JPH1058494A - Cassette type injection molding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To expand an allowable range of a processing accuracy by preventing generation of a flash in a cassette type injection molding device. SOLUTION: A plurality of cassette molds 2 are inserted into a fixed side base plate 1 disposed on a front surface of a fixed side mold P. A runner groove R for communicating a first sprue 7b with a second sprue 2a is provided on a back surface of a runner plate 4 in opposite contact with a back surface of the plate 1. The groove is branched on the back surface of the plate 4, and its end 4d is opposed to the second sprue via a communicating hole 4e. The hole 4e has an opening surface larger than the second sprue. A runner groove 4a is provided on a back surface side of the plate, and is not provided at a boundary between a base plate and a cassette mold, and hence a flash to be generated due to introduction of injected resin into a gap of the boundary is eliminated. Since an opening surface of the hole is increased, an alignment in the case of processing the second sprue of the mold can be facilitated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cassette type injection mold apparatus.

[0002]

2. Description of the Related Art In recent years, there has been a tendency to use a cassette-type injection molding apparatus in which a mold can be easily replaced and a running cost is low.

[0003] A general configuration of a cassette type injection molding die apparatus is such that an element corresponding to a template of an ordinary injection molding die apparatus is used as a base plate, and a cassette die is inserted into a plurality of recesses provided in the base plate. To wear,
There is a configuration in which the cassette die is fixed to a base plate via a fixing key.

In general, the supply path of the injection resin in the fixed mold communicates from a first sprue connected to a nozzle of a molding machine main body to a second sprue provided in a cassette mold through a runner groove, and a leading end of the second sprue. It goes from the gate to the cavity.

There are the following two methods as examples of how to provide a molding resin supply path.

As a first example, as shown in FIG. 5, a cassette mold 52 is inserted into a concave portion 51a of a base plate 51, and
This is fixed to the base plate with a fixed key (not shown). A sprue bush 54 is fitted into the center of a receiving plate 53 provided on the back surface of the base plate 51 so as to be able to contact and separate therefrom. The first sprue 5 is attached to the sprue bush 54.
4a is provided. The center R1 of the runner groove R is located on the back surface of the base plate 51 facing the tip of the first sprue 54a. These runner grooves R communicate with the second sprue 52a penetrating the cassette mold in the thickness direction from the back of the base plate 51 to the back of the cassette mold 52.

On the other hand, in the cassette type injection mold apparatus of the second example, as shown in FIG. 6, a spacer plate 65 is interposed between a base plate 61 and a receiving plate 63,
A runner plate 66 is provided at a position facing the tip of the first sprue 64a so as to partially face each cassette mold 62.

On the back surface of the runner plate 66, a center portion R1 of the runner groove is provided on the surface facing the first sprue 64a provided on the sprue bush 64, and the runner groove R branches off from the center, and the runner plate R Is communicated with a runner R3 provided on the back surface of the cassette mold 62 via a communication hole R2 formed between the side of the cassette die 62 and the inside of the spacer plate 65. The configuration of the second sprue 62a is the same as that of the first example (actual open flat 7-44463).
Reference).

[0009]

In the first example of the prior art described above, the runner grooves are provided from the back of the base plate 51 to the back of the cassette mold 52.
If there is a gap at the boundary between the base plate and the cassette mold, there is a problem that resin leaks from the gap and burrs occur. On the other hand, in order to eliminate the gap at the boundary, it is necessary to increase the dimensional accuracy of the cassette die, which has caused an increase in the manufacturing cost of the cassette die. In addition, there is a great influence of a change over time due to wear when the cassette mold is attached and detached.

On the other hand, in the second example, since the runner does not cross the boundary between the base plate 61 and the cassette mold 62, it is no longer required to increase the dimensional accuracy of this portion.

However, the length of the runner is long, and there is a portion that changes the flow direction, so that the flow path resistance increases, and the injection pressure decreases due to the pressure loss of the resin. There is a problem that the consumption increases.

In order to make it possible to remove the runner after the molding, the spacer plate 65 and the runner plate 66 need to be fixed to the receiving plate 63 and the runner plate 66 to the base plate 61 as separate independent members. Yes, the configuration is complicated.

[0013]

In order to solve the above-mentioned problems, a cassette type injection mold apparatus according to the present invention has a runner groove formed so that resin does not leak from a boundary between a base plate and a back surface of a cassette mold. A runner plate is abutted against the back of the base plate to avoid straddling the border. A runner groove provided on the back surface of the runner plate branches from a central portion of the runner facing the first sprue into a plurality of branch paths, and each branch path extends behind each cassette mold to form a cassette at a leading end thereof. It is connected to a second sprue provided in the mold. The runner was provided on the back of the runner plate so as not to cross the boundary between the base plate and the cassette mold.

