JP3272482B2 - Gas release structure in injection mold - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a fixed mold with a first cavity surface for molding the surface of a product, and also molds the back surface of the product with a movable mold that can be moved toward and away from the fixed mold. The present invention relates to a degassing structure in an injection mold provided with a second cavity surface.

[0002]

2. Description of the Related Art When a synthetic resin product is injection-molded by an injection molding die, gas generated in a cavity is discharged to the outside through an air vent provided at the end of the cavity.

[0003]

By the way, if the product shape is relatively simple, the air vent can sufficiently release the gas, but if the product shape becomes complicated, the air vent is reached. The gas that cannot be maintained stays at various points in the cavity. In such a case, there is a method of discharging the gas by using a gap on the outer periphery of the extrusion pin provided in the movable mold, but the gas stays because it interferes with a cooling water passage for cooling the injection molding mold. In some cases, the push pin cannot be provided at an easily accessible position.

If the gas stays in the cavity of the injection mold for the above-mentioned reason, the surface of the product turns white and the quality deteriorates. The discolored portion can be corrected by raising the temperature with acetylene gas, propane gas, or the like. May not be possible.

The present invention has been made in view of the above circumstances, and has as its object to reliably discharge gas from a cavity of an injection mold.

[0006]

In order to achieve the above object, according to the present invention, a first cavity surface for molding a surface of a product is provided in a fixed die, and the fixed die is provided in the fixed die. In an injection molding die provided with a second cavity surface for molding a back surface of a product in a movable mold that can be separated from and separated from the movable mold, a gas vent hole formed in the movable mold is opened in the second cavity surface. the vent hole, via gas vent path through the junction surface between the movable mold and the stationary mold, communicates with the gas discharge portion formed in the stationary mold, the negative pressure in the gas outlet portion
It is characterized by providing a raw means .

[0007]

[0008]

[0009]

Embodiments of the present invention will be described below with reference to the drawings.

1 to 5 show an embodiment of the present invention. FIG. 1 is a perspective view of an instrument panel of an automobile.
2 is a cross-sectional view taken along line 2-2 of FIG. 1, FIG. 3 is a cross-sectional view of an injection mold corresponding to the portion of FIG. 2, FIG.
FIG. 5 is a sectional view at a sectional position adjacent to the sectional position of FIG.

FIG. 1 shows an instrument panel P of an automobile.
It is injection-molded by an injection mold described later with the part a corresponding to the left end thereof facing upward and the part b corresponding to the right end thereof facing downward. The injection of the molten metal into the cavity of the injection mold is performed from a portion c corresponding to the central portion of the instrument panel P.

FIG. 2 shows the shape of a portion d near the right end of the instrument panel P. Since this portion has a complicated shape having an air conditioner outlet and a mounting portion for switches, an e portion thereof is shown. The gas tends to stay in the cavity of the injection mold corresponding to the above, and molding defects are likely to occur. Therefore,
The degassing structure of the present invention is applied to a portion corresponding to the portion e of the injection mold.

As shown in FIG. 3, the instrument panel
The injection molding die D for injection molding of the
Fixed die D attached to₁And fixed to the movable platen 2
Fixed mold D₁Movable mold D that can be moved away from_Two
And Fixed mold D₁First cavity recessed in
Surface C₁Molds the surface of the instrument panel P
Therefore, a grain pattern is formed there. Also, movable mold
D_TwoThe second is to form the back of the instrument panel P
2 cavity surface C_TwoIs protruded. Movable mold D _TwoEstablished in
The ejector plates 3 and 4 have the second cabinet.
Tee surface C_TwoMultiple extrusion pipes that can
Are fixed.

Referring to FIG. 5 as well, it is clear that
The movable die D ₂ corresponding to e of Fig. 2, the pin hole 6 that opens into the second cavity surface C ₂ are bored, the pin 7 is pressed into the pin hole 6. On the outer periphery of the pin 7, the second
1 extending in the circumferential direction of the pin 7 in communication with the cavity surface C ₂
The groove ₇₁ of the present, 120 ° intervals are three grooves 7 of ₂ ... and extending in the axial direction of the formed pin 7 formed in these grooves 7 _1; 7 ₂ ... gas venting hole 8 by the configuration Is done. As described above, the gas vent hole 8 is formed by the grooves 7 _1, 7 _2, ... Formed in the pin 7 which is press-fitted into the pin hole 6. The number can be changed.

Referring to FIG. 4 together, it is clear that
The gas vent hole 8 communicates with a first gas vent passage 9, a second gas vent passage 10, and a third gas vent passage 11 formed in the movable mold D ₂ via the bottom of the pin hole 6. gas vent passage 11 communicates with the fourth gas vent passage 12 formed in the stationary die D _1. The second gas vent passage 10 extends in a direction perpendicular to the plane of the inside of the movable mold D ₂ from the end of the first degassing passage 9, the third gas vent passage 11 is fixed metal from the end of the second gas vent passage 10 It extends toward the type D _1. The third degassing passage 11 is open to a joint surface 13 that forms an opening (see f in FIG. 2) in the instrument panel P,
The fourth degassing passage 12 formed in the fixed mold D ₁ communicates with the third degassing passage 11 at the joint surface 13.

