JP3793597B2 - Metal powder injection molding equipment - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a manufacturing apparatus for a metal powder injection molded body, and more particularly to an apparatus capable of simplifying a post-treatment process.
[0002]
[Prior art]
Conventionally, in order to obtain a sintered metal, a metal powder is mixed with an organic binder made of paraffin wax, acrylic resin, or the like, and the mixture is injection-molded by a method similar to known plastic injection molding to form a metal powder. Injection molded bodies, so-called green bodies, are made. The green body is subjected to a degreasing process for removing the organic binder and then subjected to a sintering process to obtain a metal sintered body as a product.
[0003]
2 (a) and 2 (b) show an outline of a main part of a conventional green body G manufacturing apparatus. First, as shown in FIG. The raw material of the green body G is injection-molded at a high pressure in the cavity C formed on the joint surface in the mold 10 composed of the mold 10b.
[0004]
FIG. 2B shows a state where the mold 10 is opened after the movable mold 10b is moved (sometimes referred to as movement) after injection molding of the raw material of the green body G. At this time, the molded green body G Moves with respect to the cavity C of the movable mold 10b.
[0005]
As the movable mold 10b moves, the extrusion pin P whose tip is located in the cavity C of the movable mold 10b enters the cavity C, so that the green body G in the cavity C is discharged from the cavity C. The Therefore, the green body G can be easily taken out from the cavity C, that is, the mold 10.
[0006]
[Problems to be solved by the invention]
However, since the conventional green body manufacturing apparatus is configured to be pushed out by an extrusion pin when the green body is discharged from the mold, the green body G is formed as shown in FIG. There is a defect that the trace P ′ of the extrusion pin P is attached to the product and this trace P ′ remains in the product even after the sintering process.
[0007]
Therefore, in the case where the product is a decorative product such as a watch band part, for example, a polishing process for removing the extrusion mark P ′ from the product is required, and the cost of the product is increased.
[0008]
Therefore, the present invention has been made to solve the above-described drawbacks, and an object of the present invention is to provide a manufacturing apparatus for a metal powder injection molded body in which no trace of an extrusion pin occurs in the metal powder injection molded body. is there.
[0009]
[Means for Solving the Problems]
In order to achieve the above object, a metal powder injection molded body manufacturing apparatus according to the present invention includes a mold having a cavity formed in a joint surface portion between a fixed mold and a movable mold movable toward and away from the fixed mold. In the manufacturing apparatus for a metal powder injection molded body for producing a metal powder molded body by an injection molding method, the height of the movable mold is joined to the fixed mold at a lower step portion provided with a step on the outer periphery of the cavity. An auxiliary mold that coincides with the upper surface of the movable mold is provided so as to be movable in the same direction as the movement direction of the movable mold, and a spring that constantly biases the auxiliary mold toward the fixed mold is interposed between the auxiliary mold and the movable mold. The auxiliary mold is formed with a slider that is slidable in the horizontal direction by cutting out a part of the auxiliary mold, and the slider is provided with a pin. When molding with the movable mold joined to the fixed mold, the moving direction of the movable mold When the mold moves through the cavity in the direction to move and the movable body moves away from the fixed mold, the pin tip on the opposite side of the pin slider is determined to move to the middle of the cavity. An angular pin is hooked on the fixed mold, and a lower portion of the angular pin is slidably inserted into an insertion hole provided in the slider. At the time of releasing, the slider that moves according to the auxiliary die that moves in conjunction with the movable die is moved so that the pin comes out of the green body.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIGS. 1A and 1B are schematic configuration diagrams of a main part of a manufacturing apparatus for a metal powder injection molded body according to an embodiment.
[0011]
The mold 1 is composed of a fixed mold 1a and a movable mold 1b, and a cavity C corresponding to the outer shape to be a sintered alloy product is formed at the joint surface portion between both molds 1a and 1b. Here, in order to simplify the drawing, a drive mechanism for driving the movable mold 1b and a guide pin for regulating the moving direction of the movable mold 1b are omitted.
[0012]
A step is provided around the cavity C of the movable mold 1b , and the height of the lower step portion on the outer peripheral side thereof coincides with the upper surface of the movable mold 1b (surface to be joined to the fixed mold 1a). An auxiliary mold 2 is provided. The auxiliary mold 2 is engaged with the movable movable mold 1b in the same direction as the moving direction of the movable die 1b. And between this auxiliary | assistant type | mold 2 and the movable mold | type 1b, the spring 3 which always urges | biases the auxiliary | assistant type | mold 2 to the fixed type | mold 1a side is interposed.
[0013]
Therefore, as shown in FIG. 2B, when the movable mold 1b moves away from the fixed mold 1a, the auxiliary mold 2 is delayed from the fixed mold 1a by the action of the spring 3 from the movable mold 1b. I can leave.
[0014]
In FIG. 1B, the distance by which the auxiliary mold 2 is separated from the movable mold 1b by the spring 3 is determined by a stopper (not shown) so as to be slightly smaller than the depth of the cavity C on the movable mold 1b side. That is, if the depth of the cavity C is larger than the depth of the cavity C, the holding of the green body G after the auxiliary mold 2 is separated outward and the pulling out of the pin 5 from the green body G are hindered.
[0015]
The slider 4 is movably provided on a sliding surface 2 a provided in the auxiliary mold 2. The sliding surface 2a is formed by cutting out a part of the auxiliary mold 2 in a direction orthogonal to the movable direction of the movable mold 1b, that is, in the horizontal direction.
[0016]
The slider 4 is provided with a pin 5 so as to pass through the cavity C, and the tip of the opposite side of the pin 5 is opposite in a state where the slider 4 is closest to the cavity C. The length is determined so as to be placed on the auxiliary table 2 on the side (see FIG. 1A).
[0017]
In the figure, reference numeral 6 denotes an angular pin that is hooked to the fixed die 1 a, and the lower portion of the angular pin 6 is slidably inserted into an insertion hole 4 a provided in the slider 4.
[0018]
The inclination of the angular pin 6 and the insertion hole 4a of the slider 4 is such that the slider 4 is closest to the cavity C in a state where the fixed mold 1a and the movable mold 1b are joined (see FIG. 1 (a)). It is determined that the tip of the pin 5 provided on the slider 4 is positioned approximately in the middle of the cavity C in a state where the movable die 1b is maximally movable.
[0019]
In addition, the movement of this slider 4 can also be made into the link mechanism which moves the slider 4 horizontally with the downward movement of the movable mold | type 1b, without using the angular pin 6. FIG.
[0020]
In the manufacturing apparatus for metal powder injection molded body having the above-described configuration, as shown in FIG. 1 (a), in a state where the fixed mold 1a and the movable mold 1b are joined, in the cavity C as in the known injection molding. The green body G material is injection molded at high pressure.
[0021]
Next, after the injection molding, the movable mold 1b starts to move. At the start of the movement, the auxiliary mold 2 is in contact with the fixed mold 1a as it is until the movable mold 1b is separated from the fixed mold 1a by a predetermined distance. The slider 4 that moves according to the auxiliary die 2 that moves in conjunction with the movable die 1b moves outward on the sliding surface 2a by the restriction function of the angular pin 6. Accordingly, the formed green body G is taken out from the cavity C of the movable mold 1b by the pin 5 and moved so that the pin 5 comes out of the green body G.
[0022]
In a state in which the movable distance of the movable die 1b reaches the maximum, the pin 5 is missing from the green body G, also green body G is in a state caught slightly near the cavity C. For this reason, the green body G can be easily taken out from the mold 1. Furthermore, since the slider is moved along with the movement of the movable type, the pin can be moved along with the movement of the movable type.
[0023]
As described above, since the green body G is taken out from the mold 1 without being pushed down by the extrusion pin as in the prior art, it is not necessary to process the trace of the extrusion pin thereafter, and the post-processing process is simplified. Can be.
[0024]
In addition, when the above-mentioned green body G has a hole for assembly like a timepiece band part, the hole can be formed with the pin 5, for example.
[0025]
Of course, when the above-described assembly hole is not required in the final product, the shape of the cavity C is determined so that the pin 5 is located in a portion that does not appear in the appearance of the product.
[0026]
【The invention's effect】
In the metal powder injection molded body manufacturing apparatus according to the present invention, a movable pin is provided in the cavity, and the pin is provided in an auxiliary mold that is interlocked with the movable mold after being movable. Can be discharged from the mold, and the trace of the extrusion pin can be left on the green body as in the prior art. Therefore, the processing cost in the post-processing step can be reduced. Further, it is possible to easily extract the pin from the green body.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram of a main part of a manufacturing apparatus for a metal powder injection molded body according to an embodiment of the present invention, in which (a) shows a state where a fixed mold and a movable mold are joined; b) shows a state where the movable mold is movable, and (c) is a perspective view of the molded green body.
FIG. 2 is a schematic configuration diagram of a main part of a conventional manufacturing apparatus for metal powder injection molded bodies, where (a) shows a state in which a fixed mold and a movable mold are joined, and (b) shows a movable mold that is movable. (C) is a perspective view of the molded green body.
[Explanation of symbols]
1 Mold 1a Fixed mold 1b Movable mold 2 Auxiliary mold 3 Spring 4 Slider 4a Insertion hole 5 Pin 6 Angular pin G Metal powder injection molded body (green body)

