JPH06344402A - Metal mold for injection compression molding - Google Patents

Abstract

PURPOSE:To prevent the thickness from sinking at the time of molding by a method wherein only a thick part at an optional position of a molded product is partially compressed in the molding. CONSTITUTION:In the first extruding plate 6, a partially compressing material which compresses partially resin in a cavity 10, i.e., a piece 14 and a sleeve 15 are fitted to a part being apt to cause a sink mark of a molded product 11 in the cavity 10. After filling an inside of the cavity 10 with the resin in a mold-closed state, an extruding rod 5 is pushed. Then, only the piece 14 and the sleeve 15 advances by a distance (d) via an extruding plate 6 to compress boss parts 12, 13 at positions wherein a sink mark of the resin is apt to cause in the cavity 10. The thickness is prevented from sinking by an operation of the partial compression.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection compression molding die capable of partially compressing and molding a resin filled in a cavity.

[0002]

2. Description of the Related Art A conventional injection compression molding die for compressing and molding a resin filled in a cavity is disclosed in Japanese Unexamined Patent Publication No. Hei 1
There is one described in Japanese Patent Laid-Open No. 118423. Next, the mold shown in the publication will be described with reference to FIGS. 4 and 5.
The fixed side mounting plate 41 is mounted on the fixed plate of the injection molding machine, and the cavity 31 is provided on the right side of the fixed side mounting plate 41.
A fixed-side mold plate 45 having a core 43a forming the is mounted. A sprue bush 47 forming a sprue 35 is provided at the center between the fixed side mounting plate 41 and the fixed side template 45, and the movable side mounting plate 51 and the movable side template 54 are provided with a spacer block. 52 and a receiving plate 53 are integrally sandwiched. Fixed mold plate 45 and movable mold plate 54
For the positioning at the time of mold clamping, the support pin 48 provided on the fixed-side mounting plate 41 and the guide pin 56 provided on the movable-side mold plate 54 and a guide bush (not shown) are fitted to perform highly accurate positioning. Done. The ejector guide pin 66 is sandwiched between the movable side mounting plate 51 and the receiving plate 53. The ejector guide pin 66 guides the ejector plates 63a and 63b and the pressure plates 65a and 65b, respectively. 51
And the receiving plate 53 are slidably held.

The right sides of the ejector pins 62a and 62b and the return pin 61 are sandwiched between the ejector plates 63a and 63b. Further, the left ends of the ejector pins 62a and 62b are configured not to project into the material flow passages such as the cavity 31, the spool 35, and the runner 37 during mold clamping. On the other hand, an ejector pin guide that loosely fits the ejector pins 62a and 62b is formed on the movable side mold plate 54, and a core 43b and a material flow path that form a cavity 31 are formed between the movable side mold plate 54 and the fixed side mold plate 45. Has been done. The right end of the pressure pin 64 is integrally sandwiched between the pressure plates 65a and 65b, and an ejector plate elastic spring 69 is provided between the ejector plates 63a and 63b and the pressure plates 65a and 65b. ing. The elastic spring 69 acts so that the ejector plate and the pressure plate elastically separate from each other, and at the same time, the distance between the two is regulated by the plate spacing regulating pin 68.

The pressure plates 65a and 65b are connected to a pressure drive device 36, for example, a hydraulic ejector provided in an injection molding machine, and in the mold open state as shown in FIG. 4, the pressure drive device 36.
When the pressure plates 65a and 65b are moved in the direction of arrow A by the ejector plates 63a and 63b elastically coupled by the ejector plate elastic spring 69 and the plate spacing regulating pin 68, the ejector guide pins 66 also guide the ejector plates 63a and 63b. Move while being done. As a result, the pressure plates 65a, 65a
b, the pressure pin 64 and the return pin 6 whose right ends are clamped by the ejector plates 63a and 63b
1. The ejector pins 62a and 62b project between the fixed-side mold plate 45 and the movable-side mold plate 54,
It is possible to release the product molded in the state of being fitted to the movable side mold plate 54 from the movable side mold plate 54 by a and 62b.

