Method for manufacturing metal powder

Abstract

The present invention provides a method for producing metal powder with a high material yield. [Solution] The method includes a plastic deformation step P1 in which the shape of a mold 2 having a plurality of fine recesses 21 is transferred to the surface of a metal workpiece 1 by electromagnetic molding to form a plurality of protrusions 11, and a cutting step P2 in which the plurality of protrusions 11 are cut using a cutting tool 3 to generate metal powder 4.

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, a cutting surface of a metal workpiece is cut in a first cutting direction by a cutting tool, and the cut cutting surface is cut in a direction intersecting the first cutting direction by the cutting tool, and a fine powder forming method is known in which cutting powder generated in the latter cutting step is recovered as fine powder particles (Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the above conventional technology, the cutting powder generated in the first cutting step is not recovered because it does not become the desired fine powder (paragraph 0017), so there is a problem that the material yield is low.

[0005] The problem to be solved by the present invention is to provide a method for producing metal powder with a high material yield. [[ID=4l]]

Means for Solving the Problems

[0006] The present invention solves the above problems by transferring the shape of a mold having a plurality of fine recesses to the surface of a metal workpiece by electromagnetic forming to form a plurality of protrusions, cutting the plurality of protrusions using a cutting tool, and generating metal powder.

Effects of the Invention

[0007] According to the present invention, it is possible to provide a method for producing metal powder with a high material yield. [Brief explanation of the drawing]

[0008] [Figure 1] This is a process diagram showing one embodiment of the method for producing metal powder according to the present invention. [Figure 2] This is a cross-sectional view showing an example of an electromagnetic molding apparatus used in the method for producing metal powder according to the present invention. [Figure 3] This is a cross-sectional view showing another example of an electromagnetic molding apparatus used in the method for producing metal powder according to the present invention. [Figure 4] A side view and a top view showing an example of a cutting apparatus used in the metal powder manufacturing method of the present invention. [Figure 5] Side view and top view showing other examples of cutting apparatus used in the metal powder manufacturing method of the present invention. [Figure 6] Figures 4 and 5 are cross-sectional views showing the cutting surface and cutting tool in the cutting apparatus. [Figure 7] A perspective view showing an example of a manufacturing line using the metal powder manufacturing method of the present invention. [Modes for carrying out the invention]

[0009] Hereinafter, examples of embodiments for carrying out the present invention will be described 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, but examples include aluminum, aluminum alloys, iron, stainless steel, titanium, titanium alloys, nickel, nickel alloys, and cobalt alloys. The particle size of the fine metal powder produced in this embodiment is not particularly limited, but for example, it is a powder with an average particle diameter of several tens of micrometers.

[0010] The applications of the fine metal powder manufactured in this embodiment are not particularly limited, but examples include metal powder for metal 3D printing and metal powder mixed into resin pellets. When the metal powder manufactured in this embodiment is used as metal for metal 3D printing, for example, it can be used as metal powder for powder bed 3D printing. When the metal powder manufactured in this embodiment is used as metal for metal 3D printing, it can also be used in 3D printing methods called Fused Deposition Modeling (FDM) or Fused Filament Fabrication (FFF), which involve mixing metal powder into resin filaments to form a laminate. Furthermore, when the metal powder manufactured in this embodiment is used as metal powder mixed into resin pellets, resin pellets mixed with the metal powder can be formed, and these pellets can be used for injection molding.

[0011] Furthermore, injection-molded parts and laminates 3D printed using the fused deposition modeling (FDM) or filament filament melting (FFF) methods described above can be degreased and fired to obtain metal parts from which the resin has been removed. For these applications, it is preferable that the particle aspect ratio (the ratio of the long axis to the short axis of the particle) is close to 1, i.e., that the particle is spherical.

[0012] Figure 1 is a process diagram showing one embodiment of the present invention for manufacturing metal powder, and Figure 7 is a perspective view showing an example of a manufacturing line using the present invention for manufacturing metal powder. As shown in Figure 1, the present invention for manufacturing metal powder involves preparing a metal workpiece 1, transferring the shape of a mold 2 having a plurality of fine recesses 21 onto the surface of the workpiece 1 by electromagnetic molding to form a plurality of protrusions 11 (plastic deformation process P1), cutting the plurality of protrusions 11 formed on the surface of the workpiece 1 using a cutting tool 3 to generate metal powder 4 (cutting process P2), and recovering the generated metal powder 4 as a product (powder recovery process P3). After the cutting process P2 is completed and the plurality of protrusions 11 have been cut off, the workpiece 1 is returned to the plastic deformation process P1, and the transfer process of the plastic deformation process P1 and the cutting process of the cutting process P2 are performed at least once on the cut surface of the workpiece 1.

[0013] In Figure 7, the metal workpiece 1 is brought into the workpiece loading process P0 at the left end of the figure, and is sequentially transported by a conveyor belt to the plastic deformation process P1 and the cutting process P2, where each processing is carried out. After the processing in the cutting process P2, the workpiece 1 is transported back to the workpiece loading process P0 as long as the remaining plate thickness is above a predetermined value and plastic deformation is possible, while the metal powder 4 generated in the cutting process P2 is recovered as a product in the powder recovery process P3.

