JP2000167880A - Method for injection molding and mold for injection molding used for the method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for injection molding capable of preventing an improper melt deformation of an insert material such as a sheet or the like and maintaining and improving an appearance, function and the like of a product. SOLUTION: In the mold for injection molding comprising a holder 7, and a sheet 13 rear end side of which is held at the holder 7 and a front end 13a of which is inserted into a narrow part 6 of a product forming space 4, the holder 1 is constituted of a block 8, a pair of sandwiching pieces 9 molded at an end of the block 8 to sandwich the rear end sides of the sheet 13, a hollow molding material filling part 10 molded in the block 8, and a plurality of protrusions 11 protruded from front and rear surfaces of the block 8 to form a space between the front and rear surfaces and a partitioned flat surface 5a of an enlarged part 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding method and an improvement of an injection mold used for the injection molding method.

[0002]

2. Description of the Related Art Insert molding is widely used for embedding metal parts such as bolts in products.
It is also used when a product holds a part of a sheet used in various fields such as electric and electronic. In such a case, in the related art, although not shown, a sheet is placed in a mold, a part of which is protruded into a product forming space of the mold, the mold is clamped, and a mold formed in the product forming space is melted. A product is formed by injection-filling a material, and after cooling the product, a mold is opened to manufacture a product holding a part of a sheet.

[0003]

However, in the case where the sheet is thinly formed into a substantially plate-shaped cross section using a thermoplastic resin, the sheet is extremely easily melted by the pressure and heat of the injected molding material. It will be deformed. Conventionally, the melting deformation often impairs the appearance of the product or loses all or a part of the function of the product.

The present invention has been made in view of the above problems, and an injection molding method and an injection molding method capable of preventing inappropriate melt deformation of an insert material such as a sheet and maintaining and improving the appearance and function of a product. The purpose of the present invention is to provide an injection molding die used for the above.

[0005]

According to the first aspect of the present invention, in order to achieve the above-mentioned object, a mold, a holder arranged in a product forming space of the mold, and an end portion provided on the holder. And an insert material whose side is retained, the retainer comprising:
A block body, a pair of holding pieces provided at the tip of the block body, a hollow molding material filling portion formed in the block body, a plurality of protrusions respectively protruding from the front and back surfaces of the block body, A first molding material filling hole provided in the holding piece, and a second molding material filling hole provided on the front and back surfaces of the block body and communicating with the molding material filling portion; And a method for injection-molding a product in which the holder and the insert material are integrated by using the insert material, wherein a pair of holding pieces of the holder hold the distal end side of the insert material. Then, the holder is disposed in the widened portion of the product forming space of the mold, the tip of the insert material is inserted into the narrow portion of the product forming space, and the mold is clamped to close the holder. Space between the front and back surfaces of Forming each of the holding pieces and making the inner surface of each of the holding pieces substantially continuous with the partitioning flat surface of the narrow portion, filling the product forming space with a molten molding material, and removing the insert material from the pair of holding pieces. And a step of cooling the product, opening the mold, and taking out the product. The holder and the insert may be made of a thermoplastic resin, and the molding material may be a thermoplastic resin.

In order to achieve the above object, the invention according to claim 3 includes a product forming space formed in a mold, and a holder arranged in an enlarged portion of the product forming space, The holding tool holds the distal end side of the insert material, and inserts the tip of the insert material into the narrow portion of the product forming space. The holding tool includes a block body and a tip of the block body. A pair of holding pieces provided at the portion and sandwiching the end portion side of the insert material, a hollow molding material filling portion formed in the block body, and the front and back surfaces respectively protruding from the front and back surfaces of the block body. A plurality of projections that form a space between the expanding flat section and the partition flat surface,
The inner surface of each holding piece is formed so as to be substantially continuous with the partitioned flat surface of the narrow portion at the time of disposing the holder, and a first molding material filling hole is provided in each holding piece, and on the front and back surfaces of the block body. Is characterized in that a second molding material filling hole communicating with the molding material filling section is provided.

