JPH07148792A - Injection mold - Google Patents

Abstract

PURPOSE:To provide an injection mold having a simple mold structure, by use of which a molded product is released easily and stick in mold is prevented. CONSTITUTION:A stripper plate 3 for forming a part of a molded product is provided outside a fixed mold 2 and a compressed air supply hole is provided in the stripper plate 3 so as to cross a compressed air passage 3b at right angles and the valve stem 3c for opening and closing the compressed air passage 3b is provided in the passage 3b and a compressed air blowoff port 3c is provided as the port opened to the surface forming a part of the molded product 4 of the stripper plate 3 and the molded product is released by the compressed air blown out of the blowoff port.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for injection molding of plastic molded products.

[0002]

2. Description of the Related Art Conventionally, in a metal mold for injection molding of a plastic molded product, when a stripper plate which forms a part of the molded product is provided, the molded product is released from the stripper plate and a fixed mold. A two-stage projecting die structure is adopted by the projecting pin.

The above-mentioned two-stage protruding mold structure will be described with reference to the drawings. FIG. 3 is a cross-sectional view showing an open state of a conventional two-stage protruding mold. In FIG. 3, 10 is a movable mold, 20 is a fixed mold insert, and this fixed mold insert 20 is fixed to the mold plate 20a. A stripper plate 30 is provided on the outer side of the fixed mold insert 20 so as to be slidable on the outer peripheral side surface of the fixed mold insert 20, and forms a peripheral portion of the molded product 40 on the inner side of the upper surface that abuts the fixed mold insert 10. An insert portion 30a is provided.

Reference numeral 50 denotes a projecting pin, and the projecting pin 50
Is fixed to the projecting plate 50a at the lower end so as to interlock with the operation of the projecting plate 50a. Reference numeral 60 denotes a guide shaft for operating the stripper plate 30.
0 is fixed at the lower end by the second projecting plate 60a, and the upper part is screwed to the stripper plate 30.

When the injection of the molten resin is completed by closing the mold and the mold is opened after the pressure is maintained and cooled, the stripper plate 30 is started by the operation of the projecting plate 60a.
Subsequently, the protruding pin 50 is operated by the operation of the protruding plate 50a, and the molded product 40 is separated from the fixed mold 20 and the stripper plate 30.

As a conventional technique, an air cylinder is attached to the back surface of the fixed mold, and a valve shaft (piston) provided in the air cylinder operates a molded product closely attached to the fixed mold from the back of the fixed mold. An injection molding die which is pushed up by a valve shaft (piston) and released from a fixed die is described in Japanese Utility Model Publication No. 5-7426.

[0007]

However, in the case of the former two-stage projecting injection molding die described above, a fixed plate requires a projecting plate and an operating device for operating the projecting pin. The die becomes complicated and the die machining cost increases,
In addition, there is a problem that the molded product is caught on the protruding pin, which causes defective release. Further, in the case of the latter injection molding die described in Japanese Utility Model Laid-Open No. 5-7426, a large-scale device is required, and more than one is required depending on the presence or absence of space on the back surface of the fixed die and the shape and size of the molded product. There is a problem that it is necessary to install it at the location.

The present invention has been made by paying attention to such problems as described above. These problems are solved, the mold structure is simple, and the molded product can be reliably released from the mold. The object of the present invention is to provide an injection molding die that does not cause defective release.

[0009]

In the injection molding die of the present invention, a stripper plate for forming a part of a molded product is provided on the outer side of the fixed die, and a passage for pressurized air is formed in the stripper plate. A part of the molded product of the stripper plate is provided with a pressurizing air supply hole which is orthogonal to the path of the pressurizing air and penetrates through the path, and a valve shaft which opens and closes the supply hole is provided in the path. A blowout port for pressurized air is provided so as to open on the surface forming the mold, and the molded product is released by the pressurized air blown out from the blowout port.

