Mold and method for manufacturing powder molded body

Abstract

A die is provided with: a die head having a hollow portion penetrating in a first direction; a first core that divides the hollow portion into a plurality of space portions arranged in parallel in a direction orthogonal to the first direction; and an upper punch and a lower punch embedded in each of the plurality of space portions, the first core having a partial region provided midway in the first direction in a side surface of the first core facing the plurality of space portions, the partial region including a protruding portion protruding from the side surface.

Description

Technical Field

[0001] The present disclosure relates to a mold and a method for producing a powder compact.

[0002] This application claims the priority based on Japanese application No. 2022-128789 filed on August 12, 2022, and cites all the contents described in the Japanese application. Background Art

[0003] Patent document 1 discloses a mold for manufacturing a molded body having an undercut shape. The mold comprises a first die head, a second die head, a first punch and a second punch. The second die head is provided with an undercut molding portion for imparting an undercut shape to the molded body. The second die head is inserted into the through hole in a manner that the outer surface of the second die head contacts the inner side surface of the through hole of the first die head. The molded body is molded by compressing powder in a cavity surrounded by the inner side surface of the through hole, the second die head, the first punch and the second punch.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2017-159360 Summary of the invention

[0007] The mold disclosed in the present invention comprises: a die head having a hollow portion extending through in a first direction; a first core dividing the hollow portion into a plurality of space portions arranged in parallel in a direction orthogonal to the first direction; and an upper punch and a lower punch embedded in each of the plurality of space portions, the first core comprising a partial area, the partial area being arranged midway in the first direction on a side surface of the first core facing the plurality of space portions, the partial area including a protrusion protruding from the side surface. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a cross-sectional view of the mold involved in embodiment.

[0009] Figure 2 It is a longitudinal cross-sectional view of a state in which the upper punch, the lower punch, the first core, and the second core are not inserted into the die head in the die according to the embodiment.

[0010] Figure 3 It is a longitudinal cross-sectional view of a state in which a lower punch, a first core, and a second core are inserted into a die head, and an upper punch is not inserted into the die head, in the die according to the embodiment.

[0011] Figure 4 It is a perspective view of a powder compact formed using the mold according to the embodiment.

[0012] Figure 5 It is an explanatory diagram of a powder filling step in a method for producing a powder compact using a mold according to an embodiment.

[0013] Figure 6 It is an explanatory diagram of a step of molding a powder compact in a method of manufacturing a powder compact using a mold according to an embodiment.

[0014] Figure 7 It is an explanatory diagram of the step of taking out the powder compact in the method for producing the powder compact using the die according to the embodiment. DETAILED DESCRIPTION

[0015] [Technical Problems to be Solved by the Present Disclosure]

[0016] The mold disclosed in Patent Document 1 has a cavity filled with powder. When the powder in the cavity is compressed, the lateral pressure from the powder acts on the contact surface between the first die head and the second die head. When the first die head and the second die head move relative to each other, the lateral pressure may cause seizure between the first die head and the second die head.

[0017] One of the objects of the present disclosure is to provide a mold capable of suppressing the seizure of components of the mold during powder compression.

[0018] [Effects of the present disclosure]

[0019] The die of the present disclosure can suppress the seizure of constituent members of the die during powder compression.

[0020] [Description of Embodiments of the Present Disclosure]

[0021] First, embodiments of the present disclosure will be described by way of examples.

[0022] (1) The mold involved in the embodiment of the present disclosure comprises: a die head having a hollow portion penetrating in a first direction; a first core dividing the hollow portion into a plurality of space portions arranged in parallel in a direction orthogonal to the first direction; and an upper punch and a lower punch embedded in each of the plurality of space portions, the first core comprising a partial area, the partial area being arranged midway in the first direction on a side surface of the first core facing the plurality of space portions, the partial area including a protrusion protruding from the side surface.

[0023] The first core is referred to as a core in the disclosure of this specification, but may be constituted by a member generally referred to as a punch depending on the configuration of the die. The first core may be a member that serves to divide the hollow portion into a plurality of space portions, and the name does not matter.

[0024] In the mold of the present invention, since a plurality of space portions are formed, a plurality of powder compacts can be manufactured by a single compression. Partial areas face each space portion. Therefore, in the mold of the present invention, a powder compact having an undercut shape can be efficiently manufactured.

