JP3381000B2 - Thermoforming 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 molding method for molding a thermoformed material such as a synthetic resin in a heated state to obtain a thermoformed product, and particularly to maintain elasticity in heat resistance such as a metal material. Elastic material (called heat resistant elastic material in this invention)
In the molding process of fusing and molding the thermoformed product to the insert having the flat plate-shaped part, the deformation after taking out the thermoformed product is provided by providing the half-opening cooling process in which the mold is held in the half-opened state and cooled. The present invention relates to a molding method capable of suppressing the above.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 3, an insert 10 having a flat plate-like portion 11 made of a heat-resistant elastic material and two rising portions 12 and 13 on an inner peripheral side and an outer peripheral side thereof is used. A mold used in a molding operation for fusing and molding a thermoformed product 20 having a molding hole 21 penetrating a central portion is generally arranged in a vertical direction as shown in FIG. It is the mold 30 that has been processed. Taking the case of injection molding using such a mold as an example, the mold 30
The upper and lower molds 31 and 32 of the concave and convex mold spaces 3 for accommodating the insert 10 and forming the thermoformed product 20 on the mating surfaces facing each other.
1A and 32A are provided, and a core 32B for forming the molding hole 21 is implanted as a part of the engraving space 32A, and the direction of the molding hole 21, that is, the core 3 is formed.
2B axial direction and molds 31, 32 opening / closing directions 40A, 4
It is configured to match 0B.

When molding a plurality of thermoformed products 20 at the same time, a plurality of molding spaces 31 are formed in the molds 31 and 32.
A and 32A are provided, the upper mold 31 is divided into an intermediate plate 311 and an upper plate 312, and the mold engraving space 31A of the upper mold 31 is heated and plasticized with synthetic resin or the like. A branch passage 31C for additionally providing a casting passage 31B for injecting the materialized thermoforming material into a plurality of passages, and for branching into a plurality of casting passages 31B at a boundary portion between the intermediate plate 311 and the upper plate 312. Is provided to dispense from one integrated injection passage 31D.

To explain the molding operation, first, the inserts 1 are moved by moving the molds 31 and 32 relative to the direction of the molding hole 21 of the thermoformed product 20 and as shown in FIG.
A mold opening step for holding these molds 31, 32 in an open state is performed so that 0 becomes an opening state in which the mold engraving space 32A can be inserted, and then the insert 10 is manually or automatically inserted. After performing an insert inserting step for inserting the molds 31 and 32 at a predetermined position, the molds 31 and 32 are relatively moved to make the mating surfaces of the molds 31 and 32 closed as shown in FIG. The mold closing step for

However, in the case of the insert 10 having the flat plate-like portion 11 of the heat-resistant elastic material, the flat plate-like portion 11 has some processing distortion during the manufacturing process of the insert 10 and becomes a complete flat surface. However, if it is exaggerated and drawn in an easy-to-understand manner, for example, as shown in FIG. 4, the shape is often curved upward.

For this reason, the flat plate-like portion 11 is formed into the engraving space 31.
Unless it is forcibly pressed so as to correct between A and the molding space 32A, the insert 10 and the molding space 31A,
There is an unnecessary gap between 32A and
During the mold clamping process after the mold closing process, a high mold clamping pressure is applied to clamp the plate-shaped part 11 and the engraving space 31 sandwiching the plate-shaped part 11.
As shown in FIG. 6, the thermoforming material 51 is injected from the injection passage 31B by, for example, an injection molding machine while the A and 32A are pressed together to form the complete engraving space 50. The thermoformed product 20 is molded by performing a filling step for filling the melt-molded material in 50.

After that, a pressure holding / cooling process for cooling and solidifying the thermoformed product 20 is performed while applying a mold clamping pressure for a predetermined period. Then, continue the mold opening process,
The mating surface between the mold 31 and the mold 32 is opened, and a molded product take-out process for taking out the thermoformed product 20 fused to the insert 10 by a manual or automatic take-out device is performed, thereby completing a round of steps. FIG. 7 shows the above process sequence.

