JP3041167U - Mold for synthetic resin molding - Google Patents

Abstract

(57) [Abstract] (Correction) [Problem] Using a punching die, manufacture a product having an inverse taper portion such as a bottom leg of a bowl or a cup, or a machine part having an inverse taper portion. In this case, it is possible to provide a molding die capable of releasing the molded product efficiently without causing damage to the molded product, deformation, or traces of the pestle and leaving the molded product with good efficiency. SOLUTION: A molding die 3 is composed of a punching die 4, an upper die 5, a lower die 6 and a surface plate 7, and the die 4 and the surface plate 7 are provided with respective annular concave grooves 8 and 9 facing each other. And the concave grooves 8 and 9
An elastic material 10 such as a silicon ring is attached between them. The surface plate 7 is provided with a compressed air supply hole 11, and the tip 11a of the compressed air supply hole 11 is opened to the surface of the surface plate 7 and the lower surface of the punching die 4 and the joint surface of the lower die 6 and the elastic material 10. ing.

Description

[Detailed description of the invention]

[0001]

[Industrial applications]

 The present invention relates to a molding die (hereinafter referred to as a molding die) of a thermosetting resin or a thermoplastic resin molded article, particularly a synthetic resin molded article having a portion such as an inversely tapered bottom leg portion.

[0002]

[Prior art]

 Conventionally, a synthetic resin molded product (hereinafter referred to as a molded product) having a reverse taper-shaped portion, which is generally called an undercut, such as the bottom leg of a bowl or a cup, or a machine part having a reverse taper portion, is a split mold. Was produced in. Since it is difficult to manufacture a split mold, there is a problem in that the cost of manufacturing a mold is added to the price of the molded product, which makes it expensive. In addition, when the split mold is used, burrs are generated at the joints of the molds, and it is necessary to remove the burrs. Since this work is mainly done by hand, it is very troublesome and inefficient. It was Moreover, this type of molded article also tended to be of low value. Therefore, in order to solve the above-mentioned problems, a molding method is proposed in which compression molding or injection molding is performed using a cutting die, and the bottom of the molded product is pushed with a stick bar immediately after the molding is completed and released from the cutting die. (Shokai Sho-94-274). However, while this molding method can produce a burr-free molded product, it presses the uncured molded product immediately after molding with the stick bar and forces it to release from the mold, so damage and deformation of the bottom of the molded product easily occur. In addition, there is a problem that a pushing mark by a stick stick remains.

[0003]

[Problems to be solved by the device]

 Therefore, when using a punching die to manufacture a molded product with a reverse taper such as the bottom leg of a bowl or a cup, or a machine part that also has a reverse taper, the molded product will not be damaged. Therefore, the present invention provides a molding die that does not leave any deformation or marks of a pestle and is reasonably easy to release from a mold.

[0004]

[Means to solve the problem]

 The molding die is composed of a punching die, an upper die, a lower die and a platen. The punching die and the platen are provided with opposed annular recessed grooves, and between the recessed grooves, there is an elastic ring such as a silicon ring. The material is attached. The platen is provided with a compressed air feed hole, and the tip of the compressed air feed hole is opened to the surface of the platen, the lower surface of the punching die, and the joint surface of the lower die and the elastic material. Insert an appropriate amount of thermosetting resin or thermoplastic resin into the space between the die and the lower die (cavity), set the upper die, and pressurize at the same time with heating in this state. Immediately after the completion of molding, the pressurization state is released, the upper mold is released from the punching mold and the lower mold, and compressed air is pressure-fed to the compressed air feed hole provided in the surface plate to release the molded product.

[0005]

[Action]

 According to the molding die according to the present invention, the molded product is released by the pressing force of the compressed air, so that the molded product in the uncured state can be easily and smoothly released, and the molded product cannot be released. There is an effect that no force such as deformation will occur and the situation such as deformation will not occur.

