JPH0970859A - Injection molding machine having hot runner and mold replacing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To replace a mold by a drop-in method without allowing the nozzle part of a hot runner part to interfere with a fixed mold. SOLUTION: In an injection molding machine having a hot runner part 2, an attaching plate 4 is made relatively movable to a hot runner unit 3 in the axial direction of the hot runner part 2 to replace a mold by a drop-in method without generating the interference of a fixed mold with a nozzle part 30.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection molding apparatus having a hot runner and a method for exchanging molds using this injection molding apparatus.

[0002]

2. Description of the Related Art A general injection molding apparatus includes a pressure device for clamping a movable die and a fixed die, and a fixed die plate for holding the fixed die through which a nozzle penetrates a nozzle touch portion of the fixed die. And an injection molding machine that abuts and supplies molten material from the sprue and runner to the cavity. The mold clamping center and the injection center of the molding apparatus are generally on the same straight line, and the nozzle penetrates the center of the fixed die plate.

By the way, in the case of forming a relatively large molded product, internal strain is generated in the vicinity of the gate due to the molecular orientation due to the flow of the molten resin, which may cause a problem depending on the type of molded product. . In such a case, it is preferable to use the gate not at the center of the cavity but at the end. However, the nozzle of the injection molding machine is generally provided in the center of the fixed die plate as described above, and the distance from the nozzle to the gate becomes long. In this case, it is effective to use the hot runner. .

However, since the hot runner is conventionally formed as a part of the fixed die, there is a problem that the cost for each die is high. Therefore, the present inventor
Japanese Patent No. 8410 proposes an injection molding apparatus that solves the above-mentioned problems by providing a hot runner as a unit separately from a mold and disposing the unit and a fixed mold in a removable manner.

This injection molding apparatus shown in FIG. 4 has a fixed die plate 101 through which a nozzle 100 of the injection molding machine passes through a central portion thereof, a hot runner unit 200 held by the fixed die plate 101, and a hot runner unit which is detachable. A fixed die 300 that is fixed as possible, a movable die 301 that is clamped to the fixed die 300, and a movable die plate 102 that holds the movable die 301 and that is driven in a direction approaching the fixed die plate 101 and a direction moving away from the fixed die plate 101. , A cylinder device 103 that drives the movable die plate 102.

The hot runner unit 200 includes a first plate 201 fixed to a fixed die plate 101, a spacer 202 fixed to the fixed die plate 101 via the first plate 201, and a mounting plate fixed to the spacer 202. 203, the first plate 201, and the mounting plate 203
And a hot runner portion 205 having a nozzle portion 204 at the other end thereof, the molten material being held in contact with the nozzle 100 at one end thereof. The hot runner portion 205 has a substantially L shape, and maintains the molten state of the molten material supplied from the central nozzle 100 while maintaining the nozzle portion 20.
4 to the sprue at the end of the fixed mold 300.

Since the mounting plate 203 is provided with a through hole 206 and the nozzle portion 204 contacts the fixed die 300, the nozzle portion 204 inevitably projects from the through hole 206 toward the fixed die 300. The fixed mold 300 is a back plate 302.
A movable die plate 10 that is detachably fixed to a mounting plate 203 via a cylinder and moves by driving the cylinder device 103.
The movable die 102 held by 2 is clamped and opened.

In this injection molding apparatus, since the fixed die 300 can be separated from the hot runner unit 200 together with the back plate 302, it is not necessary to provide a hot runner for each die, and one hot runner unit 200 is used for the die. It is characterized in that various molded products can be formed by simply replacing.

[0009]

By the way, when replacing a mold in a general injection molding apparatus, the distance between the fixed die plate and the movable die plate is set to be slightly larger than the mold thickness, and the mold is hung by a crane or the like. The method of vertical attachment and detachment (drop-in method) is used. However, in the injection molding apparatus disclosed in Japanese Utility Model Publication No. 3-8410, when the fixed mold 300 having the back plate 302 and the movable mold 301 are exchanged, the nozzle portion 204 projects from the mounting plate 203. , The back plate 302 in the above dropping method
Alternatively, there is a problem that the fixed die 300 and the nozzle portion 204 interfere with each other. Therefore, the fixed mold 300 is attached to the nozzle unit 20.
4 had to be moved in the axial direction, the replacement time was long, and the man-hours for replacement were large. In addition, the nozzle unit 204
There is also a problem that is easily damaged.

If the nozzle portion 204 can be driven backward, the above problem does not occur, but the hot runner unit 200
The thickness of the structure increases, and as a result, the daylight is insufficient and the mold structure cannot be established. The present invention has been made in view of the above circumstances, and an object thereof is to improve the injection molding apparatus disclosed in Japanese Utility Model Publication No. 3-8410 so that a mold can be replaced by a dropping method. .

