JPH09272140A - In-mold gate-cutter and in-mold gate-cutting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the control system of a gate cutting pin. SOLUTION: An apparatus is equipped with a fixed mold 11, a movable mold 12 which is arranged freely forward/backward movably, constitutes a molding mold with the fixed mold 11, and forms a cavity space 13 between it and the fixed mold 11 in a mold clamping state, a gate cutting pin 20 the tip of which faces a gate 19 between the cavity space 13 and a runner 16 and which is arranged freely forward/backward movably, a detection means which is arranged in the molding mold and detects the supply of a resin injected from an injection nozzle into the molding mold, and a driving means which advances the gate cutting pin 20 with set timing when the supply of the resin is detected by the detection means. In the molding mold, the gate cutting pin 20 A is advanced with set timing to cut the gate 19.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an in-mold gate cutting device and an in-mold gate cutting method.

[0002]

2. Description of the Related Art Conventionally, in an injection molding machine, resin injected from an injection nozzle of an injection device is supplied to a runner through a sprue of a molding die, and is supplied from the runner to a cavity space through a gate. . Then, when the entire cavity space is filled with the resin, the pressure of the resin in the cavity space is maintained and the cooling of the resin is started. Subsequently, when the resin is cooled and becomes a molded product, the ejector pin is advanced into the cavity space and the molded product is ejected.

However, since the resin in the cavity space and the resin in the runner are integrally solidified, after the molded product is ejected by the ejector pin, the resin portion in the runner is broken off or cut by a cutter. It needs to be cut off. Therefore, the work of breaking or cutting is not only troublesome, but also the quality of the molded product is deteriorated or the molded product is damaged due to the breaking or cutting.

Therefore, the gate cut pin is arranged so as to move forward and backward so as to face the resin flow path between the cavity space and the runner, and after the cavity space is filled with the resin, the resin flow path Before the resin is solidified, the gate cut pin is advanced to separate the resin in the cavity space from the resin in the runner.

[0005]

However, in the above conventional injection molding machine, it is necessary to adjust the timing of advancing the gate cut pin and the timing of injecting the resin in the injection device. Therefore, the control system of the gate cut pin becomes complicated. Further, it is necessary to dispose the driving means for advancing the gate cut pin separately from the driving means for advancing the ejector pin, and the size of the injection molding machine is accordingly increased.

The present invention solves the problems of the conventional injection molding machine, simplifies the control system of the gate cut pin, and can reduce the size of the injection molding machine. An object is to provide an apparatus and a method for cutting a gate in a mold.

[0007]

Therefore, in the in-mold gate cutting device of the present invention, a fixed mold and a movable mold are arranged so as to be movable back and forth to form a mold together with the fixed mold. A movable mold for forming a cavity space between the mold and a fixed mold, a gate cut pin disposed so as to advance and retreat with its tip facing the gate between the cavity space and the runner, and the mold. The detection means arranged to detect that the resin injected from the injection nozzle has been supplied into the mold, and the timing set when the detection means detects that the resin has been supplied. Drive means for advancing the gate cut pin.

In the in-mold gate cutting method of the present invention,
The fact that the resin injected from the injection nozzle has been supplied into the molding die is detected by the detection means arranged in the molding die,
After the resin is supplied, the gate cut pin is moved forward at the set timing while the resin is soft to perform the gate cut.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a sectional view of a mold according to an embodiment of the present invention. In the figure, 11 is a fixed mold attached to a fixed platen (not shown), 12 is a movable mold attached to a movable platen (not shown) and constitutes a mold together with the fixed mold 11, 13 is the fixed mold 11 and A cavity space 14 formed between the movable mold 12 and the movable mold 12 is a sprue bush disposed in the center of the fixed mold 11, and a sprue 15 is formed through the sprue bush 14. The sprue 15 and the cavity space 13 are communicated with each other by the runner 16, and the sprue 15 and the runner 1 are connected.
6, a cold slug well 18 is formed between the runner 16 and the cavity space 13, and a gate 19 is formed between the runner 16 and the cavity space 13.

