JPH0419008B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention mainly relates to a chip piece device for a multi-gate of a new synthetic resin injection molding machine, which is suitable for picking up a large number of small items with high precision.

[Conventional technology]

Regarding this type of piece device, the technique disclosed in Japanese Patent Application Laid-Open No. 61-63427, which was already developed by the present inventor, is known.

In this prior example, a short conical channel is provided in the gate section leading to the cavity, and the conical end of the sharp heating element is exposed to the conical channel, and the thermoplastic synthetic resin in the gate section is heated and melted. At the same time, a main flow channel communicating with the nozzle of the injection molding machine and an inclined flow channel communicating with this main flow channel are bored in the manifold in which the heating means is embedded, and further, the inclined flow channel is
The present invention relates to a runnerless injection molding apparatus that is connected to the conical flow path and is suitable for high-precision, small-sized molding.

[Problem to be solved by the invention]

However, in the above-mentioned conventional example, the manifold, which corresponds to the piece body of the present invention, only has a sharp heating element inserted and projected, and the overall thickness of the manifold cannot be reduced. Incorporating a sharp heating element increases the weight and size, making it extremely inconvenient to handle.
In addition, at the same time as heating and keeping the molten resin supplied and injected into the cavity from the manifold, the ability to quickly cool and solidify the resin in the gate area after injection to close the gate has been improved, allowing for faster and larger-volume molding operations. There is also a need to respond to these demands.

[Means to solve the problem]

This invention has been made with attention to the above points, and includes a plurality of sharp heating elements that are inserted into a piece body having a desired shape and whose front parts protrude, and other parts of the sharp heating elements except for the tip part. and a small annular flow path for molten resin formed between the projecting wall and the sharp heating element, and the main flow path penetrating into the piece body is connected to the main flow path through a branch flow path. The tip of the projecting wall is brought into contact with the mold surface, and the tip of the sharp heating element faces the gate of the cavity through a conical recess on the inner surface of the mold. It is characterized by

The projecting wall is characterized in that it is shaped like a circular tube that independently surrounds each sharp heating element, and further, the projecting wall is shaped like a straight trellis including a plurality of adjacent sharp heating elements, and each sharp heating element is shaped like a straight trellis. The feature is that a small annular flow path is formed around the heating element, and the lead wire of the built-in heater of the sharp heating element is connected in series with the built-in heater of the adjacent sharp heating element to connect the lead wire of the built-in heater of the adjacent sharp heating element to the It is characterized by being led out from the outer periphery.

With such a configuration, the present invention makes the piece body equipped with a large number of sharp heating elements suitable for multi-piece molding compact and lightweight, and also improves the heat insulation effect in the mold by the projecting wall configuration. By increasing the height, it is possible to perform compact molding with higher precision, and even if many sharp heating elements are installed in parallel, the number of lead wires is less than 1/2, eliminating the inconvenience of wiring, and the controller can also be made smaller. .

[Effect]

When the sharp heating element is inserted into the piece body, the protruding wall that surrounds it, leaving the tip part, comes into contact with the mold surface, and the tip part of the sharp heating element passes through the conical recess of the mold and enters the gate of the cavity. In this case, the molten resin flowing from the main channel of the piece body is injected into the cavity from the gate through the conical recess through the small channel through the branch channel by the injection operation.

The piece body is equipped with a large number of sharp heating elements, and these sharp heating elements can heat the inside of the small annular channel formed between the projecting walls and the inside of the conical recess, so that the molten state of the flowing resin can be maintained. In addition, the intermittent heating operation of the heater built into the tip of the sharp heating element intermittently heats the resin in the extremely narrow space called the gate, melting it, or solidifying it, which enables injection molding to open and close the gate. It can be performed effectively depending on the operation.

The above action is such that the piece contacts the mold only at the tip of the protruding wall, not the entire surface of the piece, and a space serving as a heat insulator can be maintained outside the protruding wall.
This is due to the fact that it acts as an effective heat retainer for the molten resin in the small annular flow path, but it also acts to prevent heat transfer from the piece side to the mold side, which requires cooling. .

〔Example〕

Examples of the present invention will be described below.

In each figure, 1 is a piece body with a manifold configuration,
Reference numeral 2 denotes a main channel for the molten resin extending vertically through the center of the piece body 1, and 3 denotes a plurality of sharp heating elements arranged in parallel. There is. It is preferable that the sharp heating elements 3 are arranged in parallel in two or three rows in a straight line as shown in the figure, but the arrangement method is not necessarily specified, and the front shape of the piece 1 is rectangular or square. Alternatively, you can freely select a shape such as a circle.

