JP3356411B2 - Vacuum forming method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum molding method in which a thermoplastic plastic plate or sheet is heated and softened, and is closely attached to a molding die by vacuum suction from the molding die side. The present invention relates to a vacuum forming method in which an insert part having an undercut in a vacuum suction direction is integrally assembled (built-in) in a molded product during vacuum forming.

[0002]

2. Description of the Related Art In a conventional vacuum forming method of this kind, as shown in FIG. 5, an insert part 1 having a vertical wall portion 1a and a horizontal wall portion 1b crossing at a substantially right angle and having an undercut 1c in a vacuum suction direction is used. When set in the mold 2 and vacuum-suctioned through the suction hole 3, the thermoplastic plastic plate or sheet 5
However, the air flow in the undercut 1c cannot be vacuum-sucked due to the close contact with the middle part of the vertical wall portion 1a forming the undercut 1c in the insert part 1, and therefore, the insert part 1 The undercut portion 4a of the vacuum formed product 4 facing the undercut 1c portion does not have a shape along the undercut 1c of the insert part 1, but has a large radius, which impairs the commercial value of the product. There was a defect.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and has been made by using a simple method to form an undercut portion of a vacuum-formed product that is opposed to an undercut portion of an insert component. An object of the present invention is to provide a vacuum forming method capable of forming a shape along an undercut portion of an insert part.

[0004]

A vacuum forming method of the present invention for achieving the above object is a vacuum forming method in which an insert part having an undercut in a vacuum suction direction is integrally assembled into a molded product. In addition, a sheet material having air permeability is arranged in advance on a vertical wall portion forming an undercut in the insert part. At this time, it is preferable to use a nonwoven fabric, a woven fabric, or Japanese paper as the breathable sheet material.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the illustrated embodiment, and various variations are considered. Can be In the drawings, reference numeral 1 denotes an insert part, reference numeral 2 denotes a mold, reference numeral 3 denotes a suction hole, reference numeral 4 denotes a vacuum molded product, and reference numeral 5 denotes a thermoplastic plate or sheet, which is the same throughout the drawings. The constituent members are given the same reference numerals.

[0006] The insert part 1 is formed of a rigid material such as a metal plate into a substantially T-shape having, for example, an undercut 1c in which the horizontal wall portion 1b intersects at a substantially right angle at the top of the vertical wall portion 1a. Then, the mold 2 is set so as to have an undercut 1c at a predetermined position in the vacuum suction direction. The vertical wall portion 1a and the horizontal wall portion 1b
Need not be strictly vertical or horizontal.

A mold 2 having the same structure as that of the related art formed into a desired shape is used. An insert part 1 is set at a predetermined position, and a thermoplastic plastic plate or sheet heated and softened from above. 5 is formed, and the thermoplastic plate or sheet 3 is brought into close contact with the molding die 2 by vacuum suction through a large number of suction holes 3 formed in the molding die 2 in this state to perform vacuum molding. .

At this time, a sheet material 6 having air permeability is arranged in advance on the vertical wall portion 1a forming the undercut 1c in the insert part 1. As the sheet material 6 having air permeability, a nonwoven fabric, a woven fabric, or Japanese paper, which is appropriately formed in thickness, is used. As a nonwoven fabric,
Conventionally known ones can be used. Among them, needle-punched non-woven fabrics and woven fabrics having irregularities are not so preferable because they easily affect the surface finish of the vacuum formed product 4, and natural fibers cut to an appropriate length are not preferable.・ The use of spunbond non-woven fabrics formed by laminating chemical fibers, synthetic fibers, etc. without using a loom and bonding or entangled with each other by mechanical, chemical, or thermal methods to form a flat cloth. preferable.

When the air-permeable sheet material 6 is disposed on the vertical wall portion 1a of the insert part 1, it may be disposed only on a part of the vertical wall portion 1a as shown in the illustrated embodiment, or may be disposed on the vertical wall portion 1a. It may be arranged over the entire surface of the vertical wall portion 1a, but in either case, it is preferable to arrange the vertical wall portion 1a over almost the entire height. That is, even if the thermoplastic plastic plate or sheet 5 contacts the middle part of the vertical wall portion 1a of the insert part 1 in the vacuum forming process, the air remaining in the undercut 1c of the insert part 1 is sucked through the sheet material 6. The upper part of the sheet material 6 is inserted into the insert part 1 so that the
It is preferable that the vertical wall portion 1a is disposed over almost the entire height up to a position reaching the undercut 1c portion. Incidentally, in the illustrated embodiment, two sheet members 6 formed in a strip shape having a length substantially equal to the entire height of the vertical wall portion 1a.
Are disposed on the vertical wall portion 1a at appropriate intervals, and are arranged such that the upper side thereof reaches the lower surface of the horizontal wall portion 1b of the insert part 1.

