Method for manufacturing metal powder

Abstract

To suppress over-cutting or under-cutting of the workpiece. [Solution] In a method for manufacturing metal powder, a rolling process P1 is performed in parallel to a metal workpiece 1 by pressing a rolling tool 2 against the workpiece surface to form a plurality of protrusions 11 on the workpiece 1, and a cutting process P2 is performed to manufacture metal powder 4 by cutting the protrusions 11 of the workpiece 1 with a cutting tool 3. The amount of displacement δ of the workpiece surface caused by pressing the rolling tool 2 is determined, and the amount of feed z of the cutting tool 3 to the workpiece 1 is set according to the amount of displacement δ.

Description

Technical Field

[0001] The present invention relates to a method for producing metal powder. Background Art

[0002] As a method for producing this type of metal powder, there is known a metal powder forming method for forming metal powder by cutting the surface of a metallic workpiece, the method comprising: a plastic working step of forming, on a first surface of the workpiece, a second surface having a plurality of protrusions aligned in at least one direction using a plastic working tool; and a cutting step of forming metal powder by cutting the plurality of protrusions with a cutting tool (Patent Document 1). Prior Art Literature Patent Literature

[0003] Patent Document 1 International Publication WO2023 / 148980 Pamphlet Summary of the Invention Problem to be Solved by the Invention

[0004] However, in the above-mentioned conventional technique, since a rolling tool is pressed against the workpiece with a high load toward the axial center of the workpiece, deflection of the workpiece and backlash with the chuck cause the processed surface of the workpiece to deviate from its original position. As a result, there is a problem that overcutting or insufficient cutting occurs in the cutting step.

[0005] The problem to be solved by the present invention is to provide a method for producing metal powder that can suppress overcutting or insufficient cutting of a workpiece. Means for Solving the Problem

[0006] The present invention provides a method for manufacturing metal powder, which involves a rolling process in which a rolling tool is pressed against the workpiece surface to perform rolling, and a cutting process in which a plurality of protrusions formed on the workpiece are cut with a cutting tool, in parallel. The present invention solves the above problem by determining the first displacement amount of the workpiece surface caused by pressing the rolling tool, and setting the feed amount of the cutting tool according to the first displacement amount. [Effects of the Invention]

[0007] According to the present invention, it is possible to suppress over-cutting or under-cutting of the workpiece. [Brief explanation of the drawing]

[0008] [Figure 1] This is a process diagram showing a method for producing metal powder according to one embodiment of the present invention. [Figure 2] This is a schematic diagram showing the processing layout in the rolling process and cutting process according to one embodiment of the present invention. [Figure 3] This is a view from arrow III in Figure 2. [Figure 4] This is a schematic diagram showing the machining state in a cutting process according to one embodiment of the present invention. [Figure 5] This is a schematic diagram showing the machining state in a cutting process according to one embodiment of the present invention. [Figure 6] This is a schematic diagram illustrating the problems that arise when rolling and cutting processes are performed on a workpiece in parallel. [Figure 7] This is a schematic diagram showing an example of setting the feed rate in a cutting process according to one embodiment of the present invention. [Figure 8] This is a schematic diagram illustrating an example of a method for measuring displacement according to one embodiment of the present invention. [Figure 9] This is a schematic diagram showing the processing layout in the rolling and cutting processes according to another embodiment of the present invention. [Figure 10] Figure 9 is a schematic diagram showing an example of a displacement measurement method and an example of setting the feed rate of a cutting tool according to the embodiment shown. [Figure 11]This is a control circuit diagram showing an example of setting the feed rate in a cutting process according to another embodiment of the present invention. [Figure 12] This graph shows an example of the relationship between the radius of the workpiece and the amount of deflection. [Figure 13] This is a schematic diagram showing the processing layout in the rolling and cutting processes according to yet another embodiment of the present invention. [Figure 14] Figure 13 is a graph showing an example of the relationship between the position of the machined surface of the workpiece and the amount of displacement according to the embodiment shown. [Figure 15] This is a schematic diagram showing the processing layout in the rolling and cutting processes according to yet another embodiment of the present invention. [Figure 16] This is a schematic diagram showing the processing layout in the rolling and cutting processes according to yet another embodiment of the present invention. [Figure 17] This is a schematic diagram showing the processing layout in the rolling and cutting processes according to yet another embodiment of the present invention. [Modes for carrying out the invention]