[0010]

In the injection-molding die of the present invention, the molded product is released by the pressurized air blown from the outlet of the stripper plate, so that the mold release can be performed reliably and no defective release occurs. Can be obtained.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view showing an example of the injection molding die of the present invention, and FIG. 2 is a cross-sectional view of the open mold state of FIG. This embodiment is an example of a molded product of a circular container made of polyethylene resin. In FIG. 1, 1 is a movable mold, 2 is a fixed mold insert, and this fixed mold insert 2 is fixed to a mold plate 2a. Has been done. A stripper plate 3 is provided on the outer side of the fixed mold insert 2 so as to be slidable on the outer peripheral side surface of the fixed mold insert 2, and forms the outer peripheral portion of the above-mentioned molded product 4 on the inner side of the upper surface contacting the fixed mold 1. The engraving part 3a is provided.

Fixed insert 2 of stripper plate 3
The compressed air passage 3 is provided just below the engraving portion 3a.
b is provided, and a blowout port 3c for pressurized air is opened at the upper end surface of the passage 3b. 3d is a valve shaft, and the valve shaft 3d is inserted into the passage 3b, the lower end is fixed to the template 2a, and is smoothly slid in the passage 3b. Reference numeral 3e is a supply hole for pressurized air, which is provided above the stripper plate orthogonal to the passage 3b and penetrates through the passage 3b for the pressurized air.
It is blocked by d and is in communication with the passage 3b when the mold is opened. Reference numeral 5 denotes a guide shaft for operating the stripper plate 30, and the guide shaft 5 is fixed at its lower end by a projecting plate 5a and is screwed to the stripper plate 30 above.

The operation of the embodiment will be described with reference to FIG.
In FIG. 2, the mold opening is completed, and the molded product 4 is completely fixed to the mold 2.
And the state of being released from the stripper plate 3. When the injection of the molten resin is completed by the mold closing and the mold opening is performed after the pressure holding and cooling, the projecting plate 5a is operated and when the stripper plate 3 starts to move forward, the pressurized air blocked by the valve shaft 3c is released. The supply hole 3e is opened as shown in FIG. 3, pressurized air is blown to the peripheral edge of the molded product 4 of the engraved portion 3a, and the molded product 4 is released from the engraved portion 3a and the fixed mold 2, Removal from the mold is completed.

Therefore, unlike the conventional case, it is not necessary to provide the fixed mold 2 with the protruding pin, and the molded product can be reliably released from the mold by the pressurized air with a simple mold structure.

In the molded article molded using the injection molding die of the present invention, the applicable synthetic resin may be various thermoplastic synthetic resins that can be injection-molded, or thermosetting synthetic resin. Well, it is not limited to the embodiment.

[0016]

In the injection molding die of the present invention, since the molded product is released by the pressurized air blown from the blower port of the stripper plate, the mold release can be performed reliably.
It is possible to obtain a molded product that does not cause defective release. Therefore,
It is suitable as an injection mold.

[Brief description of drawings]

FIG. 1 is a sectional view showing an example of an injection molding die of the present invention.

FIG. 2 is a sectional view of the open state of FIG.

FIG. 3 is a cross-sectional view showing an open state of a conventional two-stage protruding mold.

[Explanation of symbols]

 1 Mobile type 2 Fixed type nesting 3 Stripper plate 3a Engraving part 3b Passage 3c Air outlet 3d Valve shaft 3e Supply hole 4 Molded product

Claims (1)

[Claims] 1. A mold for injection-molding a plastic molded product comprising a fixed mold and a movable mold, wherein a stripper plate forming a part of the molded product is provided outside the fixed mold, and a stripper plate is formed in the stripper plate. A passage for the compressed air and a supply hole for the compressed air which is orthogonal to the passage for the compressed air are provided through the passage. A valve shaft for opening and closing the supply hole is provided in the passage, and a stripper plate of the stripper plate is provided. A blow-out port for pressurized air is provided on the surface forming a part of the molded product, and the molded product is released by the pressurized air blown out from the blow-out port. Injection mold.