JPH0383619A - Mold assembly - Google Patents

Abstract

PURPOSE:To shorten molding cycle without manual assistance and obtain a molded item having fine external appearance by a method wherein local heating means is incorporated near the cavity of a mold stock. CONSTITUTION:After the filling of molding material in a cavity 30, local heating is started with a local heating means (heater) 26, which is incorporated near the cavity 30 of a mold block 20. Thus, the hardening of the part, which lies between a thick walled part 32a and thin walled parts and tends to easily deform, among the respective parts of a molded item 32 is fully accelerated, resulting in allowing to decrease the deformation of the molded item 32 after its release from the mold block.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a mold device.

[Conventional technology]

For example, an injection molding apparatus using a thermosetting resin material as a molding material includes two mold bodies: a fixed mold body and a movable mold body. Both mold bodies each have a mold body on a mounting body. These mold bodies face each other so that one movable side can move forward and backward toward the other stationary side, and when both mold bodies move forward and come together, a cavity is formed between them. A sprue is passed through the mold body on the stationary side, and the molding material introduced through the central sprue (injection hole) is guided into the cavity. The molding material introduced into the cavity is thermally hardened by the heat from the heated mold body to form a molded product, and then taken out with an ejector that is provided so that it can move forward and backward into the mold body. There is.

By the way, some of the above-mentioned molded products are thick-walled or deflected, but these products are removed from the mold at a high temperature of 160 to 180°C. After being taken out, deformation may occur in easily deformable areas such as the joint between a thick part and a thin part.

[Problem to be solved by the invention]

Therefore, in the past, deformation was forcibly prevented by using a cooling jig after molding, or by taking a sufficiently long curing time.

Using the cooling jig requires manual labor, and if the curing time is made sufficiently long, the molding cycle takes a long time, which is disadvantageous.

This invention was made in view of the above-mentioned circumstances, and its objective is to provide a molded product that does not require manpower, shortens the molding cycle, and is less likely to deform later at a low cost. At the same time, it is possible to obtain a molded product with an excellent appearance.

[Means to solve the problem]

In order to solve the above problems, a molding device according to the present invention includes opposing mold bodies, at least one of which is a movable side, and both mold bodies are heated and brought together. In a mold device in which a cavity is formed, a local heating means is incorporated in the vicinity of the cavity of the mold body, and the local heating means includes:
Local heating is started after the molding material is filled into the cavity.

[For production]

If the local heating means is incorporated in the vicinity of the cavity of the mold, curing of easily deformable parts of the molded product will be sufficiently promoted, and the molded product will be less likely to deform after being taken out. Allowing the molding material to completely harden within the cavity eliminates the need for any manual labor required after removing the molded product. When the local heating means starts heating after the molding material is filled into the cavity, rapid heat is not applied to the surface of the molded product, and thermal effects are reduced.

〔Example〕

Hereinafter, embodiments of the present invention will be explained in detail with reference to the accompanying drawings.

FIG. 1 shows an embodiment of a mold apparatus according to the present invention, and this embodiment is directed to an injection molding apparatus using thermosetting resin as a material. As shown in this figure, the device includes a stationary mold body 1 and a movable mold body 20. The stationary mold body 1 includes a mounting body 2, and the movable mold body 20 includes a mounting body 21. Inside the mounting body 2,
The mold body 4 on the fixed side having the plate 3 on the back also has
A movable mold body 23 having a plate 22 on the back thereof is attached to each of the mounting bodies 21 . A core pin 5 is provided in the mold body 4 on the stationary side, and a core 24 is provided in the mold body 23 on the movable side by press fitting. A cavity 30 is formed between the core pin 5 and the core 24.
A runner hole 31 communicates with the molding member 0, and the molding material injected through a sprue (not shown) is filled into the cavity 30 through the runner hole 31. The two mold bodies 4.23 are heated so that the heat curing progresses as a whole.
It is heated to a certain temperature range. An ejection pin 25.25 is passed through the mold body 20 on the movable side so as to face the cavity 30, and the molded product 32 formed in the cavity 30 is ejected upward. The molded product 32 has a thick wall portion 32a.
It has become a thing that has.

Incidentally, a heater 26 is provided on the outer peripheral portion of the core 24 as a local heating means that heats the easily deformable portion between the thick wall portion 32a and the thin wall portion. Local heating is started after the molding material is filled into the molding material.

As mentioned above, the mold device according to the present invention has a local heating means installed near the cavity of the mold body.
The hardening of the parts of the molded product that are easily deformed is sufficiently promoted, and the molded product becomes difficult to deform after being taken out. Allowing the molding material to completely harden within the cavity eliminates the need for any manual labor required after removing the molded product. When the local heating means starts heating after the molding material is filled into the cavity, rapid heat is not applied to the surface of the molded product, and thermal effects are reduced.

Note that the molded product may be a thick-walled product. If a heater cannot be installed in the mold part due to the mold structure or the shape of the molded product, for example, if the molded product is 6φ
If the molded product is very thin, outside curing may be performed using a jig core after removing the molded product.

〔Effect of the invention〕

Since the molding device according to the present invention is configured as described above, it is possible to shorten the bottom shape cycle without requiring manual labor, and to obtain a molded product that does not later deform at a low cost. Along with this, it became possible to obtain molded products with good appearance.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an embodiment of a molding device according to the present invention.

Claims (1)

[Claims] 1. A molding device comprising opposing mold bodies, at least one of which is on the moving side, both mold bodies being heated and forming a cavity when brought together, A local heating means is incorporated in the vicinity of the cavity of the mold body, and the local heating means includes:
A molding device characterized in that local heating is started after the molding material is filled into the cavity.