JPH06278161A - Injection molding method of resin molded piece molded integrally with decorative member - Google Patents

Abstract

PURPOSE:To decide a correct position of a decorative member and mold the decorative member to have the same face level as that of a resin part, in manufacturing a protector mold for vehicle equipped with the decorative member. CONSTITUTION:An upper mold 10 has a movable mold 16. The movable mold 16 can move forward and backward with respect to a cavity. A decorative member 18 is arranged in a space where the movable mold 16 is sunk. The upper mold 10 and a lower mold 12 are closed. Resin is injected into the cavity. The quantity of the resin is smaller than the capacity of the cavity. The movable mold 16 operates and the decorative member 18 is pushed out into the resin. The surface of the decorative member 18 and the surface of the resin part are made to have the same face level. Gas is injected into a thick part. The decorative member is pressed against the inner wall of the cavity by the gas pressure. After cooling, the molds 10 and 12 are opened so as to take out a resin molded piece.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding method for producing a resin molded product in which a decorative member is integrally molded. More specifically, the present invention relates to an injection molding method for a vehicle protector molding (hereinafter, “molding” is abbreviated as “mole”) in which a decorative member is integrally molded flush with the surface.

[0002]

2. Description of the Related Art Some vehicle protector moldings have a glossy decorative member. Such a protector molding is formed by disposing a decorative member in a cavity of a mold and injecting resin into the cavity.

[0003]

However, since the decorative member is not supported or constrained by the cavity, the decorative member may be displaced from a predetermined position in the resin molded product. In addition, the decorative member may sink into the resin and the resin may surround the decorative member. Therefore, the appearance of the resin molded product is impaired, and a certain quality cannot be maintained.

An object of the present invention is to provide an injection molding method capable of accurately positioning and molding a decorative member.

[0005]

The present invention is, firstly, an injection molding method for a resin molded product integrally molded with a decorative member, wherein the inner wall of the cavity corresponding to the thick portion of the resin molded product is formed. The above-mentioned problem is solved by an injection molding method that includes arranging the decorative member so as to be in contact with the cavity, injecting a resin having a volume smaller than that volume into the cavity, and injecting gas into the resin injected into the thick portion. did.

A second aspect of the present invention is an injection molding method for a resin molded product in which a decorative member is integrally molded, wherein the decoration is placed at a position depressed from the inner wall of the cavity corresponding to the thick portion of the resin molded product. A member is arranged, a resin having a smaller volume than that of the cavity is injected into the cavity, the decorative member is extruded so as to be flush with the inner wall of the cavity, and gas is injected into the resin injected into the thick portion. The above-mentioned problems were solved by an injection molding method consisting of pouring.

[0007]

According to the first invention, the resin molded article is molded as follows. A smaller amount of resin is injected into the cavity than its volume. The decorative member is only arranged so as to contact the inner wall of the cavity corresponding to the thick portion,
The decorative member is hardly affected by the resin at the time of injection. That is, the thicker the cross section of the cavity is, the smaller the influence of the resin flow on the decorative member due to the flow of the molten resin due to the injection is. There is almost no deviation. Next, when gas is poured into the thick portion, the resin spreads to every corner of the cavity and the decorative member is pressed toward the inner wall of the cavity. As a result, the decorative member is positioned with respect to the remaining resin portion. After natural cooling or forced cooling, the resin molded product is taken out from the cavity. In this way, it is possible to obtain a resin molded product in which the decorative member is accurately positioned at a predetermined portion.

According to the second invention, the resin molded product is molded as follows. A smaller amount of resin is injected into the cavity, and the decorative member is extruded in a predetermined amount, that is, the surface of the decorative member is flush with the inner wall.
Further, gas is injected into the resin in the cavity. As a result, the decorative member is pressed against the inner wall of the cavity, and the decorative member and the resin are kept flush with each other. After natural cooling or forced cooling, the resin molded product is taken out from the cavity. In this way, the decorative member is accurately positioned and
It is possible to obtain a resin molded product in which the decorative member is flush with other resin portions.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will be described below with reference to the drawings. In the description of the embodiments, the resin molded product will be described as a long vehicle protector molding. 1 to 5 show the sequence of methods.

