by using machine learning. The multiple factor variable distributions and multiple molding variable distributions prepared in this way, as well as their correspondences, may be stored in the memory unit 71. In this case, the estimation unit 73 can identify the factor variable distribution at the time of manufacturing the molded body 51 from among the multiple factor variable distributions stored in the memory unit 71, and select the corresponding molding variable distribution as the reference molding variable distribution.

[0133] The factor variable distribution used when selecting a standard molding variable distribution from among multiple molding variable distributions may be an actual factor variable distribution. The actual factor variable distribution may be a factor variable distribution obtained by revising the factor variable distribution stored in the memory unit 71 before the operation of the molded body manufacturing apparatus 2 each time the aforementioned measured data is acquired.

[0134] <Estimation Process> The molded article manufacturing method according to this embodiment includes an estimation process S20 along with a molding process S11. An example of the estimation process S20 will be explained using Figure 10. Figure 10 is a flowchart of an example of the estimation process S20. The estimation process S20 may be carried out during the molding process S11, in other words, in parallel with the molding process S11.

[0135] In estimation step S20, first, from among multiple molding variable distributions corresponding to multiple factor variable distributions stored in the memory unit 71, a molding variable distribution corresponding to the actual factor variable distribution is selected as the reference molding variable distribution (selection step S21).

[0136] Next, the standard molding variable distribution and the actual molding variable distribution are compared to determine whether the molded body 51 to be manufactured is defective or not (determination step S22). Specifically, if the amount of deviation of the actual molding variable distribution from the standard molding variable distribution exceeds the determination threshold (or determination criterion), the molded body 51 to be manufactured is determined to be defective, and if the amount of deviation is less than or equal to the determination threshold (or determination criterion), the molded body 51 to be manufactured is determined to be good.

[0137] If the molded body 51 to be manufactured is determined to be defective (YES in the determination step S22), the manufacturing of the molded body 51 by the molded body manufacturing apparatus 2 is stopped, and the estimation step S20 and the molding step S11 are terminated. If the manufacturing of the molded body 51 by the molded body manufacturing apparatus 2 is stopped in this manner, the molding conditions, etc., can be readjusted. If the molded body 51 to be manufactured is determined to be good (NO in the determination step S22), the estimation step S20 and the molding step S11 are continued. When manufacturing multiple molded bodies 51 using the same raw material powder 30 and the same mold 20, continuing the molding step S11 means that the manufacturing of the planned multiple molded bodies 51 will continue as long as the molded body 51 to be manufactured is not determined to be defective in the estimation step S20.

[0138] In the molded body manufacturing apparatus 2, the sintered body manufacturing apparatus 1 including the same, and the molded body manufacturing method and sintered body manufacturing method including the same described in this embodiment, it is possible to estimate whether the molded body 51 is of good or bad quality during the manufacturing of the molded body 51. Therefore, if it is estimated that the molded body 51 to be manufactured is a defective product, the manufacturing of the molded body 51 can be immediately stopped.

[0139] Since it is possible to estimate in real time during the manufacturing of the molded body 51 whether or not it is a defective product, the manufacturing yield of both the molded body 51 and the sintered body 52 can be improved compared to, for example, when it is discovered that a crack has occurred in the molded body 51 by inspecting the sintered body 52. ​​As the proportion of defective molded bodies produced is reduced, and consequently the proportion of defective sintered bodies produced is also reduced, the raw material powder 30 for the manufacture of the molded body 51 and the sintered body 52 can be used more effectively, and the power required for manufacturing can be reduced.

[0140] Since the manufacturing process of the molded body 51 is presumed to determine whether the molded body 51 produced is defective or not, the sintered body 52 can be manufactured based on a good molded body 51. Therefore, if a defect (malfunction) is found when the sintered body 52 is inspected, the cause should be something other than the manufacturing process of the molded body 51. This makes it easier to pinpoint the cause of the defect in the sintered body 52.

[0141] The molding variable distribution includes multiple molding variables. Therefore, as described in this embodiment, the estimation unit 73 of the control device 2C automatically compares the reference molding variable distribution with the actual molding variable distribution, making it easy to estimate the quality of the molded body 51 to be manufactured. In particular, when the mold 20 has a first movable mold 21 that includes independently driven members, the number of variables increases, so it is effective for the control device 2C to be equipped with an estimation unit 73 and to automatically perform the estimation process S20. When the mold 20 has a second movable mold 22, the molding variables for the second movable mold 22 also need to be considered, so the number of variables increases even further. Therefore, it is even more effective for the control device 2C to be equipped with an estimation unit 73 and to automatically perform the estimation process S20.

[0142] If it is estimated that the molded body 51 to be manufactured will be defective based on the amount of deviation of the actual molding variable distribution from the standard molding variable distribution, further analysis may be performed to determine how each molding variable deviates. In this case, it is easier to adjust the molding conditions or each component of the molded body manufacturing apparatus 2.

[0143] When selecting a reference molding variable distribution from among multiple molding variable distributions based on the distribution of real-factor variables, it becomes possible to more accurately estimate the quality of the molded body 51 during its manufacture.

