JPH0788888A - Molding method for molding end - Google Patents

Abstract

PURPOSE:To provide a method for molding a molding end in which introduction of resin to a rear surface of a core material is effectively prevented and an end of such a molding can be accurately formed with excellent external appearance. CONSTITUTION:A method for molding a molding end comprises the steps of arranging a core material 31 protruding from an end of a molding body 30 on an inner surface of an end molding cavity 13 of an injection mold 10 having the cavity 13 through a gate 14, and a casting molten resin in a residual space of the cavity to cover the surface of the core material 31 with the resin, wherein a resin flow control protrusion 20 for guiding flow of the cast resin to a surface side of the core material 31 is stood on the inner surface of the cavity forward of the gate. Further, a cutout recess 21 is formed at an end of the core material 31, engaged with the protrusion 20 to lock the end of the core material to the inner surface of the cavity, and the molten resin is cast.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a molding terminal molding method in which a resin for core coating is injection-molded on the surface of a core protruding from the end of a molding body.

[0002]

2. Description of the Related Art A car body or the like is equipped with a molding for decoration or for preventing damage to the car body.
In order to improve the efficiency of the molding operation, the molding is often used by continuously extruding the molding into a predetermined cross-sectional shape and cutting the extrusion-molded product into a predetermined size according to the application.

However, in a molding in which the extruded product is cut, the continuity of the molding is suddenly interrupted at the cut surface,
There is a defect that it is inferior in decorativeness. Further, depending on the purpose of use of the mall, a material or shape different from that of the mall body may be required for the mall terminal. Therefore, as shown in FIG. 5, a core material 41 is projected from the end of the molding body 40 formed by extrusion molding by adhesion or the like, and the core material 41 together with the molding body end portion is used for the cavity 5 of the injection molding die 50.
1, the molten resin P is injected from the gate 52 into the cavity 51, the surface of the core material 41 is coated with the resin in a predetermined shape, and the molding terminal is integrally injection-molded. .

The gate 52 has a problem of preventing a mark of the gate from remaining on the design surface of the molding terminal after molding the molding terminal and impairing the appearance of the molding, or generating a flow mark or a weld line on the design surface of the product. In order to prevent it, it is usually provided along the inner surface of the cavity in which the core material 41 is arranged.

However, in this method, there is a possibility that the molten resin P injected from the gate 52 into the cavity 51 may go around to the back surface (lower side in the figure) of the core material 41. Therefore, the resin on the surface side of the core material 41 may be insufficient, and a defective product such as a poor design surface of the molding terminal may occur. Even when the molten resin P does not go around to the back surface of the core material 41, the molten resin P injected from the gate
May flow once along the side surface of the core material 41 and then merge toward the surface side of the core material 41. In that case, a flow mark resulting from the merge of the resin on the design surface of the molding terminal,
May cause weld lines.

In order to prevent the molten resin P from flowing around the back surface of the core material 41, it is conceivable to provide the gate 52 on the molding terminal design surface side (core material surface side) of the cavity 51, but as described above. Because it causes a problem of product appearance,
It was not feasible.

[0007]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above problems, and reliably prevents the resin from flowing into the back surface of the core material to form a terminal of such a molding having a good appearance. It is intended to provide a molding method of a molding terminal that can be performed.

[0008]

[Means for Solving the Problems] That is, this invention is
The core material protruding from the end of the molding body is arranged on the inner surface of the cavity of the injection molding die having the terminal molding cavity leading to the gate, and the molten resin is injected into the residual space in the cavity to form the resin on the surface of the core material. In the molding method of the molding terminal to be covered with, a resin flow regulating projection for guiding the flow of the injected resin to the surface side of the core material is provided on the inner surface of the cavity in front of the gate, and the tip of the core material is cut. Molding of a molding terminal characterized in that a notched concave portion is formed, the notched concave portion is engaged with the resin flow regulating projection, the end of the core material is locked to the inner surface of the cavity, and the molten resin is injected. According to the method.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 is a sectional view showing an embodiment of the method of the present invention,
2 is a plan view showing the lower mold, FIG. 3 is a perspective view showing an example of the core material used in the method of the present invention, and FIG. 4 is a plan view of the lower mold showing another example of the present invention.

According to the molding method of the present invention, the core material 31 protruding from the end of the molding body 30 is placed in the cavity of the injection molding die 10 and the molten resin is injected into the remaining space of the cavity to form the core. The surface of the material 31 is coated with a resin to integrally form a molding terminal.

As shown in FIGS. 1 and 2, the injection mold 10 used in the method of the present invention comprises a fixed mold 11 and a movable mold 12, and has a terminal molding cavity 13. Reference numeral 14 is a gate, and 15 is a runner. The terminal molding cavity 13 is formed in a shape corresponding to the molding terminal to be molded, and one end thereof communicates with the gate 14 and the other end communicates with the molding body end portion storage portion 16. The core material 31 is
This end molding cavity 1 together with the end of the molding body 30
3 is arranged on the inner surface.