[0009] The following describes embodiments for carrying out the present invention with reference to the drawings. The method for producing metal powder in this embodiment involves cutting the surface of a workpiece made of a metal material and recovering the fine cutting powder generated by the cutting as a metal powder product. The material of the target metal powder is not particularly limited as long as it is a metal. For example, aluminum, aluminum alloys, copper, copper alloys, iron, stainless steel, titanium, titanium alloys, nickel, nickel alloys, cobalt alloys, etc., can be used as examples. The particle size of the fine metal powder produced in this embodiment is not particularly limited. For example, it is a metal powder with an average particle size of several tens of micrometers to about 500 micrometers.

[0010] The application of the fine metal powder produced in the present embodiment is not particularly limited. Examples thereof include metal powder for metal 3D printing and metal powder to be mixed into resin pellets. When the metal powder produced in the present embodiment is used as a metal material for metal 3D printing, it can be used, for example, as a metal powder for powder bed type 3D printing. Further, when the metal powder produced in the present embodiment is used as a metal material for metal 3D printing, it can also be used in 3D printing of a method called Fused Deposition Modeling (FDM) or Fused Filament Fabrication (FFF), in which a resin filament is mixed with metal powder to form a laminated body. Furthermore, when the metal powder produced in the present embodiment is used as metal powder to be mixed into resin pellets, resin pellets mixed with the metal powder can be formed, and injection molding can be performed using the pellets.

[0011] Note that an injection molded body or a laminated body 3D-printed by the above-described Fused Deposition Modeling (FDM) or Fused Filament Fabrication (FFF) can be degreased and fired to obtain a metal part from which the resin has been removed. In these applications, it is considered that the closer the particle aspect ratio (the ratio of the major axis to the minor axis of a particle) is to 1, that is, the more spherical the particle is, the more preferable it is.

[0012] FIG. 1 is a process diagram showing a method for producing metal powder according to an embodiment of the present invention. As shown in FIG. 1, the method for producing metal powder of the present embodiment includes preparing a metallic workpiece 1, forming a plurality of protrusions 11 aligned in one direction on the surface of the workpiece 1 (rolling step P1), cutting the plurality of protrusions 11 formed on the surface of the workpiece 1 with a cutting tool 3 to generate metal powder 4 (cutting step P2), and recovering the generated metal powder 4 as a product (powder recovery step P3). After the cutting step P2 is completed, the workpiece 1 from which the plurality of protrusions 11 have been cut is subsequently (continuously) subjected to the processing of the rolling step P1 and the processing of the cutting step P2 on the cut surface of the workpiece 1 as needed.

[0013] Fig. 2 is a schematic diagram showing a processing state in a rolling step P1 and a cutting step P2 according to an embodiment of the present invention, and Fig. 3 is a view seen from arrow III in Fig. 2. A workpiece 1 of the present embodiment shown in Fig. 2 and Fig. 3 extends with a first axis A1 as a central axis, and has a circular or substantially circular shape in a cross section perpendicular to the first axis A1, whereby the workpiece 1 is formed into a cylindrical shape as a whole. The shape of the workpiece 1 is not limited thereto, and for example, the workpiece 1 may partially include a portion having a smaller radial dimension than other portions. Further, the workpiece 1 may have a shape such as an elliptic cylindrical shape or a polygonal prismatic shape. In the rolling step P1 and the cutting step P2 of the present embodiment, an end portion 12 on one side of the workpiece 1 is fixed to a chuck of an NC lathe, the workpiece 1 is rotated around the first axis A1 in the direction of arrow H, and while feeding the workpiece 1 in the direction of the first axis A1, rolling processing and cutting processing are continuously performed on an end portion 13 on the other side of the workpiece 1.

[0014] The workpiece 1 of the present embodiment has a first surface S1 in a state before the rolling step P1 and the cutting step P2 are performed. The first surface S1 has an axisymmetrical shape around the first axis A1. In the example shown in Fig. 2 and Fig. 3, the first surface S1 is configured by an outer circumferential surface of the workpiece 1. That is, the first surface S1 is formed in the shape of a cylindrical surface having the first axis A1 as a central axis.