[0014] Figure 2 is a cross-sectional view showing an example of an electromagnetic molding apparatus 30 used in the metal powder manufacturing method of the present invention. The workpiece 1 in this embodiment is a plate-shaped member. Electromagnetic molding is a molding method that transfers the shape of the mold 2 to the surface of the workpiece 1 by instantaneously applying magnetic field energy to the workpiece 1 and causing it to collide with the mold 2. Therefore, as shown in Figure 2, the electromagnetic molding apparatus 30 of this embodiment comprises an electromagnetic coil 5 that generates electromagnetic force, a steel plate 6 which is a conductive member that holds the workpiece 1 and on which the electromagnetic force from the electromagnetic coil 5 acts, and a mold 2 having a plurality of fine recesses 21.

[0015] As shown in Figure 2, multiple fine recesses 21 are formed on the lower surface of the mold 2, and the workpiece 1 is held in the steel plate 6 with a small gap between them. When a large current is instantaneously passed through the electromagnetic coil 5 in this state to generate a magnetic field, an induced current is induced in the steel plate 6, and an electromagnetic force, indicated by the white arrow, acts on the steel plate 6, causing the workpiece 1 held in the steel plate 6 to instantaneously collide with the mold 2. As a result, the shape of the multiple fine recesses 21 of the mold 2 is transferred to the surface of the workpiece 1, so that multiple fine protrusions 11 are formed on the surface of the workpiece 1.

[0016] Figure 3 is a cross-sectional view showing another example of the electromagnetic molding apparatus 30 used in the metal powder manufacturing method of the present invention. In this embodiment, the workpiece 1 is a cylindrical member (pipe-shaped member). In this example as well, similar to the electromagnetic molding apparatus 30 of the embodiment shown in Figure 2, the electromagnetic molding method transfers the shape of the mold 2 to the surface of the workpiece 1 by instantaneously supplying magnetic field energy to the workpiece 1 and causing it to collide with the mold 2. Therefore, as shown in Figure 3, the electromagnetic molding apparatus 30 of this embodiment comprises an electromagnetic coil 5 that generates an electromagnetic force and a cylindrical mold 2 having a plurality of fine recesses 21.

[0017] As shown in Figure 3, multiple fine recesses 21 are formed on the inner surface of the cylindrical mold 2, and a cylindrical workpiece 1 is placed against it with a small gap in between. When a large current is instantaneously passed through the electromagnetic coil 5 in this state to generate a magnetic field, an induced current is induced in the workpiece 1, and an electromagnetic force, indicated by the white arrow, acts on the workpiece 1, causing the cylindrical workpiece 1 to expand in diameter and instantaneously collide with the mold 2. As a result, the shape of the multiple fine recesses 21 of the mold 2 is transferred to the outer surface of the workpiece 1, so that multiple fine protrusions 11 are formed on the outer surface of the workpiece 1.

[0018] In the plastic working process P1 of the present embodiment, the height H (see FIG. 6) of each of the plurality of convex portions 11 formed on the surface of the workpiece 1 can be controlled by the shape of the concave portion 21 of the mold 2. If the concave portion 21 of the mold 2 is made deeper, the height of the convex portion 11 can be controlled to be higher. Alternatively or in addition to this, the height H of each of the plurality of convex portions 11 formed on the surface of the workpiece 1 can be controlled by the electromagnetic force generated by the electromagnetic coil 5 of the electromagnetic forming device 30. If the current flowing through the electromagnetic coil 5 is increased to increase the electromagnetic force, the height of the convex portion 11 can be controlled to be higher.

[0019] FIG. 4 is a side view (left figure) and a plan view (right figure) showing an example of the cutting device 40 used in the method for producing metal powder of the present invention, and FIG. 6 is a cross-sectional view showing the cutting surface and the cutting tool 3 in the cutting device 40 of FIG. 4. In the embodiment shown in FIG. 4, a rotary tool is used as the cutting tool 3, and the workpiece 1 is a plate-like member and the cutting surface of the workpiece 1 is a flat surface. In this case, the workpiece 1 is fixed to a base or the like, and the cutting tool 3 which is a rotary tool moves in the cutting direction D while rotating. Also, the case where the cutting direction D is perpendicular to the rotation axis O of the cutting tool 3 which is a rotary tool is illustrated. In the example shown in FIG. 3, the moving direction (feed direction) of the cutting tool 3 which is a rotary tool and the cutting direction D coincide.

[0020] Examples of such a rotary tool as the cutting tool 3 include a regular-edge end mill and a comb-edge end mill. The regular-edge end mill may be an end mill such as a square end mill, a radius end mill, a taper end mill, or a ball end mill. The comb-edge end mill may be a roughing-edge end mill. Note that as long as the desired cutting can be performed, the rotary tool is not limited to an end mill, and other rotary tools such as a drill, a reamer, or a rotary cutter may also be used.