[0008]

In the above prior art, after the thermoformed product is taken out from the mold, the elasticity of the flat plate-like portion 11 of the insert 10 causes a stress to return to the original strained shape. Therefore, the thermoformed product 20 after the molded product take-out step is deformed in the cooling process, and if it is exaggeratedly drawn, for example, as shown in FIG.
However, there is a problem that a defective product due to a molding shape is successively produced such that the predetermined size of 1 cannot be obtained. Also,
In order to avoid this, the engraved part of the molding hole 21, that is,
In the example of the molding die 30 in FIG. 4, the core 32B may be modified by increasing / decreasing by an expected deformation amount. However, as expected due to the influence of pressure and density unevenness during filling of the thermoforming material. There was also an inconvenience that it could not be corrected.

[0009]

SUMMARY OF THE INVENTION In view of the inconvenience that defective products continue to be produced due to deformation after molding in the above-mentioned prior art, resulting in manufacturing loss, all of the pressure-holding / cooling processes preceding the mold opening process. Alternatively, it is overlapped with a part of the mold 30 so that at least the molten thermoformed product does not leak from the mold 30.
The while maintaining the half-open state, by providing a half-open cooling steps so as to cool substantially thermoformed object 20 under no pressure conditions, after removal of thermoformed object 20, insert
Due to the stress that causes the workpiece to return to its original shape with processing strain.
It is intended to solve the above-mentioned inconvenience by making it possible to suppress the influence of the incoming deformation on the thermoformed product 20 .

[0010]

In the structure of the present invention, a half-opening cooling step is inserted in place of part or all of the pressure-holding / cooling step after molding of the thermoformed product, and at least the hole 2 formed by the molding space is formed.
While 1 is held by uncured resin, it is pressed under the substantially pressureless condition, that is, it is pressed and corrected in the preceding mold clamping / filling process.
The shape of the insert 10 that has been
Allowing the shape of the insert to return to its original shape,
Under the condition of being released from the stress of returning to the original shape
Then, when the thermoformed product 20 is cooled and removed from the mold 30 , at least a part of the thermoformed product 20 , typically the flat plate-shaped portion 11
Since the portion or the like that fuses and holds the same on the surface is already solidified to the required hardness, the stress due to the elasticity of the flat plate-shaped portion can be counteracted, and the deformation of the thermoformed article 20 as a whole is suppressed. It works.

[0011]

Embodiments of the present invention will be described below with reference to the drawings. In the molding operation of the present invention, as shown in FIG. 1, in many cases, after the first mold opening step to the filling step are performed in the same manner as in the prior art,
A holding pressure / cooling process which is shortened as compared with the conventional one is inserted thereinto, and subsequently, as shown in FIG. 2, the melting heat is generated from each molding space for defining the outer shape of the thermoformed object 20. While keeping the mold 30 slightly open and keeping the mold half open so that the molded product does not leak
Performs a half-opening cooling process to cool the slab in a substantially pressureless state , which allows pressing in the preceding mold clamping / filling process.
Then, the shape of the insert 10 that has been straightened is processed.
Allowing it to return to its original distorted shape results in the original distortion
By the insert 10 trying to return to the state with
After cooling the thermoformed article 20 under stress-free condition
In the same manner as in the prior art , the mold opening process and the molded product removing process are performed again to take out the thermoformed product 20 with the insert 10 completely fused and solidified.

Further, in the mold 30 in the half-opening process of FIG. 2, as to the mold opening amount 30A, as understood from the drawing, the heat-resistant elasticity of the flat plate portion 11 of the insert 10, that is, the metal material Processing of the flat plate-shaped portion 11 by elasticity
The amount of strain at the time of completing the restoration from the corrected state at the time of the mold clamping / filling process to the original state, and the mold 30
The thermoforming 20 does not come out of the mold engraving spaces 31A and 32A.
To some extent, preferably, the molten thermoformed product does not leak from the mold engraving space.
It should be opened to such an extent that it does not come out, and regarding the cooling time in the half-opening cooling step, the heat forming material surrounding the flat plate-shaped portion 11 and the rising portion 12 on the inner peripheral side, that is, the synthetic resin is cooled and required. Until solidified to
They are selected in a very short time to the extent required for, bear in negligible the influence of heat molding 20 deformation to the entire caused by the restoring force derived from the elasticity of the plate-like portion 11
You can

[Modified Implementation] The present invention includes the following modifications and implementations. (1) The present invention is applied to a molding configuration using a laterally arranged molding die in which the molds 31 and 32 are arranged on the left and right.