[0015] The rolling process P1 of this embodiment is a process of forming a plurality of protrusions 11 on the first surface S1 of the workpiece 1 by rolling (plastic deformation), as shown in Figure 4. In the following description, the surface of the workpiece 1 on which the plurality of protrusions 11 have been formed by rolling will be referred to as the second surface S2. In the rolling process P1, the workpiece 1 is plastically deformed by pressing the rolling tool 2 against the first surface S1, thereby forming a plurality of protrusions 11. The plurality of protrusions 11 are formed in a state where they are aligned in at least one direction. The material of the rolling tool 2 only needs to have a higher hardness than the workpiece 1. For example, the rolling tool 2 may be made of cemented carbide. In addition, a sliding film (not shown) may be formed on the processing die of the rolling tool 2. The sliding film may be, for example, a DLC (Diamond Like Carbon) coating. In addition, the sliding film may be formed by known film formation methods such as PVD (Physical Vapor Deposition) or CVD (Chemical Vapor Deposition). A "processing die" refers to a portion of a rolling tool that has a predetermined shape and is formed on its surface to plastically deform the surface of a workpiece into a desired shape.

[0016] In this embodiment, a knurling tool 21 can be used as the rolling tool 2. The knurling tool 21 is one form of a rolling tool. In this embodiment, a cutting tool 31 can be used as the cutting tool 3. In the example shown in Figures 2 and 3, the knurling tool 21 is placed on one radial side of the workpiece 1, and the cutting tool 31 is placed on the other side opposite to it. Note that the arrangement relationship between the workpiece 1, the knurling tool 21, and the cutting tool 31 is not limited to the illustrated example, and can be appropriately set according to the shape and dimensions of the processing apparatus for carrying out the metal powder manufacturing method according to the embodiment. For example, one cutting tool 31 may be placed on one radial side of the workpiece 1, and a knurling tool 21 may be placed on the other side that does not face it.

[0017] The knurling tool 21 of this embodiment includes a first knurling tool 21a and a second knurling tool 21b, as shown in Figure 2. In the illustrated example, the first knurling tool 21a is rotatable around the second axis A2 and is a roller-type tool with a disc shape when viewed in the axial direction of the second axis A2. The second knurling tool 21b is rotatable around the third axis A3 and is a roller-type tool with a disc shape when viewed in the axial direction of the third axis A3. The first knurling tool 21a rotates in the direction of arrow I in accordance with the rotation of the workpiece 1, and the second knurling tool 21b rotates in the direction of arrow J. Although the second axis A2 and third axis A3 illustrated in the figure extend parallel to the first axis A1, the present invention is not limited to this. For example, the second axis A2 or the third axis A3 may extend in a direction inclined with respect to the first axis A1.

[0018] A processing die 22 is formed on the outer circumferential surface of the first knurling tool 21a. The processing die 22 is composed of a plurality of raised ridges. In the example shown in Figure 3, each of the plurality of raised ridges extends in a direction intersecting the second axis A2 when viewed radially from the first knurling tool 21a and is arranged parallel to each other. Furthermore, the processing die (not shown) formed on the outer circumferential surface of the second knurling tool 21b is formed by extending a plurality of raised ridges (not shown) in a direction intersecting the direction in which the raised ridges of the first knurling tool 21a extend. In the rolling process of this embodiment, by pressing the knurling tool 21 against the first surface S1 of the workpiece 1 rotating around the first axis A1 with a predetermined pressing load, the first surface S1 is raised in a shape corresponding to the processing die 22 of the knurling tool 21, forming a plurality of raised ridges 11 that make up a so-called diagonal pattern.

[0019] The knurling tool 21 illustrated in Figures 2 and 3 includes two roller-type tools, a first knurling tool 21a and a second knurling tool 21b, but the present invention is not limited thereto. For example, the knurling tool 21 may consist of only one roller-type tool. In that case, the outer circumferential surface of the single roller-type tool may have multiple recesses formed thereon, such as a square pyramidal shape or a hemispherical shape.

[0020] The cutting process P2 is a process in which the multiple protrusions 11 formed by the rolling process P1 are cut with a cutting tool 3. When the multiple protrusions 11 are cut, metal powder 4 is obtained as cutting dust. In the following description, the surface of the workpiece 1 after the multiple protrusions 11 have been cut will also be referred to as the third surface S3.

[0021] The cutting tool 31 of this embodiment is equipped with a cutting edge 32. The cutting edge 32 has a flat blade shape that extends in a direction parallel to the first axis A1. As shown in Figure 3, the width of the cutting edge 32 of the cutting tool 31 and the width of the knurling tool 21 may be approximately equal in the direction parallel to the first axis A1.

