JPH03216318A - Manufacture of injection mold - Google Patents

Abstract

PURPOSE:To take out easily a model without destroying the same and make a reduction of a post-manufacturing process possible, by a method wherein at the time of casting into a cavity, a gate and sprue members are laid along with the model. CONSTITUTION:A parting face forming plate 3 and model 4 are provided within a casting frame 2 on a bottom plate 1 and a sprue forming part 4a is provided in a projected state on the central part of its upper part. Resin 5a is cast, which is reversed after primary cure by covering an opening part with an upper plate 6, resin 5b is cast, a screw member 11 similar to a screw member 8 is provided on a fitting plate 10 and the resin 5b is cured secondarily. Then the same is reversed, an upper part is removed from the casting frame 2, a sprue forming part 4a is extruded with an ejector pin A and the model 4 is separated easily from the casting frame 2 without destroying the model 4. An ejector pin hole is formed into a core 5B to be obtained by performing finish processing of an outer circumferential part of the cured resin 5a, 5b and post-processing is not necessary for a cavity 5A. The cavity 5A and core 5B are incorporated into a mold base and made into an injection mold.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a method for manufacturing an injection mold made of resin, which is suitable as an injection mold for molded products produced in small quantities in a wide variety of products.

(Prior art) Conventionally, injection molds have generally been made of metal, but when the molded product is produced in small quantities, the manufacturing period of the injection mold is short, the mold is easy to handle, etc. Because of these advantages, resins are increasingly being used as injection molds. FIGS. 9 to 15 show conventional examples of this type. In the conventional method, first, as shown in FIG. A plate 52 is set, a model 53 is placed on it, and then, as shown in FIG. 10, resin 54a is injected and the upper opening is covered with an upper plate 55.

Then, as shown in FIG. 11, after curing, the parting surface forming plate 52 and the bottom plate 51 are removed, and the casting frame 5 is removed.
0 was inverted, and as shown in FIG. 12, resin 54b was injected and a mounting plate 56 was provided.

As shown in FIG. 13, after curing, it is turned over and
In addition, the casting frame 50, top plate 55, mounting plate 56, model 53, etc. were removed. In this case, when the model 53 was demolded from plastic, it was heated to soften it. After that, as shown in FIG. 14, the ejector bin hole 57 and the cooling water pipe 58 are inserted into the core 54B made of resin 54b.
In addition, a spool 59 and a cooling water pipe 58 are formed in the cavity 54A by machining, and FIG. 15 shows the core 54B.
, shows the state in which the cavity 54A, etc. are assembled into the mold base. In the figure, 60 and 6l 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. Further, 67 is an ejector bin, and the mounting plate 6
The third side is the fixed side and the opposite side is the movable side. (lI8 to be solved by the invention) However, in the above conventional example, when manufacturing an injection mold, the model 53 is removed when removing the mold part as shown in FIG. 13, but in this case, the model 53 is heated, etc. The process is complicated, and as shown in Fig. 14,
In the finishing process of the mold part after the resin has hardened, it is necessary to form the subur 59 and the like in the cavity 54 by machining, and in this respect as well, there is a UIB that manufacturing is complicated.

The present invention has been proposed in view of the above circumstances, and its purpose is to easily remove the model from the mold, and to remove the spool etc. in the finishing process of the mold part. It is an object of the present invention to provide a method for manufacturing an injection mold that does not require processing, can be easily manufactured, and can shorten the time.

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

(Function) The present invention is configured as described above, and the gate/spool member embedded during casting is used to demold the model, and the step of forming the spool by post-processing is unnecessary.

(Example) 1 to 8 show one embodiment of the present invention.

In this example, an injection mold is manufactured through the following steps.

That is, first, as shown in FIG. 1, a parting surface forming plate 13 is provided in a casting frame 2 provided on a bottom plate 1, and a model 4 is provided thereon. In the second case, model 4
A spool forming portion 4a serving as a gate and a spool member is integrally protruded from the upper center portion.