(2) The thermoforming material 51 is applied to a molding composition made of a thermoforming material other than a synthetic resin material, for example, a low temperature plasticized metal such as a lead-tin alloy.

(3) Form the cross section of the molding hole 21 and the outer shape of the thermoformed product 20 into an appropriate shape, such as a triangle or a polygon, or position the molding hole 21 relative to the outer shape. The present invention is applied to a molding configuration of a thermoformed product such as being provided at an eccentric position or forming a plurality of molding holes 21.

(4) The shape of the thermoformed product 20 arranged above and below the insert 10 is transformed into an appropriate shape, for example, hemispherical or semielliptical, or one of the formed products arranged above and below is deformed. It is applied to the molding composition of thermoformed objects such as forming by making it extremely short.

(5) The inserts 10 are formed such that the rising portions 12 and 13 are turned upside down, or one or both of the rising portions 12 and 13 are eliminated, or the shape is triangular or polygonal. Or the like, or the inner peripheral side and the outer peripheral side are eccentric to each other, and the thermoformed product is fused to the one formed by eliminating the hole on the inner peripheral side.

(6) The present invention is applied to a molding structure in which a molding space for the forming hole 21 is not directly planted like the core 32B but is directly carved into a mold to form a molding space.

(7) Holes that do not pass through the molding hole 21 and stop halfway from the upper side or the lower side, or separate upper and lower holes that are divided in the middle, and holes where the upper and lower separate holes are in different positions It is applied to the molding composition of a thermoformed product formed by the above method.

(8) A molding die of the molding hole 21, for example, a portion corresponding to the core 32B is provided with respect to the dies 31 and 32.
It is applied to a molding structure by a mold structure formed so as to be detachable.

(9) The thermoforming material 51 is filled in a position corresponding to the molding space 50 in the mold open state without using an injection molding machine.
The present invention is applied to molding configurations having different molding procedures, such as a build-up type molding configuration in which a required amount of thermoforming material 51 is incorporated for molding.

(10) Cooling in the half-opening cooling step
The present invention is applied to a forced cooling structure in which cooling air is sent into the gap between the molds 31 and 32 to cool it.

(11) The present invention is applied to a formation structure in which a thermoformer 20 is fused to an insert 10 formed of a heat resistant elastic material other than a metal material, for example, a thin toughness ceramic material or a high heat resistant rigid resin material. .

(12) Before the half-opening cooling step, a half-opening cooling step is affected by providing a holding pressure cooling step that cools the thermoformed article 20 in a mold-closed state after the filling step to facilitate mold release. Add an appropriate step that does not give, or
The work process is configured by completely eliminating the pressure holding / cooling process.

(13) In order to prevent the deformation of only the forming hole 21 part, the mold opening amount 30A is further increased so that only the molding space for the forming hole 21, for example, the core 32B does not come out from the forming hole 21. In this state, the half-open cooling step is configured to open the space between the molds 31 and 32 to the extent that the engraving space 31A corresponding to the outer shape side of the thermoformed product 20 comes out of the thermoformed product 20 to facilitate cooling.

(14) When the flat plate-shaped portion 11 has a regular shape, for example, in a molding configuration in which the thermoformed product 20 is fused to the insert 10 provided with a slight inclination of about 0.5 °, Rather than providing such a regular inclination in each engraving space of the sandwiched portion, the inclination is forcibly pressed into a flat shape, and is formed and configured to restore the regular inclination during the half-opening cooling process.