[0022] Next, I will explain the mechanism of action. As shown in Figure 2, in the rolling process P1 and cutting process P2 of this embodiment, one end 12 of the workpiece 1 is fixed to the chuck of the NC lathe, and the workpiece 1 is rotated in the direction of arrow H around the first axis A1. While feeding the workpiece 1 in the direction of the first axis A1, rolling and cutting processes are continuously performed on the other end 13 of the workpiece 1.

[0023] As a result, the first surface S1 of the workpiece 1 becomes a second surface S2 with multiple protrusions 11 made up of a diagonal pattern, and then some or all of the protrusions 11 of the second surface S2 are cut away to become a third surface S3. Metal powder 4 is generated at this time. Furthermore, if the rotation of the workpiece 1 is continued, the third surface S3 of the workpiece 1 becomes a second surface S2 with multiple protrusions 11 made up of a diagonal pattern, and then some or all of the protrusions 11 of the second surface S2 are cut away to become a third surface S3 again.

[0024] Furthermore, when performing the rolling process, the pitch of the multiple protrusions 11 can be adjusted by adjusting the pitch of the protrusions of the first knurling tool 21a or the second knurling tool 21b. In addition, the height H1 of each of the multiple protrusions 11 in the radial direction of the workpiece 1 (see Figure 4) can be controlled by the pressing load of the knurling tool 21 during the rolling process. For example, when performing the rolling process, the height H1 of the protrusions 11 can be made lower by reducing the pressing load of the knurling tool 21. Note that height H1 refers to the distance between the top 11a and the first surface S1 in an axial view parallel to the first axis A1 in Figure 4.

[0025] Furthermore, when performing cutting, the cutting tool 31 shown in Figure 4 may be used to cut in the direction of arrow K with a predetermined depth of cut D. At this time, the movement of the cutting tool 31 in a direction perpendicular to the cutting direction may be restricted. In the example shown in the figure, the depth of cut D refers to the distance in the radial direction of the workpiece 1 between the top 11a of the protrusion 11 and the point P of the cutting blade 32 that is closest to the first axis A1. The depth of cut D may also be less than or equal to the height H1 of each of the multiple protrusions 11 in the radial direction of the workpiece 1. By cutting the cutting tool 31 into the second surface S2 having multiple protrusions 11, at least a portion of the multiple protrusions 11 is cut by the cutting blade 32, as illustrated in Figure 5, and metal powder 4 is generated as cutting chips.

[0026] Figure 6 is a schematic diagram illustrating the problems that arise when rolling and cutting processes are performed on a workpiece 1 in parallel (simultaneously). As shown in the left diagram of Figure 6, the rolling tool 2 is pressed with a high load toward the axial center of the workpiece 1, causing the workpiece 1 to bend, or, in addition to this, to have play with the NC lathe chuck, causing the machined surface of the workpiece 1 to be displaced from its initial position. When cutting is performed with the machined surface of the workpiece 1 displaced from its original position in this way, as shown in the upper right cross-sectional view of Figure 6, the feed rate of the cutting tool becomes larger than the original set value, resulting in a cut deeper than the convex portion formed by the rolling process. This type of cutting defect is called overcutting, and the metal powder obtained when overcutting occurs has the problem of unstable quality in terms of shape and particle size, as shown by the white circle in the lower right photograph of Figure 6.

[0027] Therefore, in the metal powder manufacturing method of this embodiment, the amount of displacement δ of the machined surface of the workpiece caused by the pressing of the rolling tool 2 is determined, and the feed amount z of the cutting tool 3 to the workpiece 1 is set according to the amount of displacement δ. This suppresses the occurrence of over-cutting.

[0028] Figure 7 is a schematic diagram showing an example of feed rate setting in a cutting process according to one embodiment of the present invention, with the left diagram corresponding to the view from arrow III in Figure 2. The middle diagram of Figure 7 shows the state in which the feed rate of the cutting tool 3 is set to the original z, and the right diagram shows the state in which the feed rate of the cutting tool 3 is set considering the displacement amount δ of the machined surface. In this example, the rolling tool 2 and the cutting tool 3 are arranged facing each other in the diametrical direction of the workpiece 1 as shown in Figure 2, so the pressing direction of the rolling tool 2 is on the same line as the feed direction of the cutting tool 3. Therefore, the displacement amount δ of the machined surface of the workpiece 1 directly affects the feed rate z of the cutting tool 3, so the feed rate of the cutting tool in this example is set to z-δ.