Here, the mold in the claims is
Any of a vertical arrangement, a horizontal arrangement, a two-plate type, a three-plate type, multi-cavity, or single-cavity may be used. The material of the holder is not particularly limited as in the case of the insert material and the molding material, but ethylene, AS resin, ABS
Thermoplastic resins represented by resin, propylene, polybutene, vinyl chloride, polyamide, polycarbonate, styrene, vinylidene chloride, and ethylene fluoride are preferred. Examples of the insert material include, but are not particularly limited to, sheets and films used in at least the fields of mechanical, electrical and electronic, optical, architectural and civil engineering, and packaging. The distal end side of the insert material may be the distal end of the insert material, or may be a portion excluding the distal end of the insert material.

[0008] The inner surface of each holding piece may have a configuration that is continuous with the partition flat surface of the narrow portion, or a configuration that is approximately continuous with the partition flat surface, as long as deformation of the insert material or the like can be prevented. Further, the number of the first and second molding material filling holes may be one, but a plurality is desirable. Furthermore, as a molding material, various rubbers such as silicone rubber,
Various thermoplastic resins or various thermosetting resins can be used. A filler, a reinforcing material, a coloring agent, a stabilizer, or the like can be appropriately added to the molding material according to needs and applications.

According to the first or third aspect of the present invention, when the molding material is filled in the product forming space of the mold, the molding material is filled with the second molding material filling hole, the molding material filling portion, and the second hole of the holder. It flows through the second molding material filling hole and fills the widened portion.
In addition, it flows into the molding material filling portion from the second molding material filling hole and is integrated with the holder. Also, it flows into the first molding material filling hole of the holder and is integrated with the insert material. By filling with such a molding material, a product in which the holder and the insert material are integrated and the tip end of the insert material is exposed from the pair of holding pieces is formed. Further, since the partition flat surface of the narrow portion and the inner surface of each holding piece are substantially continuous, even if the insert material is a sheet or a film, the insert material does not deform in a direction substantially orthogonal to the partition flat surface or the inner surface. .

According to the second aspect of the present invention, since the holder, the insert material, and the molding material are made of a one-dimensional thermoplastic resin which is softened by heating to show plasticity and solidified by cooling. At times, a part of the holder and the insert material are melted, respectively, and the holder and the insert material are firmly connected.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings, but the present invention is not limited to the following embodiments. As shown in FIG. 7 and the like, the injection mold according to the present embodiment includes a mold 1 having a horizontal arrangement for insert molding and a holding member 7 made of a thermoplastic resin arranged in the mold 1. The holding member 7 has a sheet 13 made of a thermoplastic resin and having a substantially plate-shaped cross section.
b is held.

As shown in FIG. 1, a mold 1 has a fixed side 2 mounted on a fixed side platen of an injection molding apparatus having a horizontal arrangement (not shown) and a movable side 3 mounted on a movable side platen of the injection molding apparatus. The parting line (PL) between the fixed side 2 and the movable side 3 is provided with a product forming space 4 which is a cavity and has a substantially inverted convex cross section. The product forming space 4 is composed of an enlarged portion 5 for accommodating the holder 7 through a gap, and a narrow portion 6 continuously formed at the tip of the enlarged portion 5. Accommodates the leading end 13a of the thin sheet 13 with almost no gap.

As shown in FIGS. 2 to 6, the holder 7 is provided with a flat rectangular plate-like block body 8 which is short in the front-rear direction (horizontal direction in FIG. 4) and long in the left-right direction (vertical direction in FIG. 4). The thin block body 8 has a pair of holding pieces 9, a molding material filling portion 10, a plurality of protrusions 11, and a plurality of first molding material filling holes 1.
Two and a plurality of second molding material filling holes 12A are respectively formed. As shown in FIGS. 3, 5, and 6, the pair of holding pieces 9 are integrally formed in a substantially inverted U-shape at the tip of the block body 8, hold the end 13b of the sheet 13, and hold the tip of the sheet 13. It functions to project the portion 13a. As shown in FIG. 7, the inner surface of each holding piece 9 is formed flat so as to be continuous at the same height as the top and bottom of the partitioning flat surface 6a of the narrow portion 6 when the holder 7 is arranged.

