JPH05309702A - Injection mold and method of extracting molding in use of mold - Google Patents

Abstract

PURPOSE:To achieve the prevention of ejector pun butting marks of a molding from remaining ensuring of wall thickness of the cavity plate, and reduction of the number of parts and man-hours. CONSTITUTION:A spiral groove part 1c is formed on the core pin 1. A pin 7 is put in the bush 8 and it is then inserted into the movable side receiving plate 9. In order to fit the pin 7 into the spiral groove part 1c of the core pun 1, the core pin 1 is incorporated into the movable side cavity plate 1. A hole for guiding the guide diameter part 1a of the core pin 1 is made in the movable side cavity plate 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding die for a molding machine using an injection molding method and a method for extracting a molded product by the die.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 4, molten resin is injected under high pressure into a cavity formed by being sandwiched between a movable side cavity plate 2 and a fixed side cavity plate 4 to form a resin. After the solidification is completed, the mold is opened with the parting line which is the boundary line between the fixed side cavity plate 4 and the movable side cavity plate 2 as a boundary.

Then, the molded product 6 adheres to the movable side cavity plate 2. Then, the ejector pin 5 is brought into contact with the molded product 6 in the cavity portion 2c of the movable side cavity plate 2 to take out the molded product 6 from the cavity portion 2c.

[0004]

However, the conventional molding die has the following problems. 1. When the molded product is taken out from the cavity, the ejector pin abuts against the molded product, and a trace of the tip of the ejector pin remains on the molded product. 2. In the ejector pin extraction mechanism, if the molded product is small, ejector pins, core pins, etc. will be densely packed in the movable side cavity plate, and a thin portion will be formed in the movable side cavity plate. And the durability of the cavity plate deteriorates. 3. When the resin is injected into the cavity portion, the resin leaks from the gap between the ejector pin and the guide hole portion of the ejector pin in the movable side cavity plate, and a flaky bur that is solidified in the molded product is generated. 4. In the structure for ejecting a molded product by abutting with ejector pins, a plurality of ejector pins are required, a guide hole is required in the cavity plate, and the number of parts and man-hours increase.

[0005]

In order to solve the above-mentioned problems, the present invention is directed to a core pin having a spiral groove portion on a collar diameter portion, a movable side cavity plate for guiding a guide portion of the core pin, and a spiral core pin. A configuration is provided in which a pin that guides the groove portion and a bush that guides the collar diameter portion of the core pin and is provided with a driving hole for the pin are provided.

[0006]

In the molding die configured as described above,
The core pin guide portion of the core pin is guided by the cavity plate, and the flange diameter portion of the core pin is guided by the bush fixed to the movable side receiving plate. The pin protruding from near the center of the bush guide portion guides the spiral groove portion of the core pin. The solidified molded product contracts to adhere to the core pin. By ejecting the core pin, the molded product is also separated from the cavity. As a result, the core pin also serves as an ejector pin.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. In FIG. 1, the guide diameter portion 1a of the core pin 1
Is rotatably incorporated in the guide hole 2a of the movable side cavity plate 2. Movable side cavity plate 2
A cavity 2c for forming the shape of the molded product 6 is formed in the. Bushing 8 mounted and fixed to the movable side receiving plate 9
A pin 7 for guiding the spiral groove portion 1c provided in the collar diameter portion 1b of the core pin 1 is incorporated and fixed in the. The tip portion 1d of the core pin 1 abuts the fixed side cavity plate 4.

Now, the resin is poured into the cavity 2c,
After cooling, when the movable side cavity plate 2 is opened with respect to the fixed side cavity plate 4 with the parting line as a boundary and the core pin 1 is projected in the tip direction, the molded product contracts, so as shown in FIG. , The core pin 1 is entangled with the tip portion 1d so as not to separate. Figure 1
, When the core pin 1 is projected upward, the spiral groove portion 1c of the core pin is guided by the pin 7, and the molded product 6 rotates as shown in FIG. It becomes the position of.

After the core pin 1 is fixed at the uppermost point, the movable cavity plate 2 is pushed up, so that the molded product 6 is pulled out from the tip portion 1d of the core pin 1.

[0010]

As described above, according to the present invention, the movable cavity plate of the molding die functions as an ejector pin, and the core pin is provided with a spiral groove on the flange diameter portion.
A pin that guides the spiral groove of the core pin, a bush that fixes the pin and guides the collar diameter of the core pin, a cavity that forms the shape of the molded product, and a hole that includes the cavity and that guides the guide diameter and the clearance diameter of the core pin. Since the structure has the cavity plate provided with, the following effects are obtained. (1) No trace of abutting by the ejector pin is left on the molded product. (2) Since the ejector pin is not used for taking out the molded product, it is possible to secure a sufficient thickness in the cavity plate. (3) Since the ejector pin is not used, it is possible to obtain a molding die extracting mechanism with a small number of parts and man-hours.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an ejection mechanism of a molding die according to the present invention.

FIG. 2 is a cross-sectional view showing the operation of the core pin tip portion in the molding die extracting mechanism of the present invention.

FIG. 3 is a diagram showing the relative position of the tooth profile of the cavity with respect to the tooth profile of the molded product in the ejection mechanism of the molding die of the present invention.

FIG. 4 is a cross-sectional view of a conventional molding die extracting mechanism.

[Explanation of symbols]

 1 core pin 2 movable side cavity plate 4 fixed side cavity plate 5 ejector pin 6 molded product 7 pin 8 bush 9 movable side receiving plate

Claims (2)

[Claims] 1. An injection molding die comprising a fixed side cavity plate, a movable side cavity plate, a movable side receiving plate, a core pin and the like, and a cavity portion formed on a separation surface of the fixed side cavity plate and the movable side cavity plate. And a spiral groove guided by a pin protruding on an inner surface of a cylindrical bush attached to the movable side receiving plate, and is guided by a guide hole of the movable side cavity plate to ascend, and a tip portion on the fixed side cavity plate. An injection-molding die, characterized in that it consists of a core pin that abuts against. 2. A method for extracting a molded product using an injection molding die according to claim 1, which comprises the following steps: (a) A molten resin is injected into the cavity, and after solidification, it is movable with respect to the fixed side cavity plate. The other part including the side cavity plate is opened at the parting line as a boundary. (B) The core pin is raised to perform an operation accompanied by a predetermined rotation (θ). (C) Only the movable side cavity plate is raised. Then, the upper surface and the molded product fixed to the tip of the core pin interfere with each other and collide with each other, and the molded product is extracted.