[0029] As shown in the middle diagram of Figure 7, when rolling and cutting are performed in parallel with the feed rate of the cutting tool set to z, the machined surface of the workpiece 1 is displaced by δ in the direction of the feed of the cutting tool 3, resulting in overcutting. However, when rolling and cutting are performed in parallel with the feed rate of the cutting tool 3 set to z-δ, taking this displacement δ into consideration, the occurrence of overcutting is suppressed, as shown in the right diagram of Figure 7, and only the protrusions 11 formed by rolling can be cut.

[0030] The displacement δ of the machined surface of the workpiece 1 caused by the pressing of the rolling tool 2 can be measured in various ways. Figure 8 is a schematic diagram showing an example of a method for measuring the displacement δ according to one embodiment of the present invention. In the illustrated example, one end 12 of the workpiece 1 is fixed to the chuck 14 of the NC lathe, and the rolling tool 2 is pressed against the workpiece 1 with a pressing load set during the rolling process without rotating the workpiece 1. This is also called a static pressing state. A displacement measuring instrument 34, such as a dial gauge, is fixed to the end mill spindle 33 on which the cutting tool 3 is mounted, and this displacement measuring instrument 34 is used to measure the displacement δ of the machined surface of the workpiece 1 in a static pressing state by the rolling tool 2. Once the displacement δ of the machined surface of the workpiece 1 is determined in this way, the feed rate of the cutting tool 3 is set to z-δ as shown in the right diagram of Figure 7, and the actual rolling process and cutting process are performed in parallel.

[0031] Figure 9 is a schematic diagram showing the processing layout in the rolling process P1 and cutting process P2 according to another embodiment of the present invention, and Figure 10 is a schematic diagram showing an example of a method for measuring the displacement amount δ and an example of setting the feed amount z of the cutting tool according to the embodiment shown in Figure 9. In the embodiments shown in Figures 2 and 7, the rolling tool 2 and the cutting tool 3 are arranged facing each other in the diametrical direction of the workpiece 1, whereas in the embodiments shown in Figures 9 and 10, the rolling tool 2 and the cutting tool 3 are not arranged facing each other in the diametrical direction of the workpiece 1, but are arranged at positions with a phase angle of 90° (or 270°).

[0032] In the illustrated example, one end 12 of the workpiece 1 is fixed to the chuck 14 (not shown) of an NC lathe, and the rolling tool 2 is pressed against the workpiece 1 with a pressing load set for rolling, without rotating the workpiece 1. As shown in the middle diagram of Figure 10, a displacement measuring instrument 34 such as a dial gauge is fixed to the end mill spindle 33 on which the cutting tool 3 is mounted, and this displacement measuring instrument 34 is used to measure the displacement amount δ of the machined surface of the workpiece 1 under static pressing by the rolling tool 2.

[0033] In the layout shown in Figures 9 and 10, that is, when the rolling tool 2 and cutting tool 3 are not positioned facing each other in the diametrical direction of the workpiece 1, the pressing direction of the rolling tool 2 and the feed direction of the cutting tool 3 are not on the same line, as shown in the left diagram of Figure 10, but are in a positional relationship with an angle of 90° (or 270°). Therefore, the displacement amount δ of the machined surface of the workpiece 1 does not directly affect the feed amount z of the cutting tool 3, but rather, as shown in the right diagram of Figure 10, the value of the geometrical positional relationship, i.e., the correction value of the feed amount of the cutting tool 3 with respect to the displacement amount δ of the machined surface of the workpiece 1, becomes r-rcosθ1=r(1-cosθ1). Here, r is the radius of the workpiece 1, and θ1 is the central angle of the sector formed by the original cutting position of the cutting tool 3, the actual cutting position, and the center of the workpiece 1. Therefore, the feed amount of the cutting tool 3 is set to z+r(1-cosθ1) with respect to the original z.