[0025] In the die of the present disclosure, since a plurality of spaces are formed by sandwiching the first core, when the powder filled in each space is compressed, the lateral pressure acting on the inner peripheral surface of the die head tends to act on the contact surface with the powder, and is not likely to act on the contact surface with the first core. Therefore, even if the first core and the die head move relative to each other, it is not likely to cause seizure between the first core and the die head.

[0026] (2) In the mold of (1) above, the number of the plurality of space portions may be two.

[0027] When two spaces are formed across the first core, the direction of the lateral pressure from the powder is symmetrical with respect to the first core, and it is not easy to locally apply excessive lateral pressure. If the direction of the lateral pressure is symmetrical, two powder compacts with small local deviations in density can be manufactured. The first core in which the hollow portion is divided into two spaces is a simpler structure than the first core in which the hollow portion is divided into three or more spaces.

[0028] (3) In the mold described in (1) or (2), all of the plurality of space portions may have the same shape.

[0029] If all the multiple spaces are of the same shape, multiple powder compacts of the same shape can be formed simultaneously. When the spaces of the same shape are formed by sandwiching the first core, the direction of the lateral pressure from the powder is easy to be symmetrical with respect to the first core. When the spaces of the same shape are formed by sandwiching the first core, the powders of the multiple spaces can be compressed evenly, so stable manufacturing can be achieved.

[0030] (4) In any one of the dies described in (1) to (3), the first core and the lower punch may be inserted into the hollow portion from the same direction.

[0031] In the step of manufacturing the powder compact, firstly, the powder is filled into each of the plurality of space portions while the lower punch and the first core are inserted into the hollow portion, and then the upper punch is inserted into each of the plurality of space portions and the powder is compressed by the upper punch and the lower punch. When the lower punch and the first core are inserted into the hollow portion from the same direction, it is easy to form a space filled with powder.

[0032] (5) Any one of the molds described in (1) to (4) above may further include a second core inserted into each of the plurality of space portions.

[0033] When the second core is provided, the degree of freedom in the shape of the manufactured powder compact increases.

[0034] (6) In any one of the molds described in (1) to (5), the partial region may be the protrusion.

[0035] When a partial region is a protrusion, a powder compact having a concave undercut shape can be produced.

[0036] (7) The method for manufacturing a powder compact according to an embodiment of the present disclosure comprises: a step of preparing a mold of any one of (1) to (6) above; a step of filling each of the plurality of space portions with powder while the lower punch and the first core are inserted into the hollow portion; a step of inserting the upper punch into each of the plurality of space portions and compressing the powder with the upper punch and the lower punch to form a powder compact; and a step of removing the powder compact by moving the die head and the upper punch relative to the lower punch.

[0037] In the manufacturing method of the powder compact of the present disclosure, since the mold of the present disclosure is used, a plurality of powder compacts having an undercut shape can be efficiently manufactured by one compression. In the manufacturing method of the powder compact of the present disclosure, since the mold of the present disclosure is used, it is not easy to cause sticking between the first core and the die head even if the first core and the die head move relative to each other.

[0038] [Details of the embodiments of the present disclosure]

[0039] Specific examples of the mold disclosed in the present invention and the method for manufacturing a powder compact using the mold disclosed in the present invention are described with reference to the accompanying drawings. The same reference numerals in the figures indicate the same or equivalent parts. In each of the drawings, for the sake of convenience of explanation, a part of the structure is sometimes exaggerated or simplified. The dimensional ratios of the various parts in the drawings are sometimes different from the actual ones. In addition, the present invention is not limited to these examples, but is shown by the claims, and is intended to include all changes within the meaning and scope equivalent to the claims.

[0040] <Mold>

[0041] Reference Figures 1 to 3 , the die 1 of the embodiment is described. The die 1 includes a die head 2, an upper punch 3, and a lower punch 4. The die head 2 and the lower punch 4 form a cavity 9. The cavity 9 is filled with Figure 5 Powder 9P shown. Figure 4 and Figure 7 The powder compact 10 shown is formed by compressing the powder 9P filled in the cavity 9 with the upper punch 3 and the lower punch 4 . Figure 1The die 1 is shown cut along a plane perpendicular to the first direction D1 so as to include the upper punch 3 in a state where the constituent members of the die 1 are assembled. Figure 2 The mold 1 is shown cut along a plane along the first direction D1 in a state before the cavity 9 is formed. Figure 3 FIG. 2 shows the mold 1 cut along a plane along the first direction D1 in a state where the cavity 9 is formed. Figure 3 In the embodiment, the upper punch 3 is located above the cavity 9.

