JP2530166B2 - Molding manufacturing method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for manufacturing a molding used for a side molding for an automobile or the like.

(Prior Art) Molding is used for protecting a vehicle body or improving decorativeness, such as a side molding for an automobile. On the other hand, an extruded product of a long plastic is suitable for constituting the molding,
It is often used by cutting it to a predetermined size. However, the cut surface of the extruded product is not only sharp and dangerous, but also not very beautiful.

Therefore, in order to add a radius (R: curved surface) to the cut surface of the conventional extruded product by heat processing or to make the cut surface beautiful, the end 10 of the extruded product is used for a predetermined terminal cap as shown in FIG. The device is installed in a mold 14 having a cavity, and the end cap 16 shown in FIG. 5 is injection-molded, and at the same time, it is attached to the cut end portion 10 of the extruded product.

However, the molding is provided with a groove 18 in the longitudinal direction of the surface from the viewpoint of improving decorativeness, or a band different in color from the molding body is attached to the groove 18, and the cross section of the extruded product is It has various shapes.
Therefore, the inner surface of the cavity 12 for the terminal cap is formed into a curved surface although it is a curved surface.

(Problems to be Solved by the Invention) Although the molten resin injected into the terminal cap cavity 12 by injection is filled along the cavity surface, the molten resin filled in the initial stage of filling loses heat to the mold surface and the like. It cures early, and due to the temperature difference with the molten resin that is filled subsequently,
Defects such as flow marks and uneven luster often appear on the surface of the molded terminal cap 16. In addition, since the inner surface of the cavity for the terminal cap is formed of a complicated uneven surface, the flow mark or the like forms a complicated surface pattern, and the appearance of the cap may be greatly impaired. Further, in the molding obtained by the above method, the terminal cap is welded only to the cut surface of the extruded product, and thus the fixing strength of the terminal cap may be poor.

Therefore, the present invention is intended to solve the problems of flow marks, gloss unevenness, or insufficient fixing strength of the terminal cap on the outer surface of the terminal cap, which have occurred in the prior art.

(Means for Solving the Problem) The present invention is a method of manufacturing a molding in which a terminal cap is integrally formed by injection molding at a cut end of an extruded product, and the extruded product is previously cut on the back side of the extruded product. A groove is formed on the end face of the end, and at least the end of the extruded product is placed in a mold having a predetermined cap cavity, and the molten resin is filled from the end of the end cap cavity. It is characterized in that the resin filled in is pressed into the concave groove of the extrusion molded product.

(Function) The molten resin filled in the cavity for the terminal cap is
After flowing along the cavity surface and reaching the cut end surface of the extruded product, it flows along the end surface to the back surface side of the extruded product. Then, the front end of the molten resin is pushed by the molten resin to be filled subsequently, and is press-fitted so as to flow into the groove on the back surface of the extrusion molded product.

That is, the resin at the initial stage of filling, which contacts the mold surface and hardens early, is press-fitted so as to be accommodated in the groove on the back surface of the extrusion molded product, and the remaining resin having a substantially uniform temperature fills the cavity for the terminal cap. The occurrence of flow marks, uneven gloss, etc. on the surface of the molded cap is extremely reduced.

Also, since the molded end cap is partly connected to the resin that has flowed into the groove on the back of the extruded product, not only the cut end surface of the extruded product but also the recessed groove on the back of the extruded product can be extruded. The product is welded and bonded, and the bond strength is extremely high.

(Example) This invention is demonstrated based on an Example below.

FIG. 1 is a sectional view of a main part of a mold and an extrusion-molded product when manufacturing a molding according to the present invention, FIG. 2 is a perspective view of an end of the extrusion-molded product before a cap is attached, and FIG. It is an end perspective view of the molded molding.

The mold shown is used when the end caps 22 are attached to both ends of the extruded product 20, and the movable mold 24 and the runner plate are used.
26, fixed type 28. The movable mold 24 has a cavity 30 for accommodating the extruded product 20 and terminal cap cavities 32, 32 formed at both ends thereof. Also, on the runner plate 26,
A runner 34 and molten resin injection ports 36, 36 are formed. The molten resin injection ports 36, 36 are the cavity 32, 32 for the terminal cap.
Is located at the end on the back side of the
34 and the cavity 32 for caps are connected. on the other hand,
The fixed mold 28 is formed with a sprue 38 following the runner 34.

As the extruded product 20, an extruded product of a foamed or non-foamed plastic such as a soft vinyl chloride resin cut into a predetermined size is used. Pre-grooved on the back side in the longitudinal direction
40 is provided, and the concave groove 40 is open to the end surface of the cutting end. The groove 40 is preferably formed in advance when the extrusion-molded product 20 is molded, and the groove width of the groove 40 opened on the back surface of the extrusion-molded product is smaller than the groove width of the inner bottom surface of the groove. It is preferable to use grooves. The cutting of the extrusion-molded product 20 is preferably performed so that the cut end surfaces 20a, 20a thereof become a surface inclined from the front surface side to the back surface side, and particularly, the longitudinal length of the back surface side of the extrusion molded product is set to the front surface side. It is preferable that the inclined surface is shorter than the length in the longitudinal direction.