[0021] In the cutting process P2 of the present embodiment, when the above-described rotary cutting tool is used as the cutting tool 3, as shown in FIG. 6, cutting is performed with a cutting amount that is less than or equal to the height H of the convex portion 11 of the workpiece 1. Also, when the above-described rotary cutting tool is used as the cutting tool 3, the shape of the metal powder can be controlled by the rotational speed of the rotary cutting tool.

[0022] Figure 5 is a side view and a top view showing another example of the cutting apparatus 40 used in the metal powder manufacturing method of the present invention, and Figure 6 is a cross-sectional view showing the cutting surface and cutting tool 3 in the cutting apparatus 40 of Figure 5. In the embodiment shown in Figure 5, a non-rotating cutting tool such as a cutting tool bit is used as the cutting tool 3, rather than a rotary tool as shown in Figure 4, and the workpiece 1 is a cylindrical member, and cutting is performed while the workpiece 1 is rotated. The cutting surface is the circumferential surface of the workpiece 1. The cutting tool 3 shown in Figure 5 is a comb-type cutting tool bit. Here, the cutting tool 3 moves parallel to the rotation axis O of the workpiece 1. By moving the cutting tool 3 in this way, the distance over which cutting is performed continuously becomes longer, and the amount of cutting powder formed per unit time increases.

[0023] In the cutting process P2 of this embodiment, when a non-rotating cutting tool is used as the cutting tool 3, the cutting is performed with a depth of cut that is less than or equal to the height H of the protrusion 11 of the workpiece 1, as shown in Figure 6.

[0024] As described above, the method for producing metal powder in this embodiment includes a plastic deformation step P1 in which the shape of a mold 2 having a plurality of fine recesses 21 is transferred to the surface of a metal workpiece 1 by electromagnetic molding to form a plurality of protrusions 11, and a cutting step P2 in which the plurality of protrusions 11 are cut using a cutting tool 3 to produce metal powder 4. Here, since the metal powder 4 is produced by cutting the plurality of protrusions 11 using a cutting tool 3, the material yield is high. Furthermore, since the shape of the plurality of fine recesses 21 is transferred to the surface of the workpiece 1 by electromagnetic molding to form a plurality of protrusions 11, the processing speed is about 200 times faster than conventional press working, and productivity is significantly better.

[0025] Furthermore, in the metal powder manufacturing method of this embodiment, the processing treatment of the plastic deformation process P1 and the processing treatment of the cutting process P2 are performed at least once on the cut surface of the workpiece 1 from which the plurality of protrusions 11 have been cut by the cutting process P2, thereby improving the material yield of the workpiece 1.

[0026] Furthermore, in this embodiment, the method for manufacturing metal powder controls the height H of each of the multiple protrusions 11 by the shape of the mold 2 and / or the electromagnetic force of the electromagnetic molding method, so that metal powder of various shapes can be manufactured.

[0027] Furthermore, in the metal powder manufacturing method of this embodiment, a non-rotating cutting tool is used as the cutting tool 3, and the cutting is performed with a depth of cut less than or equal to the height H of the protrusion 11, thus further improving the material yield.

[0028] Furthermore, in the metal powder manufacturing method of this embodiment, a rotary cutting tool is used as the cutting tool 3, and the cutting is performed with a depth of cut that is less than or equal to the height H of the protrusion 11, thus further improving the material yield.

[0029] Furthermore, the method for manufacturing metal powder in this embodiment controls the shape of the metal powder 4 by the rotational speed of the rotary cutting tool, thus further improving productivity. [Explanation of symbols]

[0030] 1…Work material 11…Convex part 2…Molding mold 21…recess 3…Cutting tools 4...Metal powder 5… Electromagnetic coil 6…Steel plate 30...Electromagnetic forming device 40...Cutting device P0…Work material loading process P1…Plastic working process P2…Cutting process P3... Powder recovery process H... Height of the protrusion

Claims

1. A plastic deformation process in which the shape of a mold having multiple fine recesses is transferred to the surface of a metal workpiece by electromagnetic molding, thereby forming multiple protrusions, A method for producing metal powder, comprising a cutting step of cutting the plurality of protrusions using a cutting tool to produce metal powder.

2. The method for producing metal powder according to claim 1, wherein the processing treatment of the plastic deformation step and the processing treatment of the cutting step are performed at least once on the cut surface of the workpiece from which the plurality of protrusions have been cut by the cutting step.

3. A method for producing metal powder according to claim 1 or 2, wherein the height of each of the plurality of protrusions is controlled by the shape of the mold and / or the electromagnetic force of the electromagnetic molding method.

4. A method for producing metal powder according to claim 1 or 2, wherein a non-rotating cutting tool is used as the cutting tool, and the cutting is performed with a depth of cut less than or equal to the height of the protrusion.

5. A method for producing metal powder according to claim 1 or 2, wherein a rotary cutting tool is used as the cutting tool, and the cutting is performed with a depth of cut less than or equal to the height of the protrusion.

6. The method for producing metal powder according to claim 5, wherein the shape of the metal powder is controlled by the rotational speed of the rotary cutting tool.

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