JPH0649333B2 - Vacuum forming apparatus and method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention can secure the thickness of a molding material by reducing the elongation of a sheet-shaped molding material at a portion having a large elongation amount during vacuum molding. The present invention relates to a vacuum forming apparatus and method.

[Conventional technology]

Conventionally, when a sheet-shaped molding material made of a synthetic resin material is molded, vacuum molding is performed using a molding die as shown in FIG.

In FIG. 3, reference numeral 51 denotes a molding die, and this molding die 5
1, a cavity 52 is formed, and a pipe 53 leading to a vacuum device (not shown) is formed in the cavity 52. The cavity 5 is formed on the molding surface 51a of the molding die 51.
2. A plurality of vacuum suction holes (not shown) leading to No. 2 are formed.

When molding the molding material M, the molding material M is cut into a size larger than the size to be molded, and two or four sides of the molding material M are clamped by the clamp 54 as shown in FIG. 3 (a). While being held, it is placed between the molding die 51 and the heater 55 to heat it. Next, as shown in FIG. 3B, the heater 55 is retracted and the molding die 51 is raised. As a result, the molding material M covers the entire molding surface 51a of the molding die 51 as shown in FIG. 3 (c). In this state, as shown in FIG. 3 (d), the pipe 53 is evacuated, and the molding material M is attracted to the molding surface 51a side for molding.

[Problems to be solved by the invention]

However, when vacuum molding is performed using such a molding die, the molding material M of a portion having a large attracting amount in the vacuum molding due to the molding surface shape and the outer peripheral shape of the molding die 51 becomes thin and the molding material M In addition to the disappearance of the embossed pattern formed in the above, there is a problem that the molding material M in the portion that becomes thin during molding is broken.

Therefore, the present invention has been made in order to eliminate the above-mentioned problems, and the purpose thereof is to provide a cutting tool at the end of the molding die corresponding to the portion where the thickness of the molding material is desired to be secured, It is to prevent the molding material from extending and to prevent the disappearance of the embossed pattern and the breakage of the molding material by cutting the portion when it is stretched on the molding die.

[Means for solving problems]

That is, in the vacuum forming apparatus according to the present invention, a plurality of vacuum suction holes communicating with the cavity are formed on the forming surface of the forming die in which the cavity is formed, and the forming surface of this forming die is heated. A vacuum forming apparatus for stretching a sheet-like forming material and drawing a vacuum from the cavity, wherein the forming material is attached to the end of the forming die corresponding to the portion for ensuring the thickness of the forming material to be vacuum formed. Provided with a cutting tool that cuts a part of it when it is stretched on the molding die, and molding that is smoothly continuous and cut with the cutting tool from a position lower than the cutting edge of this cutting tool to a position near the molding surface. A seal portion is formed to maintain the sealing property by keeping the end portions of the material in contact with each other.

Further, the method of the present invention covers the molding surface of a molding die by covering the molding surface of a molding die with a sheet-shaped molding material to which tension is applied in the surface direction, and exhausting from a space defined by the molding die and the molding material. In the vacuum forming method in which the molding material is closely adhered to the molding surface, the molding material applied with tension in the surface direction is connected between the highest edge of the molding surface and the contact portion on the outer periphery of the molding die. The step of uniformly stretching, the step of cutting the molding material at the end of the molding die corresponding to the portion of the stretched molding material that is to be secured in thickness, and the tension including the cut portion. And a step of exhausting the formed molding material from a space defined by the molding die and the molding material while maintaining a sealing property between the molding material and the molding die.

[Action]

In the vacuum forming apparatus and the vacuum forming method, when forming a sheet-shaped forming material, the forming material is arranged in a clamped state above the forming surface of the forming die in which the cavity is formed, The molding material is uniformly heated by a heating means such as a heater. Next, the molding die is raised to cover the molding die with the molding material. Then, when the molding material is uniformly stretched between the highest edge of the molding surface of the molding die and the contact portion on the outer periphery of the molding die, the molding material is molded by the cutting tool provided with the end portion of the molding die. A part of the material is cut.

Then, at the same time that a part of the molding material is cut, vacuuming is performed from a plurality of vacuuming holes formed on the molding surface of the molding die to perform molding. At this time, the molding material is attracted and molded in a stretched state with tension applied to the molding surface side, and the molding material of the cut portion is not tensioned and tension is applied to the portion adjacent to the seal portion. Because of the action, the adjoining portion is brought into contact with the seal portion and slid on the seal portion to be attracted to the molding surface side for molding.

As a result, molding is performed in a state in which the portion where the thickness of the molding material is desired to be ensured is hardly expanded, so that molding can be performed without reducing the thickness of the molding material.

〔Example〕

An embodiment of the present invention will be described in detail below with reference to the drawings.

FIG. 1 is an enlarged perspective view of a part of a vacuum forming apparatus according to the present invention, and FIG. 2 is a schematic view illustrating a forming method by the vacuum forming apparatus according to the present invention.

In FIG. 1 and FIG. 2, reference numeral 1 is a molding die, and a convex molding portion 2 formed in substantially the same shape as the shape of the molded product is formed on the upper surface of the molding die 1. It is a molding surface of a molding material formed in a sheet shape from a resin material. A cavity 3 is formed inside the molding die 1, and a plurality of vacuum suction holes 4 communicating with the cavity 3 are formed in the vicinity of the corners of the molding section 2.

Further, a concave molding surface 5 for ensuring the thickness of the molding material M is formed in a part of the molding portion 2, and the molding surface 5 is formed.
A saw-tooth-shaped cutting tool 7 is provided on the end 6 of the molding die 1 corresponding to. The size of the cutting tool 7 is slightly larger than the width of the molding surface 5 in the lateral direction, and when the molding material M is stretched on the molding die 1, a part thereof is cut. ing.