In the fixed mold D ₁ , the fourth degassing passage 1 is provided.
And the gas discharge unit 14 second end is open is through, the gas discharge portion 15 to the movable die D ₂ so as to be connected to the gas discharge portion 14 is formed. The gas discharge portion 14 of the stationary mold D _1, air pipe 16 connected to an air supply source (not shown) is inserted. The air ejected from the air pipe 16 passes through the terminal opening of the fourth degassing passage 12, and
It is discharged from the gas discharge portion 15 of the movable die D _2.

Next, the operation of the embodiment of the present invention having the above configuration will be described.

The injection mold D is clamped, and the fixed mold D₁
First cavity surface C₁And movable mold D_TwoSecond Cavite
Surface C_TwoMolten resin in the cavity defined between
inject. At this time, fix from the tip of the air pipe 16
Mold D₁Air is blown out to the gas discharge part 14
And the fourth gas vent passage 1 opening to the gas discharge portion 14.
2, a negative pressure is generated. As a result, it stays in the cavity
The movable gas D _TwoOf the pin 7 pressed into the pin hole 6 of
From the gas vent hole 8 formed in the outer periphery, the first gas vent passage
9, the second degassing passage 10, the third degassing passage 11, and
The gas is sucked through the fourth gas vent passage 12 and
It is discharged from the injection molding die D from 4, 15. Injection
Once the molded instrument panel P has cured,
Dynamic mold D_TwoFixed die D₁After separating from the extrusion pin
The movable mold D by projecting 5 ..._TwoSecond cavity surface C_Two
From the instrument panel P.

Thus, the gas remaining in the cavity at the time of injection molding can be reliably discharged to the outside of the injection molding die D, and the molding failure of the instrument panel P due to the gas can be avoided. In addition, the pins 7 forming the gas vent holes 8
There therefore is provided in the second cavity surface C ₂ side for molding the back surface of the instrument panel P, it is never stick appearance important instrument panel surface of the pin 7 remains of P. Further, since the first to fourth degassing passage 9-12 is communicated with the fixed mold D ₁ side through the junction plane 8 from the movable mold D ₂ side, push-out pin to the movable die D ₂ 5 ... There is no risk of hindering the degree of freedom of design when providing.

Although the embodiments of the present invention have been described in detail above, the present invention is not limited to the above embodiments, and various design changes can be made.

[0021]

As described above, according to the present invention, since the gas vent hole is opened in the second cavity surface of the movable mold for molding the back surface of the product, the surface of the product which is important in appearance is molded. The first cavity surface of the fixed mold is not affected. Moreover, the gas vent holes of the movable mold side via a venting path through the junction surface between the movable mold and the fixed mold, so that communicates with the gas discharge portion formed in the stationary mold, the movable mold The gas can be discharged to the outside without restricting the layout of the extrusion pins and the like provided on the mold.

[0022]

[0023] By providing the negative pressure generating means to the gas outlet was or can be forcibly discharging gas in the cavity.

[Brief description of the drawings]

FIG. 1 is a perspective view of an instrument panel of an automobile.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a sectional view of an injection mold corresponding to FIG. 2;

FIG. 4 is an enlarged view of a main part of FIG. 3;

FIG. 5 is a cross-sectional view of the injection mold at a cross-sectional position adjacent to the cross-sectional position of FIG. 4;

[Explanation of symbols]

C ₁ first cavity surface C ₂ second cavity surface D ₁ fixed die D ₂ movable mold P instrument panel (product) 8 venting holes 9 venting passage 10 the gas vent passage 11 venting passage 12 the gas vent passage 14 Gas discharge section 16 Air pipe (Negative pressure generating means)

Claims (1)

(57) [Claims] 1. A stationary mold (D ₁ ) having a first cavity surface (C ₁ ) for molding a surface of a product (P),
A movable mold (D) that can be moved toward and away from the fixed mold (D ₁ ).
₂ ) The second cavity surface (C ₂ ) for molding the back surface of the product
In injection mold formed by providing a movable die (D ₂₎ to form the gas release openings (8) second cavity surface (C ₂₎ to is opened, the gas vent hole (8)
A movable mold (D ₂₎ and through the gas release passage (9-12) through the bonding surface of the stationary mold and (D _1), fixed mold (D
Communicates with the gas outlet (14) formed in _1), the moth
Wherein the scan discharge portion (14) provided with a negative pressure generator (16), venting structure in the injection mold.