[0042] The first direction D1 is a vertical direction. Figure 2 As shown, the first direction D1 is also the direction in which the hollow portion 20 of the die 2 passes. The upper punch 3 and the lower punch 4 are embedded in the hollow portion 20. In each figure, the first direction D1 is shown by a single arrow, but the opposite direction of the first direction D1 is sometimes also referred to as the first direction D1. The first direction D1 is the moving direction of the upper punch 3 and the lower punch 4 relative to the die 2, and is the compression direction of the powder 9P.

[0043] One of the characteristics of the mold 1 of the embodiment is that it has a first core 5 that divides the hollow portion 20 of the die head 2 into a plurality of space portions 8. The plurality of space portions 8 are arranged in parallel in a direction orthogonal to the first direction D1. In this example, two space portions 8 are arranged in a second direction D2. A plurality of cavities 9 are formed corresponding to the plurality of space portions 8. Hereinafter, a direction orthogonal to both the first direction D1 and the second direction D2 is sometimes referred to as a third direction D3. The mold 1 of this example also has a second core 7.

[0044] Die Head

[0045] like Figure 2 As shown, the die 2 is a cylindrical member having a hollow portion 20 extending through the first direction D1. The hollow portion 20 has an end portion opening upward and an end portion opening downward. The hollow portion 20 is a space open at both ends. The shape of the hollow portion 20 corresponds to the outer shape of the powder compact 10 to be compressed and formed. The inner surface 21 of the die 2 constituting the hollow portion 20 is, for example, a smooth surface without bumps. The opening edge of the hollow portion 20 when viewed from the first direction D1 may be composed of a straight line or a curved line. The above-mentioned opening edge in this example is, for example, composed of a combination of a plurality of straight lines and curved lines. As Figure 1 As shown, the shape of the above-mentioned opening edge of this example is roughly rectangular, including four straight lines and four curves. The four curves constitute the corners connecting adjacent straight lines to each other. The three-dimensional shape of the hollow part 20 of this example is roughly rectangular, including four planes. The corners connecting the four planes to each other have rounded corners.

[0046] The die head 2 is moved in the first direction D1 by a driving mechanism (not shown).

[0047] "Upward Punch"

[0048] The upper punch 3 is inserted into the upper part of the hollow portion 20. A plurality of upper punches 3 are provided corresponding to the number of the plurality of space portions 8 described later. Figure 3 As shown, the upper punch 3 of this example is provided with a first upper punch 31 and a second upper punch 32 corresponding to the two space portions 8. The first upper punch 31 and the second upper punch 32 are each a columnar member. The outer shape of the end face of each of the first upper punch 31 and the second upper punch 32 corresponds to the outer shape of the first end face 11 of the powder compact 10 to be compressed and formed. The outer shape of the end face of each of the first upper punch 31 and the second upper punch 32 of this example is a roughly rectangular shape. A roughly rectangular shape includes a shape in which the corners are chamfered, or a shape with rounded corners, including a range that is substantially regarded as a rectangle.

[0049] When the powder 9P is compressed, a part of the first core 5 described later is inserted between the first upper punch 31 and the second upper punch 32. The first upper punch 31 and the second upper punch 32 are arranged with a gap therebetween so that a part of the first core 5 can slide freely.

[0050] In this example, a through hole 34 is provided in each of the first upper punch 31 and the second upper punch 32. A part of the second core 7 described later is inserted into the through hole 34 so as to be slidable.

[0051] Each of the first upper punch 31 and the second upper punch 32 slides in the first direction D1 relative to the die 2 , the first core 5 , and the second core 7 .