Next, as shown in FIG. 2, the resin 5a is injected into the upper part, the model 4 is embedded, the upper opening is covered with the upper plate 6, and the resin 5a is placed at room temperature or in a drying oven for primary hardening. Incidentally, the upper plate 6 is provided with a screw member 8 for obtaining a mounting hole 7 when the upper plate 6 is assembled into a mold base after the resin has hardened. Note that the tip of the spool forming portion 4a has a length that projects above the injected resin 5a. Next, as shown in FIG.
After removing the bottom plate 1, the resin 5b serving as the core is injected and secondary hardened. In this case, the mounting Fi 10 is provided with a screw member 1l similar to the screw member 8. Note that A in the figure is a protruding ejector bin whose tip abuts against the protruding spool forming portion 4a, and is provided through the center of the upper plate 6. Thereafter, as shown in FIG. 4, the model 4 having the Subur forming part 4a, the cured resin 5a, the upper plate 6, etc. are removed from the casting frame 2 by inverting the mold.

Then, as shown in FIG. 5, the rod B provided on the ejector bin A is extended, the subur forming part 4a is pushed out by the ejector bin A, and the model 4 is taken out. In this way, the model 4 can be easily removed from the resin 5 without being destroyed.
It can be separated from the resin mold formed by a.

Therefore, as shown in FIG. 6, the casting frame 2, the screw member 8
, 9, etc., remove the upper temporary 6, mounting plate 10, etc. Then, as shown in FIG. 7, the cured resins 5a and 5b are
Finish processing the outer periphery of the cavity 5A and core 5.
get B. In other words, the dashed dotted line on the outer periphery of the figure is this finishing margin. In this case, an ejector bin hole 9a is formed in the core 5B by machining. Note that since the subur 12 has already been formed in the cavity 5A4, no further processing is required.

Figure 8 shows the cavity 5A and core 5 as an injection mold.
B is shown assembled into the mold base. 13 in the diagram
is a base, and a spacer block 14 is attached to the upper outer part of this base.
is erected, and a receiving plate 15 is provided above it. A core 5B is provided on the receiving plate 15 via a screw member 16, and a template 17 is provided on the outside of the core 5B. Further, a template 19 facing the template 17 and facing the cavity 5A is provided, and a mounting plate 19 to which the cavity 5A is attached via a screw member 18 is provided on the upper part of the template 19.

Incidentally, a spool 12a is formed on the mounting plate 19 and is connected to the spool l2 of the cavity 5A. Further, 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 l5 and is supported by the upper ejector plate 20. Further, a lower ejector plate 21 is provided below this ejector plate 20, and these are provided above the base 13, and as in a well-known configuration, after the mold is opened, the ejector pin 9 is driven and the molded product is 22 is configured so that it can be removed from the mold.

In the above embodiment, the spool was shown as an example, but it goes without saying that the runner may also be similarly embedded together with the model.

(Effects of the Invention) As described above, according to the present invention, in the method of manufacturing an injection mold using resin, the gate and the
Since the spool member is configured to be embedded together with the model, the model can be easily taken out without destroying the model by pressing the spool forming part from the outside.

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

It has the following effects.

[Brief explanation of drawings]

Figures 1 to 8 show the first embodiment of the present invention, in which Figure 1 is a model with a subur forming part in a cenote state, Figure 2 is an explanatory diagram of the resin injection and primary curing process that will become a cavity, and Figure 3 is an explanatory diagram of the primary curing process.
The figure shows the core manufacturing process, Figure 4 is an explanatory diagram of the division of the mold part, Figure 5 is the model demolding process, Figure 6 is the mold part removal process, screw member removal process, and Figure 7 is machining and finishing. FIG. 8 is an explanatory diagram showing a state in which it is assembled into a mold base, and FIGS. 9 to 15 are explanatory diagrams showing the conventional manufacturing process. 4 ・ ・ 4 a ・ 5a, 5A ・ 5 B ・Model Subur forming part Resin Cavity Core (1 other person) Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 1Q Figure 11 Figure 12 Figure 13 Figure 14 Figure 59 Figure 15 (Sea constant bill)

Claims (1)

[Claims] A method for manufacturing an injection mold using a resin, the method comprising embedding a gate and spool member together with a model during molding of a cavity.