JP2016043374A - Green compact manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a green compact manufacturing method that ensures short manufacturing time.SOLUTION: A green compact manufacturing method comprises: a filled-area forming step (S1); a filing step (S2); a compressing step (S3) fitting an upper punch (4) into a through-hole (1a), compressing metal powder (P), and forming a green compact (B); and an unloading step (S4). An outer die (1) includes an upper outer die (2) and a lower outer die (3) that are movable in the vertical direction. A lower punch (5) is disposed to be movable in the vertical direction. In the filled-area forming step (S1), a contact surface (23) on which the upper outer die (2) contacts the lower outer die (3) is located at the same height as a height of a center of a filled area (Z). In the compressing step (S3), the upper punch (4) and the lower punch (5) move substantially at the same velocity so as to be proximate to each other. In the unloading step (S4), the upper outer die (2) and the lower outer die (3) move to be apart from each other.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a method for manufacturing a green compact, and more particularly to a method for manufacturing a green compact using a mold.

  There is a mold including a die having a through hole in the vertical direction and an upper punch and a lower punch which are fitted into the through hole and are slidable. As disclosed in Patent Document 1, when such a mold is used, the metal powder can be compressed by an upper punch and a lower punch inside the through hole to obtain a metal powder molded product.

JP 2014-129572 A

  Incidentally, there is a demand for shortening the manufacturing time. In the manufacturing method disclosed in Patent Document 1 described above, for example, the operation stroke of the die for taking out the green compact is long, and there is room for shortening the manufacturing time.

  Then, it is made | formed against the background of said situation, and it aims at providing the manufacturing method of the compacting body with short manufacturing time.

The method for producing a green compact according to the present invention is as follows.
Using a mold including an outer mold (for example, a die) having a through-hole penetrating in the vertical direction, an upper punch, and a lower punch,
A filling region forming step of inserting the lower punch into the through hole and forming a filling region;
A filling step of filling the filling region with metal powder;
A compression step of inserting the upper punch into the through hole and compressing the metal powder to form a green compact;
A step of taking out the green compact from the mold, and a method for producing the green compact,
The outer mold includes an upper outer mold (for example, an upper die) and a lower outer mold (for example, a lower die) movable in the vertical direction,
The lower punch is arranged to be movable in the vertical direction,
In the filling region forming step, the contact surface between the upper outer mold and the lower outer mold is located at the same height as the center of the filling region,
In the compression step, the upper punch and the lower punch move close together at substantially the same speed,
In the extraction step, the upper outer mold and the lower outer mold move apart.

  According to such a configuration, in the compression process, the upper punch and the lower punch move close to each other at substantially the same speed, so that the boundary surface between the upper outer mold and the lower outer mold is from the filling process to the removal process. It is maintained at the same height as the center of the filling area. Therefore, the operation stroke of the die for taking out the green compact from the mold is shortened, and the green compact can be manufactured in a short time.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of a compacting body with short manufacturing time can be provided.

FIG. 3 is a schematic diagram of one step of the manufacturing method according to the first embodiment. FIG. 3 is a schematic diagram of one step of the manufacturing method according to the first embodiment. FIG. 3 is a schematic diagram of one step of the manufacturing method according to the first embodiment. FIG. 3 is a schematic diagram of one step of the manufacturing method according to the first embodiment.

Embodiment 1
The manufacturing method according to the first embodiment will be described with reference to FIGS. 1 to 4 are schematic views of one step of the manufacturing method according to the first embodiment.

  As shown in FIG. 1, in the manufacturing method according to the first embodiment, a mold 10 is used. The mold 10 includes a die 1 (which may also be referred to as an outer mold), an upper punch 4 and a lower punch 5. The die 1, the upper punch 4, and the lower punch 5 are all controlled to move in the vertical direction by a control device (not shown) and a driving device (not shown).

  The die 1 includes an upper die 2 (also referred to as an upper / outer mold) and a lower die 3 (also referred to as a lower / outer mold). The die 1 has a through hole 1a penetrating in the vertical direction, and the upper punch 4 and the lower punch 5 are slidably fitted into the through hole 1a. The through hole 1a is formed by connecting through holes 12a and 13a penetrating the upper die 2 and the lower die 3 in the vertical direction. The upper punch 4 and the lower punch 5 are, for example, substantially cylindrical bodies having a flange at one end thereof. The upper punch 4 has a flange at its upper end, while the lower punch 5 has a flange at its lower end.

