JPH03173629A - Method and apparatus for molding synthetic resin - Google Patents

Abstract

PURPOSE:To mold a synthetic resin in an extremely efficient manner in low cost in a reduced space by alternately molding a synthetic resin in two clamp stages. CONSTITUTION:The peripheral edge part of a synthetic resin sheet S to be molded is placed on a lower clamp piece 12a and an upper clamp piece 12b is lowered to tightly clamp the synthetic resin sheet S. Then, the synthetic resin sheet S clamped to a clamp stage 1 is heated and softened by heaters 3, 4 preliminarily raised in temp. Thereafter, a vacuum mold 5 is raised by a lift apparatus 51 and the synthetic resin sheet S is mated with the molding surface of the mold 5 and the pressure in the chamber 50 is released. A vacuum pump is turned ON to perfectly mate the synthetic resin sheet S with the mold 5 and, thereafter, the synthetic resin S is hardened by cooling to complete molding. The new synthetic resin sheet S is clamped to the clamp stage 1 from which the molded product is removed and a vacuum chamber 30 and a heater box 40 are arranged above and below the synthetic resin sheet S in the same way to heat and soften the synthetic resin sheet S.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a thermoforming method such as vacuum, compressed air or embossing for synthetic resins, and an apparatus therefor.

(Prior art) As is well known, packages and other molded products made of synthetic resin sheets are made by softening the synthetic resin sheet with heat, and then vacuuming it.
A method in which the material is molded in close contact with a pressurized air or embossing mold is widely used.

” 1. To describe the molding method and equipment that have been put into practical use more specifically, they include: ■ One molding die, one clamping stage for a synthetic resin sheet, and one pair of movable heaters. A method in which the synthetic resin sheet 1~ is thermally softened by the heater, the heater is retreated, and then the mold is molded and cooled to harden it. A method in which a synthetic resin sheet, which is movable between a mold and a heater and heat-softened by a heater, is transferred to a molding die for molding; ■ A heater is movable between two molding molds, and each molding A method in which a clamp stage is arranged corresponding to the mold, and after a synthetic resin sheet is thermally softened and molded on one mold, the heater is moved to the other mold -1- and the same molding is performed. Examples include a method in which a clamp stage rotates, a heating zone and a molding zone are arranged in the rotation trajectory, and the synthetic resin sheet 1 is thermally softened and molded and taken out through the heating zone and molding zone. .

(Problems to be Solved by the Invention) However, the above molding method and apparatus have advantages and disadvantages in terms of molding efficiency, installation space, etc., and improvements have been desired. That is, in the case of (1), the process of heating and softening the next synthetic resin sheet cannot be started until the molding with the molding die, cooling and hardening, and removal of the molded product are completed, which is inefficient. In this case, it is difficult to hold the sheet horizontally because it is necessary to transfer the heat-softened synthetic resin sheet.
Furthermore, in the case of (2), it is necessary to prepare two molds and incidental equipment (for example, vacuum or compressed air piping, etc.), resulting in high costs. On the other hand, in the case of ■, it is necessary to take up a large installation space.

The present invention has been made in view of the above, and it is an object of the present invention to provide a synthetic resin molding method that is extremely efficient, space-saving, and cost-saving, and an apparatus therefor.

(Means for Solving the Problems) A synthetic resin molding method of the present invention which achieves the above object = 4 and an apparatus will be explained based on the accompanying drawings. Figure 1 is a schematic diagram showing an example of the molding apparatus of the present invention, taking a vacuum forming apparatus as an example, Figure 2 is an explanatory diagram showing the procedure for molding using the same apparatus, and Figure 3
The figure is a more detailed process diagram of the molding procedure in the same device.
The figures are similar to FIG. 1 showing another aspect of the same apparatus, FIG. 5 is a similar view to FIG. 1 of the molding apparatus of the present invention taking a compressed air apparatus as an example, and FIG. It is the same figure as FIG. 2 of the molding procedure.