[0034] The displacement amount δ of the machined surface of the workpiece 1 caused by the pressing of the rolling tool 2 of the present invention is measured in a static pressing state by the rolling tool 2, as shown in Figures 8 and 10. Based on this measurement result, the feed amount z of the cutting tool 3 to the workpiece 1 is set. Alternatively, the displacement amount δ during rolling may be measured in real time, and the feed amount z of the cutting tool 3 to the workpiece 1 may be feedback controlled based on this measurement result. Figure 11 is a control circuit diagram showing an example of setting the feed amount z in a cutting process P2 according to another embodiment of the present invention.

[0035] The control circuit shown in Figure 11 includes a controller 5. The displacement measuring instrument 34 measures the displacement amount δ of the machined surface of the workpiece 1 in real time while the rolling and cutting processes are being performed in parallel. The controller 5 receives an initial target value for the feed rate of the cutting tool 3, and the feed rate z of the cutting tool 3 is set according to this target value. However, when the rolling and cutting processes start in parallel, the pressure applied during the rolling process causes a disturbance in the displacement of the workpiece 1. The displacement measuring instrument 34 measures the displacement amount δ of the machined surface of the workpiece 1, including this disturbance displacement, in real time, corrects the target value, and outputs the feed rate z. This feedback control makes it possible to reflect the actual displacement amount δ of the machined surface, which cannot be measured under static pressure conditions, in the feed rate z of the cutting tool 3.

[0036] Figure 12 is a graph showing an example of the relationship between the radius r of the workpiece 1 and the amount of deflection. In the metal powder manufacturing method of this embodiment, when rolling and cutting are performed consecutively, the diameter of the workpiece 1 gradually decreases. However, since the pressing load of the rolling tool 2 is kept constant, the amount of deflection of the workpiece 1, i.e., the displacement δ of the machined surface, gradually changes. Therefore, as shown in Figure 12, the change in the displacement δ caused by the decrease in the radius or diameter of the workpiece 1 can be determined, and the feed amount z of the cutting tool 3 to the workpiece 1 can be set according to the change in the displacement δ.

[0037] Figure 13 is a schematic diagram showing the processing layout in the rolling and cutting processes according to yet another embodiment of the present invention. The workpiece 1 in this embodiment has a plurality of processing surfaces along the axial direction of the workpiece 1. In the workpiece 1 shown in Figure 13, five processing surfaces are provided, and their positions are indicated by X1 to X5. A rolling tool 2 and a cutting tool 3 are provided for each of the five processing surfaces. In the rolling process P1, each of the five rolling tools 2 is pressed against each of the five processing surfaces to perform rolling, and in the cutting process P2, the plurality of protrusions 11 formed on each of the five processing surfaces are cut by each of the five cutting tools 3.

[0038] Here, since the workpiece 1 is cantilevered at one end 12 on the chuck 14 of the NC lathe, the displacement δ when the rolling tool 2 is pressed against each of the five machining surfaces will differ. Therefore, in this example, the displacements δ1 to δ5 are determined for each of the five machining surfaces. Figure 14 is a graph showing an example of the relationship between the positions X1 to X5 of the machining surfaces of the workpiece 1 according to the embodiment shown in Figure 13 and the displacement δ. Note that F1 to F4 in Figure 14 indicate the pressing load of the rolling tool 2. Then, the feed amount z of each of the five cutting tools 3 to the workpiece 1 is set according to the displacements δ1 to δ5.

[0039] Figure 15 is a schematic diagram showing the processing layout in the rolling and cutting processes according to yet another embodiment of the present invention. When the processed surface of the workpiece 1 is displaced by the pressure of the rolling tool 2, the inclination θ2 of the processed surface also changes. Therefore, in this example, the displacement angle θ2 of the processed surface of the workpiece 1 is measured under static pressure by the rolling tool 2, and the amount of inclination of the processing axis of the cutting tool 3 is set by tilting it by θ2 based on this measurement result.

[0040] Figure 16 is a schematic diagram showing the processing layout in the rolling and cutting processes according to yet another embodiment of the present invention. As described in the embodiment shown in Figure 15, when the processed surface of the workpiece 1 is displaced by the pressing of the rolling tool 2, the inclination θ2 of the processed surface also changes. Therefore, in this example, the displacement angle θ2 of the processed surface of the workpiece 1 is measured under static pressing by the rolling tool 2, and the amount of inclination of the processing axis of the rolling tool 2 is set by tilting it by θ2 based on this measurement result.