[0144] Each process (each function) in the above-described embodiment is executed by a common circuit or a combination of multiple circuits (collectively referred to as a circuit). The circuit may consist of at least one processor, at least one memory, various analog circuits, various digital circuits, and other integrated circuits. The memory stores programs (instructions) that cause the processor to execute the function. The processor may execute the function according to the program read from the memory, or it may execute the function according to a logic circuit that has been pre-designed to execute the function. The processor may be a CPU, GPU, DSP (Digital Signal Processor), FPGA (Field Programmable Gate Array), ASIC, or any other processor suitable for controlling a computer (including a cloud server). The processors installed in each physically separated computer may cooperate with each other via a network such as a LAN (Local Area Network), WAN (Wide Area Network), or the Internet to perform some or all of their functions. Programs may be installed into memory via a network from an external server device, or they may be distributed on recording media such as CD-ROM (Compact Disc Read Only Memory), DVD-ROM (Digital Versatile Disc Read Only Memory), or semiconductor memory, and then installed into memory from the recording media.

[0145] Although various embodiments relating to this disclosure have been described above, this disclosure is not limited to the embodiments illustrated.

[0146] For example, in the estimation process, a molding variable distribution that has been pre-designed for manufacturing the molded body (i.e., one that produces good products according to the design) may be used as the reference molding variable distribution. In this case, the selection process S21 shown in Figure 10 may be omitted.

[0147] The molding variables and factor variables are not limited to those exemplified. For example, the factor variables may include data representing the dimensions and other aspects of the finished product of the sintered body as inspected in inspection step S14 (see Figure 1) after the sintered body has been manufactured. When multiple molded bodies are manufactured sequentially using the same raw material powder and the same mold, the quality of the second molded body manufactured after the first molded body can be more appropriately estimated by using the data representing the dimensions and other aspects of the finished product as a factor variable when the first sintered body obtained from the first molded body is inspected in inspection step S14. The number of molding variables and factor variables may be more or less than the exemplified numbers. A larger number of molding variables improves the effectiveness of the method and apparatus described in this disclosure. Although temperature and humidity are given as examples of factor variables, either temperature or humidity may be adopted as a factor variable. Vibration frequency does not necessarily have to be adopted as a factor variable.

[0148] The first and second drive mechanisms are not limited to hydraulic drive mechanisms.

[0149] The position of the first movable die included in the molding variable distribution may be the position of the surface of each of the multiple first punches that contacts the raw material powder, depending on the structure (e.g., length) of each of the multiple first punches that the first movable die has. The position of the second movable die included in the molding variable distribution may be the position of the surface of each of the multiple second punches that contacts the raw material powder, depending on the structure (e.g., length) of each of the multiple second punches that the second movable die has, even when the multiple second punches that the second movable die has are driven integrally.

[0150] For example, the description mentioned a case where the first and second molds of a mold are both movable molds, but for example, the second mold may be a fixed mold. The number of punches that each of the first and second molds has may be just one.

[0151] Although the example given illustrates a configuration in which the first and second molds of a mold are arranged along the vertical direction, the first and second molds may also be arranged along a direction that intersects (or is inclined to) the vertical direction. For example, the first and second molds may be arranged along the horizontal direction.

[0152] It should be understood that at least one configuration or feature described in each embodiment and variation can be combined with other embodiments and variations, or modified in various ways.

[0153] 1...Sintered body manufacturing apparatus, 2...Molded body manufacturing apparatus, 2A...Press machine, 2B...Powder supply device, 2C...Control device, 3...Processing apparatus, 4...Sintering apparatus, 5...Inspection apparatus, 11...Base plate, 12...Support column, 13...Frame, 14...Movable plate, 15...First drive mechanism, 16...Second drive mechanism, 17...Upper cylinder, 18...Link mechanism, 20...Mold, 21...First movable mold, 22...Second movable mold, 30...Raw material powder, 41...Hydraulic cylinder Linda, 42...Housing, 43...Hydraulic fluid supply source, 44...Valve, 45a...Pressure sensor, 45b...Pressure sensor, 46...Position sensor, 47...Support rod, 51...Molded body, 51a...Hole, 51b...Step, 51c...Step, 52...Sintered body, 52a...Gear part, 52b...Transverse groove, 61...Powder supply amount adjustment part, 62...Vibration generation part, 63...Hydraulic fluid supply control part, 64...Data acquisition part, 71...Storage part, 72...Molding control part, 73...Estimation part, 210 ...First punch set, 220...Second punch set, 211...Die, 212...Core rod, 213...First punch, 213a...First punch, 213b...First punch, 213c...First punch, 213d...First punch, 214...Lower ram, 221...Second punch, 221a...Second punch, 221b...Second punch, 222...Upper ram, 222a...Hole, 411...Cylinder rod, 412...Cylinder head, 413...Cylinder Container, 413a...First space, 413b...Second space, 641...Vibration detection unit, 642...Movement time detection unit, 643...Drive pressure detection unit, 644...Position detection unit, 645...Mold temperature detection unit, 646...Powder remaining amount detection unit, 647...Environmental condition detection unit, 648...Particle size detection unit, A...Driven target, S11...Molding process, S12...Processing process, S13...Sintering process, S14...Inspection process, S20...Estimation process, S21...Selection process, S22...Determination process