Now, the molding body 30 and the core material 31 will be described. The molding main body 30 is made of various materials and structures, such as resin extruded into a predetermined cross-sectional shape, or a metallic main body whose surface is covered with a resin film as in this embodiment. Become. The core material 31 is made of a resin injection molded product, a metal extrusion molded product, a press molded product, or the like. The core material 31
Is joined to the end of the molding body 30 by an appropriate method such as thermal crimping or adhesion. In this example, as shown in FIG. 1, a protrusion 32 is provided on the back surface of the resin core material 31, and the protrusion 32 is fitted into a hole 33 provided at a predetermined position of the end of the molding body 30 and fixed by thermal caulking. is doing.

On the inner surface of the cavity in which the core material 31 of the fixed mold 11 is arranged, a resin flow regulating projection 20 is provided upright in front of the gate 14. The resin flow restricting projection 20 is formed of a pin member having a circular cross section, and is provided at the position where the tip of the core member 31 reaches the inner surface of the cavity 13.

The resin flow restricting projection 20 is provided on the gate 1
In order to efficiently guide the flow of the molten resin injected from No. 4 to the surface of the core material 31 (the molding terminal design surface side), and to engage with the core material 31 to be described later to lock the cavity inner surface. It is preferable that the tip end surface 22 and the core material side outer peripheral surface 23 are constituted by inclined surfaces that are inclined toward the core material 31 side as shown in the figure. When the outer peripheral surface 23 is an inclined surface, the inclined surface can press the core material 31 against the inner surface of the cavity. Therefore, when the molten resin is injected into the cavity, the core material 31 is more reliably pressure-bonded to the inner surface of the cavity. it can. In order to effectively lock the core material 31 and efficiently guide the molten resin to the surface side of the core material 31, the height of the resin flow regulating projection 20 is the same as or slightly higher than that of the core material tip 34. It is preferably formed. In addition, it is preferable that the diameter of the resin flow restricting protrusion 20 is formed larger than the width of the gate 14. This prevents the injected molten resin from directly contacting the core material 31, and prevents the molten resin from flowing into the back side of the core material 31.

On the other hand, as shown in FIG. 3, the core material 3
A cutout concave portion 21 is formed at the tip 34 of the No. 1.
The notch concave portion 21 is for engaging with the resin flow regulating projection 20 when the core material 31 is arranged in the cavity, and is formed in an arc shape into which the resin flow regulating projection 20 is fitted. Has been done.

According to this structure, the molten resin injected from the gate 14 into the cavity 13 does not directly hit the core material 31, but the resin flow restricting projections 20 cause the flow of the molten resin on the surface of the core material 31 (mold terminal design). It is quickly guided in the (plane) direction. Further, the molten resin that has flowed to the surface side of the core material 31 presses the core material 31 from the surface side to the inner surface of the cavity by the resin pressure and press-bonds it to the inner surface of the cavity.
It is possible to reliably prevent the resin from wrapping around the back surface of the core material. The molten resin is used as the core material 31 and the molding body 30.
The end surface is covered to form a molding terminal. The cavity 13 may be configured so that the molten resin covers only the surface of the core material 31.

FIG. 4 shows another example of the present invention. In the figure, reference numeral 35 is an injection molding die, 36 is a terminal molding cavity, 37 is a resin flow regulating projection, 38 is a gate, 3
9 is a core material.

[0018]

As shown and described above, according to the molding method of the present invention, the molten resin injected into the cavity is promptly guided to the surface of the core material, and the induced resin pressure of the molten resin is increased. The core material is pressed against the inner surface of the cavity to prevent a gap from being formed between the back surface of the core material and the inner surface of the cavity. Therefore, it is possible to reliably prevent the molten resin from wrapping around to the back side of the core material, and to obtain a molding terminal having a good appearance without weld lines. Further, since the core material is correctly arranged in the cavity by engaging with the resin flow restricting projection, the thickness of the resin covering the core material becomes constant, and the molding terminal can be accurately molded.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an example of an injection molding die used in a molding method of a molding terminal of the present invention.

FIG. 2 is a plan view showing a lower die thereof.

FIG. 3 is a perspective view showing an example of a core material used in the method of the present invention.

FIG. 4 is a plan view of a lower mold showing another example of the present invention.

FIG. 5 is a cross-sectional view showing an example of a general molding terminal molding method.

[Explanation of symbols]

 10 Injection Mold 13 End Mold Cavity 20 Resin Flow Control Protrusion 21 Notch Recess 30 Mold Body 31 Core Material 34 Core Material Tip

Claims (1)

[Claims] 1. A core material projecting from an end of a molding body is arranged on an inner surface of the cavity of an injection molding die having a terminal molding cavity communicating with a gate, and a molten resin is injected into a residual space in the cavity to form the core. In a molding method of a molding terminal in which a surface of a core material is covered with a resin, a resin flow restricting projection for guiding a flow of injected resin to a surface side of the core material is erected on the inner surface of the cavity in front of the gate, A notched recess is formed at the tip of the resin, and the notched recess is engaged with the resin flow restricting projection to lock the end of the core material to the inner surface of the cavity to inject the molten resin. Molding method for molding terminals.