JPS6282012A - Manufacture of molding - Google Patents

Abstract

PURPOSE:To provide a manufacturing method of molding through which dimensional shrinkage is hard to occur even with heat history, by a method wherein the molding whose one end is made into a predetermined form is molded through an injection molding method, the other end is mounted within a split mold after annealing, and the other end of the molding is made into a predetermined form by injecting molten resin into a cavity. CONSTITUTION:Molding 10 is molded through injection into a long-sized molded article having a desired terminal form at least on one end 12, which is heated at a predetermined temperature by an infrared heating device 20, to which treatment what is called annealing is applied, and a molding distortion created at the time of injection molding is released. A split mold 30 possesses a cavity 32 accepting an end part 13 of the molding in succession to a cavity 31 restricting a terminal form and a desired external appearance is engraved on a cavity surface 33 for a terminal molded article. The end part 13 of the molding is fitted to a predetermined position by so constituting the same that the same is abutted against a protrusion 34. A heat sensitive adhesive agent may be kept applied to a clad surface 14 with the molded article of the other end part 13. The cavity 31 for the terminal molded article is filled with molten resin through a flow path 35 and a molded article 15 is clad to the other part 13 of the molding along with molding of the terminal molded article 15.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for manufacturing a plastic molding that is fixed to the side surface of an automobile body and used for protection and decoration of the automobile body.

(Prior art) In recent years, most of the moldings used on the sides of automobiles for protection and decoration are made of plastic, and among them, plastic extrusion molded products mainly made of soft vinyl chloride resin are frequently used. . This is because the extrusion molded product is a long product with a constant cross-section, and it is easy to form a design line in a substantially straight line from the front to the rear of the vehicle body.

However, since the side of the vehicle body has openings such as doors, the extrusion molded product must be cut to a predetermined length such as the width of the door, and the cut end may pose a danger to the human body or prevent the door from opening or closing. It is necessary to finish the ends with a streamlined shape or a predetermined stepped shape so as not to cause any obstruction to the surface.

Therefore, conventionally, as shown in FIG. 4, a molded product 12a having a desired end shape is integrally attached to both ends of an extrusion molded product 10a cut to a predetermined length by injection molding.

However, in this method, the injection molding process described above must be performed twice on both cut ends 11a, 11a of the molding body 10a made of an extrusion molded product, which has the disadvantage that the process becomes long. Since it is an extrusion molded product, it often has striations or the like in the longitudinal direction of its surface, and is different in appearance from the end molded product 12a to which it is attached, and tends to give a sense of discomfort.

Therefore, in recent years, attempts have been made to manufacture the molding itself into a shape having a predetermined shape at both ends by injection molding.

(Problems to be Solved by the Invention) However, even in this injection molding method, since the molding is generally long, molding distortion tends to accumulate in the longitudinal direction. This molding strain is gradually released by subsequent thermal history, such as temperature and temperature, and the molding generally contracts. This shrinkage causes the mounting position to shift after the molding is mounted on a vehicle body, etc., and is a factor that may lead to damage to the mounting in some cases. Therefore, it is possible to forcibly release the molding strain by annealing the molding after injection molding, but the molding strain is not necessarily uniform, and the length of the molding after annealing varies and it is not possible to always obtain a product with a predetermined length. has a number of difficulties. This means that even if both terminals are injection molded into a predetermined shape, the terminals will not be located in the predetermined locations and will not perform their protective functions as designed. .

Therefore, the present invention has been made in view of these points, and its object is to provide a novel method for manufacturing a molding that is less susceptible to dimensional shrinkage even when heated.

(Means for solving the problem) The gist is that a molding with at least one end in a predetermined shape is molded by injection molding, and after annealing the molding, the other end is in a predetermined end shape. The device is placed in a split mold having a cavity, and the other end of the molding is shaped into a predetermined shape by press-fitting molten resin into the cavity.

(Function) A molding formed by injection molding and having a predetermined end shape at one end has molding distortion, but by annealing, the distortion, especially in the longitudinal direction of the molding, is released and the dimensions are stabilized. Since a molded product having a predetermined end shape is molded and adhered to the other end of the stabilized molding, the dimensions from one end of the molding to the other end must be accurately designed and molded.

Furthermore, since both the molding body and the end molded product to be adhered are molded by injection molding, the design of the outer surface can be easily adapted. The present invention will be explained below based on examples.