The present invention relates to thermoforming methods such as vacuum, compressed air, or embossing for synthetic resins, and a molding apparatus therefor. Step (I) of clamping the synthetic resin sheet S to be molded to one of the two, and placing a heater 3.4 on the clamp stage 1 to soften the synthetic resin sheet +-S clamped on the clamp stage 1. At the same time, a step (IT) of clamping another synthetic resin sheet S' to the other clamp stage 2, and a step (IT) of moving the heater 3.4 to the other clamp stage 2 and clamping another synthetic resin sheet S' clamped to the clamp stage 2. While the resin sheets 1 to S' are softened, a molding die 5 (6) is placed on one of the clamp stages 1 to mold the softened synthetic resin sheet S, and at the same time, the softened synthetic resin sheet S is cooled and hardened to be demolded. Step (III);
The molding die 5 (6) is transferred to the other clamp stage 2, and the softened synthetic resin sheet I-S' clamped on the clamp stage 2 is molded, hardened, and demolded, and the molded product is removed. The method consists of a step DV) of clamping a new synthetic resin sheet 1-S to be molded onto the other clamp stage 1 and arranging the heater 3.4 to soften the synthetic resin sheet S. ) ~ (I
The gist is that by repeating step V), the synthetic resin sheets s and s' are alternately formed on the two clamp stages 1.2.

Further, the molding apparatus according to the second claim includes a clamp stage 1 for two resin sheets to be synthesized arranged on the same horizontal plane.
2, a pair of upper and lower heaters 3.4 which can be moved between the clamp stage 1.2, and the clamp stage 1.
．． The gist is that the molding die 5 (6) is movable between the molding die 5 (6).

The above-mentioned molding methods include vacuum forming, pressure forming, embossing molding, etc. Therefore, vacuum forming molds such as rotating
, a pressure molding mold 6 or an embossing mold (not shown) is used depending on each embodiment.

(Function) Next, the function of the present invention will be explained by taking a vacuum forming method and its apparatus as an example.

In the vacuum forming method and its apparatus, first, in step (I), two clamp stages 1.
A synthetic resin sheet S to be molded is clamped to one of the two.

In step (II), a heater 3.4 is arranged on one clamp stage 1, and the synthetic resin sheet S clamped on the clamp stage 1 is thermally softened, and another synthetic resin to be molded is placed on the other clamp stage 2. The sheet S' is clamped [Fig. 2 (a)]. This synthetic resin sheet S
When it is sufficiently softened, in step (m), the heater 3
．． 4 moves to another clamp stage 2, and another synthetic resin sheet S' clamped on the clamp stage 2 is thermally softened. During this time, the already softened synthetic resin sheet S
The vacuum forming mold 5 was transferred to the clamp stage 1 where the sheet S was clamped, and the softened synthetic resin sheet S was vacuum formed along the mold 5 [Fig. 2 (b)], and then cooled and hardened. The molded product is demolded from the mold 5 and moved to clamp stage 1.
removed from In step (IV), a new synthetic resin sheet S is clamped on the clamp stage 1 from which the molded product has been removed, and the heater 3.4 is transferred to the clamp stage 1 to thermally soften the synthetic resin sheet S. During this time, the vacuum forming mold 5 is transferred to the other clamp stage 2, and the softened synthetic resin sheet S' clamped on the clamp stage 2 is vacuum formed by the mold 5, and is cooled and hardened to form a molded product. is demolded and removed. A new synthetic resin sheet S' is clamped on the clamp stage 2 from which the molded product has been removed, and after being thermally softened by the heater 3.4, it is molded in the same manner as described above.

The above steps (1) to (IV) are repeated, and while the synthetic resin sheet is clamped and thermally softened on one clamp stage, molding, cooling hardening, and demolding are performed on the other clamp stage. are performed alternately in sequence. Therefore, the synthetic resin sheet can be molded very efficiently with little time loss.

In pressure forming, a pressure forming mold 6 is used in place of the vacuum forming mold 5, and molding is carried out extremely efficiently through substantially the same process as above [see Figures 6 (a) and (b)]. ].

In embossing molding, two molds, a male mold and a female mold, are used in place of the vacuum molding mold 5, and the same process as above is carried out, and the softened synthetic resin sheet is placed between the molds. It is sandwiched and efficiently molded.

(Example) Next, an example will be described.

(Example 1) Figures 1 to 3 show a vacuum forming method using a convex mold and an apparatus therefor.

In the figure, clamp stage 1.2 is stage frame 1.
1.21 and a clamp 12.22 disposed inside it. The clamps 12.22 are attached to the stage frame 11.
．． It consists of lower clamp pieces 12a, 22a fixed to 21, and upper clamp pieces 12b, 22b that are movable up and down, and the synthetic resin sheets s, s' to be molded are attached to the upper clamp piece 1.
The peripheral edge thereof is clamped between 2b, 22b and the lower clamp pieces 12a, 22a. A metal plate 13.23 having airtightness and heat resistance is interposed between the stage frame 11.21 and the clamp 12.22.

