JPS6216807B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field of the Invention] This invention relates to a method in which a core member is brought into contact with the end portion of a long material and inserted into an injection mold, and a terminal resin portion (end cap) is formed by injection molding. The present invention relates to a method of manufacturing moldings used for vehicles, particularly moldings used for vehicles.

[Conventional technology]

Moldings with terminal resin parts are used for decoration and protection in automobile bodies, etc., but if the terminal resin part is relatively large and long, a core member may be brought into contact with the terminal part. The terminal resin portion is formed by using the terminal resin portion.

FIG. 1 is a perspective view with the front section of this type of molding cut away, and FIG. 2 is a sectional view of an injection mold showing a conventional manufacturing method. The molding 1 has an outer surface 4 formed by a metal part 2 serving as a core material and a resin part 3.
A terminal resin part 7 is formed at the terminal part of a long material 6 formed to have an internal space 5, and a core member 8 is interposed as a reinforcing material inside the resin part 7. The core member 8 is made of foamed resin with fine air bubbles inside, and includes a main body part 8a that is joined to the inner surface of the terminal resin part 7, a step part 8b that is joined to the cut end of the elongated material 6, and a stepped part 8b that is joined to the cut end of the elongated material 6. It is integrally molded to have a protruding portion 8c that is inserted into and fits into the internal space 5 of.

In the conventional molding manufacturing method, first, a metal part 2 made of a galvanized steel plate or the like, which has been formed to have a predetermined cross section by roll forming, is supplied to an extrusion mold, and then a long piece with a resin part 3 formed by extrusion molding is supplied. The material 6 is cut to a predetermined length, and a core member 8 separately molded by injection molding or the like is brought into contact with the end portion as shown in FIG. 2, to form an injection mold consisting of a cavity mold 9 and a core mold 10. Insert and tighten the mold,
Resin is injected into the cavity 12 through the gate 11 to form the terminal resin portion 7 so as to be integrated with the terminal portion of the elongated material 6 and the core member 8.

However, in the conventional molding manufacturing method as described above, the thickness of the long material 6 is
It is unavoidable that errors and variations of about 0.2 mm will occur. This is not limited to extruded products, but also long materials 6
The same applies when a roll-formed or press-formed metal product is used. For this reason, the long material 6
If the thickness is thin, burrs 15 will be generated in the relief part 14 through the contact part 13 with the elongated material 6 of the injection molding mold, and this burr 15 must be removed manually. There was a problem in that the removed marks significantly impaired the appearance.

[Purpose of the invention]

This invention is aimed at solving the above-mentioned problems, and includes forming an overhang on the core member so as to form a constriction for the inflow of the injected resin into the cavity near the end of the long material. An object of the present invention is to provide a molding manufacturing method that does not generate burrs even when there are errors or variations in the long material by filling the cavity with injected resin through the constriction part to form a terminal resin part. It is said that

[Structure of the invention]

In this invention, a core member is brought into contact with an end portion of a long material cut to a predetermined length, and the core member is inserted into an injection mold, and the end portion is made of resin so as to be integrated with the end portion and the core member by injection molding. In the method for forming a part, a protruding part is formed on the core member so as to form a constricted part for inflow of the injected resin into the cavity near the end part, and the injected resin is filled into the cavity through the constricted part. , a molding manufacturing method characterized by forming a terminal resin portion.

[Embodiments of the invention]

Examples of the present invention will be described below. FIGS. 3 and 4 are cross-sectional views of an injection molding die showing a manufacturing method according to another embodiment of the present invention, and FIG.
The figure is a perspective view of the core member, and FIG. 6 is a graph showing the pressure and injection amount during injection molding, and the same reference numerals as in FIGS. 1 and 2 indicate the same or corresponding parts.

In the injection mold, the cavity 12 in FIG. 3 is formed to be large so as to cover the outer periphery of the end of the long material 6, as in FIG. 2, but in FIG. It is formed small. Core member 8
is a projecting portion 8 formed to project outward from the main body portion 8a of the end portion of the elongated material 6 toward the cavity mold 9 over the entire length of the outer surface in the width direction.
d, and a stepped portion 8b is formed on this projecting portion 8d. The projecting portion 8d is high in the case of FIG. In the case shown in the figure, the height is lowered, and the cavity 12 is divided into a first cavity 12a, a second cavity 12b, and a third cavity 12c (only in the case of FIG. 3).