[0041] Figure 17 is a schematic diagram showing the processing layout in the rolling and cutting processes according to yet another embodiment of the present invention. In a cutting tool 3 such as a cutting tool 31, the angle formed between the surface of the workpiece being cut (reference surface) and the surface from which chips are discharged when the cutting tool rubs (rake surface) is called the rake angle θ3. Since the chips flow along the rake surface, the rake angle θ3 determines the thickness and flow direction of the chips. When the rake angle θ3 is large, the chip shear angle becomes small and the chip thickness also becomes thin. As a result, the cutting force is reduced, which has the effect of lowering the cutting temperature and reducing tool wear. However, if the rake angle θ3 is made too large, the strength of the cutting edge decreases, and the cutting edge becomes prone to chipping when processing high-hardness materials. Therefore, it is desirable to set the rake angle θ3 of the cutting tool 3 to a predetermined angle.

[0042] However, as shown in the left diagram of Figure 17, even if a cutting tool 3 having a predetermined rake angle θ3 is used, as shown in the middle diagram of the same figure, when the machined surface of the workpiece 1 is displaced by the pressure of the rolling tool 2, the rake angle θ4 of the cutting tool 3 becomes smaller than the initially planned rake angle θ3 (θ4 < θ3). Therefore, in this example, the rake angle θ4 of the cutting tool 3 is determined from the amount of displacement δ of the machined surface of the workpiece 1 due to the pressure of the rolling tool 2, and the rake face 35 of the cutting tool 3 is set so that this becomes the predetermined rake angle θ3. To set the rake face 35 of the cutting tool 3 so that the rake angle of the cutting tool 3 becomes the appropriate predetermined rake angle θ3, the feed direction of the cutting tool 3 should be tilted by θ4 - θ3. Alternatively, the feed direction of the cutting tool 3 may be kept as is, and it may be replaced with another cutting tool 3 having a different angle of the rake face 35, while the rake angle becomes θ3.

[0043] As described above, the metal powder manufacturing method of this embodiment is a method for manufacturing metal powder in which a rolling process P1 is performed by pressing a rolling tool 2 against the processed surface of a metal workpiece 1 to form a plurality of protrusions 11 on the workpiece 1, and a cutting process P2 is performed in parallel by cutting the protrusions 11 of the workpiece 1 with a cutting tool 3 to manufacture metal powder 4. The amount of displacement δ of the processed surface of the workpiece 1 caused by pressing the rolling tool 2 is determined, and the feed amount z of the cutting tool 3 to the workpiece 1 is set according to the amount of displacement δ, so that cutting can be performed with an appropriate feed amount, and over-cutting or under-cutting in the cutting process P2 can be suppressed. As a result, the quality of the manufactured metal powder, such as the shape and particle size, is stabilized.

[0044] Furthermore, in the metal powder manufacturing method of this embodiment, the displacement amount δ is measured under static pressing conditions by the rolling tool 2, and the feed amount z of the cutting tool 3 to the workpiece 1 is set based on this measurement result. This allows cutting with an appropriate feed amount, and prevents over-cutting or under-cutting in the cutting process P2.

[0045] Furthermore, the metal powder manufacturing method of this embodiment measures the displacement amount δ during the rolling process in real time and provides feedback control to the feed amount z of the cutting tool 3 to the workpiece 1 based on this measurement result. This allows for cutting with a more appropriate feed amount, suppressing over-cutting or under-cutting in the cutting process P2. In addition, the work of measuring the displacement amount δ in advance can be omitted.

[0046] Furthermore, in the metal powder manufacturing method of this embodiment, the amount of change in the displacement amount δ caused by the decrease in the diameter of the workpiece 1 is determined, and the feed amount z of the cutting tool 3 to the workpiece 1 is set according to the amount of change in the displacement amount δ. This allows for cutting with a more appropriate feed amount, and suppresses over-cutting or under-cutting in the cutting process P2.

[0047] Furthermore, in the metal powder manufacturing method of this embodiment, the workpiece 1 includes a plurality of machined surfaces along the axial direction of the workpiece 1, and in the rolling process P1, each of the plurality of rolling tools 2 is pressed against each of the plurality of machined surfaces to perform rolling, and in the cutting process P2, each of the plurality of protrusions 11 formed on each of the plurality of machined surfaces is cut by each of the plurality of cutting tools 3, the displacement amounts δ1 to δ5 are determined for each of the plurality of machined surfaces, and the feed amount z of each of the plurality of cutting tools 3 to the workpiece 1 is set according to the displacement amounts δ1 to δ5, so that even when there are multiple machined surfaces, cutting can be done with an appropriate feed amount and over-cutting or under-cutting in the cutting process P2 can be suppressed.

