JPH01317719A - Manufacture of resin mold for secondary molding - Google Patents

Abstract

PURPOSE:To mold even a complicated primary molded product by an inexpensive resin mold and to make the mass production of a secondary molded product possible by a method wherein a master model is prepared while a silicone rubber mold is formed to mold a metal powder mixed resin and the master model is removed from the formed resin mold to prepare the resin mold. CONSTITUTION:A master model 2 having the shape of a secondary molded product is prepared from a primary molded product 1. The master model 2 is received in a retaining mold 4 and silicone rubber 6 is injected therein to form a silicone rubber mold 7 which is, in turn, split into two upper and lower parts. One split mold 7A is returned to the retaining mold 4 so as to turn the split surface thereof upwardly to mold a metal powder mixed resin 9 and, after the resin 9 is cured, the obtained mold is taken out of the retaining mold 4 to remove the split mold 7A. One resin mold 10A having the master model 2 protruding therefrom the received in the retaining mold 4 so that the open surface 10a thereof is turned upwardly and the metal powder mixed resin 9 is injected to take a mold. After the resin 9 is cured, a metal powder mixed resin mold 10 is taken out to be separated into upper and lower molds 10A, 10B from a parting line (l) and the master model 2 is removed to complete the resin mold 10.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for manufacturing a resin mold for secondary molding, and more specifically, when it is necessary to perform post-processing on a primary molded product, such secondary molding The present invention relates to a method for manufacturing a resin mold used for secondary molding, which enables processing to be performed using a resin mold.

(Prior art and its problems) Conventionally, for example, when making a finished molded product by integrally forming a rubber layer on a primary molded product of synthetic resin,
For example, in addition to the molding die for the blow-molded product, a molding die for molding the rubber layer on the next molded product has been prepared.

However, this method has a disadvantage in that when the next molded product has a complicated shape, the manufacturing cost of the mold for molding the rubber layer is high. In particular, in this mold for secondary molding, it is necessary to take the shrinkage rate of the secondary molded product into account when manufacturing the mold, which tends to increase the manufacturing cost of the secondary molding.

Conventionally, when manufacturing this type of molded product, a method has been adopted in which, for example, a rubber material is manually bonded to the next molded product to create a finished product. However, this method requires time and effort because it requires manual labor, resulting in poor work efficiency and the problem of not being able to perform mass production.

(Technical Problem of the Invention) The present invention has been proposed in view of such conventional circumstances.

Therefore, the technical problem of the present invention is to perform secondary processing using a resin mold, thereby reducing the cost of manufacturing molds even in the case of complex primary moldings, and taking into account the shrinkage rate of the secondary moldings. It is an object of the present invention to provide a method for manufacturing a resin mold used for secondary molding, which allows molding to be carried out without any molding, and also enables mass production of secondary molded products.

(Means for Achieving the Object) In order to achieve the above object, the present invention adopts the following configuration.

That is, the present invention processes a semi-finished primary molded product or model to produce a master model that has the shape of a finished secondary molded product, and then molds this master model using silicone rubber. A silicone rubber mold is made, then this mold is divided, the exposed divided surface of the master model of one of the divided molds is molded with metal powder mixed resin, and then the above divided mold, which is a silicone rubber mold, is removed from this mold. At the same time, the open surface of one of the resin molds where the master model is exposed is similarly molded with metal powder mixed resin, and then the master model is removed from the thus obtained metal powder mixed resin mold.

In this case, in the present invention, as the metal powder mixed resin, for example, a resin mixed with aluminum powder is used, and the surface of the resin mold thus made is preferably plated with hard nickel.

(Embodiment) A preferred embodiment of the present invention will be described below with reference to the accompanying drawings.

Reference numeral 1 indicates a primary molded product which is a semi-finished product, and l represents a pre-molded product, for example, in a metal mold. In the present invention, which is a case for a vehicle lighting device, etc., first, this secondary molded product 1 is processed to produce a master model 2 having the shape of a completed secondary molded product. That is, in this embodiment, a plastic member 3, which has been previously formed into a hook-shaped cross section, for example, is continuously bonded along the opening edge of the case. This plastic member 3 is 1. For example, when secondary molding of rubber is performed along the opening edge of the case, the mold 6 serves as a mold. Therefore, this plastic member 3
When processing, it is necessary to manufacture the master model 2 assuming the shape of the finished product after secondary molding. In the case of this embodiment, the reason why, for example, rubber is secondarily formed on the opening edge of the case is to ensure watertightness between the case and the lamp cover that abuts on the opening edge of the case.