  Prior to the start of this manufacturing method, the upper die 2, the lower die 3, the upper punch 4 and the lower punch 5 may be moved so as to be located at their original positions. Specifically, the upper die 2 and the lower die 3 are arranged with a predetermined distance in this order from top to bottom. Further, the upper die 2 and the lower die 3 are arranged so that the through hole 12a and the through hole 13a overlap each other when viewed from above or below. The upper punch 4 is disposed above the upper die 2 and extends along the axis of the through hole 1a. The lower punch 5 is fitted into the through hole 13 a so that the upper end surface 51 of the lower punch 5 is at the same height as the upper end surface 31 of the lower die 3. The upper die 2 and the lower die 3 are arranged along the same axis as the axis of the through hole 1a.

First, as shown in FIG. 2, the upper die 2, the lower die 3, and the lower punch 5 are moved from the original position to the filling position to form a cavity (filling region forming step S <b> 1). Specifically, the contact surface 23 between the upper die 2 and the lower die 3 is moved to the filling region Z by moving the lower punch downward while moving the upper die 2 and the lower die 3 close to each other. Located at the same height as the center of the. The filling region Z is a region where the metal powder P is filled in a later filling step S2 which will be described later. More specifically, assuming that the depth of the filling region Z is the required filling depth Dz, the position of the contact surface 23 is, for example, a height of 0.40 × Dz to 0.60 × Dz from the upper end surface 51 of the lower punch. The height is preferably 0.45 × Dz to 0.55 Dz. When the movement of the upper die 2, the lower die 3 and the lower punch 5 to the filling position is completed, the inner wall surface of the through hole 1a of the die 1 and the upper end surface 51 of the lower punch 5 surround a predetermined space, A cavity is formed.
Here, an operation stroke when the upper die 2 moves from the original position to the filling position is L21, and an operation stroke L31 when the lower die 3 moves from the original position to the filling position. The operation stroke L21 of the upper die 2, the operation stroke L31 of the lower die 3, and the necessary filling depth Dz satisfy the relationship of the following formula 1.
Dz ≦ L21 + L31 (Formula 1)
Here, since the upper die 2 and the lower die 3 start to move substantially simultaneously, the operation stroke in the filling region forming step S1 is substantially shortened. The operation stroke L21 of the upper die 2 and the operation stroke L31 of the lower die 3 are preferably equal. When the operation strokes L21 and L31 are equal, the substantial shortening of the operation stroke in the filling region forming step S1 is large.

  Next, the metal powder P is filled into the cavity (filling step S2). Specifically, the metal powder P is a powder made of a sintering material for forming the green compact B for sintering. Further, the metal powder P is filled in the cavity until the depth of the metal powder P in the cavity becomes equal to or greater than the necessary filling depth Dz. When the necessary filling depth Dz is the same as the depth of the cavity, the metal powder P is scraped off as necessary, and the upper end surface P1 of the metal powder P is aligned with the upper end surface 21 of the upper die 2.

