JPH01235626A - Vacuum forming method - Google Patents

Abstract

PURPOSE:To make the terminal processing unnecessary by a method wherein thick sheeting material, which is in close contact onto core material, is pulled in an annular groove, which is provided on a vacuum forming mold, so as to be stretched so much in order to reduce its thickness and at the same roundly cover the edge of the core material. CONSTITUTION:A sheet 14 is in close contact onto the surface of core material 11 by vacuum forming and integrally joined to the core material by means of adhesive 13. In this case, the skirt region of the sheet 14 is pulled in a groove along the curved concave surface of the groove 12 so as to be so stretched more than the other region that the initial length (a) is stretched to the length (b) indicated with the dotted line due to the suction in the groove under vacuum. As a result, the thick sheet 14 in the skirt region becomes gradually thinner due to the strong stretching over the skirt region so as to be finished in a rounded shape along the edge face of the core material 11. Next, when a laminated composite formed body is intended to be taken out of a mold 18, the body can be easily demolded even under the condition that the form of the groove 12 is undercut-like one, since the sheet 14 originally has flexible characteristic.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to vacuum forming, and in particular, the invention relates to vacuum forming, and in particular to forming automobiles such as instrument panels and door consoles by closely bonding thick sheet materials onto core materials by vacuum forming. This invention relates to a technique for obtaining a soft-feeling composite molded product suitable for use in the interior of automobiles.

[Conventional technology]

As shown in FIG. 4, the conventional molding method in this field involves first forming a hollow core made of a hard material such as polypropylene resin or ABS resin into a predetermined shape by appropriate means such as injection molding. The material 1 is placed on a vacuum forming mold 2 having the same shape as this, and after applying adhesive 3 to the surface, a thick sheet 4 made of foamed resin such as polyethylene is placed on top of this, and the mold is placed. A vacuum is applied to the surface through the air conduction channel inside the core material 2, and the thick sheet 4 is brought into close contact with the surface of the core material 1 through holes (not shown) provided in the core material 1 to give it a predetermined shape. With,
Join both. The thus obtained composite molded body 5 is cut out along the core material 1 at the hem of the sheet 4 by a cutting means such as a knife 6 on the mold 2, and then removed from the mold 2, as shown in FIG. Then, the sharp cut surface is heated and corrected using a welder 7 or the like to give an appropriate roundness and become a finished product.

[Problem to be solved by the invention]

However, according to this prior art, it is difficult to control the knife when cutting the joined thick sheets, and the contact angle tends to be off and the cutting line tends to be distorted. Furthermore, since the surface of the product is melted when the end of a thick sheet is modified by welding, it is necessary to apply a skin to this area after modification.

In order to avoid this kind of trouble, it may be possible to form the end area of the core material to which the thick sheet is pasted with a roundness in advance, but in this case, the mold used to form the core material The structure becomes complicated and the number of man-hours increases.

An object of the present invention is to solve the problems of the prior art and provide a method for obtaining a composite molded body covered with a thick sheet that does not require end treatment during vacuum forming.

[Means for solving the problem] The purpose of this is to cover a vacuum forming mold with a core material that has been formed into a predetermined shape, and then to stack a thick sheet material on top of the core material and simultaneously vacuum form the core material. In a method of manufacturing a composite molded article by pasting it on a surface, an annular groove surrounding the acid mold is provided in a region of the mold corresponding to an edge of the core material, and the sheet is laminated on the core material during vacuum forming. By suctioning the hem region of the material into the groove, a greater stretch is applied to the hem region of the sheet material than in other regions, thereby reducing the wall thickness in the hem region, thereby reducing the resulting composite molding. This is achieved by a molding method characterized by rounding the ends of the body.

[For production]

During vacuum forming, the thick sheet material that is brought into close contact with the core material is drawn into an annular groove provided in the vacuum mold with its skirt region extending beyond the edge of the core material. Due to the curvature of the groove surface, the sheet material is stretched more than would normally be the case in this region, reducing its thickness and rounding it to cover the edges of the core material.

〔Example〕

Hereinafter, the present invention will be explained in more detail based on preferred embodiments shown in the drawings.

1 and 2 are schematic sectional views showing the procedure of the present invention. As shown in the figure, vacuum forming mold 1 used in the present invention
0 differs from the conventional type described above in that an annular groove 12 having an appropriate depth is provided immediately below the edge of the core material 11 placed over the mold.

First, as shown in FIG. 1, a core material 11 previously formed into a predetermined shape by an appropriate means is placed over the mold 10.

Then, adhesive 13 is applied to the entire surface. As mentioned above, the edge of the core material 11 ends in the area directly above the groove 12 provided in the mold. A thick sheet 14 which has been heated and softened is laminated on top of this, and its hem region hangs down beyond the edge of the core material.

In this state, vacuum forming is performed in a known manner.

Then, the sheet 14 comes into close contact with the surface of the core material 11, as shown in FIG. 2, and the two are integrally joined by the adhesive 13. At this time, the hem region of the sheet 14 is drawn into the groove along the curved concave surface of the groove 12 and covers the end surface of the core material 11. It will be apparent, for example, with reference to FIG. 3, that in the vicinity of the groove the sheet 14 is stretched to a greater extent than in other regions. That is, the initial length a shown by the solid line is extended to the length b shown by the dotted line by vacuum suction into the groove. As a result, the thick sheet 14 gradually becomes thinner due to strong stretching in its hem region, and is finished into a rounded shape along the end surface of the core material 11.

Next, the laminated composite molded body 15 is removed from the mold 10, but since the sheet 14 inherently has flexible properties, it can be easily removed from the mold even if it has an undercut groove 12 shape. Then, as shown in FIG. 2, a knife 16 is applied along the edge of the resulting composite compact 15, and the excess sheet 14 is cut off, yielding the finished product.

〔Effect of the invention〕

According to the present invention, an annular groove is provided in the mold, and the hem of the thick inner sheet is drawn into the groove and strongly stretched, so that special processing such as secondary processing using a welder as in the conventional method is not possible. A rounded edge can be obtained only by the forming operation without the need for a correction process.

[Brief explanation of the drawing]

Figures 1 and 2 are schematic cross-sectional views showing the process of the present invention, Figure 3 is a partially enlarged cross-sectional view showing the effect of the grooves, and Figures 4 and 5 are schematic views showing the conventional vacuum forming process. FIG. 10 type, 11 core material, 12 groove,
13 Adhesive, 14 Thick sheet, 15
Composite molding, 16 knives. Marriage 4

Claims (1)

[Claims] (1) A core material pre-formed into a predetermined shape is placed over a vacuum forming mold, a thick sheet material is laminated on top of the core material, and a composite molded article is manufactured by attaching it to the surface of the core material at the same time as vacuum forming. In the method, an annular groove surrounding the mold is provided in a region of the mold corresponding to an edge of the core material, and a hem region of the sheet material laminated on the core material is sucked into the groove during vacuum forming. By doing so, the hem region of the sheet material is stretched to a greater extent than other regions, thereby reducing the thickness of the hem region and rounding the ends of the resulting composite molded product. Characteristic molding method.