[0011]

An injection molding apparatus having a hot runner according to the present invention, which solves the above problems, has a fixed die plate through which a nozzle of an injection molding machine penetrates and one end held by the fixed die plate contacts the nozzle. It has a hot runner part that has a nozzle part that contacts the molten material and abuts the fixed mold at the other end, and has a through hole that the nozzle part penetrates and can move in the direction close to the fixed die plate and in the direction away from the fixed die plate. A mounting plate, locking means that is held by the fixed die plate and locks the fixed die through the mounting plate, and a movable die that is held and driven in a direction approaching the fixed die plate and away from the fixed die plate. It is characterized by comprising a movable die plate and a driving means for driving the movable die plate.

Further, the mold exchanging method of the present invention of the second invention is
A fixed die plate through which the nozzle of the injection molding machine penetrates, a hot runner portion having a nozzle portion held by the fixed die plate and having one end abutting the nozzle to receive the molten material and the other end abutting the fixed die, and the nozzle portion. A mounting plate having a through-hole penetrating therethrough and movable in a direction approaching the fixed die plate and away from the fixed die plate; and a locking means held by the fixed die plate and locking the fixed mold through the mounting plate. , The movable die is held and is driven in the direction approaching the fixed die plate and in the direction away from the fixed die plate, and the driving means for driving the movable die plate, and an injection molding apparatus comprising: Move the fixed die and the movable die away from the fixed die plate so that the nozzle does not protrude from the through hole. Characterized by conversion.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION In the injection molding apparatus of the present invention, the distance between the fixed die plate and the movable die plate is set to be slightly larger than the total of the mold thickness and the structural thickness of the hot runner portion, and the mounting plate is fixed. Move it away from the plate. As a result, the nozzle portion is relatively retracted, and the nozzle portion is retracted from the through hole of the mounting plate. If the nozzle portion does not protrude from the through hole, interference with the fixed die does not occur, so that the fixed die can be replaced by the drop method. In addition, the movable type can also be replaced by the drop method as before.

The fixed die is held on the fixed die plate through the mounting plate by the locking means, and the die can be clamped and opened with the movable die.

[0015]

EXAMPLES The present invention will be described in more detail below with reference to examples. 1 to 3 are sectional views of an injection molding apparatus according to an embodiment of the present invention. This injection molding apparatus includes a fixed die plate 1 through which a nozzle 10 of the injection molding machine penetrates, a hot runner unit 2 having a hot runner portion 3 held by the fixed die plate 1, a mounting plate 4, and a fixed mold portion 5. ,
Movable die portion 6, movable die plate 7 holding movable die portion 6, and cylinder device 8 for driving movable die plate 7.
And is composed of

The hot runner unit 2 has a first plate 20 fixed to the fixed die plate 1, a spacer 21 fixed to the first plate 20, a second plate 22 fixed to the spacer 21, and a first plate. 20 and the hot runner portion 3 held between the second plate 22. The hot runner portion 3 is bent into a substantially L-shape, and a nozzle portion 30 that abuts on one end of the nozzle 10 to communicate with the hot runner portion 3 and that abuts the fixed mold portion 5 on the other end. Then, the hot runner portion 3 is connected to the first through the ring-shaped washer 31.
It abuts on the plate 20 and abuts on the second plate 22 via the pressing plate 32. Further, the first plate 20 has a biasing portion 33 formed of a cylinder device built therein.
Is capable of urging the hot runner portion 3 toward the fixed die portion 5.

A hydraulic clamp 24 (manufactured by SR Engineering Co., Ltd.) is held on the first plate 20 and the spacer 21. A clamp shaft 24a extending from the hydraulic clamp 24 is configured to be capable of advancing and retracting and being rotatable, and has a T-shaped head portion 24b at the tip of the clamp shaft 24a. The clamp shaft 24a is connected to the second plate 22.
Also, it is configured to extend through the mounting plate 4 and engage with the back plate 51 of the fixed mold part 5.

A guide pin 25 is provided on the first plate 20.
Has been fixed. The guide pin 25 penetrates through the mounting plate 4 and projects, and the tip head portion 25a is attached to the mounting plate 4.
By engaging with, the movement of the mounting plate 4 is restricted. Further, a cylinder device 26 is fixed to the first plate 20, and a tip end of a piston rod of the cylinder device 26 is fixed to the mounting plate 4 so that the mounting plate 4 can be driven forward and backward.

A through hole 40 is provided in the mounting plate 4 so that the nozzle portion 30 of the hot runner portion 3 can be inserted and removed. The fixed mold part 5 is composed of a fixed mold 50 and a back plate 51 fixed to the back surface of the fixed mold 50. The nozzle part 30 is attached to the nozzle touch part of the fixed mold 50 through a through hole 52 provided in the back plate 51. Is pressed.