In this way, the extrusion molded article 20 formed in advance into a predetermined shape is installed in the extrusion molded article accommodating cavity 30 of the mold, and the sprue 38 by injection molding and the molten resin injection port 36 via the runner 34.
The molten resin is filled into the terminal cap cavities 32, 32 from 36. The resin to be filled is preferably the same type and the same color as the resin constituting most of the extrusion molded article 20, but different types,
It may be a different color. When the extrusion-molded product 20 is long, first, one end of the extrusion-molded product 20 is used as a mold to form a terminal cap at the end portion, and then similarly, a terminal cap is formed at the other end of the extrusion-molded product. May be formed.

The molten resin filled in the terminal cap cavities 32, 32 first flows along the cavity surface. When the end faces 20a, 20a of the extruded product are reached, this end face 20a
Along the a and 20a, the extruded product 20 flows to the back surface side, and the tip resin flows into the recessed groove 40 while being pushed by the subsequent molten resin. At this time, if the end surfaces 20a, 20a are inclined surfaces whose longitudinal length on the back surface side of the extruded product is shorter than that on the front surface side, as described above, the inflow into the concave groove is performed very smoothly.

Therefore, the molten resin at the initial stage of filling, which is filled in the cap cavities 32, 32 and cooled by the cavity surface and hardened early, is accommodated in the groove 40, and the cap cavities 32, 32 are filled with the subsequent resin, The end caps 22, 22 that cover the end faces 20a, 20a of the extruded product 20 are integrally formed. As a result, the terminal caps 22, 22 are made of a resin having a uniform temperature excluding the hardened portion at the early stage of the filling, so that there is no flow mark or uneven gloss.

Further, the terminal caps 22, 22 are cut end faces 20 of the extruded product 20.
Not only a and 20a, but also the recessed groove 40 portion is bonded to the extruded product 20 by welding or the like, so that the fixing strength becomes extremely high. Further, in the case where the concave groove 40 is a dovetail groove, in addition to the above, a structurally engaging structure is provided, so that the fixing strength is further increased. In addition, the end face 20 of the extruded product
Since a and 20a are inclined surfaces, the welding area between the extruded product and the terminal cap on the end surface becomes wider,
High fixing strength can be obtained also by this.

(Effects of the Invention) As described above, the present invention is characterized in that when an end portion of an extrusion-molded article having a concave groove on the back surface is installed in a mold and a cavity for a terminal cap is filled with molten resin, Since the resin that has hardened early is pressed into the concave groove on the back surface of the extruded product, the molded cap is hardly affected by the resin whose temperature dropped at the initial stage of filling, and flow marks and uneven gloss on the surface of the terminal cap. It was possible to prevent the occurrence of such.

Also, since the molded end cap is bonded to the extruded product by welding etc. not only in the cut end face of the extruded product but also in the concave groove on the back surface, the end cap is attached to the cut end face of the extruded product with extremely strong adhesion. It is something that can be worn. In addition, since the back surface side of the extrusion molded product having the concave groove serves as the mounting surface of the molding, it is possible to eliminate the possibility of the terminal cap falling off.

[Brief description of drawings]

FIG. 1 is a partially omitted cross-sectional view showing a main part of a mold and an extrusion molded product at the time of manufacturing a molding in one embodiment of the present invention,
FIG. 2 is a perspective view of an end portion of an extruded product before a cap is attached, FIG. 3 is a perspective view of an end portion of a molding obtained by the present invention as seen from the back side, and FIG. FIG. 5 is a cross-sectional view of a main part of the extrusion molded product, and FIG. 5 is a perspective view of a molding end obtained by a conventional method. Explanation of symbols 20 …… Extruded product, 20a …… Cut end face of extruded product 22 …… End cap, 24 …… Movable mold 26 …… Runner plate, 28 …… Fixed mold 30 …… Extruded product accommodating cavity 32 ...... Terminal cap cavity 34 …… Runner, 36 …… Injection port 38 …… Sprue, 40 …… Groove

Claims (2)

(57) [Claims] 1. A method of manufacturing a molding in which a terminal cap is integrally formed by injection molding on a cut end of an extruded product, and a recessed groove that opens to an end face of the extruded product is provided on the back surface side of the extruded product in advance. At least the end of the extruded product is installed in the mold, and the molten resin is filled into the cavity from the injection port provided at the end of the cavity for the terminal cap, and the resin filled at the initial stage of filling the extruded product A method of manufacturing a molding, characterized by press-fitting into the groove. 2. The end surface of the cut end portion of the extruded product is an inclined surface having a longitudinal length on the back surface side of the extruded product shorter than that on the front surface side. The method for manufacturing a molding according to.