Further, the upper surface of the molding die 1 is provided with the cutting tool 7, and a seal portion 8 having a cross section of a long triangle is formed inside the molding tool 1. The molding material cut by the cutting tool 7 comes into contact with the sealing section 8 to improve the sealing property. It has become so. The sealing portion 8 is formed so as to be higher on the side of the cutting tool 7 and inclined so as to be gradually lowered, and is flush with the upper surface of the molding die 1 in front of the molding surface 5. Further, the seal portion 8 is formed lower than the cutting tool 7 even at a high place, and its width is substantially the same as the width of the molding surface 5. Therefore, in this seal portion 8, the end portion of the molding material cut by the cutting tool 7 maintains the contact state to ensure the sealing property.

Further, a pipe 9 is connected to the bottom surface of the molding die 1,
One end thereof is open to the hollow portion 3 of the molding die 1, and the other end is connected to a vacuum device (not shown). Further, an elevator (not shown) is provided at the bottom of the mold 1.
The molding die 1 is moved up and down during molding.

In the vacuum forming apparatus configured as described above, when the sheet-shaped forming material M is formed from the synthetic resin material, as shown in FIG. Molding tool 1 with four sides held by the clamp tool 10
It is set on the molding part 2 of. Next, the heater 11 is arranged above the molding material M and the molding material M is heated uniformly. Then, when the molding material M is heated uniformly, the heater 11 is retracted.

Subsequently, as shown in FIG. 2B, the molding die 1 is raised by an elevator to cover the molding die 1 with the molding material M. When the molding material M is evenly stretched between the highest edge of the molding portion of the molding die 1 and the contact portion on the outer periphery of the molding die 1, the molding material M is provided at the end portion of the molding die 1. A part of the molding material M is cut by the cutting tool 7 present.

Then, at the same time that a part of the molding material M is cut, the vacuum device is operated as shown in FIG. 2 (C), and a plurality of vacuum drawing holes formed in the molding part 2 of the molding die 1. 4 is evacuated and molded.

At that time, the molding material M is attracted and molded in a state where tension is applied to the molding portion 2 side and the molding material M is stretched, and the cutting tool 7
Since the molding material M at the portion cut by is free, the molding material M is slid on the sealing portion 8 in a state where no tension is applied and is attracted to the molding surface 5 side for molding.

As a result, molding is performed in a state in which the portion where the thickness of the molding material is desired to be ensured is hardly expanded, so that the molding material M can be molded without being thinned.

In addition, in the above-mentioned embodiment, the mounting position of the cutting tool 7 is limited to one position, but the present invention is not limited to this embodiment and corresponds to a portion where the thickness of the molding material is desired to be secured. A plurality of molds can be provided at the end of the mold.

〔The invention's effect〕

As described above, in the vacuum forming apparatus and method according to the present invention, a cutting tool is provided at the end of the molding die corresponding to the portion where the thickness of the molding material is desired to be secured, and the molding material is stretched over the molding die. At that time, since that portion is cut, it is possible to prevent the expansion of the molding material during vacuum molding, so that it is possible to prevent the disappearance of the grain pattern of the molding material.

Further, in the vacuum forming apparatus and method according to the present invention, since the elongation of the molding material can be prevented during the vacuum forming, there is an effect that the breaking of the molding material can be prevented.

Further, in the vacuum forming apparatus and method according to the present invention, since it is possible to prevent the elongation of the molding material during vacuum forming, it is possible to improve the quality of the molded product.

Further, in the vacuum forming apparatus and method according to the present invention, there is an effect that the size of the molding material can be reduced to reduce the molding cost.

[Brief description of drawings]

FIG. 1 is an enlarged perspective view of a part of the vacuum forming apparatus according to the present invention. FIG. 2 is a schematic view for explaining the forming method by the vacuum forming apparatus according to the present invention. FIG. 3 is a schematic diagram for explaining a forming method using a conventional vacuum forming apparatus. 1 ... Mold 2 ... Molding part (molding surface) 3 ... Cavity part 4 ... Vacuum suction hole 5 ... Molding surface 6 ... End part 7 ... Blade 8 ... Seal part

Claims (2)

[Claims] 1. A plurality of vacuum suction holes communicating with the cavity are formed in a molding surface of a molding die in which the cavity is formed, and a heated sheet-shaped molding material is formed on the molding surface side of the molding die. A vacuum forming device that stretches and vacuums from the cavity,
At the end of the molding die corresponding to the portion for ensuring the thickness of the molding material to be vacuum-formed, when the molding material is stretched on the molding die, a cutting tool for cutting a part thereof is provided, and the cutting edge of this cutting tool It is characterized in that a seal portion is formed between the lower position and a portion in the vicinity of the molding surface, which is smoothly continuous and maintains the end portion of the molding material cut by the cutting tool in a contact state to ensure the sealing property. Vacuum forming equipment. 2. A sheet-like molding material having a surface tension applied to the molding surface of a molding die to cover the molding surface, and exhaust from a space defined by the molding die and the molding material to perform molding. In a vacuum forming method for forming a material by bringing the material into close contact with the molding surface, the molding material applied with tension in the surface direction is uniformly applied between the highest edge of the molding surface and the contact portion on the outer periphery of the molding die. The step of stretching, the step of cutting the molding material at the end of the molding die corresponding to the portion of the stretched molding material that is to be secured in thickness, and the tensioned portion including the cut portion A vacuum forming method comprising a step of exhausting a molding material from a space defined by the molding die and the molding material while maintaining a sealing property between the molding material and the molding die.