[0006]

【Example】

 An embodiment will be described below with reference to the drawings, in which 1 is a cup-shaped molded product made of a thermosetting resin or a thermoplastic resin, and 2 is a bottom leg of an inverse taper-shaped molded product. There is. This type of molded product 1 is compression-molded or injection-molded by a molding die 3 as shown in FIG. That is, the molding die 3 comprises a die 4 for molding the outside of the molded product, an upper mold 5 for molding the inside of the molded product, a lower mold 6 for molding the bottom and legs of the molded product, and a surface plate 7. Has been. The upper portion 6a of the lower die 6 is formed so as to coincide with the inner peripheral side of the bottom leg portion 2. On the lower surface of the punching die 4 and the upper surface of the surface plate 7, facing concave grooves 8 and 9 each having a substantially rectangular cross section or a substantially semicircular cross section are provided in a ring shape, and a silicon ring is provided between the concave grooves 8 and 9. An elastic material 10 such as is attached. The surface plate 7 is provided with a compressed air supply hole 11, and a tip 11 a of the compressed air supply hole 11 has a surface of the surface plate 7 and a lower surface of the die 4 and a joint surface 12 of the lower mold 6 and the elastic material 10. It has an opening. 13 is a cavity provided in the molding die 3, 14 is a locking tool for fixing the punching die 4 to the surface plate 7, and 15 is a tip of a locking tool 14 provided under the punching die 4. It is a lateral groove that stops. FIG. 5 shows another embodiment in which the lower die 6 has a conical shape, and the lower portion 4a of the punching die 4 is used as the bottom leg 2 forming portion of the molded product 1.

In order to manufacture a molded product using the above-mentioned molding die 3, a thermosetting resin or a thermosetting resin is used in the cavities (spaces) 13 of the punching die 4 and the lower die 6 installed on the surface plate 7. An appropriate amount of a plastic resin is put in the upper mold 5, and in this state pressure is applied simultaneously with heating. At that time, as shown in FIG. 2, the punching die 4 is wholly pressed downward, the tip of the locking tool 14 is located at the center position of the lateral groove 15 of the punching die 4, and the elastic member 10 is in a pressed state. . Immediately after the completion of molding, the pressed state is released, the upper mold 5 is released from the punching mold 4 and the lower mold 6, and then compressed air is pressure-fed to the compressed air feeding hole 11 provided in the surface plate 7. Then, the compressed air is supplied to the surface of the surface plate 7, the lower surface of the punching die 4, the side surface of the lower die 6, and the contact surface 12 between the elastic members 10, and the elasticity of the elastic member 10 and the pressing of the compressed air cause the lateral groove 15 to move. The punching die 4 is pushed up until the lower side comes into close contact with the tip of the locking tool 14 (FIG. 4). At that time, as is clear from the drawing, a compressed air passage 12a is formed between the surface plate 7 and the punching die 4, and the bottom leg portion of the reverse taper shaped article of the punching die 4 and the lower die 6 is molded. A gap A is formed in each of the bonding surfaces of the mold. Therefore, the compressed air that has pushed up the punching die 4 is filled from the compressed air passage 12a between the lower die 6 and the bottom surface of the gap A of the molded product, and gradually pushes the bottom of the molded product. At that time, the outer peripheral surface of the bottom leg portion 2 of the molded product is in a locked state with the corner portion of the bottom leg portion of the punching die 4, but since the molded article is in an uncured state, the punching die 4 and the lower die. Since a gap A is formed between 6 and the bottom of the molded product is pressed by compressed air, the lower end of the bottom of the molded product easily escapes toward the above gap, which not only facilitates mold release, but also creates a molded product. Since no unreasonable force acts, there is no possibility of deformation. Needless to say, the same effect can be obtained in another embodiment in which the lower die 6 has a conical shape and the lower portion 4a of the punching die 4 is the bottom leg portion forming portion of the molded product 1.