Reference numeral 4 denotes a protruding wall surrounding the protruding portion of the sharp heating element 3 except for the tip portion of the tip portion t, and 5 indicates a small annular stream formed between the protruding wall 4 and the sharp heating element 3. Show the path.

In the embodiment shown in FIGS. 1 and 2, the projecting wall 4
is formed as a cylindrical tube α that independently surrounds the outer periphery of each sharp heating element 3, but as in the embodiments shown in FIGS. , each sharp heating element 3
A small annular stream 5 is formed around the area.

Moreover, if the shape of the projecting wall 4 is made into a straight trapezoidal shape β, the distance between adjacent sharp heating elements 3 can be shortened compared to the shape of a circular tube α.
Can be installed in large numbers.

Further, the protruding wall 4 can be formed by "shrink fitting" while maintaining dimensional accuracy or by high precision cutting using an NC machine tool or the like.

A plurality of branch channels 6 are branched from the main channel 2 and communicate with the small channel 5. For example, as shown in FIG. 4, there is a first branch channel 6a branched into two from the frontmost part of the main channel 2, and a second branch channel 6b branched from each part of the first branch channel 6a. It is formed by

Reference numeral 7 denotes a fixed mold part composed of a large number of members into which the piece body 1 can be attached, and is provided with a large number of cavities 8 between it and a movable mold part (not shown). It has a mold 10 with a hole drilled therein. 11
indicates a short conical recess leading to each of the gates 9, and at the same time when the tip portion t of the sharp heating element 3 attached to the piece body 1 is faced, the tip of the projecting wall 4 is facing the mold 1.
By colliding with the mold surface 10a of 0, the tip of the sharp heating element 3 can be held in a correct position in the narrow space of the gate 9.

In the embodiment shown in FIG. 5, two piece bodies 1 are attached to the mold 10, and the piece body 1 and the mold 1
0 means that a space A can be formed between the projecting wall 4 and the spacing mold 12.

Reference numeral 13 denotes a main manifold constituting the mold section 7, which holds the piece body 1 between the mold 10 and a main runner 14 connected to a nozzle of an injection mechanism (not shown).
The sub-runners 15, which are branched from each other, are communicated with the main channels 2 of each of the pieces 1.

In the figure, 16 is a fixing plate for fixing the mold part 7, 17 is a number of locking rods, 18 is a heater for the piece body 1, 19 is a heater for the main manifold 13, and 20 is a cooling plate for circulating cooling water. Each hole is shown.

Of the heaters 18 and 19, those inside the piece body 1 are omitted, leaving only the heater 19 mounted vertically on the main manifold 13, and the piece body 1 is configured to be heated by heat conduction of this heater 19. Sometimes.

Next, the specific structure of the sharp heating element 3 will be explained with reference to FIGS. 6a, b, and c.

Each has a pencil-shaped outer shape with a tip t, and a coiled nichrome wire or platinum wire is disposed as a heater 21 inside the tip of the main body 3a.

In the embodiment shown in FIG. 6a, an extension part 21 is integrally wound into a coil shape with the heater 21.
In the embodiment shown in FIG. 6B, the heater 21 is connected to another preliminary heater 23 via a connector 22.

Further, in the embodiment shown in FIG. 6c, only the heater 21 is formed, and other heaters are omitted.

The main body 3a is filled with an insulating material 24 such as ceramic powder to firmly fix the heater and the like.

Furthermore, since the purpose of the heater 21 is to partially heat and melt the resin in the gate 9, it can be energized intermittently in conjunction with the injection molding operation to perform heating and melting and cooling and solidification. .

In the figure, reference numeral 25 indicates a lead wire.

The operation will be explained based on the above configuration and with reference to FIG. Molten resin injected by an injection mechanism (not shown) passes through the main runner 14 of the main manifold 13, is branched off at the sub-runner 15, and advances into the main channel 2 of each piece body 1.

Further, it passes through a large number of branch channels 6 from the main channel 2, enters the small stream 5, and enters the conical recess 1.
1 into the cavity 8 through the gate 9.

By the way, in this invention, a large number of pieces 1 are arranged in parallel in the mold part 7, and each piece 1 is provided with a large number of sharp heating elements 3, so that a large number of cavities 8 are connected to the gate 9 of the mold 10. Since molten resin can be injected into the mold, a large number of molded products can be obtained in one injection molding operation.