In this case, the runner 16 is the movable mold 1
It is formed on the surface facing the fixed mold 11 in 2.
It may be formed on the surface of the fixed mold 11 that faces the movable mold 12, or may be formed on the surfaces of the fixed mold 11 and the movable mold 12 that face each other. Further, the movable platen is moved back and forth by a mold clamping device (not shown),
The movable platen is moved forward, and the fixed mold 11 and the movable mold 12 are moved.
The molds are closed by abutting and, and the molds are clamped by applying a mold clamping force to the fixed molds 11 and the movable molds 12 that are abutted, and the movable platen is retracted to fix the fixed molds 11. The mold can be opened by separating the movable mold 12 from the mold.

Then, after the cavity space 13 is filled with a resin (not shown) and before the resin is solidified, that is, at a timing set while the resin is soft, the runner 16 and the cavity are set in the gate 19. A gate cut pin 20 is disposed so as to block the space 13 from the space 13 so that the tip of the gate cut pin 20 faces the gate 19, and an air cylinder 22 as a drive unit is provided to move the gate cut pin 20 forward. It is arranged.

The gate cut pin 20 penetrates the movable mold 12 and extends rearward (downward in the figure).
The piston rod 23 of the air cylinder 22 is fixed to the rear end. The air cylinder 22 is attached to the back surface of the movable die 12, and when compressed air is supplied from an air supply source (not shown) to one air chamber (not shown) arranged in the air cylinder 22, the piston rod The gate cut pin 20 is advanced via 23, and when the compressed air is supplied to the other air chamber from the air supply source, the gate cut pin 20 is moved back via the piston rod 23. An electromagnetic valve (not shown) is provided for selectively supplying the compressed air supplied from the air supply source to each air chamber, and a control device (not shown) is provided for operating the electromagnetic valve.

By the way, when the filling of the resin into the cavity space 13 is completed, the resin in the cavity space 13 is cooled and solidified to form a molded product. In order to eject the molded product, the first ejector pin is used. 26 is disposed so that its tip faces the cavity space 13 and can move back and forth. The ejector pin 26 penetrates the movable mold 12 and extends rearward (downward in the drawing), and its rear end is attached to the pair of ejector plates 28 and 29 in a floating manner. Further, a hydraulic cylinder (not shown) is arranged further behind the ejector plates 28 and 29, and the rod of the hydraulic cylinder and the ejector plate 29 are brought into contact with each other.

Further, the hydraulic cylinder moves the ejector pin 26 forward (moves upward in the figure) via the ejector plates 28 and 29 when oil from an oil supply source (not shown) is supplied to the oil chamber. Therefore, the molded product in the cavity space 13 is ejected by the ejector pin 26. A return spring (not shown) is arranged between the movable mold 12 and the ejector plate 28, and the ejector pin 26 is retracted by the urging force of the return spring.

On the other hand, in order to project the solidified resin in the runner 16, the second ejector pin 32 is disposed so that its tip faces the cold slug well 18 and can move back and forth. The ejector pin 32 penetrates the movable mold 12 and extends rearward, and its rear end is fixed to a pair of ejector plates 28 and 29 via a spring 33, and is forwarded (upward in the figure) by the spring 33. Be energized.

Therefore, the ejector pin 32 is
When the resin is supplied to the cold slag well 18, the ejector plates 28, 29 are pressed by the pressure of the resin.
Is ejected relative to the ejector plate 2
9 is brought into contact with the restriction portion 34 formed on the shaft 9 and stopped.
Further, the ejector pin 32, when the oil supplied from the oil supply source is supplied to the oil chamber of the hydraulic cylinder,
It is advanced together with the ejector pin 26 via the ejector plates 28, 29. Therefore, the resin solidified in the runner 16 is ejected by the ejector pin 32 at the same time when the molded product is ejected.

