JPH07195453A - Plastic-molding die and its molding - Google Patents

Abstract

PURPOSE:To form the same grain pattern as a whole and adopt a desired design without an influence on an appearance by a method wherein a molding surface in a cavity has a grain pattern of the same shape as a whole, and the depth of the grain pattern is determined on the basis of the shrinkage and draft of a molded piece in a cooling process with respect to the surface part of the molded piece. CONSTITUTION:In a molding die, a grain pattern 3 is formed on a part 1 of a cavity free from a removal resistance at the time of removing a molded piece 4A. The same grain pattern is formed on a part 2 of a molding surface requiring a draft. In this case, the grain pattern has a shevron-shaped form. The depth T is determined on the basis of the shrinkage and draft of the molded piece 4A in the mold in a cooling process with respect to a grain pattern-transferred part 5 on the surface part of the molded piece 4A to be removed from the mold at a required draft.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention mainly relates to a plastic molding die used for injection molding and the like and a molded product thereof.

[0002]

2. Description of the Related Art Conventionally, when molding a plastic molded product by injection molding or the like, it is necessary to provide a cavity of a plastic molding die with a draft of, for example, about 3 degrees. On the other hand, in design, when it is required to form a grain pattern on the outer surface of the molded article as a whole, the shape of the grain pattern and the formation depth are determined by the designer while considering the draft. It is set unilaterally.

[0003]

However, in practice, considering the draft, the selection width of the grain pattern is narrowed, so that the design requires a considerably unreasonable design, and the surface related to the draft has a large separation distance. At the time of molding, so-called "rubbing" occurs between the grain pattern surface of the molding die and the grain pattern transfer surface of the molded product, resulting in defective products.
Therefore, it is also conceivable that the shape and the formation depth of the grain pattern on the molding surface corresponding to the draft are different from each other, which is close to the shape and the formation depth of the grain pattern on the other molding surface. This is not preferable because it affects the appearance of the molded product.

[0004]

SUMMARY OF THE INVENTION The present invention has been made based on the above circumstances, and forms the same grain pattern on the outer surface of a molded article as a whole, but at the draft angle of the molding die at the time of molding, Shrinkage of the molded product and a plastic molding die having a grain surface with a grain pattern to a formation depth based on the above-mentioned draft,
And, it is intended to provide the molded product.

[0005]

Therefore, in the present invention,
In a plastic mold that forms a grain pattern on the outer surface of the molded product, the shape of the grain pattern on the entire mold surface in the cavity is the same, and the formation depth is the surface of the molded product that is released at the required draft. The portion is set based on the shrinkage of the molded product during the cooling process in the mold and the draft.

Further, according to the present invention, the surface portion of the molded product which is released at a required draft with respect to the mold surface in the cavity of the mold during molding is the molded product during the cooling process in the mold. And the formation depth allowed by the above-mentioned shrinkage and the above-mentioned draft, the shape of the grain pattern on the entire outer surface is the same.

[0007]

As a result, at the time of releasing the molded product from the molding die, there is no possibility of causing "rubbing" at the draft position, and the outer surface of the molded product can be formed in the same grain pattern as a whole. Therefore, a desired design can be adopted without affecting the appearance.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on each embodiment shown in FIGS. In the first embodiment of the present invention, as shown in FIG. 1 (at the time of molding), the molding die is provided in the cavity 4 at a portion 1 which is not subject to the release resistance when the molded product 4A is demolded. Forming pattern 3 and also
The same grain pattern 3 as described above is formed at the portion 2 of the molding surface that requires a draft (upper and lower directions in the figure). In this case, the shape of the grain pattern is a mountain shape, and the formation depth T thereof is, as shown in FIG. 2 (when cooling) and FIG. The grain pattern transfer portion 5 on the surface portion of 4A is set based on the shrinkage of the molded product 4A during the cooling process in the mold and the draft. In this embodiment, since the draft angle α is large, even if the forming depth T of the molding surface portion 2 is the same as that of the molding surface portion 1, there is no problem in die cutting (see FIG. 4).

On the other hand, in the second embodiment shown in FIGS. 5 and 6, since the draft of the mold is β <α, the grain pattern 3 is obtained.
Have the same chevron shape, but the grain depth 3 ′ of the molding surface where the draft is required has a formation depth t <T,
For example, t = 0.5T is set. This is set based on the shrinkage of the molded product 4B during the cooling process in the mold and the draft. The grain-pattern transfer portions 5 and 5'of the molded product thus formed have the same shape and differ only in the formation depth.

As described above, the grain pattern on the molding surface related to the draft has the same shape as the grain pattern at other places,
Since only the formation depth is changed based on the shrinkage (related to the wall thickness) and the draft of the molded product 4B, there is no risk of "rubbing" at the time of molding, defects of the molded product can be avoided, and From the outside, it looks like the same grain pattern, and you can satisfy the intended design.

[0011]

As described above, according to the present invention, in a plastic molding die for forming a grain pattern on the outer surface of a molded product, the shape of the grain pattern on the entire mold surface in the cavity is the same, and the formation depth thereof is the same. Was set based on the shrinkage of the molded product during the cooling process in the mold and the above-mentioned draft, so that the Since there is no risk of “rubbing” in the grain pattern at the point, it is possible to avoid defective molded products. In addition, for the surface of the molded product that is released at a required draft with respect to the mold surface in the cavity of the mold during molding, the shrinkage of the molded product during the cooling process in the mold and the draft Since the allowable depth of formation and the shape of the grain pattern on the entire outer surface are the same, the appearance is the same, and the design restrictions can be reduced and the intended design can be sufficiently satisfied.

[Brief description of drawings]

FIG. 1 is a sectional view of the shape of a main part of a molding die showing a first embodiment of the present invention.

FIG. 2 is likewise a sectional view of the shape of the essential part showing the cooling process of the molding die.

FIG. 3 is likewise a sectional view of the shape of the main part when the molding die is removed.

FIG. 4 is likewise an enlarged cross-sectional view showing the shape of the main part of the molding die.

FIG. 5 is a cross-sectional view of the shape of a main part of a molding die showing another embodiment of the present invention.

FIG. 6 is likewise an enlarged cross-sectional view showing the shape of the main part of the molding die.

[Explanation of symbols]

 1 Location of molding surface of molding die 2, 6 Location of molding surface related to draft 3, 3'Drink pattern 4 Cavities 4A, 4B Molded product 5, 5'Diffusion pattern transfer portion

Claims (2)

[Claims] 1. In a plastic molding die for forming a grain pattern on the outer surface of a molded product, the shape of the grain pattern on the entire mold surface in the cavity is made the same, and the formation depth is released with a required draft. The plastic molding die is characterized in that the surface portion of the molded product is set based on the shrinkage of the molded product during the cooling process in the mold and the draft. 2. The surface part of the molded product which is released at a required draft with respect to the mold surface in the cavity of the molding mold at the time of molding, the shrinkage of the molded product during the cooling process in the mold and the above The formation depth allowed by the draft,
A plastic molding characterized in that the entire outer surface has the same grain pattern.