In addition, since the projecting wall 4 collides with the mold surface 10a of the mold 10 and a space A is formed in the mold 7 section, a kind of heat insulating layer is formed between the mold 10 and the projecting wall 4, and the sudden Smooth injection molding operations can be performed by suppressing temperature changes.

That is, the heaters 21, 22a, 23 in the sharp heating element 3 effectively act on the annular small flow path 5 formed between the projecting wall 4 and the sharp heating element 3 to cool the flowing molten resin. Solidification is prevented, and heat dissipation from the projecting wall 4 is also prevented by the highly insulating space A, so there is no inconvenience that would adversely affect the molten resin flowing through the small channel 5.

Furthermore, since the mold 10 and the piece body 1 are separated by the projecting wall 4, rapid heat conduction can be avoided, and the thermal effect is alleviated by the insulated space A, improving molding efficiency. can be increased.

〔Effect of the invention〕

According to this invention, by forming the protruding wall to protrude, the wall pressure of the piece body can be made thinner by that amount.Furthermore, because of the protruding wall, when mounting the mold, the space is reduced by the protruding wall. In addition, by intermittently operating the sharp heating element during each injection molding operation, the gate of the mold can be opened and closed, making it possible to perform highly accurate runnerless injection molding.

In other words, it is possible to maintain the molten state of the resin inside the piece body, and also to intermittently heat and melt the resin in the gate area.
Alternatively, the gate can be effectively opened and closed according to the injection molding operation by solidifying it. And 1
Not only can each piece be used to accommodate multiple cavities, but multiple pieces can also be easily attached to an injection molding machine. A multi-gate chip piece device for an injection molding machine can be provided.

In addition, by connecting at least two or more electrical connections of the heaters in a large number of sharp heating elements in series, the number of lead wires led out from the bridge body can be reduced to less than half, and the controller can also be made smaller and cheaper. can.

Furthermore, by making the tube wall of the sharp heating element inserted through the bridge body into a straight trellis shape, the interval between adjacent annular small channels is narrowed, and a large number of sharp heating bodies are installed in the bridge body, making it more efficient. A good multi-cavity device can be obtained.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway side view showing an embodiment of a multi-gate chip piece device for a synthetic resin injection molding machine according to the present invention, and FIG. 2 is a partially cutaway plan view of the same.
FIG. 3 is a partially cutaway side view showing another example, FIG. 4 is a partially cutaway plan view of the same as above, FIG. 5 is a vertical side view in use, and FIG. 6 is a, b, and c. FIG. 6 is a partially enlarged longitudinal sectional side view of a main part of each sharp heating element. DESCRIPTION OF SYMBOLS 1... Piece body, 2... Main channel, 3... Sharp heating body, 4... Projection wall, 5... Annular small channel, 6... Branch channel, α... Circular tube shape, β... Straight plate, 8...Cavity, 9...Gate, 10...Mold, A...
Space, 18, 19, 21, 23...heater.

Claims (1)

[Scope of Claims] 1. A plurality of sharp heating elements that are inserted into a piece body having a desired shape and whose front portions protrude, a projecting wall that surrounds the other parts except for the tip of the sharp heating members, and this projecting wall. and a small annular channel for molten resin formed between the sharp heating body and the main channel penetrating into the piece body and inserted into the small channel via a branch channel, A synthetic resin injection molding machine characterized in that the tip of the protruding wall is brought into contact with the mold surface, and the tip of the sharp heating element faces the gate of the cavity through a conical recess on the inner surface of the mold. Multi-gate chip piece device. 2. The synthetic resin according to claim 1, wherein the projecting wall has a circular tube shape that independently surrounds each sharp heating element, and a small annular channel is formed around each sharp heating element. Chip piece device for multiple gates of injection molding machines. 3. The synthetic resin injection method according to claim 1, wherein the projecting wall has a straight table shape including a plurality of adjacent sharp heating elements, and a small annular flow path is formed around each sharp heating element. Chip piece device for multiple gates of molding machine. 4. Synthetic resin injection according to any one of claims 1 to 3, characterized in that the lead wire of the built-in heater of the sharp heating element is connected in series with the built-in heater of the adjacent sharp heating element and led out from the outer periphery of the piece body. Chip piece device for multiple gates of molding machine.