Next, as shown in FIG. 3, the upper punch 4 and the lower punch 5 are moved close to each other to compress the metal powder P (compression step S3). Specifically, the upper punch 4 is moved downward until it contacts the upper end surface P1 of the metal powder P. Subsequently, the upper punch 4 and the lower punch 5 are moved in the compression direction for compressing the metal powder P substantially simultaneously and at substantially the same speed. Here, it is preferable that the upper punch 4 and the lower punch 5 are moved with the same operation stroke. The speed of the upper punch 4 is preferably 80% to 120% of the speed of the lower punch 5, and more preferably 95% to 105%. A green compact B for sintering is formed. The contact surface 23 between the upper die 2 and the lower die 3 remains at the same height as the center of the green compact B for sintering. Note that the ratio between the required filling depth Dz and the height Db of the green compact B for sintering is the compression ratio of the metal powder P (the green compact B for sintering).
Here, let L42 be an operation stroke when the upper punch 4 moves from the contact with the upper end surface P1 of the metal powder P until the metal powder P is compressed. Further, the operation stroke when the lower punch 5 moves before the metal powder P is compressed is L52. The operation stroke L42 of the upper punch 4, the operation stroke L52 of the lower punch 5, the required filling depth Dz, and the height Db of the green compact B for sintering satisfy the relationship of the following formula 2. The difference (Db−Dz) between the height Db of the green compact B for sintering and the required filling depth Dz is the sum (L42 + L52) of the operation strokes of the upper punch 4 and the lower punch 5.
Db−Dz = L42 + L52 (Expression 2)
Here, since the upper punch 4 and the lower punch 5 start to move substantially simultaneously and move at substantially the same speed, the operation stroke substantially required in the compression step S3 is shortened. The operation stroke L42 of the upper punch 4 is preferably equal to the operation stroke L52 of the lower punch 5, and when the operation strokes L42 and L52 are equal, the substantial shortening of the operation stroke in the compression step S3 is large.

Finally, as shown in FIG. 4, the upper punch 4, the upper die 2 and the lower die 3 are moved to take out the green compact B for sintering from the mold 10 (extraction step S4). Specifically, the upper punch 4 is moved upward. Further, the upper die 2 and the lower die 3 are moved away from each other. More specifically, the upper die 2 is moved upward so that the lower end surface thereof is the same as or higher than the green compact B. Further, the lower die 3 is moved downward until the upper end surface 31 becomes a height equal to or lower than the upper end surface 51 of the lower punch 5. The upper die 2 and the lower die 3 start moving substantially simultaneously and move at substantially the same speed. The green compact B for sintering is taken out from the mold 10 by passing between the upper die 2 and the lower die 3.
Here, the operation stroke L23 of the upper die 2, the operation stroke L33 of the lower die 3, and the height Db of the green compact B for sintering satisfy the relationship of the following mathematical formula 3.
Db ≦ L23 + L33 (Formula 3)
Here, since the upper die 2 and the lower die 3 start to move substantially simultaneously, the operation stroke required in the extraction step S4 is substantially shortened. The operation stroke L23 of the upper die 2 and the operation stroke L33 of the lower die 3 are preferably equal, and when the operation strokes L23 and L33 are equal, the substantial shortening of the operation stroke in the extraction step S4 is large.

  A wide variety of sintered products can be obtained by sintering the green compact B for sintering. As an example of the sintered product, there is an inverter component mounted on a vehicle.

  As described above, according to the manufacturing method according to the first embodiment, in the compression step S3, the upper punch and the lower punch move close to each other at substantially the same speed, and from the filling step S2 to the removal step S4, the upper die and the lower punch are moved. The position of the interface with the die is maintained at the same height as the center of the filling area. Therefore, in the extraction step S4, the operation strokes of the upper die and the lower die are shortened, and the manufacturing time of the green compact B for sintering is shortened.

  Note that the present invention is not limited to the above-described embodiment, and can be changed as appropriate without departing from the spirit of the present invention.

10 Die 1 Die 1a Through hole 2 Upper die 23 Contact surface 3 Lower die
4 Upper punch 5 Lower punch B Sintering green compact P Metal powder Z Filling region S1 Filling region forming step S2 Filling step S3 Compression step S4 Extraction step

Claims (1)

Using a mold comprising an outer mold having a through-hole penetrating in the vertical direction, an upper punch, and a lower punch,
A filling region forming step of inserting the lower punch into the through hole and forming a filling region;
A filling step of filling the filling region with metal powder;
A compression step of inserting the upper punch into the through hole and compressing the metal powder to form a green compact;
A step of taking out the green compact from the mold, and a method for producing the green compact,
The outer mold includes an upper outer mold and a lower outer mold movable in the vertical direction,
The lower punch is arranged to be movable in the vertical direction,
In the filling region forming step, the contact surface between the upper outer mold and the lower outer mold is located at the same height as the center of the filling region,
In the compression step, the upper punch and the lower punch move close together at substantially the same speed,
In the extracting step, the upper outer mold and the lower outer mold are separated from each other, and the green compact is manufactured.

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