Claims

1. A method for manufacturing a molded body, comprising: a molding step of manufacturing a molded body by pressurizing raw material powder containing metal powder using a die of a press machine based on molding conditions including a plurality of molding variables; and an estimation step of estimating the quality of the molded body to be manufactured based on a molding variable distribution which is the distribution of the plurality of molding variables, wherein the estimation step estimates the quality of the molded body to be manufactured based on an actual molding variable distribution which is the actual molding variable distribution during the execution of the molding step and a reference molding variable distribution which is the molding variable distribution when a good product is manufactured.

2. When the distribution of multiple factor variables for setting the molding conditions is called a factor variable distribution, the estimation step comprises: a selection step of selecting a molding variable distribution that corresponds to the actual factor variable distribution which is the factor variable distribution during the molding process, from among a plurality of molding variable distributions which correspond to a plurality of factor variable distributions and which produce a good molded body, as the reference molding variable distribution; and a determination step of determining whether the molded body to be manufactured is good or bad by comparing the reference molding variable distribution selected in the selection step with the actual molding variable distribution.

3. The mold comprises a first mold and a second mold, the first mold being a first movable mold driven toward the second mold, the molding step pressurizes the raw material powder by driving the first mold toward the second mold, the first mold having a plurality of first punches driven independently of each other, and the plurality of molding variables including at least the position of each of the plurality of first punches and the driving pressure for driving each of the plurality of first punches, the method for manufacturing a molded article according to claim 1 or claim 2.

4. The method for manufacturing a molded article according to claim 3, wherein the second mold is a second movable mold driven toward the first mold, and in the molding step, the raw material powder is pressurized by driving both the first mold and the second mold, and the plurality of molding variables include the position of the second mold and the driving pressure for driving the second mold.

5. A method for manufacturing a sintered body, comprising the method for manufacturing a molded body described in any one of claims 1 to 4.

6. A molded body manufacturing apparatus comprising: a press machine including a mold for pressurizing raw material powder containing metal powder; a control device for controlling the press machine based on molding conditions including a plurality of molding variables; and a data acquisition unit for acquiring data of the plurality of molding variables during the manufacture of a molded body, wherein the control device comprises: a molding control unit for controlling the press machine to manufacture the molded body by pressurizing the raw material powder based on the molding conditions; and an estimation unit for estimating the quality of the manufactured molded body based on a molding variable distribution which is a distribution of the plurality of molding variables, wherein the estimation unit estimates the quality of the manufactured molded body based on an actual molding variable distribution which is the distribution of the plurality of molding variables acquired by the data acquisition unit, and a reference molding variable distribution which is the distribution of the molding variables when a good product is manufactured.

7. The control device has a storage unit, and when the distribution of a plurality of factor variables for setting the molding conditions is called a factor variable distribution, the data acquisition unit acquires data of some of the plurality of factor variables during the manufacturing of the molded body, the storage unit stores the plurality of factor variable distributions and a plurality of molding variable distributions that correspond to the plurality of factor variable distributions and in which good molded bodies are manufactured, and the estimation unit selects from the plurality of molding variable distributions a molding variable distribution that corresponds to the actual factor variable distribution which is the factor variable distribution that includes the data of some of the factor variables acquired by the data acquisition unit as the reference molding variable distribution, and determines whether the molded body to be manufactured is good or bad by comparing the selected reference molding variable distribution with the actual molding variable distribution, the molded body manufacturing apparatus according to claim 6.

8. The molded article manufacturing apparatus according to claim 7, further comprising a powder supply device that supplies the raw material powder to the mold while applying vibration to the raw material powder, wherein some of the factor variables acquired by the data acquisition unit include at least one of temperature, humidity, the transfer time of the raw material powder from the powder supply device to the mold, and the particle size distribution of the raw material powder contained in the powder supply device.

9. The mold comprising a first mold and a second mold, the first mold being a first movable mold driven toward the second mold, the press having a first drive mechanism for driving the first movable mold, the first movable mold having a plurality of first punches driven independently of each other, the molding control unit pressurizing the raw material powder by driving the first mold toward the second mold by controlling the first drive mechanism, and the plurality of molding variables including at least the position of each of the plurality of first punches and the drive pressure for driving each of the plurality of first punches, the mold manufacturing apparatus according to any one of claims 6 to 8.

10. The molded body manufacturing apparatus according to claim 9, wherein the second mold is a second movable mold driven toward the first mold, the press has a second drive mechanism for driving the second movable mold, the molding control unit pressurizes the raw material powder by controlling the first drive mechanism to drive the first mold toward the second mold and by controlling the second drive mechanism to drive the second mold toward the first mold, and the plurality of molding variables include the position of the second mold and the drive pressure for driving the second mold.

11. A sintered body manufacturing apparatus comprising a molded body manufacturing apparatus according to any one of claims 6 to 10.

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