(Example) FIG. 1 is a cross-sectional view of a main part of a long injection molding having a predetermined end shape at one end, the other end of which is installed in a split mold having a predetermined end cavity. The figure is a side view showing the molding in an annealed state prior to the device.

The molding 10 is first injection molded into an elongated molded article having the desired end shape on at least one end 12, as shown in FIG. This injection molding is carried out by a conventional method, and a plastic material suitable for molding, such as a soft vinyl chloride resin, is appropriately selected and used as the raw material. Note that the other end 13 is set to have an arbitrary shape.

Next, as shown in the figure, the injection molded molding 10 is heated to a predetermined temperature by an infrared heating means 20 and subjected to a so-called annealing treatment to release molding distortion caused by injection molding. The temperature and time of this annealing treatment are set depending on the type of plastic used and the size of the molding 10. For example, in the case of a molding made of soft vinyl chloride resin,
An annealing treatment of ~b20 minutes is suitable. In addition to the above-mentioned infrared rays, a heating furnace or the like may be used as the annealing treatment means 20. As a result of this annealing process, molding 10 is freed from molding strains and generally shrinks, reducing its overall length in the longitudinal direction.

Thereafter, a mark or the like is placed at a position a predetermined distance from one end to the other end of the desired end shape, and is used for positioning the device to the split mold 30 in the next step. Note that instead of this mark, or together with the mark, the other end 13 may be cut at a predetermined position using a press 25 or the like. If this is done, the molding adhesion of the terminal molded product in the next step will be constantly stabilized. In this case, the shape of the cut end product is preferably cut so that the adhesion area to the end molded product to be molded is large. In the embodiment shown in FIG. 1, an example is shown in which the other end 13 is cut into a slope.

Then, the other end portion 13 of the molding 10 prepared in this manner is placed in a split mold 30 having a cavity 31 for a desired end molded product.

The split mold 30 has a cavity 31 that defines the end shape and a cavity 32 that receives the molding end 13, and the cavity surface 33 for the end molded product has a desired appearance, for example, the same appearance as the molding body 10. A predetermined pattern or the like is engraved to be attached to the terminal molded product. 34 is a protrusion for positioning the end of the molding that is erected on the lower mold, and 35 is a flow path for press-fitting the molten resin into the cavity.

When molding the other end of the split mold 30 formed in this manner, the mark is aligned with a predetermined position, or the molding end 13 is placed in a predetermined position so as to come into contact with the protrusion 34. equipment. Note that the molded product adhering surface 14 of the other end 13 of the molding to be installed is
A heat-sensitive adhesive or the like may be applied in advance. and,
In this state, the cavity 31 for the end molded product is filled with molten resin from the flow path 35 to form the end molded product 15, and the molded product 15 is attached to the other end 13 of the molding. FIG. 3 shows ten examples of moldings formed in this manner. As shown in the figure, the molding 10 is fixed to the vehicle body or the like by means of fixing means such as double-sided adhesive tape 16 attached to the seat surface of the molding 10. Although the figure shows the terminal molded product 15 with a flat mounting surface, it is possible to insert a fixing means such as a clip (not shown) into the mold when molding the molding body and when attaching the terminal molded product. It goes without saying that the clip or the like may be formed so as to be partially buried therein, or the fixing means may be formed so as to stand up.

(Effects) As described above, the present invention molds a molding having a desired end shape on at least one end, and after annealing the molding, a predetermined end molded product is molded and attached to the other end, so that molding distortion is avoided. It is possible to efficiently manufacture moldings of a constant length with almost no . Furthermore, since the molding body and the end molded product are both injection molded, it is easy to match the appearance, and a molding with an excellent sense of unity can be provided.

[Brief explanation of drawings]

1 to 3 relate to one embodiment of the present invention, in which FIG. 1 shows an elongated injection molding having a predetermined end shape at one end, the other end of which is installed in a split mold having a predetermined end cavity. FIG. 2 is a side view showing the molding in an annealed state, FIG. 3 is a perspective view of the molding, and FIG. 4 is a sectional view of the main part of a conventional molding. IO molding, 20 Heating means, 30° split type Patent applicant: Inoue MCP Co., Ltd. Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A molding body having a predetermined end shape at least on one end is molded by injection molding, and after annealing the molding body, the other end is placed in a split mold having a cavity with a predetermined end shape, and the molding body is melted into the cavity. A method of manufacturing a molding, characterized in that the other end is shaped into a predetermined shape by press-fitting a resin.