In FIG. 1, reference numeral 10 is an upper die, and reference numeral 12 is a lower die. The cavity 14 is formed between the molds 10 and 12. The cross-sectional shape of the cavity 14 is such that the protector molding has a thick portion in the center. The upper die 12 has a movable die 16. The movable die 16 extends over substantially the entire length of the cavity 14. Movable type 16
Moves back and forth toward the cavity 14.

First, the movable die 16 is set in the retracted position, and the decorative member 1 is placed in the space formed by the upper die 10 and the movable die 16.
8 is locked. After that, the upper mold 10 and the lower mold 12 are clamped, and the resin is injected as shown in FIG. The amount of resin is less than the volume of the cavity 14. The movable die 16 operates while the thick portion is in the softened state, and the inner wall of the upper die 10 and the inner wall of the movable die 16 are flush with each other, as shown in FIG.

Next, as shown in FIG. 4, gas is injected into the thick portion. When the gas pressure acts on the thick portion, the resin spreads to every corner of the cavity 14, and the decorative member 18 causes the inner wall of the cavity 14, that is, the movable die 1.
The inner wall of 6 is pressed. Then, after natural cooling or forced cooling, as shown in FIG. 5, the upper mold 10 and the lower mold 12 are
When the molding is performed, the resin molded product 20 is taken out.

FIG. 6 shows a resin molded product 20 molded by the above method. In this way, the inner wall of the movable die 16 and the inner wall of the upper die 10 are made flush with each other, and the gas pressure is applied to the thick portion to accurately determine the position of the decorative member 18 in the resin molded product 20. In addition, the surface of the decorative member 18 and the surface of the resin portion are flush with each other, and a resin molded product having a good appearance can be obtained.

Although the decorative member is held in advance in the cavity 14 by using the movable die 16 in the above embodiments, the movable die 16 need not be provided if the decorative member can be held by another method. For example, it is possible to hold a decorative member in the cavity by using a suction force generated by depressurizing the holes by providing a large number of holes in the upper mold.

[0015]

According to the present invention, the position of the decorative member in the resin molded product can be accurately determined by injecting the resin smaller than the volume of the cavity and further applying the gas pressure to the thick portion. At the same time, the surface of the decorative member and the surface of the other resin portion can be flush with each other. Further, since the resin does not get around the surface of the decorative member due to this gas pressure, it is possible to obtain a resin molded product having a good appearance.

[Brief description of drawings]

FIG. 1 is a diagram illustrating an injection molding method according to the present invention, and is a cross-sectional view of an upper mold and a lower mold in a mold open state.

FIG. 2 is a cross-sectional view of the mold in a state where the mold is clamped from the state of FIG. 1 and resin is injected.

FIG. 3 is a cross-sectional view of the mold in a state where the movable mold is operated from the state of FIG. 2 and the inner wall of the upper mold and the inner wall of the movable mold are flush with each other.

FIG. 4 is a cross-sectional view of a mold in which gas is injected from the state of FIG.

5 is a cross-sectional view of the mold in a state where the mold is opened and a resin molded product is taken out from the state of FIG.

FIG. 6 is a perspective view of a molded resin product.

[Explanation of symbols]

 10 Upper mold 12 Lower mold 14 Cavity 16 Movable mold 18 Decorative member 20 Resin molded product

Claims (2)

[Claims] 1. A method for injection-molding a resin molded product, in which a decorative member is integrally molded, wherein the decorative member is arranged so as to contact an inner wall of a cavity corresponding to a thick portion of the resin molded product, An injection molding method for a resin molded product, which comprises injecting a resin having a volume smaller than that volume into the resin and injecting a gas into the resin injected into the thick portion. 2. A method for injection-molding a resin-molded product in which a decorative member is integrally molded, wherein the decorative member is arranged at a position depressed from an inner wall of a cavity corresponding to a thick portion of the resin-molded product, Injecting a smaller volume of resin into the cavity, extruding the decorative member to be flush with the inner wall of the cavity, and injecting gas into the resin injected into the thick portion, Injection molding method for resin molded products.