[0052] The first upper punch 31 and the second upper punch 32 are moved along the first direction D1 by a driving mechanism not shown in the figure. The first upper punch 31 and the second upper punch 32 may also move in conjunction with each other. For example, the first upper punch 31 and the second upper punch 32 may be connected at a position not inserted into the die 2, and the first upper punch 31 and the second upper punch 32 may move simultaneously along the first direction D1 by a driving mechanism. The first upper punch 31 and the second upper punch 32 may also move independently of each other. For example, the driving mechanism may include a first driving mechanism that moves only the first upper punch 31 and a second driving mechanism that moves only the second upper punch 32. Even if the first upper punch 31 and the second upper punch 32 move independently of each other, compression based on the first upper punch 31 and compression based on the second upper punch 32 may be performed simultaneously. When compression is performed simultaneously, the powder in each cavity 9 is compressed equally.

[0053] "Down Punch"

[0054] The lower punch 4 is inserted into the lower part of the hollow portion 20. A plurality of lower punches 4 are provided corresponding to the number of the plurality of space portions 8 described later. Figure 3As shown, the lower punch 4 of this example has a first lower punch 41 and a second lower punch 42 corresponding to the two space portions 8. The first upper punch 31 and the first lower punch 41 are a pair. The second upper punch 32 and the second lower punch 42 are a pair. The first lower punch 41 and the second lower punch 42 are each a columnar member. The outer shape of the end face of each of the first lower punch 41 and the second lower punch 42 corresponds to the outer shape of the second end face of the powder compact 10 to be compressed. The second end face is Figure 4 The first end face 11 of the powder compact 10 is shown as a surface facing the first end face 11. The outer shape of the end face of each of the first lower punch 41 and the second lower punch 42 of this example is a substantially rectangular shape.

[0055] When the powder 9P is compressed, a portion of the first core 5 described later is inserted between the first lower punch 41 and the second lower punch 42. The first lower punch 41 and the second lower punch 42 are configured so that a portion of the first core 5 has a slidable interval. The first core 5 of this example is inserted into the hollow portion 20 from the same direction as the lower punch 4. Therefore, the first core 5 of this example is always configured between the first lower punch 41 and the second lower punch 42. In other words, the first lower punch 41 and the second lower punch 42 of this example clamp the first core 5.

[0056] In this example, each of the first lower punch 41 and the second lower punch 42 is provided with a through hole 44. A portion of the second core 7 described later is slidably inserted into the through hole 44. The second core 7 of this example is inserted into the hollow portion 20 from the same direction as the lower punch 4. Therefore, the second core 7 of this example is always arranged inside each through hole 44 of the first lower punch 41 and the second lower punch 42.

[0057] The first lower punch 41 and the second lower punch 42 each slide in the first direction D1 relative to the die 2 , the first core 5 , and the second core 7 .

[0058] The lower punch 4 is usually fixed. The die 2 , the upper punch 3 , and the first core 5 move relative to the lower punch 4 along the first direction D1 .

[0059] The First Core

[0060] The first core 5 is a columnar member that divides the hollow portion 20 into a plurality of space portions 8 arranged in parallel in a direction orthogonal to the first direction D1. The first core 5 is arranged at a position that divides the hollow portion 20 into a plurality of space portions 8. The first core 5 of this example is arranged at a position that divides the hollow portion 20 into two space portions 8, namely, a first space portion 81 and a second space portion 82. In this example, two cavities 9, namely, a first cavity 91 and a second cavity 92, are formed corresponding to the number of the space portions 8. The shape of the first core 5 is determined in accordance with the shape and number of the powder compact 10 to be compressed and formed. The shape of the first core 5 of this example is roughly rectangular. The roughly rectangular shape includes a shape in which the corners are chamfered, or a shape with rounded corners, including a range that is substantially regarded as a rectangular parallelepiped. The first core 5 of this example has a side surface 51 facing the first space portion 81, a side surface 52 facing the second space portion 82, sliding surfaces 53, 53 facing the die head 2, and an end surface 54. The first core 5 of this example has a substantially rectangular cross-sectional shape whose length in the third direction D3 is longer than its length in the second direction D2 .