Next, this master model 2 is housed in a box-shaped formwork 4 and fixed with a support member 5. Then, a solution of silicone rubber 6 is injected into the mold frame 4, a mold is made, and a silicone rubber mold 7 is formed.
make.

After curing, the silicone rubber mold 7 is divided into two parts, for example, into upper and lower parts. In this case, the parting line should be positioned so as to overlap the cavity 8. After 0 division, one of the divided molds 7A, for example, the lower mold, is placed on the mold frame 4 with its divided surface 7a facing upward. The exposed divided surface 7a of the master model 2 is then molded with metal powder mixed resin 9. This metal powder mixed resin 9 includes, for example, FBT 0555 j manufactured by Mitsubishi Gas Chemical Co., Ltd., which is made of two components: a main resin mixed with aluminum powder and a curing resin.
(Product name) should be used.

Next, once this resin 9 has hardened, this mold is taken out from the mold frame 4, and the above-mentioned split mold 7A formed on the other side is removed. And, the exposed master model 2 above,
One of the resin molds 10A is placed again into the mold frame 4 with the open surface 10a facing upward, and the metal powder mixed resin 9 is similarly injected and molded. After that, once the resin 9 has hardened, the integrated metal powder mixed resin mold l is removed from the mold 4.
O is taken out, and the resin mold lO obtained in this way is
From the parting line, the resin mold is separated into an upper mold 10A, which is one of the resin molds, and a lower mold 10B.

Then, the master model 2 embedded as a stone mold in the resin mold 10 is removed, and as a result, as shown in FIG. A resin mold 10 for secondary molding including a lower mold 10B to be fitted is completed.

Therefore, when using the resin mold 10 manufactured by the method of the present invention, it is assembled into a predetermined location of the mold base, and the primary molded product 10 is set in advance in the lower mold 10B as shown in FIG. 2B. After that, the upper mold 10A is matched with the lower mold 10B, and then a plastic material such as rubber is press-fitted into the cavity 8. As a result, this plastic material becomes
- It is integrally molded on the opening edge of the next molded product 1, resulting in a second molded product as a finished product.

Since the resin mold 10 described above lacks durability as it is, it is preferable to apply hard nickel plating to its surface, for example.

In the above, in the present invention, instead of processing using the primary molded product l, which is a semi-finished product, for example, a model for product production is created and this model is processed to create the master model 2. good.

(Effects of the Invention) In the method of the present invention, for example, a primary molded product, which is a semi-finished product, is processed to produce a master model that has the shape of a secondary molded product, which is a finished product, and from this master model, a silicone rubber mold is formed. This mold is then molded with a resin mixed with metal powder, and the above-mentioned master model is removed from this resin mold to produce a resin mold that can be used for secondary molding.

Therefore, in the present invention, as a result of performing secondary processing using a resin mold, even in the case of a complicated primary molded product, it is possible to mold it with a resin mold that requires less cost, and without considering the shrinkage rate of the next molded product. The present invention has the advantage of being able to provide a resin mold that allows for the production of secondary molded products as well as the mass production of secondary molded products.

[Brief explanation of the drawing]

FIG. 1 is a flowchart showing a preferred embodiment of the method of the present invention;
FIG. 2A is a partially cutaway perspective view showing a resin mold for secondary molding, and FIG. 2B is a sectional view of the same resin mold as above, showing a state in which a primary molded product is set. In the figure, l is the primary molded product and 2 is the master model. 6 is silicone rubber, 7 is silicone rubber mold, 7A is one split mold, 7a is the exposed split surface of the master model,
9 is metal powder mixed resin, lO is metal powder mixed resin type, lOA
10a shows one exposed resin mold of the master model, and 10a shows the open surface of one resin mold.

Claims (1)

[Claims] A semi-finished primary molded product or model is processed to create a master model that has the shape of a finished secondary molded product, and then this master model is molded with silicone rubber to create a silicone rubber mold. After that, this mold is divided and the exposed divided surface of the master model of one divided mold is molded with resin mixed with metal powder, and then the aforementioned divided mold, which is a silicone rubber mold, is removed from this mold, and the master model is exposed. A resin mold for secondary molding characterized in that the open surface of one of the resin molds is similarly molded with metal powder mixed resin, and then the master model is removed from the metal powder mixed resin mold thus obtained. Production method.