[0008]

[Effect of the invention]

 The molding die 3 of the present invention is as described above. According to the molding die 3, a molding having a bottom leg portion 2 having an inverse taper shape on the bottom like a bowl or a cup, or an inverse taper shape. Machine parts that have parts can be released smoothly with compressed air without causing damage or deformation of the bottom of the molded product and marks of sticks at all, as in the past. Further, since the ring-shaped recessed grooves 8 and 9 facing the punching die 4 and the surface plate 7 are provided and the ring-shaped elastic material 10 is provided between the recessed grooves 8 and 9, the punching die 4 and the surface plate 7 are formed at the time of molding. The space between them is hermetically closed to prevent escape of compressed air, and when the molded product is released from the mold, the die 4 is pushed up by elasticity, and the compressed air passage 12a, the die 4 and the die 6 are provided between the surface plate 7 and the die 4. It has an effect of promoting formation of the gap A therebetween. It should be noted that if the feeding of compressed air is linked with the molding operation by a timer, a molded product having a reversely tapered bottom leg can be efficiently manufactured.

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing an example of a molded product.

FIG. 2 is a vertical cross-sectional view of a central portion of a molding die.

FIG. 3 is a plan view of a molding die.

FIG. 4 is an enlarged cross-sectional view of a main part of a molding die.

FIG. 4 is an enlarged sectional view of a main part showing another embodiment of the molding die.

[Explanation of symbols]

 1 synthetic resin molded product 2 bottom leg part of synthetic resin molded product 3 molding die 4 cutting mold 4a lower part of cutting mold 5 upper mold 6 lower mold 6a upper part of lower mold 7 surface plate 8 concave groove of cutting mold 9 fixed Board groove 10 Elastic material 11 Compressed air feed hole 11a Compressed air feed hole tip 12 Joining surface 12a Compressed air passage 13 Cavity 14 Locking tool 15 Lateral groove A Gap

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[Procedure amendment]

[Submission date] April 21, 1997

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] Brief description of drawings

[Correction method] Change

[Correction contents]

[Brief description of the drawings]

FIG. 1 is a perspective view schematically showing an example of a molded product.

FIG. 2 is a vertical cross-sectional view of a central portion of a molding die.

FIG. 3 is a plan view of a molding die.

FIG. 4 is an enlarged cross-sectional view of a main part of a molding die.

FIG. 5 is an enlarged sectional view of a main part showing another embodiment of the molding die.

[Explanation of symbols] 1 synthetic resin molded product 2 bottom leg of synthetic resin molded product 3 molding die 4 cutting die 4a lower part of cutting die 5 upper mold 6 lower mold 6a lower part of upper mold 7 surface plate 8 cutting mold Concave groove 9 Surface groove 10 Elastic material 11 Compressed air inlet hole 11a Compressed air inlet hole tip 12 Joint surface 12a Compressed air passageway 13 Cavity 14 Locking tool 15 Lateral groove A Gap

Claims (2)

[Utility model registration claims] 1. A molding die 3 for molding a synthetic resin molded article 1 having an inversely tapered bottom leg 2 comprises a punching die 4, an upper die 5, a lower die 6 having a trapezoidal cross section, and a surface plate 7. Concave grooves 8 and 9 are provided on the lower surface of the punching die 4 and the upper surface of the surface plate 7 so as to face each other. Further, a compressed air feed hole 11 opening to the joint surface 12 is provided in the surface plate 7, and immediately after molding,
Compressed air is pressure-fed to the joint surface 12, and the punching die 4 is slightly raised by the restoring force of the elastic material 10 and the pressing force of the compressed air to form a compressed air passage 12a between the surface plate 7 and the punching die 4. At the same time, the die 4 and the lower die 6 are moved to form a gap A between the bottom leg forming portions, and when pressed with compressed air, the uncured molded product bottom leg 2 escapes into the gap A. Mold for synthetic resin moldings that allows smooth release. 2. The molding die 3 according to claim 1, wherein the lower mold 6 is formed into a conical shape, and the lower part 4a of the punching mold 4 is used as the bottom leg 2 forming part of the molded product 1 to mold a synthetic resin molded product. Mold.