By the way, the ejector pin 32 has
A bracket 37 is fixed to the ejector plate 28 by a screw 36, and a microswitch 39 as a detecting means is fixed to the ejector plate 28 via a bracket 40. The micro switch 39 is turned on when the bracket 37 is retracted with respect to the ejector plates 28 and 29, resin is injected from an injection nozzle of an injection device (not shown), and the resin is supplied into the molding die. Detect that

Next, the gate cut operation by the gate cut pin 20 will be described. First, in a state where the mold is clamped, the injection nozzle is pressed against the sprue bush 14 and resin is injected from the injection nozzle, and the resin passes through the sprue 15 and is supplied to the runner 16 via the cold slag well 18. It is supplied to the cavity space 13 via the gate 19.

At this time, the ejector pin 32 is retracted under the pressure of the resin supplied to the cold slag well 18. Then, as the ejector pin 32 retracts, the bracket 37 also retracts, actuating the microswitch 39 to turn it on. The control device is
It incorporates a timer (not shown), which starts timing when the micro switch 39 is turned on and activates the solenoid valve when the set time has elapsed. As a result, compressed air is supplied to the one air chamber of the air cylinder 22 from the air supply source, and the gate cut pin 20 is advanced via the piston rod 23.

Therefore, after the cavity space 13 is filled with the resin and before the resin is solidified, that is, at the timing set while the resin is soft, the runner 16 and the cavity space 13 in the gate 19 are set.
Can be cut off between The resin is supplied to the cold slag well 18, the ejector pin 32 is retracted by the pressure of the resin, and the micro switch 39 is turned on during the set time of the control device. It is set based on the time until filling.

Thus, in the molding die, the movable mold 1
2, the air cylinder 22 is provided, and the ejector plate 28 is provided with the micro switch 39. Gate cutting can be performed by detecting that the resin is supplied into the molding die. Therefore, the gate cutting pin 20 is moved forward. It is not necessary to adjust the timing of the injection and the timing of injecting the resin in the injection device. Therefore,
The control system of the gate cut pin 20 can be simplified.

Since the gate cut pin 20 is advanced while the resin is soft, the gate 1
The resistance of the resin in 9 is small. Therefore, it is not necessary to make the tip of the gate cut pin 20 sharp, and the gate cut can be performed even if the tip is worn, so that the durability is high. Since the resistance of the resin in the gate 19 is small, the driving force necessary to move the gate cut pin 20 forward is small. Therefore, since the air cylinder 22 can be downsized, the air cylinder 22 can be attached to the movable mold 12 even when the shape of the molded product, the position of the gate 19 and the like are different.

As a result, the injection molding machine can be downsized and the cost can be reduced. Further, since the air supply source generally arranged in a factory or the like can be used to drive the air cylinder 22, the cost can be reduced. In this case, gate cut pin 2
Since the driving force for moving the 0 forward only needs to adjust the pressure of the compressed air supplied from the air supply source by the pressure adjusting valve, the control system of the gate cut pin 20 can be simplified.

In the present embodiment, the air cylinder 22 is used as the driving means for generating the driving force.
However, instead of the air cylinder 22, a hydraulic device, an electromagnetic solenoid, or the like can be used. Further, in the present embodiment, the microswitch 39 is provided as a detection means for detecting the supply of the resin into the molding die, but the pressure of the resin in the cold slag well 18 is directly detected. You can also do it.

Further, as the resin, both a thermoplastic resin and a thermosetting resin can be used. It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified based on the gist of the present invention, and these are not excluded from the scope of the present invention.