The heater 3.4 is arranged above and below the clamp stage 1.2, and is horizontally movable between the two clamp stages 1.2. Upper heater 3 is clamp stage 1
．． It is installed in a box-shaped decompression chamber 30 with an open bottom surface that can be moved horizontally and vertically on 2. The vacuum chamber 30 has an intake port 3 connected to a suction pump (not shown).
0a, and is equipped with a gasket 30b on the lower surface of its lower periphery, and when it is lowered, the gasket 30b is attached to the clamp stage 2 or 2 to be airtightly installed on the stage frame 11 or 21. Further, a light-emitting element 30c and a light-receiving element 30d are installed in a facing relationship between the lower surfaces of the decompression chamber 30.

On the other hand, the lower heater 4 is installed in a flat heater box 4o with an open top surface that can be moved horizontally between the clamp stages 1-12 in close proximity to the bottom surface thereof, and the heater box 40 has an opening on the top surface. A light emitting element 40a and a light receiving element T-40b are installed in a facing relationship.

The vacuum forming mold 5 has a lower part that can be moved horizontally and vertically between the clamp stages 1 and 2.
, is installed in a box-shaped pressurized chamber 50 with an open surface. The pressurized chamber 50 has an air supply port 50a connected to a compressed air pump (not shown), and a gasket 50b is attached to the upper surface of its two peripheries. 2, the stage frame 1] or 21 is airtightly installed on the lower surface of the stage frame 1 or 21. The vacuum molding mold 5 is placed on a lifting device 51 installed in a pressurized chamber 50, and has an intake passage 52 in the interior of the mold 5 that opens to the molding surface. ... are connected to a vacuum pump (not shown) via a suction hose 53.

Next, a vacuum forming method for synthetic resin sheets s and s' to be formed using the vacuum forming apparatus having the above configuration will be described in detail.

Raise the clamp piece 12b of the clamp stage 1 and place the molded synthetic resin sheet 1- on the lower clamp piece 1.2a.
Place the peripheral edge of the synthetic resin sheet S, lower the clamp piece 12b, and reflamp the synthetic resin sheet S.

On the other hand, there is a vacuum chamber 3 below -F of the clamp stage 2.
0 and a heater box 40 are arranged, and the heaters 3.4 installed therein are switched on to raise the temperature.

Engineering side -) - Move the decompression chamber 30 to the clamp stage 1 side, lower it, and install the gasket 30b on the stage frame 1 of the clamp stage 1 in an airtight manner, and at the same time install the heater box 40. The synthetic resin sheet 1-S clamped on the clamp stage 1 is heated and softened by a heater 3.4 which is disposed close to the bottom of the clamp stage 1 and heated in advance.

As the synthetic resin sheet +-S is softened by heating, its central portion sag, but the degree of this sagging is controlled by the light emitting element 40a and light receiving element 4. placed in the heater box 4o. Detected by Ob, and this detection information is sent to the decompression chamber 3.
If the input voltage is input to the suction pump 0 and the degree of drooping is severe, the suction pump is turned on and the inside of the decompression chamber 30 becomes depressurized.

As a result, the central part of the synthetic resin sheet S is lifted up, but the degree of lifting is detected by the light emitting element 30c and the light receiving element 30d installed in the decompression chamber 30 and fed back to the suction pump, and based on the detected information. The suction pump is controlled on and off as appropriate to maintain the synthetic resin sheet S in a substantially horizontal state. This synthetic resin sheet 1
- While S is being heated, the synthetic resin sheet S' to be formed is placed between the clamp pieces 22a and 22b of the clamp stage 2.
Clamp the periphery of the

When the synthetic resin sheets 1 to S are heated to an appropriate molding temperature, the heater box 4o is moved to the lower part of the clamp stage 2, and the pressurizing chamber 50 is immediately moved to the lower part of the clamp stage 1. And raise it to Patsukin 5
0b and airtightly install it on the lower surface of the stage frame 11.

Thereafter, the vacuum in the vacuum chamber 30 is released, and the vacuum chamber 30 is raised and moved to the clamp stage 2 side. At the same time, the compressed air pump of the pressurized chamber 50 is turned on to increase the internal pressure of the pressurized chamber 50 and inflate the synthetic resin sheet S upward.

Thereafter, the vacuum molding mold 5 is raised by the lifting device 51, and the synthetic resin sheet S is placed along the molding surface of the mold 5, and the pressure inside the chamber 50 is released.

