JPH0732019Y2 - Injection mold - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to an injection mold for supplying a molten resin into a cavity through a submarine gate to mold a molded product.

[Conventional technology]

In general, when injection molding is performed using a heat resistant resin, the moldability thereof is likely to decrease due to the following features. That is, 1) Since the melting point is high, molding is impossible unless the temperature is high.

2) When solidified, the resin is very brittle.

3) A lot of gas is generated.

4) Low melt flow (poor fluidity).

[Problems to be solved by the device]

By the way, as shown in FIG. 5, the runner 4 and the submarine gate 5 are used in the cavity 3 between the fixed mold plate 1 and the movable mold plate 2 which is provided so as to freely come into contact with and separate from the fixed mold plate 1. When supplying molten resin, open both mold plates 1 and 2,
When the molded product in the cavity 3 and the solidified resin in the runner 4 are projected, the molded product and the solidified resin are cut at the gate portion at the same time. However, conventionally, gate disconnection defects have occurred due to factors such as the mold structure (gate and runner shapes), molding conditions, and resin characteristics used.
In particular, the loss of the gate dust and the tip of the gate is a problem. Above all, in the two-color molding die, dust scattered due to defective gate cutting is caught in the die product part,
There is a problem that the adverse effect appears remarkably on the product surface.

The present invention has been made in view of the above circumstances, and an object thereof is to perform good gate disconnection at the time of mold opening, and to separate a product from other solidified resin without generating a gate residue. It is to provide an injection molding die that is smoothly performed.

[Means for Solving the Problems]

In order to achieve the above object, the present invention is an injection molding method in which a molten resin is supplied to a cavity formed between a fixed mold plate and a movable mold plate through a submarine gate formed in the movable mold plate to mold a molded product. A mold for molding, wherein the movable mold plate has a fixed mold plate from each of the injection ports such that the thickness of the solidified resin in the submarine gate rapidly increases as the distance from the injection port into the cavity increases. And a pair of inclined surfaces facing the movable receiving plate side, and a flat surface perpendicular to the mold opening / closing direction is formed by being connected to one of the pair of inclined surfaces facing the movable receiving plate. It is characterized by being.

[Action]

In the present invention configured as described above, the pair of inclined surfaces rapidly increases the wall thickness of the solidified resin as it moves away from the inlet of the submarine gate to improve the strength, and improves the strength of the solidified resin inlet. Weaken relatively. Further, by forming the flat surface, the thickness of the solidified resin in the communicating portion of the runner with the submarine gate is increased, and the strength is improved.

As a result, when the center portion of the product in the cavity and the center portion of the runner are respectively protruded to the fixed mold plate side by appropriate protrusion pins, the solidified resin can be easily and reliably cut at the injection port portion, which is the weakest portion.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 4.

In the figure, reference numeral 10 is a fixed mold plate, and the fixed mold plate 10 has a cavity insert 11 for forming a part of the cavity 20 and the runner 21, and a runner insert 12 for forming the runner 21. It is installed. A movable mold plate 13 is provided to face the fixed mold plate 10 so that the movable mold plate 13 can move toward and away from the fixed mold plate 10. The movable mold plate 13 has a core insert for forming the cavity 20.
14 and gate nests to form submarine gate 22
15 and a runner insert 16 provided so as to face the center of the runner insert 12 are mounted. The mold plates 10 and 13 are attached to a fixed receiving plate and a movable receiving plate, respectively.

The gate insert 15 has an injection port 23 into the cavity 20.
A pair of inclined surfaces 24, 25 facing the fixed mold plate 10 and the movable receiving plate side are formed as the distance from the movable mold plate is increased. The flat surface 26 is formed. Then, the flat surface 26
An inclined surface 27 facing the fixed mold plate 10 side is formed continuously with.

In the injection molding die configured as described above, the molten resin that has passed through the runner 21 and the submarine gate 22 in the state where the fixed mold plate 10 and the movable mold plate 13 are closed as in the conventional case. Through the inside of the cavity 20. Then, after the resin in the cavity 20 is cooled and solidified, the mold is opened and the product is taken out.

In this case, when the movable mold plate 13 is separated from the fixed mold plate 10, the product in the cavity 20 and the runner are moved to the movable mold plate 13 side.
Twenty-one parts of the solidified resin adhere and move with the movable template 13. Then, the product in the cavity 20 and the center portion 28 of the runner portion are respectively projected and are projected to the fixed template 10 side by the pins. At this time, the product and the solidified resin are separated from each other as they are released from the mold and cut.

In this case, the solidified resin inside the submarine gate 22 is
The thickness increases sharply as it moves away from 23, and the strength is improved. Further, by forming the flat surface 26, the thickness of the solidified resin in the communicating portion of the runner 21 to the submarine gate 22 is increased, and the strength is improved. With these, when the central portion of the product in the cavity 20 and the center portion of the runner 21 are respectively ejected to the fixed template 10 side by the appropriate ejection pins as described above, the solidified resin is cut at the injection port 23 portion which is the weakest portion. Easy and reliable. It is smoothly cut at the weakest portion, that is, the injection port 23, and a good cut surface is obtained.

[Effect of device]

As described above, the injection molding die of the present invention has the pair of inclined surfaces that rapidly increases the thickness of the solidified resin as it moves away from the injection port of the submarine gate to improve the strength, and the injection port of the solidified resin. Weaken the strength of parts relatively. Further, by forming the flat surface, the thickness of the solidified resin in the communicating portion of the runner with the submarine gate is increased, and the strength is improved.

As a result, when the center portion of the product in the cavity and the center portion of the runner are respectively protruded to the fixed mold plate side by appropriate protrusion pins, the solidified resin can be easily and reliably cut at the injection port portion, which is the weakest portion.

As a result, it is possible to smoothly cut the gate at the injection port portion and prevent the generation of gate residue,
It is possible to surely cut the product and the other solidified resin and to obtain a good cut surface.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 4 show an embodiment of the present invention.
FIG. 1 is a sectional view, FIG. 2 is a sectional view of a gate insert, FIG. 3 is a plan view, FIG. 4 is a view taken along the line IV-IV in FIG. 3, and FIG. 5 is a conventional submarine gate. FIG. 10 …… Fixed template, 13 …… Movable template, 15 …… Gate insert,
20 …… cavity, 22 …… submarine gate, 23 …… injection port, 25 …… tilted surface.

Claims (1)

[Scope of utility model registration request] 1. An injection molding die for molding a molded product by supplying a molten resin to a cavity formed between a fixed mold plate and a movable mold plate through a submarine gate formed on the movable mold plate. In the movable template, the thickness of the solidified resin in the submarine gate rapidly increases as the distance from the inlet to the cavity increases, and the movable template faces the fixed template and the movable receiving plate, respectively. A pair of inclined surfaces is provided, and a flat surface perpendicular to the mold opening / closing direction is formed so as to be continuous with one of the pair of inclined surfaces facing the movable receiving plate. Injection mold to do.