Next, the vacuum forming method according to the present invention will be described in the order of steps. First, the vertical wall portion 1a of the insert part 1,
Specifically, a sheet material 6 having air permeability is previously attached to the vertical wall portion 1a on the side where the undercut 1c is formed with an adhesive 7 or the like, and this insert part 1 is attached. It is set at a predetermined position of the molding die 2 (see FIG. 2). Then, a heat-softened thermoplastic plastic plate or sheet 5 is put on the mold 2 including the insert part 1, and vacuum suction is performed through the many suction holes 3 formed in the mold 2 in this state ( (See FIG. 3). Then, the thermoplastic plastic plate or sheet 5 comes into close contact with the molding die 2 and is vacuum-formed into a desired shape, and the thermoplastic plastic plate or sheet 5a at the portion opposed to the vertical wall portion 1a of the insert component 1 is inserted. The air in the undercut 1c of the insert part 1 comes into contact with the middle part of the vertical wall part 1a and the air is sucked in vacuum through the air-permeable sheet material 6 disposed on the vertical wall part 1a of the insert part 1 ( (See FIG. 4). As a result, the thermoplastic plastic plate or sheet 5 is also in close contact with the outer peripheral surface of the insert part 1, and the undercut part 4a of the vacuum formed product 4 facing the undercut 1c part of the insert part 1 formed at a substantially right angle. Then, it is formed into a shape exactly following the shape of the undercut 1c portion of the insert part 1 (see FIG. 1).

[0011]

As described above, the vacuum forming method according to the present invention preliminarily arranges an air-permeable sheet material such as nonwoven fabric, woven fabric, or Japanese paper on the vertical wall portion of the insert part where the undercut is formed. The air in the undercut portion of the insert part can be reliably sucked in vacuum through the air-permeable sheet material, so that the vacuum molded product facing the undercut part of the insert part can be used. The undercut portion can be formed into a shape along the shape of the undercut portion of the insert part.

In addition, the vacuum forming can be achieved by a simple method in which an air-permeable sheet material such as nonwoven fabric or Japanese paper is simply provided in advance on the vertical wall portion of the insert part where the undercut is formed. be able to.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an embodiment of a vacuum forming method according to the present invention, showing a state of a final step of vacuum forming.

FIG. 2 is a perspective view showing a step of setting an insert part in a molding die in the vacuum molding method according to the present invention.

FIG. 3 is a cross-sectional view showing a step of setting a thermoplastic plastic plate or sheet on a mold including the insert part and performing vacuum suction.

FIG. 4 is a sectional view showing a step in which the vacuum suction has progressed.

FIG. 5 is a cross-sectional view illustrating a conventional example.

[Explanation of symbols]

1: Insert component 1a: Vertical wall portion 1b: Horizontal wall portion 1c: Undercut portion 2: Molding die 3: Suction hole of molding die 4: Vacuum molded product 5: Thermoplastic plate or sheet 6: Air-permeable sheet Material 7: Adhesive

Continuation of front page (56) References JP-A-6-55626 (JP, A) JP-A-2-57320 (JP, A) JP-A-57-207063 (JP, A) JP-A-57-32940 (JP) , A) Shokai Sho 55-66142 (JP, U) Shokai Hei 4-83735 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) B29C 63/02 B29C 51/10

Claims (2)

(57) [Claims] 1. A vacuum forming method in which an insert part having an undercut in a vacuum suction direction is integrally assembled into a molded article, wherein the insert part has a vertical wall portion forming an undercut. A vacuum forming method, wherein a sheet material having air permeability is provided in advance. 2. The vacuum forming method according to claim 1, wherein the air-permeable sheet material is made of a nonwoven fabric, a woven fabric, or Japanese paper.