As shown in FIG. 6, the molding material filling section 10 is formed into a hollow section having a rectangular cross section at the end of the block body 8. As shown in FIGS. 2, 3, 4, 5, and 6, the plurality of projections 11 include a plurality of left and right projections 11, and the plurality of pairs of projections 11
Are protruded and formed side by side on the front and back surfaces on the terminal side. As shown in FIG. 7, the plurality of protrusions 11 come into contact with the upper and lower surfaces of the partition flat surface 5 a of the enlarged portion 5 when the holder 7 is disposed, and the front and back surfaces of the block body 8 and the partition flat surface of the enlarged portion 5 are arranged. A space 14 having a rectangular cross section is defined between the upper and lower surfaces 5a.

The plurality of first molding material filling holes 12 are formed as shown in FIG.
As shown in FIG. 4, each of the holding pieces 9 is formed by piercing and arranging it on the left and right sides, and each of the first molding material filling holes 12 is formed into a flat circular shape. Further, as shown in the drawing, the second molding material filling hole 12A is formed by piercing and forming the second molding material filling hole on the front and rear surfaces on the end side of the block body 8 and communicates with the molding material filling portion 10. Each second molding material filling hole 12A
Is formed into a flat circular shape, and a pair of projections 11 are integrally formed upright on the left and right sides of the peripheral edge.

Next, an injection molding method using the injection mold of the present embodiment will be described. First, the distal end 13b of the sheet 13 is inserted between the pair of holding pieces 9 of the holder 7 so that the pair of holding pieces 9 hold the distal end 13b of the sheet 13 and the leading end 13a of the sheet 13 is free. And the holder 7 combined with the widened portion 5 of the product forming space 4 of the opened mold 1 is positioned and inserted, and the leading end 13a of the sheet 13 is inserted into the narrow portion 6 of the product forming space 4. I do.

After the leading end 13a of the sheet 13 is set in the narrow portion 6 of the product forming space 4, the fixed side 2 and the movable side 3 of the mold 1 are clamped, and the front and rear surfaces of the holder 7 and the widened portion are enlarged. Spaces 14 for filling the molding material are respectively formed between the upper and lower sides of the 5 flat sections 5a. Further, the inner surface of each holding piece 9 is made continuous so as to be flush with the upper and lower surfaces of the partitioned flat surface 6a of the narrow portion 6 so as not to be uneven (see FIG. 7).

After the mold clamping step of the mold 1 is completed, a molding material 15 made of a thermoplastic resin is injected and filled into the product forming space 4. Then, the molten molding material 15 passes through the sprue bush, the runner, and the gate of the unillustrated runner system of the mold 1 from the injection molding apparatus, and is filled in the widened portion 5 of the product forming space 4. Note that the gate is provided at a portion that does not contact the holder 7.

At the time of this filling, the molten molding material 15
Plural second molding material filling holes 12A, molding material filling portion 1
Zero and a plurality of second molding material filling holes 12 </ b> A sequentially flow to gradually fill the space 14 of the expanding portion 5. Further, the molding material filling portion 10 is formed through the plurality of second molding material filling holes 12A.
And is melted and integrated firmly with the holder 7. The sheet 1 flows into the plurality of first molding material filling holes 12 and is melted.
3 and firmly integrated. By the filling of the molding material 15, the holding member 7 and the sheet 13 are firmly integrated, and a product 16 in which the front end 13 a of the sheet 13 projects from the pair of holding pieces 9 is injection-molded (see FIG. 8). ). After the molding material 15 is injected and filled into the product forming space 4, the pressure is maintained (post-filled) to compensate for the shrinkage of the resin due to solidification, and the injection process is completed.