The synthetic resin sheet S is completely aligned with the mold 5 by turning on the vacuum pump, and then the synthetic resin sheet S is cured by cooling, and the molding is completed. During this molding, the chamber 5
If the synthetic resin sheets 1 to S are inflated upward in advance by an internal pressure of 0.0, the adhesion with the mold 5 is good, and a molded product having a desired shape can be produced efficiently and at a high yield.

After molding, the vacuum pump is turned off, air is blown between the mold 5 and the molded product (this blowing means is not shown), and the mold 5 and pressurized chamber 50 are lowered. Then, the upper clamp piece 12b is raised to remove the molded product.

During this time, on the other clamp stage 2, the synthetic resin sheets 1 to S' are heated and softened by the heater 3.4 in the same manner as described above.

Step (rV) A new synthetic resin sheet S to be molded is clamped on the clamp stage 1 from which the molded product has been removed, and a vacuum chamber 30 and a heater box 40 are placed above and below it in the same manner as above, and the synthetic resin sheet The S is heated and softened. On the other hand, in the clamp stage 2, the synthetic resin sheet S'' is molded by the vacuum forming mold 5, and a cooling hardening mold is formed. The process is the same, so a detailed explanation thereof will be omitted here.Then, a new synthetic resin sheet S' to be molded is clamped on the clamp stage 2 from which the molded product has been removed.

By repeating the above steps, synthetic resin molded products are produced alternately without interruption on the clamp stage 1.2.

Note that a gasket may be provided on the upper peripheral edge of the heater box 40 so as to be in close contact with the clamp stage 1 or 2, and air may be compressed from an air supply port (not shown) to maintain the horizontality of the softened synthetic resin sheet.

(Example 2) FIG. 4 shows an example in which the vacuum molding die 5 in the vacuum forming apparatus described above is a concave mold. In this case, clamp stage 1
．． A plug 54 is installed above the clamp stage 1.2 and is movable vertically and horizontally between the clamp stages 1.2 and 54. During molding with the vacuum mold 5, the plug 54 descends and softens the softened synthetic resin sheet S. (S') is recessed along the concave molding surface of the mold 5. This improves the adhesion between the synthetic resin sheet s (s') and the molding surface of the mold 155, allowing molded products of desired shapes to be manufactured at a high yield. In the case of this embodiment, since it is not necessary to inflate the softened synthetic resin sheet S (S') upward during molding, it is not necessary to pressurize the inside of the chamber 50. Since the other molding procedures are the same as those described above, their explanation will be omitted here. Although the plug 54 is used in this embodiment, if the pressure inside the chamber 50 is reduced during molding and the heat-softening synthetic resin sheet S (S') is forcibly recessed downward, the plug 54 can be used. 54 may not be used.

(Example 3) FIGS. 5 and 6 relate to pressure forming, and a pressure forming mold 6 is used in place of the vacuum forming mold 5 described above. Further, above the clamp stage 1.2, a box-shaped compressed air chamber 7 with an open bottom surface is installed, which is movable horizontally and vertically between the clamp stages 1.2. The compressed air chamber 7 is equipped with an air supply lower 1 connected to an air supply pump (not shown), and when the compressed air chamber 7 is lowered, the lower peripheral edge of the lower periphery of the lower part 16 is covered with a softened synthetic resin sheet S (S'). [
See Figure 6 (b)]. The air pressure molding die 6 is placed on the elevating mechanism 61 as described above, and is installed in a chamber 60 that is horizontally movable and vertically movable between the clamp stages 1.2. If the chamber 60 is of a concave type as shown in the figure, a plug similar to the above is installed to recess the softened synthetic resin sheet s (s') downward, and if the air molding mold 6 is of a convex type, In such a case, it is desirable to pressurize the inside of the soft synthetic resin sheet s (s') in the same manner as described above to inflate the soft synthetic resin sheet s (s') upward. Further, an exhaust passage 62 that opens to the molding surface is formed inside the pressure molding mold 6, and is connected to a suction pump (not shown) via an exhaust hose 63. Therefore, simultaneously pressurizing the inside of the compressed air chamber 7 and suctioning through the exhaust hose 63 allows simultaneous molding using compressed air and vacuum. Since the other configurations are the same as those described above, corresponding reference numerals are given in the drawings, and detailed explanation thereof will be omitted.