Next, in the mold clamping state shown in FIG. 5, the pressure driving device 36 is actuated to move the pressure plates 65a and 65b in the direction of arrow A,
At this time, the ejector plates 63a and 63b elastically coupled by the ejector plate elastic spring 69 and the plate gap regulating pin 68 are prevented from moving integrally by the return pin 61 that is urged against the fixed side mold plate 45. . That is, only the pressure plates 65a and 65b are moved in the direction of arrow A,
The pressure pin 64 sandwiched between a and 65b is inserted into the cylinder 33. A gate 32 is provided in an intermediate portion of the cylinder 33, and a pressure pin 64 separates a product and a material flow path, and at the same time, the molding material 34 filled in the cylinder 33 is compressed and inserted into the cavity 31 under pressure. To do. Therefore, the nozzle 80 in the cavity 31,
Even if the pressure of the molding material 34 filled through the material flow path is set low, after the molding material 34 is filled into the cavity 31, the pressure pin 64 further causes the cavity 3 to flow.
The molding material 34 is compressed and inserted under pressure into the mold 1 to form a product having a high density and no distortion.

[0006]

As described above, in the case of the above-mentioned conventional apparatus, the product and the material flow path are separated by advancing the pressure pin 64 when the mold is closed, and the cylinder 33 is filled in this separated state. Molding material 34
By pressurizing and inserting into the cavity 31, the molding material 34 can be filled into the cavity 31 with a small injection pressure, and high-density compression molding can be performed. However, in this apparatus, the pressurizing position that forms the cylinder 33 is limited to the position of the gate 32 that fills the molding material 34 into the cavity 31, so that only the thick-walled portion of the molded product at an arbitrary position is partially covered. It cannot be compressed to prevent shrinkage during molding. As a result, in order to prevent the defect of thinning of the molded product in this apparatus, it is necessary to insert a proper amount of meat slime into the mold, which makes it difficult to design and manufacture the mold. SUMMARY OF THE INVENTION The present invention is intended to solve the above-mentioned conventional problems, and provides an injection compression molding die capable of pressurizing and compressing each portion of a molded product where shrinkage occurs. .

[0007]

Therefore, according to the present invention, the resin filled in the cavity formed between the fixed-side mold plate and the movable-side mold plate is compression-molded, and the mold-open state after the molding is completed is completed. In the injection compression molding die that takes out the resin molded product in the cavity by the protrusion of the ejector pin due to the forward movement of the ejector cylinder, the ejector pin is moved to the partially compressed position of the movable side mold plate by the forward movement of the ejector cylinder in the mold closed state. The present invention is provided with a partial compression device capable of advancing without protruding and partially compressing the resin in the cavity, and this is a means for solving the problem.

[0008]

According to the present invention, a pin, a rod, which partially compresses the resin in the cavity, is provided at a partially compressing position of the movable side mold plate of a portion where the molded product is likely to shrink, for example, a boss portion having a wall thickness, a tubular shape, or a rod shape. A partially-compressed body having an arbitrary shape corresponding to the shape of a pressing portion such as a sleeve can be advanced without the ejector pin protruding by the advancing operation of the ejector cylinder in the mold closed state. Therefore, if the ejector cylinder is moved forward after filling the cavity with resin in the mold closed state, the ejector pin does not project and the partial compression body advances to compress the position where the resin in the cavity is likely to shrink. You can After that, the ejector cylinder is temporarily retracted in the completed molding state cooled in this state,
When the mold is opened and the ejector cylinder is moved forward again, the ejector pin projects and the resin molded product in the cavity is taken out.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the embodiments of the drawings. FIGS. 1 to 3 show the embodiments of the present invention. First, in FIG. 1, the fixed-side mold plate 1 and the movable-side mold plate 2 paired with each other are attached to the movable-side mounting plate 4 via the spacer blocks 3. Further, between the movable side mold plate 2 and the movable side mounting plate 4, a first pushing plate 6 integrated with a pushing rod 5 driven by an ejector cylinder (not shown) and a compression spring 7 are arranged. Further, a second push plate 9 is attached to the first push plate 6 via a stop bolt 8 and a second push plate 9 capable of forming a gap d between the first push plate 6 and the biasing force of the compression spring 7 is mounted. ing.