[0026]

As described above in detail, according to the present invention, in the in-mold gate cutting device, a fixed mold and a movable mold are arranged so that the mold can be formed together with the fixed mold. A movable mold forming a cavity space between the fixed mold and the fixed mold in a mold clamping state, and a gate cut pin disposed so as to advance and retreat with a tip facing a gate between the cavity space and the runner, A detection unit disposed in the mold and configured to detect that the resin injected from the injection nozzle is supplied to the mold, and a setting that is made when the detection unit detects that the resin has been supplied. Drive means for advancing the gate cut pin at the specified timing.

In this case, the resin injected from the injection nozzle is supplied into the molding die, and when the molding die detects that the resin has been supplied, the driving means at a set timing. Move the gate cut pin forward to cut the gate. Therefore, it is not necessary to adjust the timing of advancing the gate cut pin and the timing of injecting the resin in the injection device.
The control system of the gate cut pin can be simplified.

In the in-mold gate cutting method of the present invention,
The fact that the resin injected from the injection nozzle has been supplied into the molding die is detected by the detection means arranged in the molding die,
After the resin is supplied, the gate cut pin is moved forward at the set timing while the resin is soft to perform the gate cut. In this case, the resin injected from the injection nozzle is supplied into the molding die, and when the molding die detects that the resin has been supplied, the gate cut pin is advanced at the set timing. ,
Gate cut is performed.

Therefore, it is not necessary to adjust the timing of advancing the gate cut pin and the timing of injecting the resin in the injection device, so that the control system of the gate cut pin can be simplified. Further, since the gate cut pin is advanced while the resin is soft, the resistance of the resin at the gate is small. Therefore, it is not necessary to make the tip of the gate cut pin sharp, and even if the tip is worn, the gate can be cut, so that the durability is improved.

Since the resistance of the resin at the gate is small, the driving force required to move the gate cut pin forward is small. Therefore, since the driving means can be downsized, the driving means can be attached to the movable mold even when the shape of the molded product, the position of the gate, and the like are different. As a result, the injection molding machine can be downsized and the cost can be reduced.

Further, since the air supply source generally arranged in a factory or the like can be used to drive the driving means, the cost can be reduced.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a molding die according to an embodiment of the present invention.

[Explanation of symbols]

 11 Fixed Mold 12 Movable Mold 13 Cavity Space 15 Sprue 16 Runner 18 Cold Slug Well 19 Gate 20 Gate Cut Pin 22 Air Cylinder 26 Ejector Pin 28, 29 Ejector Plate 39 Micro Switch

Claims (5)

[Claims] 1. (a) a fixed mold, and (b) a movable mold which is arranged so as to be movable back and forth to form a mold together with the fixed mold, and
A movable die that forms a cavity space between the fixed die and the fixed die in the mold clamping state; and (c) a gate cut that is arranged so that the tip faces the gate between the cavity space and the runner and is movable back and forth. A pin, (d) disposed on the mold,
Detection means for detecting that the resin injected from the injection nozzle is supplied into the molding die; and (e) a gate at a set timing when the detection means detects that the resin has been supplied. An in-mold gate cutting device, comprising: a driving unit that advances a cut pin. 2. (a) An ejector pin is disposed so as to advance and retreat with its tip facing the cold slug well between the runner and the sprue, and the rear end thereof is attached to the ejector plate in a floating manner. At the same time, (b) the in-mold gate cutting device according to claim 1, wherein the detection means detects that the resin is supplied by retracting the ejector pin with respect to the ejector plate. 3. The driving means is an air cylinder, and the air cylinder advances the gate cut pin when compressed air is supplied from an air supply source to an air chamber arranged in the air cylinder. The in-mold gate cutting device according to claim 1. 4. The in-die gate cutting device according to claim 1, wherein the driving means is attached to the movable die. 5. (a) The fact that the resin injected from the injection nozzle has been supplied to the molding die is detected by the detection means provided in the molding die, and (b) after the resin has been supplied,
An in-mold gate cutting method, characterized in that the gate is cut by advancing the gate cut pin at a set timing while the resin is soft.