In addition, the opening surface of the communication hole for communicating the runner with the second sprue at the end of the branch path of the runner groove is enlarged to facilitate the alignment between the communication hole and the second sprue and to configure the structure. Made easy. Further, the configuration can be further simplified by connecting to a plurality of second sprues.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to the structure of a runner in a fixed mold of a cassette type injection mold apparatus. In the present invention, a runner plate is provided on the back side of the base plate of the fixed mold so as to face the base plate, and a runner groove communicating with the first sprue is provided on the back side of the runner plate. The runner groove branches off on the back surface of the runner plate and communicates with a second sprue provided in the cassette mold via a communication hole penetrating in the thickness direction at a position facing each cassette mold. Since the runner groove is provided on the back of the runner plate, it does not cross the boundary between the base plate and the cassette mold. Since the end of the runner groove communicates with the second sprue through a communication hole provided through the runner plate in the thickness direction, burrs due to resin leakage hardly occur. Further, the communication hole is provided such that the opening surface is larger than the second sprue.

In the case of using a cassette mold having a plurality of second sprues, the communication hole is formed by a plurality of second sprues.
The sprue should be sized and shaped to allow simultaneous communication.

[0017]

An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows a cross section of the entire configuration in one embodiment of the present invention, and has basically the same configuration as that of the prior art. That is, the cassette type injection mold apparatus includes a fixed mold P located on the left side of FIG. 1 and a movable mold Q located on the right side.

The fixed mold P is inserted into four cassette mold receiving recesses 1a (only two are shown) provided on the fixed base plate 1 located at the forefront (right side in the figure). And is fixed to the base plate 1 by a fixed key 3 so as not to be detached. A runner plate 4 is fixed to the back of the base plate 1. A fixed-side receiving plate 5 is in contact with the back surface of the runner plate 4, and a fixed-side mounting plate 6 is in contact with the back surface.

A sprue bush 7 is fitted into a recess provided in the center of the fixed-side mounting plate 6 and the fixed-side receiving plate 5, and is screwed. A locate ring 8 is attached to the rear of the sprue bush 7 at the back of the fixed-side mounting plate 6. Inside the sprue bush 7, there is provided a recess 7a into which the nozzle of the molding machine enters, and the first sprue 7b extends from the top of this recess to the tip of the sprue bush.
Is provided.

The tip of the first sprue 7b is provided so as to coincide with the center of the runner to be formed between the runner plate 4 and the fixed receiving plate 5 when the mold is clamped. .

As shown in FIG. 2, a runner groove 4a is provided on the back surface of the runner plate 4. The runner groove 4a is formed of a branch path 4c which branches right and left from the runner center 4b and further branches in a T-shape at the tip. The tip 4d of the branch path 4c and the cassette mold 2
Are formed through the runner plate 4 in the thickness direction for communicating with the second sprue 2a.

FIG. 3A is an enlarged view of a runner portion. Since the runner groove 4a is provided on the back surface of the runner plate 4, it crosses the boundary between the base plate 1 and the cassette mold 2. Instead, it communicates with the communication hole 4e provided to penetrate in the thickness direction on the back surface of the cassette mold 2 through the branch path 4c from the runner center portion 4b, and communicates with the second sprue 2a via this. I have. Fork 4
The leading end portion 4d of c is wide, and is connected to a communication hole 4e penetrating therethrough to the front surface of the runner plate 4 (the base plate 1 side). The second sprue 2a and the communication hole 4e are connected in a state where the cassette mold 2 is mounted. In this connection portion, the opening surface (portion A) of the communication hole 4e.
Is larger than the opening surface (portion B) of the second sprue 2a.
Therefore, the positional accuracy of the second sprue 2a can be relatively low, and the alignment between the runner plate 4 and the cassette mold 2 is facilitated.

FIG. 3B shows a runner molded product formed by the runner R and the sprue. If the opening surface of the second sprue 2a is large, the base plate 1 and the runner plate 4 cannot be opened to take out the runner molded product, but there is no such problem in the present invention.

The movable mold Q is the same as the prior art, so that only a brief description will be given. As shown in FIG. 1, the foremost part (left side) of the movable mold Q located on the right side.
, A movable base plate 9 is located, and a movable mold 10 is inserted into a cassette mold accommodating recess 9a provided therein. A movable-side receiving plate 11 is in contact with the back surface of the movable-side base plate 9,
A spacer block 12 is in contact with the back surface, and a movable-side mounting plate 13 is in contact with the back surface.

In a space 12a formed inside the spacer block 12, a first ejector plate 14 constituting a first projecting mechanism is provided so as to be able to advance and retreat. A plurality of ejector pins 15 are provided upright on the first ejector plate 14, and these ejector pins penetrate the movable-side receiving plate 11 and are provided in the movable-side cassette mold 10. The protruding operation of the protruding mechanism is enabled. The second protruding mechanism is provided in a space in the cassette mold 10 on the movable side.
Ejector plate 10a and a plurality of second ejector pins 10b provided upright on the ejector plate 10a.
A cavity 10d is formed on the front side of the mold plate 10c of the cassette mold 10 on the movable side, and a core pin 10e protrudes from the center of the cavity 10d. The ejector pin 10b can protrude into the cavity 10d.