The movable mold part 6 is composed of a movable mold 60, a plurality of back plates and knockout pins 61 and 62, and a known mold structure (not shown) similar to the conventional one allows the molded product to be knocked out from the mold surface when the mold is opened. Is configured. A method for exchanging the fixed mold part 5 and the movable mold part 6 of this injection molding apparatus will be described below. First, in the state of FIG. 1, the head 24b of the clamp shaft 24a of the hydraulic clamp 24 is engaged with the back plate 51, and the back plate 51 is attracted to the mounting plate 4 to hold the fixed mold part 5 in the hot runner unit 2. ing. Therefore, by driving the movable die plate 7 by the cylinder device 8, the fixed mold part 5 and the movable mold part 6 can be opened or clamped.

Next, in order to replace the fixed die 5 and the movable die 6,
First, the clamp shaft 24a of the hydraulic clamp 24 is rotated 90 degrees to release the engagement between the head portion 24b and the back plate 51. Then, the movable die plate 7 is driven by the cylinder device 8 in a direction away from the fixed die plate 1. At the same time, the cylinder device 26 is driven to move the mounting plate 4 in a direction away from the fixed plate 1 at substantially the same speed as the movable die plate 7. As a result, the fixed mold part 5 moves while being in contact with the movable mold part 6. Then, as shown in FIG. 2, the mounting plate 4 engages with the head portion 25 a of the guide pin 25 to restrict the movement.

In this state, as shown in FIG. 2, the nozzle portion 30 of the hot runner portion 3 is connected to the through hole 40 of the mounting plate 4.
It doesn't stick out from. Therefore, if the fixed mold part 5 and the movable mold part 6 are vertically lifted as shown in FIG.
Can be moved along the surface of the mounting plate 4 and can be taken out without interference with the nozzle portion 30. The movable mold part 6 is also lifted and taken out along the surface of the movable die plate 7.

Then, another fixed mold part 5 and movable mold part 6 are suspended and vertically lowered between the movable die plate 7 and the mounting plate 4 to fix the movable mold part 6 to the movable die plate 7 and a hydraulic clamp. The clamp shaft 24a of 24 is driven forward, the head 24a is rotated by 90 degrees to be engaged with the back plate 51, and then the fixed mold 5 is fixed to the hot runner unit 2. As a result, the hot runner unit 2 can be used as it is for molding using another mold.

[0024]

According to the injection molding apparatus and the mold replacement method of the present invention, the mold can be replaced by the dropping method without interfering with the nozzle portion of the hot runner part, so that the number of replacement steps can be greatly reduced. Also, damage to the nozzle portion can be prevented.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an injection molding die according to an embodiment of the present invention in a clamped state.

FIG. 2 is a cross-sectional view showing an injection molding die according to an embodiment of the present invention in a state where the die is being replaced.

FIG. 3 is a cross-sectional view showing an injection-molding die according to an embodiment of the present invention in a state where the die is being changed.

FIG. 4 is a cross-sectional view showing a conventional injection molding die in a clamped state.

[Explanation of symbols]

1: Fixed die plate 2: Hot runner unit
3: Hot runner part 4: Mounting plate 5: Fixed mold part
6: Movable die part 7: Movable die plate 8: Cylinder device (driving means) 24: Hydraulic clamp (locking means) 30: Nozzle part
40: Through hole

Claims (2)

[Claims] 1. A fixed die plate through which a nozzle of an injection molding machine penetrates, and a nozzle portion held by the fixed die plate, one end of which abuts the nozzle to receive a molten material and the other end of which abuts a fixed die. A hot runner portion, a mounting plate having a through hole through which the nozzle portion penetrates and movable in a direction approaching the fixed die plate and a direction moving away from the fixed die plate; and a mounting plate held by the fixed die plate. Locking means for locking the fixed die via the movable die plate, the movable die plate which is driven in the direction in which the movable die is held and approaches the fixed die plate and in the direction away from the fixed die plate, and the movable die plate An injection molding apparatus having a hot runner, which comprises: 2. A fixed die plate through which a nozzle of an injection molding machine penetrates, and a nozzle portion held by the fixed die plate and having one end abutting the nozzle to receive the molten material and the other end abutting a fixed die. A mounting plate having a hot runner portion, a through hole through which the nozzle portion penetrates, and a movable plate in a direction approaching the fixed die plate and a direction moving away from the fixed die plate, and the mounting plate held by the fixed die plate. A locking means for locking the fixed die through the movable die plate, a movable die plate which holds the movable die and is driven in a direction of approaching the fixed die plate and a direction of moving away from the fixed die plate, and driving the movable die plate. Driving means for driving the mounting plate and moving the mounting plate in a direction away from the fixed die plate through the through hole. Die change method characterized by serial nozzle unit to exchange the fixed mold and the movable mold as a position that does not protrude.