JPH05245887A - Side gate cutting device for injection molding machine - Google Patents

Abstract

PURPOSE:To simplify the mold structure and reduce the cost thereof by cutting a side gate securely at the wall of a molded product. CONSTITUTION:A cutter holder 14 is disposed under a recessed channel 6 of a side gate of a molding die 2 movably in the moving direction of a movable side molding die 3, and a spring 15 is energized in the direction of movable side molding die 3 at all times. A cutter 13 with its edge 38 fed into the recessed channel 6 of the side gate is held by the cutter holder 14, and side faces 38B of the edges of the cutter 13 are formed as parts of walls of product forming cavities 4 and 5. A thin wall section of side gate G is cut along the wall of a molded product by a cutter 13 by means of spring force of the spring 15 following the movement of the movable side molding die 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a side gate cutting device for cutting a side gate of an injection molded product molded by an injection molding device in a molding die.

[0002]

2. Description of the Related Art In an injection molding apparatus adopting a side gate method, when a mold is opened and a molded product is taken out, the gate and the molded product are separated and taken out to save the time and effort of post-processing. There is. Conventionally, as a gate cutting device of this kind, as shown in FIG.
And the product molding cavity 43 formed by the movable mold 42
Inside the side gate 44 that injects the molten resin, that is, at the burr near the cavity 43, the gate thickness is made thinner and tapered so that the thin part 45 near the wall of the molded product automatically breaks at the time of release. It has been known.

[0003]

By the way, in the above-mentioned prior art, since the thin portion is formed in the burr portion of the molded product, not the positive cutting, the mold structure becomes complicated and the cost becomes high. There is a problem that the cut part does not look good. The present invention has been made in view of the above-mentioned circumstances, and an object thereof is to be able to reliably cut the side gate near the wall of the molded product, to obtain a simple and inexpensive mold structure, and to use an existing metal mold. It is an object of the present invention to provide a side gate cutting device for an injection molded product that can be easily mounted on a mold.

[0004]

In order to achieve the above object, the present invention takes the following technical means. That is, the present invention is an injection molding machine in which a product molding cavity and a side gate concave groove for feeding molding resin from the side of the cavity are formed between the stationary side and movable side molding dies, and A cutter is provided which is constantly urged toward the movable-side molding die and projects in the demolding direction when the movable-side molding die is demolded so as to cut the molding resin between the molding cavity and the side gate concave groove. It is characterized by

[0005]

According to the present invention, when the movable mold is closed with the fixed mold, the cutter and the cutter holder are pushed by the mating mold against the elastic force of the biasing means. Then, the molten resin flow passage is formed between the side gate concave groove and the cutter blade edge. After the molten resin injected into the product molding cavity of the molding die is solidified and the movable side molding die is retracted, the constraint of the cutter is released, so the cutter is extruded through its holder by the biasing means. And cut the side gate along the wall of the molded product.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a sectional view of an embodiment in which the cutting device 1 of the present invention is embedded in a stationary-side molding die 2, 3 is a movable-side molding die, and 4, 5
Is a product forming cavity, 6 is a side gate groove, 7 is a spool, 8 is a spool lock pin hole, 9 is a spool lock pin, and 10 is a cutting device embedding hole, which is provided below the side gate groove 6.

The side gate cutting device 1 is a device body
11, a bottom plate 12, a cutter 13 and a cutter holding body 14, a spring 15 which is an urging means of the cutter holding body 14, a holding body guide pin 16, a plurality of connecting bolts 17 and mounting bolts 18, The fixed-side molding die 2 is fitted into the cutting device embedding hole 10 and is fixed to the fixed-side molding die 2 by a mounting bolt 18. A coned disc spring may be used as the spring 15 so that the maximum elastic force can be obtained in a limited vertical range.

The apparatus main body 11 is a rectangular parallelepiped and has a groove 19 on the upper surface corresponding to the side gate groove 6 as shown in FIG.
Is provided, a spool lock pin insertion hole 20 is provided in the center, and a holder guide pin hole 21 and a connecting bolt hole 22 are provided.
And mounting bolt holes 23 are provided, and from the back side it is approximately Z
Cutter holding body fitting recesses 24 are provided, and further, a cutter fitting recess groove 25 and a guide groove 26 that communicate with the gate recess groove 19 at right angles are provided on both left and right end surfaces, respectively.

As shown in FIG. 8, the bottom plate 12 has a rectangular plate shape, a spring fitting hole 27 is provided in a mounting surface 12A of the apparatus main body 11, and a spool lock pin insertion hole 28 is provided in the center thereof. A connecting bolt hole 22 and a mounting bolt hole 23 of the main body 11
Corresponding to the above, bolt holes 29 and 30 are respectively provided in a penetrating manner so that the connecting bolt 17 and the mounting bolt 18 are inserted.

As shown in FIGS. 9 to 11, the cutter holder 14 has a substantially Z shape in a plan view in which both ends are bent at right angles in mutually opposite directions, and the holder fitting recess of the apparatus main body 11 is provided. The spool lock pin insertion hole 31 is provided in the center, and the cutter engaging groove 32 and the pin head fitting groove 33 are provided on the parallel side surfaces at both ends. At the same time, a pin insertion notch hole 34 is provided on the front surface side,
Spring fitting holes 35 are provided on the back surface so as to correspond to the spring fitting holes 27 of the bottom plate 12.