The first extruding plate 6 attached in this manner has a portion in the cavity 10 where the molded product 11 is likely to shrink, for example, a boss portion 1 having a wall thickness, a tubular shape or a rod shape.
At the partial compression positions 2 and 13, a partial compression body having an arbitrary shape corresponding to the shape of a pressing portion such as a pin, a rod, or a sleeve that partially compresses the resin in the cavity 10 is provided. In the case of this example, a piece 14 and a sleeve 15 are attached as a partial compression body, and a return pin 16 for pushing back the second extrusion plate 9 when the mold is closed is attached to the second extrusion plate 9.
An ejector pin 17 that projects into the cavity 10 to take out the resin molded product 11 in the cavity 10 in the mold open state, and a sleeve push-out pin 18 are attached.

The operation of the embodiment of the present invention constructed as described above will now be described. In the case of the injection compression molding die 19 constructed as described above, the ejector cylinder retracted die closed state shown in FIG. When the cavity 10 is filled with resin and the ejector cylinder is operated to move forward, the pushing rod 5 moves rightward in the drawing. At this time, as shown in FIG. 2, since the second pushing plate 9 is pushed back by the return pin 16 that is in contact with the movable side mold plate 2, the ejector pin 17 does not project and the pushing rod 5
Only the piece 14 and the sleeve 15 of the partial compression body are advanced by the distance d in the drawing through the extrusion plate 66 that is pressed by the boss portion 1 at the position where the resin in the cavity 10 is likely to shrink.
Compress 2 and 13. In this state, after ejecting the ejector cylinder once in the cooling completed state,
When the ejector cylinder is moved forward again in the mold closed state, as shown in FIG. 3, the ejector pin 17 projects without being affected by the return pin 16, and the cavity 1
The in-zero resin molded product 11 is taken out from the released mold 18.

[0012]

As described in detail above, according to the present invention,
By providing a partial compression body at the location where the meat shrinkage is likely to occur, it is possible to easily perform pressure compression molding at each location where the meat shrinkage of the molded product occurs, so it is possible to reliably prevent defects such as meat shrinkage of the molded product. It has excellent effects such as prevention.

[Brief description of drawings]

FIG. 1 is a side sectional view of an injection compression molding die according to an embodiment of the present invention during injection.

FIG. 2 is a side sectional view of the injection compression molding die at the time of pressure compression.

FIG. 3 is a side sectional view of the injection compression molding die when a molded product is taken out.

FIG. 4 is a side sectional view of a conventional injection compression molding die when a molded product is taken out.

FIG. 5 is a side sectional view of a conventional injection compression molding die during compression molding.

[Explanation of symbols]

 1 Fixed-side mold plate 2 Movable-side mold plate 3 Spacer block 4 Movable-side mounting plate 5 Push rod 6 First push plate 7 Compression spring 8 Stop bolt 9 Second push plate 10 Cavity 11 Molded product 12, 13 Boss part 14 Piece 15 Sleep 16 Return pin 17 Ejector pin 18 Sleeve push-out pin 19 Injection compression mold

Claims (3)

[Claims] 1. A resin filled in a cavity formed between a fixed-side mold plate and a movable-side mold plate is compression-molded, and ejector pins are formed by a forward movement of an ejector cylinder in a mold-open state in which molding is completed. In the injection compression molding die that takes out the resin molded product in the cavity by projecting, the ejector pin is advanced to the partial compression position of the movable side mold plate without projecting the ejector pin by the forward operation of the ejector cylinder in the mold closed state. A mold for injection compression molding, comprising a partial compression device capable of partially compressing. 2. The mold for injection compression molding according to claim 1, wherein the partial compression position of the movable side mold plate is a thick portion for preventing shrinkage of the resin molded product in the cavity. 3. The injection compression molding die according to claim 1, wherein the partial compression body is formed in a tubular shape in order to prevent the shrinkage of the meat at the boss portion.