JP2678671B2 - Injection mold manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for producing an injection mold made of resin, which is suitable as an injection mold for a molded product manufactured in a large variety of small quantities.

(Prior Art) Conventionally, a metal injection mold has been generally used, but when a molded product is manufactured in a small amount, the injection mold has a short production period and is easy to handle. Due to the advantages described above, it has become popular to use a resin as an injection molding die.

9 to 15 show a conventional example of this kind. In the conventional case, as shown in FIG.
The parting surface forming plate 52 is set in the casting frame 50 provided on the 51, the model 53 is installed on the plate 52, and then the resin 54a is injected and the upper opening is provided as shown in FIG. The part is covered with the upper plate 55.

Then, as shown in FIG. 11, after curing, the parting surface forming plate 52 and the bottom plate 51 are removed, the casting frame 50 is reversed, and as shown in FIG. 12, the resin 54b is injected and the mounting plate is attached. There were 56.

Then, as shown in FIG. 13, after curing, turn it over,
In addition, the casting frame 50, the upper plate 55, the mounting plate 56, the model 53 and the like have been removed. In this case, when the model material was plastic, the model 53 was heated and softened. Thereafter, as shown in FIG. 14, the ejector pin hole 57 and the cooling water pipe 58 are provided in the core 54B made of the resin 54b, and the cavity 54B.
The spool 59 and the cooling water pipe 58 were formed on A by machining.

FIG. 15 shows a state in which the core 54B, the cavity 54A, etc. are assembled in the mold base. In the figure, 60 and 61 are template plates, 62
Is a receiving plate, 63 is a mounting plate, 64 is a spacer block, 65 is an upper ejector plate, and 66 is a lower ejector plate. Reference numeral 67 denotes an ejector pin, and the mounting plate 63 side is a fixed side, and the opposite side is a movable side.

(Problems to be Solved by the Invention) However, in the above conventional example, the model 53 is removed at the time of removing the mold portion in FIG. 13 in manufacturing the injection mold, but in this case, the model 53 is heated. However, as shown in FIG. 14, the spool 59 and the like must be formed in the cavity 54 by machining in the finishing process of the mold portion after resin curing. However, also in this respect, there is a problem that the manufacturing is complicated.

The present invention has been proposed in view of the above circumstances, and an object thereof is to easily remove a model from a model, that is, to remove the model, and to perform a finishing process of a mold part after a spool or the like. An object of the present invention is to provide a method for manufacturing an injection molding die that does not require processing, is easy to manufacture, and can reduce time.

(Means for Solving the Problems) The present invention achieves the above object by embedding a gate spool member together with a model at the time of casting a cavity in a method of manufacturing an injection mold with a resin.

(Operation) In the present invention, the model is demolded by using the gate / spool member embedded at the time of casting, which is configured as described above, and the step of forming the spool by post-processing is unnecessary.

(Embodiment) FIGS. 1 to 8 show an embodiment of the present invention. In this embodiment, an injection mold is manufactured by the following steps.

That is, first, as shown in FIG. 1, a parting surface forming plate 3 is provided in a casting frame 2 provided on a bottom plate 1, and a model 4 is provided thereon. In this case, a gate and a spool forming portion 4a as a spool member are integrally provided at the upper center of the model 4 so as to project.

Then, as shown in FIG. 2, the resin 5a is injected into the upper portion, the model 4 is embedded, the upper opening is covered with the upper plate 6, and the upper opening is put in a normal temperature or drying oven to be primarily cured. It should be noted that the upper plate 6 is provided with a screw member 8 for obtaining a hole 7 for mounting the upper plate 6 when the resin is hardened and then assembled into a mold base.
Is provided. The tip of the spool forming portion 4a has a length protruding upward from the injected resin 5a.

Next, as shown in FIG. 3, after the resin 5a is cured, it is inverted, and the parting surface forming plate 3 and the bottom plate 1 are removed, and the resin 5b serving as the core is injected and secondarily cured. ing. In this case, the mounting plate 10 is provided with a screw member 11 similar to the screw member 8.

In the figure, A is a projecting ejector pin, the tip of which is in contact with the projecting spool forming part 4a, and is provided so as to penetrate the central portion of the upper plate 6.

After that, as shown in FIG. 4, the model 4 having the spool forming portion 4a, the cured resin 5a, the upper plate 6 and the like are reversed and removed from the casting frame 2.

Then, as shown in FIG. 5, the rod B provided on the ejector pin A is extended, and the spool forming portion 4a is pushed out by the ejector pin A to take out the model 4. In this way, the model 4 is easily destroyed without being destroyed.
Can be separated from the resin mold.

Then, as shown in FIG. 6, the casting frame 2, the upper plate 6 having the screw members 8 and 9, the mounting plate 10 and the like are removed.

Next, as shown in FIG. 7, the outer peripheral portions of the cured resins 5a and 5b are finish-processed to obtain cavities 5A and cores 5B. That is, the one-dot chain line in the outer peripheral portion in the figure is the finishing margin.

In this case, the ejector pin hole 9a is formed in the core 5B by machining.

Note that the spool 12 has already been formed in the cavity 5A, so that subsequent processing is unnecessary.

FIG. 8 shows a cavity 5A and a core 5B as an injection mold.
The state where and are assembled in the mold base is shown. In the figure, 13 is a base, on the upper outer part of which a spacer block 14 is erected and a receiving plate 15 is provided above it. Backing plate 15
A core 5B is provided on the upper side with a screw member 16, and a template 17 is provided on the outer side of the core 5B. Further, a mold plate 19 facing the mold plate 17 is provided on the side of the cavity 5A, and a mounting plate 19 having the cavity 5A mounted on the mold plate 19 via a screw member 18 is provided.
Is provided. The mounting plate 19 is formed with a spool 12a communicating with the spool 12 of the cavity 5A.

The core 5B is provided with an ejector pin 9, and the base end side of the ejector pin 9 extends below the receiving plate 15 and is supported by the upper ejector plate 20. Also,
A lower ejector plate 21 is provided below the ejector plate 20, and these are provided above the base 13. As is well known, after the mold is opened, the ejector pin 9 is driven and the molded product 22 is removed. It is designed to be moldable.

Although the spool has been shown as an example in the above embodiment,
Of course, the runner may be embedded with the model as well.

As described above, according to the present invention, in the method of manufacturing the injection mold with the resin, the gate / spool member is embedded together with the model when the cavity is cast. By pressing from the outside, the model can be easily taken out without destroying it.

b. The post-processing of the spool for injecting the resin is unnecessary, there is no risk of damaging the resin mold, and the post-processing steps can be reduced, and the time can be shortened.

Etc. have an effect.

[Brief description of the drawings]

FIGS. 1 to 8 show a first embodiment of the present invention, FIG. 1 is a set state of a model having a spool forming portion, FIG. 2 is a resin injection forming a cavity, an explanatory view of a primary curing process, a third embodiment.
The figure shows the core manufacturing process, Fig. 4 is an explanatory view of the division of the mold part, Fig. 5 is the model demolding process, Fig. 6 is the mold part removal process, screw member removal process, and Fig. 7 is the machining and finishing process. Processing steps, FIG. 8 is an explanatory view of a state of being incorporated in a mold base, and FIGS. 9 to 15 are explanatory views showing conventional manufacturing steps. 4 …… Model 4a …… Spool forming parts 5a, 5b …… Resin 5A …… Cavity 5B …… Core

Claims (1)

(57) [Claims] 1. A method of manufacturing an injection molding die using a resin, wherein a gate / spool member is embedded together with a model when a cavity is cast.