[0048] Furthermore, in the metal powder manufacturing method of this embodiment, the displacement angle θ2 of the machined surface of the workpiece 1 is measured under static pressing conditions by the rolling tool 2, and the tilt amount θ2 of the machining axis of the cutting tool 3 is set based on this measurement result. As a result, the cutting tool 3 makes perpendicular contact with the machined surface, and variations in the shape and particle size of the metal powder due to non-surface contact can be suppressed.

[0049] Furthermore, in the metal powder manufacturing method of this embodiment, the displacement angle θ2 of the processed surface of the workpiece 1 is measured under static pressing conditions by the rolling tool 2, and the tilt amount θ2 of the processing axis of the rolling tool 2 is set based on this measurement result. As a result, the rolling tool 2 makes perpendicular contact with the processed surface, and variations in the shape and particle size of the metal powder due to non-surface contact can be suppressed.

[0050] Furthermore, in the metal powder manufacturing method of this embodiment, the rake angle θ4 of the cutting tool 3 is determined from the displacement amount δ, and the rake face 35 of the cutting tool 3 is set so that it becomes a predetermined rake angle θ3, thereby stabilizing the quality of the manufactured metal powder, such as its shape and particle size. [Explanation of Symbols]

[0051] 1…Work material 11…Convex part 12... One end 13...the other end 14... Chuck 2…Thread rolling tool 21, 21a, 21b... Knurling tools 3…Cutting tools 31...bytes 32…Cutting blade 33... End mill spindle 34…Displacement measuring instrument 35... Scoop surface 4...Metal powder 5…Controller P1... Rolling process P2…Cutting process P3... Powder recovery process H1...Height of the protrusion z... Feed rate of the cutting tool δ...Displacement of the machined surface

Claims

1. A rolling process in which a rolling tool is pressed against the workpiece surface of a metal workpiece to perform rolling and form a plurality of protrusions on the workpiece, In a method for manufacturing metal powder, which involves a cutting process in parallel with a cutting tool to cut off the protrusions of the workpiece, A method for producing metal powder, which involves determining the amount of displacement of the workpiece surface caused by pressing the rolling tool, and setting the amount of feed the cutting tool onto the workpiece according to the amount of displacement.

2. The method for producing metal powder according to claim 1, wherein the displacement is measured under static pressing conditions by the rolling tool, and the amount of feed of the cutting tool to the workpiece is set based on the measurement result.

3. The amount of displacement during the aforementioned rolling process is measured in real time, The method for producing metal powder according to claim 1, wherein the amount of feed of the cutting tool to the workpiece is fed back and controlled based on the measurement results.

4. A method for producing metal powder according to any one of claims 1 to 3, wherein the amount of change in the displacement caused by the reduction in the diameter of the workpiece is determined, and the amount of feed of the cutting tool to the workpiece is set according to the amount of change in the displacement.

5. The workpiece includes a plurality of machined surfaces along the axial direction of the workpiece, In the aforementioned rolling process, rolling is performed by pressing each of the multiple rolling tools against each of the multiple processing surfaces. In the cutting process, the multiple protrusions formed on each of the multiple machined surfaces are cut using each of the multiple cutting tools. A method for producing metal powder according to any one of claims 1 to 3, wherein the amount of displacement is determined for each of the plurality of machined surfaces, and the amount of feed given to the workpiece by each of the plurality of cutting tools is set according to the amount of displacement.

6. A method for producing metal powder according to any one of claims 1 to 3, wherein the displacement angle of the machined surface of the workpiece is measured under static pressing by the rolling tool, and the amount of inclination of the machining axis of the cutting tool is set based on the measurement result.

7. A method for producing metal powder according to any one of claims 1 to 3, wherein the displacement angle of the processed surface of the workpiece is measured under static pressing by the rolling tool, and the amount of inclination of the processing axis of the rolling tool is set based on the measurement result.

8. A method for producing metal powder according to any one of claims 1 to 3, wherein the rake angle of the cutting tool is determined from the displacement, and the rake face of the cutting tool is set so that it has a predetermined rake angle.

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