JPH01127314A - Vacuum molding method for model car - Google Patents

Abstract

PURPOSE:To enable mold release easily even if undercut is deep, by constituting the title molding method so that extension of a parting line is held within a wheel arch by making a right above part of the upper edge of a front number the said parting line, and the lower part of the parting line is made a split mold movable backward of a model car. CONSTITUTION:A mold is made a split mold 5 by making the top of extension lines 1a, 1b of the sides of a bumper a parting line and mold release of a front part is made easy by making the lower part of the parting line slidable backward on a surface plate 6, in a model car. At the same time, when the front is released, a rear part also can be released easily. With this construction, when an under cut part is deep in a vacuum molding method of the model car, this can be avoided. The title method can be used for also a product where a horizontal line of a molded product to be generated through the split mold does not exert much effect upon an appearance of a molded product like the extension line of the side part of the front bumper of the model car and vacuum molding of the model car A resembling extremely to the real thing in structure can be performed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a vacuum forming method for plastic car models, etc., and particularly to a vacuum forming method for an undercut portion that occurs in a part of a front bumper.

(Prior art) In the vacuum forming method, as shown in Fig. 2 (a), (b) e (c), a thermoplastic sheet a is fixed on a mold, and the sheet is softened by heating with a heater C and then molded in a vacuum. This method is suitable for molding large products and thin containers because the molding machines and molds are inexpensive. Figure 2 shows an example of the drape method, in which a convex mold b is used to push up the heated and softened sheet a to perform preliminary stretching (Figure 2b), and then it is sucked into the mold using a vacuum. (Second
Figure C) Method.

Usually hard vinyl chloride resin, high impact polystyrene, A
Plastics such as BS resin are used for signboards, electric refrigerator inner boxes, and ice cream cups.

It is used to mold containers for eggs and tofu.

Now, in a mold without an undercut portion, such as the mold shown in FIG. 2, it is easy to release the molded product.

However, when taking the product out of the mold, if there is a protrusion or a recessed part in the opening/closing direction of the mold, the product cannot be taken out from the mold.

However, even if there is an undercut, if the constituent material is highly elastic, the amount of undercut is small, and the shape is easy to release, the product can be forcibly released from the mold (forced removal). can be done.

However, when vacuum forming model cars, etc.
If a part of the front bumper is made to closely resemble the real thing, this part will have an undercut structure that is difficult to release from the mold.

A slide core method is known to facilitate the release of undercut parts. However, diagonal linear protrusions always occur on the sliding surface of the slide core.

When it comes to model cars, etc., lines that do not exist in the real thing appear and become a fatal problem.

For this reason, although we would like to make it resemble the real thing, we had no choice but to sacrifice this resemblance to the real thing and modify this part to make it easier to cut out.

(Problems to be Solved by the Invention) In view of the problems of the prior art, when vacuum forming a model car, even structures with noticeable undercuts, such as a part of the front bumper, can be vacuum formed to almost resemble the real thing. The present invention aims to provide such a vacuum forming method.

(Solving Means by the Invention) In the vacuum forming method for model cars using vacuum forming, the cut line is set just above the upper edge of the front bumper.

The extension of the parting line fits within the wheel arch,
The lower part of the cutting line is made into a split mold that can be moved to the rear of the model car, making it easy to release the mold even if the undercut is tight.

(Example) The vacuum forming of model cars will be explained below.

In Fig. 1, A is a molded product of a model car formed by vacuum forming. 1 is the front bumper, which extends forward. 2 is the rear bumper, which also extends to the rear. 3 is a front arch, and 4 is a rear arch. These parts are vacuum formed, released from the mold, and then cut with a cutter. la, 2a
is a lateral extension line of the upper edges of the front bumper 1 and the rear bumper 2.

These extension lines terminate at their respective rear end 1b or front end 2b in the respective arch 3 or 4.

Now, in such a model car, the side extension lines 1a and lb of the bumper do not appear as clearly as shown on the left in reality, but in the present invention, among these extension lines, the upper edge of the front bumper 1 is Even if the extension line 1a appears to some extent, it is not a problem in terms of the appearance of the product as an extension of the front bumper, so the upper part of this line is used as a cutting line and the mold for molding is split into a split mold. and,
It is designed to be able to slide toward the rear of the model car below this approximately horizontal parting line (see the two-dot chain line in Figure 1).
.

A split mold 5 is formed using the upper surface of the side extension line of the front bumper as a cutting line, and the lower part of the cutting line is made slidable rearward on a surface plate 6, making it easy to release the front part, but at the same time, the rear part is also molded. If the front part is released from the mold, it can also be released easily.

In the above explanation, the front part of the model car is made into a split type, but it goes without saying that the rear part may also be made into a split type.

The present invention was developed with the primary purpose of avoiding tight undercuts in the vacuum forming method for model cars. This can be used in products where horizontal lines on the molded product caused by this do not significantly affect the appearance of the molded product.

(Effects) The upper surface of the side extension line of the front bumper is used as a parting line, and the extension of the parting line is made to fit within the wheel arch, and the lower part of the front of the model car is made into a split mold, which allows it to slide rearward. When vacuum forming, a nearly horizontal line appears on the front trim of the model car, but since it is an extension of the upper edge of the bumper, there is no problem with the design at all, and it is possible to create a model car with a structure that is very similar to the real thing. Can be vacuum formed.

[Brief explanation of the drawing]

FIG. 1 is a side view of a vacuum-formed product according to the present invention. FIG. 2 is an explanatory diagram of the vacuum forming method. - In the figure; A Model car molded product 1 Front bumper la Side extension line lb Side extension line 2 Rear bumper 2a, 2b Side extension line 3 Front arch 4 Rear arch 5 Split mold 6 Above the surface plate

Claims (1)

[Claims] In the vacuum forming method for model cars, the parting line is set just above the upper edge of the front bumper, the extension of the parting line is placed within the wheel arch, and the lower part of the parting line is moved to the rear of the model car. A vacuum forming method for model cars characterized by a split mold that facilitates mold release at undercut parts.