The movable mold Q is supported by a support pin 16 fixed to the fixed mold P at the time of opening and closing the mold. The fixed base plate 1 and the movable base plate 9 are guided by a guide shaft 17 when the mold is opened and closed. In addition, a spacer 18 is provided on the front surface of the fixed side base plate 1 to receive not only the cassette mold but also the force of mold clamping in a dispersed manner.

[0027]

[Other Embodiments] As shown in FIG. 4A, the structure of this embodiment has the same structure as that shown in FIG. 3A, but is provided on the back surface of the runner plate 44. A communication hole 44e, which communicates with the tip end 44d of the runner groove R and penetrates in the thickness direction of the runner plate 44, is formed in a circular shape. The configuration of the fixed-side base plate 41, the cassette mold 42, the fixed key 43, the fixed-side receiving plate 45, and other components are the same as the configuration shown in FIG.
FIG. 2B shows the shape of the runner molded product.

In this embodiment, two or more second sprues 42a and the runner R can be simultaneously communicated by the communication hole 44e, and the opposing surface of the second sprue can be located anywhere in the circular connecting portion. Since no trouble is caused, the positioning of the second sprue in manufacturing the cassette mold becomes easy.

It should be noted that the present invention relates to the number of cassette dies and the second
There is no restriction on the number of sprues and the arrangement of the branch paths of the runners, and they can be changed according to the actual conditions of each.

[0030]

According to the present invention, a runner plate is provided on the back surface of the fixed base plate in which the cassette die is inserted, and the runner groove communicating with the first sprue is provided on the back surface of the runner plate. Since the runner groove is provided so as not to cross the boundary between the base plate and the cassette mold, there is no possibility that the resin may enter even if there is a gap at this boundary. Therefore, the accuracy of the cassette mold and the concave portion is not required to be so high, so that the manufacturing cost can be reduced.

Further, the opening surface of the communication hole which penetrates the runner plate in the thickness direction and communicates the tip of the runner groove and the second sprue of the cassette mold is made larger than the opening surface of the second sprue. The positioning of the second sprue with respect to the runner plate is facilitated, and a certain amount of error can be allowed, so that the manufacturing cost can be further reduced. If the communicating hole is further enlarged so that a plurality of second sprues can communicate at the same time, the second sprue can be easily aligned and the runner can be easily manufactured. Further, the manufacturing cost can be reduced. Further, in the present invention, since the runner length is shortened, it is possible to suppress a decrease in the injection pressure, and there is an effect that a molded product of a desired quality can be obtained.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a main part of an entire configuration of an embodiment.

FIG. 2 is a front view of a runner plate according to one embodiment.

3A and 3B show a state of a runner in one embodiment, in which FIG. 3A is an enlarged sectional view of a main part, and FIG. 3B is a perspective view showing a runner molded product.

4A and 4B show a state of a runner in another embodiment, in which FIG. 4A is an enlarged sectional view of a main part, and FIG. 4B is a perspective view showing a runner molded product.

5A and 5B show a first example of the prior art, in which FIG. 5A is a cross-sectional view of a main part, and FIG. 5B is an explanatory view showing a planar state of a runner molded product.

6A and 6B show a second example of the prior art, in which FIG. 6A is a cross-sectional view of a main part, and FIG. 6B is an explanatory view showing a planar state of a runner molded product.

[Explanation of symbols]

 P Fixed side mold R Runner 1,41 Base plate 1a, 41a Concave part 2,42 Cassette type mold 2a, 42a Second sprue 4,44 Runner plate 4a, 44a Runner groove 4d, 44d Connecting part 4e, 44e Communication hole 7b, 47b first sprue A, B opening surface

Claims (2)

[Claims] A plurality of recesses provided on a front surface of a base plate of a fixed mold, a plurality of recesses provided on a front surface of a base plate of the fixed mold, a runner plate laminated on a back side of the base plate, and a back surface of the runner plate. And a runner groove communicating with the first sprue connected to the nozzle of the molding machine body, and a thickness direction is formed in a cassette mold inserted into the concave portion, and is inserted into the base plate. A second sprue communicating from the mounting surface to the molding cavity; and a communication hole provided so as to penetrate the runner plate in the thickness direction and communicating the runner groove and the second sprue. A cassette type injection molding apparatus, wherein a connecting portion between the first sprue and the second sprue has a larger opening surface than the second sprue. 2. The cassette die according to claim 1, wherein a plurality of the second sprues are formed in the cassette die, and the communication hole is formed in a size and a shape that allows the plurality of second sprues to communicate simultaneously. A cassette-type injection mold apparatus characterized by being performed.