” - In the pressure forming apparatus having the configuration described above, a synthetic resin sheet s,
The procedure for forming s' will be briefly described with reference to FIG. After clamping the synthetic resin sheet S on the clamp stage in the same manner as in step (1) above, step (n)
Similarly, the synthetic resin sheet 1-S on the clamp stage 1 is heated and softened, and the synthetic resin sheet 1-S' to be molded is clamped on the other clamp stage 2 [Fig. 6 (A)].
]. After the heater 3.4 moves from the clamp stage 1 to the other clamp stage 2, in step (III), the chamber 60 is placed on the clamp stage, and the compressed air chamber 7 is lowered to move the mold 6. Soft synthetic resin sheet S placed on 1. It will be installed and airtight. If the molding die 6 is concave, the plug is lowered to concave the softened synthetic resin sheet 1-S downward. After that, the inside of the compressed air chamber half is pressurized, and the pressure causes the synthetic resin sheet 1-S to align with the molding surface of the mold 6, and at this time,
Turn on the suction pump, and remove the synthetic resin sheet S and the mold 6.
The air between the synthetic resin sheets 1 to S and the mold 6 is exhausted to the outside of the device through the exhaust passage 62 and the exhaust hose 63.
and completely adhere to each other. After that, it is cooled and hardened and molded.
Demold the molded product in the same manner as above. During this time, the synthetic resin sheet S' is heated and softened on the other clamp stage 2, as described above [FIG. 6(b)]. and,
In the process (TV), the chamber 60 and the compressed air chamber 7 are transferred to the other clamp stage 2, and pressure forming, cooling hardening, and demolding are performed in the same way as in 1. By repeating these steps, the clamp stage 1.2 Synthetic resin molded products are produced in turn.

Incidentally, during the above-mentioned air pressure molding, it is not necessarily necessary to forcibly exhaust the inside of the mold 6 as described above.

It goes without saying that simply releasing it into the atmosphere is a good idea. Furthermore, although vacuum forming and pressure forming have been described in Section -1, it is natural that the present invention can also be applied to other types of thermoforming such as embossing. Furthermore, it is not excluded that the size of the clamp 12.22 of the clamp stage 1.2 is made variable so that it can be used appropriately depending on the size and shape of the molded product.

(Effects of the Invention) As described in Section 2, in the present invention, synthetic resin molded products are alternately molded using two horizontally arranged clamp stages, a pair of upper and lower heaters, and one molding die. It is extremely efficient because it is manufactured without interruption, and requires less installation space and installation cost, and its useful value is extremely large.

[Brief explanation of the drawing]

Fig. 1 is a schematic diagram showing an example of the molding apparatus of the present invention using a vacuum forming apparatus as an example, Fig. 2 is an explanatory diagram showing the molding procedure using the same machine, and Fig. 3 is a more detailed diagram of the molding procedure in the same machine. A detailed process diagram, FIG. 4, is a diagram similar to FIG. 1 showing another aspect of the same apparatus, and FIG. 5 is a diagram similar to FIG. FIG. 6 is a diagram similar to FIG. 2 of the molding procedure in the same apparatus. (Explanation of symbols) 1.2, Clamp stage, 3.4... Heater 5... Vacuum molding mold, 6. Air pressure molding mold, s, s'.
...Synthetic resin sheet to be molded. that's all

Claims (1)

[Claims] 1. Clamping the synthetic resin sheet to be molded onto one of two clamp stages arranged in parallel on the same horizontal plane;
A step of arranging a heater on the clamp stage to soften the synthetic resin sheet clamped on the clamp stage, and clamping another synthetic resin sheet to be molded on the other clamp stage, and moving the heater to the other clamp stage. A step of softening another synthetic resin sheet clamped on the clamp stage, while placing a molding die on one of the clamp stages, molding the softened synthetic resin sheet, and cooling and hardening it to remove the mold. Then, the molding die is transferred to the other clamp stage, and the softened synthetic resin sheet clamped on the clamp stage is molded, hardened, and demolded, and a new mold is transferred to the one clamp stage from which the molded product was removed. It consists of the steps of clamping the synthetic resin sheet to be molded and arranging the heater to soften the synthetic resin sheet, and by repeating each of the above steps, the synthetic resin sheet is alternately molded on two clamp stages. A synthetic resin molding method characterized by: 2. A clamp stage for two synthetic resin sheets to be molded arranged on the same horizontal plane, a heater that can be moved between the clamp stages, and a mold that can be moved between the clamp stages. Synthetic resin molding equipment.