When the injection step is completed, the product 16 is indirectly cooled and solidified for a certain period of time with the cooling water flowing in the mold 1 to sufficiently secure the rigidity of the product 16. During this time, the screw of the injection molding apparatus is rotated to form the molding material 1 for the next molding.
5 is plasticized and weighed. Finally, if the mold 1 is opened and the ejecting pin (not shown) of the mold 1 is advanced, a high-precision and high-quality product 16 having an inverted convex shape can be taken out (see FIGS. 9 and 10). . Hereinafter, the above cycle is repeated.

According to the above configuration, the sheet 13 is supported in the product forming space 4 via the holder 7, and the molding material 15 flows into and melts in the plurality of first molding material filling holes 12.
3, the molding material 15 can be formed even if the sheet 13 is thinly formed into a substantially plate shape in cross section using a thermoplastic resin.
The sheet 13 is not very easily melted and deformed by the pressure and heat. Therefore, the sheet 13 is detached from the holder 7 and impairs the appearance of the product 16 or the product 16
The function loss can be prevented beforehand and surely. Further, since the upper and lower portions of the partitioning flat surface 6a of the narrow portion 6 and the inner surfaces of the holding pieces 9 are located at the same level and are continuous, the sheet 13
However, there is no deformation in the vertical direction in FIGS.

Since the holder 7, the sheet 13, and the molding material 15 are thermoplastic resins whose melting and solidification are reversibly repeated by heating and cooling, a part of the holder 7 and a part of the sheet 13 are melted. The retainer 7 and the sheet 13 are extremely firmly integrated. Furthermore, each second molding material filling hole 12
Since the pair of protrusions 11 are formed upright on both the left and right sides of the peripheral portion of A, the processing of the mold 1 and the like are very easy. Furthermore, since the holder 7 is a molded article having a simple configuration with a very small number of parts, it is expected that the workability, productivity, handling, and mass productivity can be significantly improved.

In the above embodiment, the fixed side 2 and the movable side 3 of the mold 1 are arranged as shown in FIG. 1. However, the present invention is not limited to this.
May be arranged on the left and right, or the fixed side 2 and the movable side 3 may be arranged upside down. Further, although the block body 8 of the holder 7 is formed in a flat rectangular shape, the block body 8 can be formed into various shapes as long as the same function and effect can be expected. Further, a plurality of molding material filling sections 10 may be section-formed on the end side in the block body 8. Also,
The plurality of protrusions 11 may be formed by projecting at the four corners on both the front and back surfaces of the block body 8 or may be formed by projecting a plurality of protrusions between the first molding material filling hole 12 and the second molding material filling hole 12A. good.

Each projection 11 can be formed into various shapes such as a cylinder, a prism, and a block. Further, the first molding material filling hole 12 and the second molding material filling hole 12A can be appropriately changed to various shapes such as long slots. Further, when the holder 7 is loosely fitted to the widened portion 5 of the product forming space 4, the end of the widened portion 5 of the product forming space 4 and the end, one side, and / or the other side of the holder 7 are connected. A gap may be appropriately formed between them.

[0025]

As described above, according to the first or third aspect of the present invention, it is possible to prevent the insert material such as a sheet or a film from being melted inappropriately, thereby maintaining and improving the appearance and function of the product. There is an effect that can be. Furthermore, according to the second aspect of the invention, the degree of coupling between the holder and the insert material is improved.

[Brief description of the drawings]

FIG. 1 is an explanatory sectional view showing a mold in an embodiment of an injection mold according to the present invention.

FIG. 2 is a reference perspective view showing a holder in the embodiment of the injection mold according to the present invention.

FIG. 3 is a perspective view showing a holder in the embodiment of the injection molding die according to the present invention.