[0061] like Figure 2 and Figure 3 As shown, the first core 5 has a partial region 6 disposed on the side surfaces 51 and 52. The partial region 6 is disposed in the middle of the side surfaces 51 and 52 in the first direction D1. The partial region 6 includes a protrusion protruding from the side surfaces 51 and 52. The protrusion protrudes in the second direction D2. The shape of the protrusion is not limited. The protrusion may be, for example, Figure 2 and Figure 3 As shown, it has a cross-sectional shape that bulges out in a curved shape. More specifically, the protrusion of this example has a cross-sectional shape of an arch surrounded by an arc and a chord. The protrusion is provided in at least a portion of the partial area 6. The protrusion may be provided in a portion of the partial area 6 or in the entire area of ​​the partial area 6. The partial area 6 may also include a partial recess. The partial area 6 of this example is a protrusion.

[0062] The partial region 6 provides the compressed powder compact 10 with Figure 4 The undercut portion 15 shown in FIG. 1 has an undercut shape. The undercut shape includes a concave shape that is concave in the second direction D2 that is orthogonal to the first direction D1. When the partial area 6 is a protrusion, the shape of the undercut portion 15 provided in the powder compact 10 is a concave shape. Figure 1 In the figure, for the convenience of explanation, a partial area 6 is shown by a dotted line.

[0063] The partial region 6 includes a first partial region 61 provided on the side 51 and a second partial region 62 provided on the side 52. Both the first partial region 61 and the second partial region 62 are protrusions. The protrusion of this example is provided in a manner protruding in the second direction D2 and extending in the third direction D3. The protrusion of this example is a columnar body having an arched cross-sectional shape and extending along the third direction D3. The protrusion may also be provided in a manner extending obliquely in a direction intersecting the third direction D3. In this example, the shape of the first partial region 61 is the same as that of the second partial region 62. In this example, the size of the first partial region 61 is the same as that of the second partial region 62. In this example, the first partial region 61 and the second partial region 62 are provided symmetrically. When the shapes, sizes and configurations of the first partial region 61 and the second partial region 62 are identical to each other, a plurality of powder compacts 10 having the same undercut 15 can be manufactured simultaneously.

[0064] At least one partial region 6 is provided on each side surface 51, 52. As shown in this example, one partial region 6 may be provided on each side surface 51, 52. A plurality of partial regions 6 may be provided on each side surface 51, 52, for example, by being divided in the third direction D3.

[0065] The first partial region 61 provided on the side 51 and the second partial region 62 provided on the side 52 may not have the same shape and size. When the first partial region 61 and the second partial region 62 have the same shape, size, and configuration, the powder 9P in each cavity 9 can be compressed equally, and stable manufacturing can be achieved.

[0066] like Figure 4 As shown, the powder compact 10 is given Figure 2 and Figure 3 The partial region 6 shown is an inverted undercut 15 .

[0067] The end face 54 is exposed to the outside and does not contact other components of the mold 1. The first core 5 of this example is inserted into the hollow portion 20 from the same direction as the lower punch 4. That is, the first core 5 of this example is inserted into the hollow portion 20 from below the die head 2. The first core 5 of this example has a structure that is embedded in the hollow portion 20 together with the lower punch 4 from the same direction as the lower punch 4. The first core 5 is moved along the first direction D1 by a driving mechanism not shown in the figure. The first core 5 is positioned, for example, by a block not shown in the figure.

[0068] The Second Core

[0069] The second core 7 is a columnar member inserted into each of the plurality of space portions 8. The second core 7 is inserted into each space portion 8 from the same direction as the lower punch 4. That is, the second core 7 is inserted into each space portion 8 from below the die 2. The second core 7 has a structure that is fitted into the hollow portion 20 together with the lower punch 4 and the first core 5 from the same direction as the lower punch 4. The second core 7 is inserted into each through hole 44 of the first lower punch 41 and the second lower punch 42. The second core 7 forms a through hole 16 in the compressed powder compact 10. The shape of the second core 7 is the same as that of the lower punch 4. Figure 4 The shape of the through hole 16 shown corresponds to that of the through hole 16. The shape of the second core 7 in this example is a cylindrical shape.