Then, the pin head fitting groove 33 and the cutout hole 34 are formed.
The holding body guide pin 16 and the head portion 16A of the holding body guide 16 are removably fitted therein. Further, the spring fitting holes 27, 3
5 are opposed to each other, the spring 15 is fitted between them, and is biased in a direction of separating the cutter holder 14 from the bottom plate 12. The apparatus main body 11 and the bottom plate 12 include a cutter holder 14, a spring 15 and a holder guide pin in the body 11.
After assembling 16, the unit is integrally connected by a connecting bolt 17 to form a unit, and a stroke S in the moving direction of the molding die is secured in the cutter holding body 14.
Is set to a size sufficient for cutting the thin portion of the side gate G. The unitized main body 11 and bottom plate 12 are removably attached to the mold recess 10 by means of attachment bolts 18.

The cutter 13, as shown in FIG.
A slide guide portion 36 and an engaging projection 37 are provided on the inner side facing the base portion, and the tip blade edge portion 38 is a single blade and the blade edge is shown in FIG.
As shown in 3 (a), the tip 38A of the cutting edge abuts the bottom 6A of the gate groove of the movable-side molding die 3 to form a triangular resin flow passage 39 with the gate groove 6. It is supposed to do.

The engaging projection 37 of the cutter 13 is removably fitted and engaged in the cutter engaging groove 32 of the cutter holder 14, and the sliding guide portion 36 is fitted in the guide groove 26 of the apparatus main body 11. The cutter 13 is fitted into the cutter fitting groove 25 so as to be slidable in the mold moving direction.
The opposite outer surface 28B of the cutting edge 28 of the
It forms part of the wall (see Figure 1) and is easily replaceable.

The shape of the cutting edge of the cutter 13 is shown in FIG.
As shown in (b), protrusions 38c can be formed at both ends of the blade edge portion 38, and the protrusions 38c can be brought into contact with the side gate recess groove bottom 6A to form a rectangular resin flow passage 39. The cutting edge 38 of the cutter 13 is substantially parallel to the bottom 6A of the side gate groove, and the tip of the holding guide pin 16 is brought into contact with the closing surface of the movable side molding die 3 so that the cutting edge of the cutting edge is The position may be regulated to form the resin flow passage.

In the above embodiment, when the movable side molding die 3 is opened, the cutter holder 14 is pushed toward the movable side molding die 3 side by the spring 15, and the cutter 13 is moved by the stroke S to the side gate G. Overhanging from. Therefore, when the movable-side molding die 3 is closed with the fixed-side molding die 2, the cutter 13 is pushed by the mold 3 against the elastic force of the spring 15, and the outer surface 38 of the cutting edge portion 38 is pushed.
B forms a part of the walls of the cavities 4 and 5 following the side gate G, and a triangular (or square) resin flow path is formed between the side gate concave groove bottom 6A of the movable side molding die 3.
Form 39.

After the molten resin injected into the cavities 4 and 5 of the molding dies 2 and 3 is solidified, the movable side molding die 3 is retracted to release the constraint of the blade edge portion 38 of the cutter 13 and the cutter. 13 is projected by the elastic force of the spring 15 through the cutter holder 14 toward the movable mold 3 side by the stroke S. At this time, the thin edge portion of the side gate G is made by the blade edge portion 38 toward the wall of the molded product. Cut along the side gate G
Are completely separated, and the cut surface on the molded product side is extremely clean.

The present invention is not limited to the above-mentioned embodiment, but can be applied to the one having molding cavities and the one having three or more molding cavities, and the bottom plate 12 can be omitted. It can also be applied to vertical and horizontal injection molding machines.

[0018]

INDUSTRIAL APPLICABILITY As described above, the present invention is an injection molding machine in which a molding cavity for a product and a side gate groove for feeding a molding resin from the side of the cavity are formed between the stationary and movable molding dies. , The fixed-side molding die is constantly urged toward the movable-side molding die, and when the movable-side molding die is demolded, protrudes in the demolding direction and forms between the molding cavity and the side gate concave groove. Since it is equipped with a cutter that cuts the resin, the gate thin-walled part is automatically and surely cut by the cutter following the movement of the movable mold and the molded product and the side gate are cut. Since it can be separated and has a simple structure in which the device embedding recess is provided in the mold, the mold can be obtained at low cost, and it can also be easily mounted on the existing mold, and gate cutting of the molded product The surface is clean and straightforward Besides it is possible to improve the quality without requiring, as well the attachment removal and replacement of the mold a cutting device as a unit, it is possible to perform the replacement of the cutter easy.

[Brief description of drawings]

FIG. 1 is a vertical sectional view showing an embodiment of the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a front view of FIG.

FIG. 4 is a left side view of FIG.

FIG. 5 is a bottom view of the apparatus body.

FIG. 6 is a cross-sectional view of the apparatus body corresponding to FIG. 2A-A line.

FIG. 7 is a sectional view of the apparatus body corresponding to FIG. 2B-B line.

FIG. 8 is a plan view of a bottom plate.

FIG. 9 is a plan view of a cutter holder.

FIG. 10 is a front view of FIG.

11 is a left side view of FIG.

FIG. 12 is an enlarged perspective view of a cutter.

13 (a) and 13 (b) are enlarged front views showing examples of cutter blade tip shapes.

FIG. 14 is a cross-sectional view showing an example of a conventional side gate automatic cutting structure.

[Explanation of symbols]

 1 Side gate cutting device 2 Fixed side molding die 3 Movable side molding die 4 Product molding cavity 5 Product molding cavity 6 Side gate groove 13 Cutter 14 Cutter holder 15 Spring (biasing means) 38 Cutting edge part 38B Cutting edge part 1 Side G Side gate

Claims (1)

[Claims] 1. An injection molding machine in which a product molding cavity and a side gate groove for feeding a molding resin from a side of the cavity are formed between a stationary side mold and a movable side molding die, wherein the stationary side molding die has: A cutter is provided that is constantly urged toward the movable-side molding die side and projects in the demolding direction when the movable-side molding die is demolded to cut the molding resin between the molding cavity and the side gate concave groove. A side gate cutting device in an injection molding machine characterized by: