JPS6210819B2 - - Google Patents

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a thermoforming device equipped with a heating device capable of controlling temperature for applying heat to a material to be molded and molding the material, and particularly relates to a thermoforming device equipped with a heating device capable of controlling temperature. The present invention relates to a thermoforming apparatus that is suitable for vacuum forming or pressure forming of resin sheets and is capable of freely adjusting the forming temperature distribution during the heating process of a material to be formed.

[Conventional technology]

In general, in order to obtain molded products with complex shapes, it is most important to control the heating temperature distribution to the molded material in the heating process of the molded material, and to achieve the desired temperature corresponding to the molded shape. There is a need for a thermoforming device with a heating device that allows easy distribution control. However, the heating device used in such conventional thermoforming equipment is often constructed using electric wire heaters. For example, the electric wire heaters are arranged approximately parallel to each other, or the upper and lower layers It has a two-layer structure that intersects in a grid pattern in the vertical and horizontal directions, and the desired temperature distribution is obtained by adjusting the voltage of each heating wire heater.

In such a method, it is difficult to adjust the temperature along the longitudinal direction of the heating wire heaters by arranging them substantially in parallel. In order to overcome this drawback, the heating wire heater itself is used by winding it loosely or tightly into a coil according to the required temperature distribution, but it is extremely difficult to process the heating wire heater. Not only that, but it is also difficult to obtain the required temperature distribution accurately. In addition, it is possible to simplify the manufacturing of electric wire heaters by connecting electric wire heaters of different materials and thicknesses, but it is extremely difficult to connect electric wire heaters made of different materials. It was not always possible to obtain an accurate temperature distribution.

On the other hand, in the case of a system in which the heating wire heaters are arranged in a grid pattern, it is possible to obtain the desired temperature distribution to some extent by carefully adjusting the voltage applied to each heating wire heater. The interference between the intersecting heating wire heaters is large, making precise temperature control extremely difficult.

[Problems to be Solved by the Invention] Therefore, all conventional heating wire heater type heating devices have the problem that fine temperature control of a certain limited area is difficult. Ta.

The present invention was made in order to eliminate the above-mentioned conventional drawbacks, and an object of the present invention is to provide a thermoforming device equipped with a heating device section that can easily obtain a desired molding temperature distribution corresponding to the molded shape. .

[Means for solving problems]

A thermoforming device according to the present invention that achieves the above object is a thermoforming device equipped with a heating device section that can adjust the temperature for applying heat to a material to be molded to form it.
The heating device section is constructed by disposing a plurality of planar heating elements, either singly or in units, in a frame with a reflective plate interposed therebetween. The heating device section is arranged at a position opposite to the mold with the material to be formed sandwiched therebetween, and the heating device section is curved so that the heating device section It is characterized by being provided with an energy adjusting section that can move forward and backward and that can independently adjust the energy supplied to the planar heating element individually or in units.

[Effect]

The heating device section is constructed by arranging planar heating elements singly or in units within a frame with a reflective plate interposed therebetween. The planar heating element is curved so that the side opposite to the reflecting plate is concave.

This heating device section is placed at a position facing the mold with the material to be molded in between, and heats the material to be molded when in this position. When heating is complete, the heating device is retracted from its position.

Thereafter, the heating device moves back and forth to the above position for each molding process.

〔Example〕

Embodiments of the present invention will be described below based on the drawings.

FIG. 1 is a front view showing a vacuum forming apparatus for thermoplastic synthetic resin sheets, which is an embodiment of the structural forming apparatus according to the present invention, and FIG. 2 is a left side view of the apparatus.

As shown in FIGS. 1 and 2, this embodiment is movable within a guide rail 12 supported by a base 10 by the action of rotary rollers 14 disposed at both ends, and a forming mold 26 A heating device 18 heats the material to be formed 16 for a certain period of time when the material to be formed 16 is moved to a position opposite to the object, and retreats to the vacuum device 26 after the elapse of a certain period of time set by a timer or the like. , a lower material clamping frame 20 fixed to the base 10 for clamping the material to be formed 16, and a lower material clamping frame 20 fixed to the operating rods of four air cylinders 22 installed on the base 10 so as to be able to move up and down. A molding chamber 27 having a material clamping frame 24, a mold 26 made of a wooden mold or a resin mold with vacuum holes bored at appropriate places, and a vacuum device for evacuating the inside of the mold 26 during molding. 2
It consists of 8.

As shown in FIGS. 3 and 4, the heating device 18 is provided with a bottomed frame 30 that forms the outside.
It is constructed by fixing a large number of planar heating elements 34 arranged side by side at regular intervals using clasps 32, either individually or in units. Each of the planar heating elements 34 in the heating device 18 is connected to an energy regulator 38 provided in an energy adjustment panel 36 individually or in units, and the supply energy is adjusted individually or in units. .

As shown in FIG. 5, each of the planar heating elements 34 is
It is slightly curved so that the upper side in the figure is convex, and a reflecting plate 40 is disposed and integrated at the upper side in the figure, and a screw hole 41 for mounting is provided in the reflecting plate 40. Such a sheet heating element 34
In order to attach the reflector plate 40 to the frame body 30, as shown in FIG. Bye. By using such a planar heating element 34, it is possible to increase the heating efficiency, but the external shape etc. of the planar heating element 34 are not particularly limited to this, and the size is also required. It can be made to have an appropriate size depending on the adjustment range of thermal temperature distribution. Also, the frame body 30
However, it is not limited to a frame with a bottom as shown in FIG. 4, and may be configured in any suitable shape that can be attached to the planar heating element 34. For example, it is possible to construct a thick plate by providing holes into which the planar heating elements are placed and embedding the heating elements.

Next, the operation of the above embodiment will be explained.

First, the upper material clamping frame 24 is pushed upward by the air cylinder 22, and the upper material clamping frame 24 is pushed up.
4 and the bottom material clamping frame 20, insert the material to be formed 16 into the space from the front left side in FIG.
Place it directly above 0. The upper material clamping frame 24 is lowered by the air cylinder 22 to clamp the material to be formed 16. Next, the heating device 18 is advanced along the guide rail 12 and stopped when positioned directly above the material to be formed 16 (FIG. 4). Then, as shown in FIG. 4, the material to be formed 16 and the heating device 1 are
The material to be formed 16 is heated in a state where the sheet heating elements 34 of 8 face each other. At this time, the moldable temperature of the material to be formed 16 differs depending on the material and material thickness, and the required heating temperature also differs between complex-shaped parts and simple-shaped parts. By operating the adjuster 38, the material to be formed 1
The molding temperature distribution was adjusted to meet the requirements of 6.
When the moldable temperature is reached, the heating device 18 is switched to the second
The mold 26 is moved back to the rear position on the right side of the drawing (a position directly above the vacuum device 28), and the mold 26 is raised to form the moldable material 16 into the shape of the mold 26. Specifically, Figure 7A
Heat as shown. Next, as shown in FIG.
By operating a switching valve 44 that can freely adjust the inflow and outflow of air provided in the center of the Then, compressed air is introduced into the molding chamber 27 to pre-stretch the heated and softened material 16 upward. Next, as shown in FIG. 7C, the molding table 46 on which the mold 26 is placed is raised to an appropriate position by an air cylinder (not shown). Next, as shown in FIG. 7D, the air supply/exhaust port 48 provided at the bottom of the molding chamber 27
The switching valve 50 is operated, and a vacuum pump (not shown) connected to the air supply/exhaust port 48 is used to connect the forming mold 26 and the material to be formed 16 through the vacuum hole 52 in the forming mold 26. The air is vacuum-sucked, and the material to be formed 16 is brought into close contact with the shape of the mold 26 and formed. After the material to be formed 16 is cured after a certain cooling period, the mold 26 is lowered by an air cylinder to form the material 1 to be formed.
Perform mold release with 6. Next, the upper material clamping frame 24 is raised by the air cylinder 22, and the molded material 16 is taken out to form a product.