Claims (1)

  Metal powder injection molded body manufacturing apparatus for manufacturing a metal powder molded body by an injection molding method using a mold in which a cavity is formed in a part of a joint surface between a fixed mold and a movable mold movable toward and away from the fixed mold In the movable die, an auxiliary die whose height coincides with the upper surface of the movable die joined to the fixed die is provided at a lower step portion provided with a step on the outer periphery of the cavity so as to be movable in the same direction as the movable die. In addition, a spring that constantly urges the auxiliary mold toward the fixed mold is interposed between the auxiliary mold and the movable mold, and the auxiliary mold is slidable in the horizontal direction by cutting out a part of the auxiliary mold. A slider is formed, and a pin is provided on the slider, and the length of the pin is in a direction orthogonal to the moving direction of the movable mold when the movable mold is joined to the fixed mold. Mold release that penetrates the cavity and moves away from the fixed mold. Is fixed so that the tip of the pin on the side opposite to the slider of the pin moves to the middle of the cavity, the fixed pin is hooked with an angular pin, and the lower part of the angular pin is The angular pin is slidably inserted into an insertion hole provided in the slider, and the angular pin moves in accordance with an auxiliary mold that moves in conjunction with the movable mold when the movable mold is separated from the fixed mold. An apparatus for manufacturing a metal powder injection molded body, wherein the child is moved so that the pin comes out of the green body.

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