FIG. 4 is a plan view showing a holder in the embodiment of the injection mold according to the present invention.

FIG. 5 is a side view showing a holder in the embodiment of the injection mold according to the present invention.

FIG. 6 is a sectional view taken along line VI-VI of FIG. 4;

FIG. 7 is an explanatory cross-sectional view showing a state in which a holder and a sheet are combined and arranged in a mold in an embodiment of an injection mold according to the present invention.

8 is an explanatory sectional view showing a state in which a molding material is filled in a product forming space of the mold of FIG. 7;

FIG. 9 is a perspective view showing a product in the embodiment of the injection mold according to the present invention.

FIG. 10 is an explanatory sectional view showing the product of FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Mold 2 Fixed side 3 Movable side 4 Product formation space 5 Enlarged part 5a Partition flat surface 6 Narrow part 6a Partition flat surface 7 Holder 8 Block body 9 A pair of holding pieces 10 Molding material filling part 11 Plural projections 12 One molding material filling hole 12A Second molding material filling hole 13 Sheet (insert material) 13a Sheet tip 13b Sheet end 14 Space 15 Molding material 16 Product

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Takumi Suzuki 4-3-5 Nihonbashi Honcho, Chuo-ku, Tokyo Shin-Etsu Polymer Co., Ltd. (72) Yoshiaki Nishijima 4-5-2-5 Nihonbashi Honcho, Chuo-ku, Tokyo Shin-Etsu Polymer Co., Ltd. F term (reference) 4F202 AD05 AD08 CA11 CB01 CB11 CK89 CM12 CQ01 CQ05 4F206 AD05 AD08 JA07 JB11 JF05 JF35 JM04 JM16 JN12 JQ81

Claims (3)

[Claims] 1. A mold comprising: a mold; a holder disposed in a product forming space of the mold; and an insert material having a distal end held by the holder. A pair of holding pieces provided at the distal end of the block body, a hollow molding material filling portion formed in the block body, a plurality of projections respectively protruding from the front and back surfaces of the block body, and provided on each holding piece. A first molding material filling hole, and a second molding material filling hole provided on the front and back surfaces of the block body and communicating with the molding material filling portion, wherein the mold, the holder, and the insert A method of injection-molding a product in which the holder and the insert material are integrated using a material, wherein a pair of holding pieces of the holder are sandwiched between end portions of the insert material, and the mold is formed. Place the holder in the widened part of the product formation space And insert the tip end of the insert material into the narrow portion of the product forming space, close the mold, and leave a space between the front and back surfaces of the holder and the flat section surface of the widened portion. Forming each of the holding pieces and making the inner surface of each of the holding pieces substantially continuous with the partitioning flat surface of the narrow portion; filling the product forming space with a molten molding material; and leading the tip of the insert material from the pair of holding pieces. An injection molding method, comprising: a step of molding a product having a protruding portion; and a step of cooling the product, opening the mold and removing the product. 2. The injection molding method according to claim 1, wherein the holder and the insert are each made of a thermoplastic resin, and the molding material is a thermoplastic resin. 3. An insert including a product forming space formed in a mold and a holding tool disposed in an enlarged portion of the product forming space, the holding tool holding a distal end side of the insert material. What is claimed is: 1. An injection molding die for inserting a tip end of a material into a narrow part of a product forming space, wherein the holder is provided at a tip end of the block body and at a distal end side of the insert material. , A pair of holding pieces, a hollow molding material filling portion formed in the block body, and projecting from the front and back surfaces of the block body, respectively, between the front and back surfaces and the section flat surface of the expanding portion. A plurality of projections forming a space, wherein the inner surface of each holding piece is formed so as to be substantially continuous with the partitioning flat surface of the narrow portion when the holder is arranged, and a first molding material filling hole is provided in each holding piece. In addition to the above, Second molding material injection mold, characterized in that the filling holes respectively communicating with the shape material filling unit.