(15) In the molding configuration in which the thermoformed product is fused to the insert 10 formed by forming the regular shape of the planar portion 11 into a mortar shape or an inclined surface in which the left and right sides are integrally inclined, Molding configuration is performed by using the molds 31 and 32 that are formed by matching the respective carved spaces to be sandwiched with the regular inclined surface. Further, even when the planar portion 11 has a curved surface shape having a slight curvature, the metal mold 31, which is similarly formed to match the curved surface,
32 is used for molding. Therefore, the planar portion 11 in the present invention includes a curved surface having a slight curvature when formed into such an inclined surface.

[0028]

According to the present invention , after the mold clamping and filling process,
Then, it was pressed and corrected in the mold clamping and filling process.
The shape of the insert 10 becomes the original shape with processing distortion
Thermoforming, at least under pressure sufficient to allow it to return
The extent to which the object 20 does not come out of the carved spaces 31A and 32A
While holding the mold 30 in the half-opened state,
A period of time required for the thermoformed product 20 surrounding the product to solidify
A half-opening cooling step for cooling the thermoformed product over
Due to the configuration, it returns to the original shape with processing distortion.
The thermoformed product 20 is welded and solidified to the inserted product 10.
Therefore, the processing distortion is corrected during the mold clamping / filling process, and
Thermoformed product 2 for insert 10 with strain stress
Unlike the conventional technology in which 0 melts and solidifies,
If the strain is corrected and the strain stress generated in the insert 10 is
It may be canceled during the half-opening process and act on the thermoformed product 20.
And the deformation of the thermoformed product 20 due to the strain stress is
Remarkably suppressed. Therefore, the processing strain of the insert 10
Despite the fact , the outer shape of the thermoformed product 20 is accurate and uniform.
It has an excellent effect that it can be maintained .

[Brief description of drawings]

FIG. 1 is a process drawing of an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of a main part of a half-opening cooling process state of the example.

3A and 3B show a molding object of an example, FIG. 3A is a front perspective view, and FIG. 3B is a vertical sectional view.

FIG. 4 is a vertical cross-sectional view of a main part of a conventional mold opening process state.

FIG. 5 is a longitudinal sectional view of a main part of a conventional mold clamping process state.

FIG. 6 is a longitudinal cross-sectional view of a main part of a conventional mold clamping process state.

FIG. 7 is a process diagram of a conventional technique.

FIG. 8 is a vertical cross-sectional view of a molded product according to a conventional technique.

[Explanation of symbols]

10 inserts 11 Flat part 20 Thermoformed 21 forming hole 30 molds 30A mold opening 311 lower plate 312 Upper plate 31 mold 31A shaped carving space 32 mold 32A shaped carving space 32B core 40A opening and closing direction 40B opening and closing direction 50 shaped carving space 51 Thermoforming material

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Claims (2)

(57) [Claims] 1. A heat resistant elastic insert 10 for a mold 3
In the molding step of inserting the thermoformed product 20 into the molding spaces 31A and 32A of 0 and fusing the thermoformed product 20 to the insert in the molding space , following the mold clamping / filling process, The
Insert that was pressed and corrected in the mold clamping and filling process
Allow the shape of the object 10 to return to the original shape with processing distortion
The mold 30 is under a sufficient pressure to prevent the thermoformed product 20 from coming out of the engraving spaces 31A and 32A, at least.
The heat surrounding the insert while holding the
The molded product 20 is kept for a period of time necessary for solidifying.
A molding method comprising a half-opening cooling step of cooling a thermoformed product . 2. The molding method according to claim 1, wherein the molding hole 21 is formed in a metal insert 10 having annular rising portions 12 and 13 on an inner peripheral side and an outer peripheral side of the flat plate-shaped portion 11. A state in which the thermoformed product 20 does not come out of the molding spaces 31A and 32A that form the molding hole 21 and the outer shape of the thermoformed product 20, after injection molding the thermoformed product 20 of the synthetic resin material to be formed into the through hole. And a half-opening cooling step of holding the same at a temperature of 1.