[0070] Multiple Space Department

[0071] When the first core 5 is arranged in the hollow portion 20 of the die head 2, the hollow portion 20 is divided into a plurality of space portions 8 by the first core 5. In this example, two space portions 8, namely a first space portion 81 and a second space portion 82, are constituted by the first core 5. In this example, the shape of the first space portion 81 is the same as the shape of the second space portion 82. In this example, the size of the first space portion 81 is the same as the size of the second space portion 82. The orientation of the first space portion 81 and the orientation of the second space portion 82 may also be different. In this example, the orientation of the first space portion 81 and the orientation of the second space portion 82 are symmetrical relative to the first core 5.

[0072] When the first lower punch 41 is arranged in the first space portion 81, the first cavity 91 is formed by the first space portion 81. When the second lower punch 42 is arranged in the second space portion 82, the second cavity 92 is formed by the second space portion 82. In this example, a second core 7 is also arranged in each of the first space portion 81 and the second space portion 82. In this example, the shapes of the first cavity 91 and the second cavity 92 are the same. In this example, each shape of the first cavity 91 and the second cavity 92 is cylindrical. In the mold 1 of this example, two powder compacts 10 of the same shape and size can be formed simultaneously.

[0073] When the first core 5 is used to form the first space 81 and the second space 82, the two space portions 8 are formed, and the direction of the lateral pressure from the powder 9P in each cavity 91, 92 is symmetrical with respect to the first core 5, and the lateral pressure is offset. When the lateral pressure is offset, it is not easy to cause bite adhesion between the first core 5 and the die 2 even if the first core 5 and the die 2 move relative to each other. In addition, if the direction of the above-mentioned lateral pressure is symmetrical, two powder compacts 10 with small local deviation of density can be manufactured. In particular, when the space portions 8 of the same shape are formed with the first core 5, two powder compacts 10 of the same shape can be formed simultaneously.

[0074] The number of the plurality of spaces 8 may be three or more. For example, the three or more spaces 8 are arranged in parallel in the second direction D2. When the opening edge of the hollow portion 20 when viewed from the first direction D1 is circular, the three or more spaces 8 may be arranged in parallel around the axis of the hollow portion 20.

[0075] The plurality of spaces 8 may include spaces 8 of different shapes. For example, the shape of the first space 81 may be different from the shape of the second space 82. The plurality of spaces 8 may include spaces 8 of different sizes. For example, the size of the first space 81 may be different from the size of the second space 82.

[0076] <Powder molded body>

[0077] like Figure 4 As shown, the powder compact 10 manufactured by the die 1 described above includes an undercut portion 15. The undercut portion 15 is a recessed portion recessed from the side surface 13. The powder compact 10 of this example further includes a through hole 16.

[0078] <Method for producing a powder compact>

[0079] Reference Figures 5 to 7 The method for producing a powder compact according to the embodiment will be described. The method for producing a powder compact includes a preparation step, a filling step, a forming step, and a removal step which are performed in sequence.

[0080] 《Preparation process》

[0081] In the preparation step, the above-mentioned die 1 is prepared. The shapes of the die head 2, upper punch 3, lower punch 4, first core 5 and second core 7 in the die 1 can be appropriately selected to form a plurality of cavities 9 corresponding to the shape of the powder compact 10 to be manufactured.

[0082] 《Filling process》

[0083] In the filling process, Figure 5 As shown, when the lower punch 4 and the first core 5 are inserted into Figure 2 and Figure 3 In the state of the hollow portion 20 shown, the powder 9P is filled into each of the plurality of space portions 8. The space portion 8 in the state where the lower punch 4 and the first core 5 are inserted into the hollow portion 20 is the cavity 9. In this example, the second core 7 is also inserted into the hollow portion 20. The end face of the second core 7 is arranged at a position above the end face of the lower punch 4. The end face 54 of the first core 5 and each end face of the second core 7 are located, for example, on the same plane as the end face of the die head 2.

[0084] 《Forming process》

[0085] In the forming process, Figure 6 As shown, insert the upper punch 3 into Figure 3In each of the plurality of space portions 8 shown, the powder 9P is compressed by the upper punch 3 and the lower punch 4. In this example, the powder 9P in the first cavity 91 is compressed by the first upper punch 31 and the first lower punch 41, and the powder 9P in the second cavity 92 is compressed by the second upper punch 32 and the second lower punch 42. In this example, the first upper punch 31 and the second upper punch 32 are simultaneously moved downward along the first direction D1 by a driving mechanism not shown. At this time, the end face 54 of the first core 5 does not contact the other components of the mold 1.