According to the embodiment described above, first, a large number of planar heating elements are arranged side by side, and the temperature distribution can be adjusted independently between individual planar heating elements or units, so partial temperature adjustment in area units is easy. can be done.
Also, when setting the temperature, the energy regulator 38 attached to each sheet heating element can arbitrarily adjust the amount of heat generated by each sheet heating element, thereby compensating for the temperature drop at the outer periphery due to the environmental temperature of the heating element. Things can be done easily.
Furthermore, depending on the size of the material to be molded, only a portion of the heating device can be used to heat the material, so it is possible to heat only the necessary parts, which was not possible with conventional electric wire heaters, and save on power consumption costs. It is.

In the above embodiment, the heating device 18 was installed only on the upper surface of the material to be formed 16, but if necessary, it may also be installed on the lower surface of the material to be formed 16, so that the heating device 18 can be installed on the lower surface of the material to be formed 16. Of course, it is also possible to configure it so as to improve the heating efficiency.

Although the present invention is applied to a vacuum forming apparatus for thermoplastic synthetic resin sheets in the above embodiment, the scope of application of the present invention is not limited thereto, and is applicable to a pressure forming apparatus for thermoplastic synthetic resin sheets or other devices. It is clear that the present invention can be similarly applied to general thermoforming equipment for molded materials.

〔Effect of the invention〕

As described above, according to the present invention, in a thermoforming apparatus equipped with a temperature-adjustable heating device section for applying heat to a material to be formed and forming the material, the heating device section is located inside the frame. Consisting of a single unit or a large number of planar heating elements arranged side by side through a reflecting plate, the planar heating element being curved so that the side opposite to the reflecting plate is concave, The heating device section is disposed at a position facing the mold with the material to be formed interposed therebetween, and the heating device section is movable forward and backward with respect to the position for each molding process, and The energy supplied to the sheet heating element is
Since an energy adjustment section is provided that can be adjusted independently for each unit or unit, it is possible to easily obtain a desired temperature distribution that is compatible with the molding shape of the material to be molded or the environmental temperature, and to make the temperature distribution uniform. effective. In addition, since the heating device has a simple configuration of just arranging sheet heating elements, it has excellent effects such as easy assembly of the heating device section and easy repair in the event of failure.

[Brief explanation of the drawing]

FIG. 1 is a front view showing a vacuum forming apparatus for thermoplastic synthetic resin sheets, which is an embodiment of the thermoforming apparatus according to the present invention, FIG. 2 is a side view of the same, and FIG. A plan view showing the heating device; FIG. 4 is a side view including a partial cross section of the heating device;
FIG. 5 is a perspective view showing an example of the planar heating element used in the heating device section of the above embodiment, and FIG. 6 is a cross section showing a part of the heating device in which the planar heating element is attached to the frame. 7 are schematic diagrams showing the molding process in the embodiment. 16... Material to be formed, 18... Heating device, 34...
...Sheet heating element, 38...Energy regulator.

Claims (1)

[Claims] 1. In a thermoforming device equipped with a heating device part whose temperature can be adjusted to form a material by applying heat to the material to be formed, the heating device part is a single unit or a plurality of surfaces installed together in units within a frame. The sheet-shaped heating element is arranged with a reflective plate interposed therebetween, and the sheet-shaped heating element is curved so that the side opposite to the reflective plate has a concave shape, and the heating device portion is arranged in a manner that the heating device portion is arranged with respect to the mold. The heating device section is disposed at positions facing each other across the material to be formed, and is capable of moving forward and backward with respect to the position for each forming process, and supplies energy to the planar heating element. 1. A thermoforming device characterized by being equipped with an energy adjustment section that can be adjusted independently on a single unit or on a unit-by-unit basis.