The manufacturing method of the molding 1 is similar to the conventional method. First, a metal part 2 made of a galvanized steel plate or the like formed by roll forming to have a predetermined cross section is supplied to an extrusion mold, and a resin part 3 is formed by extrusion molding. The elongated material 6 thus formed is cut to a predetermined length, a core member 8 separately molded by injection molding or the like is brought into contact with the end portion thereof, and the core member 8 is inserted into an injection mold and the mold is clamped. At this time, the protruding portion 8c of the core member 8 is inserted into the internal space 5 of the elongated member 6 so as to form a gap that will become the second cavity 12b between the end portion of the elongated member 6 and the protruding portion 8d. and then the molds are clamped to form a constricted portion 16 between the protruding portion 8d and the cavity mold 9.

When resin is injected through the gate 11 in this state, the injected resin almost fills the first cavity 12a of the cavity 12, and then passes through the constriction part 16 and fills the second cavity 12b and third cavity 12c. . 1st cavity 1
The resin filling 2a is cooled by the core member 8 and the cavity mold 9, increasing its viscosity and being squeezed by the constriction part 16, so that the pressure of the resin flowing into the second and third cavities 12b and 12c increases. becomes lower. Under such low pressure conditions, the second
The resin filling the third cavities 12b, 12c has a relatively high viscosity. There is no possibility that burrs 15 will be generated in the relief portion 14 due to the leakage of the burrs.

As shown in Figure 6, the resin pressure and injection amount during injection are set to change stepwise at each point from To to _T5 . _The first to third cavities 1 are filled so that the second and third cavities 12b, 12c are completely filled at or near _T5 ).
It is desirable to determine the sizes of 2a to 12c and the constriction portion 16.

By the above injection molding, the terminal resin part 7 is formed so as to be integrated with the terminal part of the elongated material 6 and the core member 8. In the case of FIG. 3, the terminal resin part 7 is formed with an overlapping part corresponding to the third cavity 12c and has a stepped shape, but in the case of FIG. 4, the overlapping part is not formed, so there is no step. is obtained.
The molding 1 manufactured in this manner is removed by opening the mold.

In the above description, the shape and structure of the elongated material 6 can be changed depending on the type of intended molding. The material may be made of only the metal part 2 or only the resin part 3, but it is generally a combination of the two, and may include a colored or glittering decorative film. As the metal part 2, in addition to the above-mentioned metal part, any material such as a stainless steel plate or an aluminum plate can be used, and it can be roll-formed, press-formed, or not. The resin portion 3 is generally extruded from a synthetic resin with high elasticity such as soft vinyl chloride resin. In addition, the core member 8 is made of vinyl chloride resin in order to reduce weight and to prevent sink marks and deformation on the outer surface.
Although it is preferable to use a foam such as ABS resin, other resins may be used, and the shape may be changed according to the shape of the molding 1.

Furthermore, the present invention is widely applicable to the production of side moldings for vehicles and other general moldings.

〔Effect of the invention〕

According to the present invention, an overhang is formed on the core member so as to form a constriction for inflow of the injected resin into the cavity near the end of the elongated material, and the injected resin is introduced into the cavity through the constriction. Since the terminal resin portion is formed by filling, burrs do not occur even if there are errors or variations in the long material. Further, since there is no need to strongly tighten the contact portion with the elongated material, no scratches occur on the outer surface of the molding, and a molding with an excellent appearance can be manufactured.

[Brief explanation of the drawing]

FIG. 1 is a perspective view with the front part of the molding cut away, FIG. 2 is a sectional view of an injection molding die showing a conventional manufacturing method, and FIGS. 3 and 4 are manufacturing methods according to other embodiments of the present invention. FIG. 5 is a sectional view of an injection mold showing the method, FIG. 5 is a perspective view of a core member, and FIG. 6 is a graph showing pressure and injection amount during injection molding. In each figure, the same reference numerals indicate the same or equivalent parts, 1 is the molding, 2 is the metal part, 3 is the resin part, 6 is the elongated material, 7 is the terminal resin part, 8 is the core member, and 8d is the overhang. 9 is a cavity type, 10 is a core type, 12 is a cavity, 13 is a contact portion, 15 is a burr, and 16 is a constriction portion.

Claims (1)

[Claims] 1. A core member is brought into contact with the end portion of a long material cut to a predetermined length, and the core member is inserted into an injection mold, and the end portion and the core member are integrated by injection molding. In the method of forming a terminal resin part in a core member, a projecting part is formed in the core member so as to form a constriction part for the injection resin to flow into the cavity near the terminal part, and the injected resin is introduced into the cavity through the constriction part. 1. A method for manufacturing a molding, which comprises filling the molding with a resin to form a terminal resin part. 2. The method of manufacturing a molding according to claim 1, wherein the projecting portion is formed to project outward over the entire length of the outer surface of the core member in the width direction. 3. Claim 1 or 2, in which the projecting part is formed with a distance between it and the terminal part.
The method for manufacturing the molding described in Section 1. 4. The method of manufacturing a molding according to any one of claims 1 to 3, wherein the core member has a protrusion that fits into a space formed in the elongated material.