[0086] When powder 9P is compressed, lateral pressure from powder 9P is applied to inner surface 21 of die head 2, side surfaces 51 and 52 of first core 5, and outer peripheral surfaces of second cores 7. The lateral pressure is not easily applied to sliding surface 53 of first core 5.

[0087] Powder 9P filled in each of first cavity 91 and second cavity 92 is compressed to simultaneously form two powder compacts 10. When three or more spaces 8 are provided, powder compacts 10 corresponding to the number of spaces 8 are simultaneously formed.

[0088] 《Removal process》

[0089] In the removal process, Figure 7 As shown, the die head 2, the upper punch 3 and the second core 7 are relatively moved with respect to the lower punch 4. That is, the die head 2, the upper punch 3 and the second core 7 are moved along the first direction D1 while the lower punch 4 and the first core 5 are fixed.

[0090] As described above, the lateral pressure from the powder 9P in each cavity 9 is not easily applied to the sliding surface 53 of the first core 5. Therefore, even if the first core 5 and the die 2 move relative to each other, it is not easy for the first core 5 and the die 2 to bite each other. In this example, two powder compacts 10 are formed by sandwiching the first core 5. Therefore, the direction of the lateral pressure from the powder 9P is symmetrical with respect to the first core 5, and the lateral pressure is offset. In this example, two powder compacts 10 with small local deviations in density can be manufactured.

[0091] Through the removal process, each powder compact 10 is located outside the hollow portion 20 of the die 2. The surface of each powder compact 10 located outside the hollow portion 20 other than the contact surface with the first core 5 is exposed. Each powder compact 10 located outside the hollow portion 20 can move in a direction away from the first core 5. Each powder compact 10 can be removed by peeling it off from the first core 5. In this example, two powder compacts 10 are moved in a direction away from each other along the second direction D2. Through this removal process, Figure 4 The powder compact 10 shown having the undercut 15 can be easily removed from the die 1 .

[0092] Description of Reference Numerals

[0093] 1. Mold

[0094] 2 die head, 20 hollow part, 21 inner surface

[0095] 3 upper punch, 31 first upper punch, 32 second upper punch

[0096] 34 Through hole

[0097] 4 lower punch, 41 first lower punch, 42 second lower punch

[0098] 44 Through hole

[0099] 5 first core, 51, 52 side surfaces, 53 sliding surface, 54 end surface

[0100] 6 Partial area, 61 First part area, 62 Second part area

[0101] 7 Second Core

[0102] 8 space part, 81 first space part, 82 second space part

[0103] 9 cavity, 91 first cavity, 92 second cavity

[0104] 9P Powder

[0105] 10 Powder formed body

[0106] 11 first end surface, 13 side surface, 15 undercut portion, 16 through hole

[0107] D1 is the first direction, D2 is the second direction, and D3 is the third direction.

Claims

1. A mold, comprising: A die head having a hollow portion extending in a first direction; a first core that divides the hollow portion into a plurality of space portions arranged in parallel in a direction orthogonal to the first direction; as well as An upper punch and a lower punch are embedded in each of the plurality of space portions, The first core includes a partial region provided in the middle of the first direction on the side surface of the first core facing the plurality of space portions. The partial region includes a protrusion protruding from the side surface.

2. The mold according to claim 1, wherein: The number of the plurality of space portions is two.

3. The mold according to claim 1 or 2, wherein: The plurality of space portions are all of the same shape.

4. The mold according to any one of claims 1 to 3, wherein The first core and the lower punch are inserted into the hollow portion from the same direction.

5. The mold according to any one of claims 1 to 4, wherein: The mold further includes a second core inserted into each of the plurality of space portions.

6. The mold according to any one of claims 1 to 5, wherein: The partial region is the protrusion.

7. A method for producing a powder compact, comprising: A step of preparing the mold according to any one of claims 1 to 6; A step of filling each of the plurality of space portions with powder while the lower punch and the first core are inserted into the hollow portion; a step of inserting the upper punch into each of the plurality of space portions and compressing the powder with the upper punch and the lower punch to form a powder compact; as well as and removing the powder compact by relatively moving the die head and the upper punch relative to the lower punch.

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