JPH06210675A - Mold for injection molding - Google Patents

Abstract

PURPOSE:To improve precision at exchanging a mold by providing a cylindrical locating ring with center at a resin inlet in a mold for injection molding, a tapered part at its tip and a parallel part at its back, and mounting a spring at a base. CONSTITUTION:A circular groove is formed in a fixed side mold 3A and a cylindrical locating ring 18 is arranged therein. The tip of the ring 18 is shaped into a tapered part 19, a parallel part 20 is formed at its back, and a spring 21 is mounted on a stem. The center of the locating ring 18 and the center of a resin inlet 17 are arranged so as to coincide with each other. When the fixed side mold 3A is to be attached to a fixed side die plate 2, a mold attaching plate 12A and the mold 3A are integrated and inserted from the side part. The locating ring 18 is pressed to the die plate 2 in opposition to the spring 21. At a position of a circular hole 11 of the die plate 2, the tapered part 19 is positioned and fixed assuredly to the circular hole 11 at the parallel part 20 by moving with spring 21 along the circular hole 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a mold for injection molding synthetic resin.

[0002]

2. Description of the Related Art In general, injection molding of synthetic resin is performed between a fixed die plate 2 and a movable die plate 4 of an injection molding machine 1 as shown in FIG. A metal mold (hereinafter referred to as a metal mold) 3 is attached, and a synthetic resin is injected into the cavity. By the way, in order to attach and detach the mold 3, the mold 3 is loaded and unloaded laterally between the die plates as shown in the figure, which is commonly called a lateral loading method. In addition, 5 is a hydraulic cylinder for mold clamping, 6 is a spare mold, 7 is a mold carriage, 8 is a tie bar, 9 is a clamp, and 10 is a safety door.

In recent years, the number of times of die replacement has been increased due to the demand for high-mix low-volume production, and with the labor saving in production plants, there is a demand for mechanization and automation of die replacement work. This horizontal loading method is widely used because it is easy to mechanize and automate the die replacement work.

Regarding this horizontal insertion method, FIG. 5 and FIG.
Further description will be made with reference to. FIG. 5 is a perspective view showing the mounting state of the mold by the horizontal loading method, 2 is a fixed die plate of the injection molding machine, and the resin heating cylinder tip nozzle of the injection molding machine is inserted in the center thereof. Circular hole 11
Is provided. 3A is a fixed side mold of the mold 3, 3B is a moving side mold, 12A is a fixed side mold mounting plate, and in the center thereof,
Circular hole 1 for communicating with circular hole 11 of die plate 2
3 is provided therein, and a resin inflow port (not shown) of the mold is installed therein. Reference numeral 12B is a moving side die mounting plate.

A movable die plate 4 is connected to the fixed die plate 2 by a tie bar 8. The moving-side die plate 4 advances or retracts the moving-side mold 3B by a hydraulic cylinder (not shown) at the rear part thereof to perform fastening and opening of the mold 3 (see FIG. 4).

FIG. 6 is an explanatory view showing a positioning mechanism when the fixed-side die mounting plate 12A is attached to the fixed-side die plate 2, and a die positioning pin 14 is provided below the die plate 2. On the other hand, the mold mounting plate 12A is provided with a recess 15 that fits into the pin 14. 8 indicates a tie bar.

When mounting the die 3 on the injection molding machine, as shown in FIG. 5, the die mounting plates 12A and 12B, the fixed side die 3A, and the moving side die 3B are integrated into a fixed side die plate. 2 and the moving side die plate 4, and the circular hole 11 of the die plate 2 and the circular hole 13 of the fixed side mold mounting plate 12B.
Position them so that they match. Finally, the mold positioning pin 14 is raised and the pin 14 is attached to the mounting plate 1.
Fine fitting is performed by fitting in the fitting recess 15 of 2A. After that, the fixed mold attachment plate 12A is firmly fixed to the die plate 2 and the movable mold attachment plate 12B is firmly fixed to the die plate 4 by the clamp 9 (see FIG. 4).

[0008]

By the way, one of the most important things at the time of attaching the mold is that the resin inlet 1 of the mold is used.
7 and the nozzle 16 at the end of the heating cylinder of the injection molding machine (see FIG. 1)
To match the centerlines of. When the center lines do not coincide with each other or when the center lines are displaced during the operation of the equipment, a gap is created between the nozzle 16 and the resin inlet 17, and the heated and melted resin leaks from the gap to the mold. The amount of resin to be injected is reduced, causing defects due to so-called short shots. Further, when the resin comes into contact with the wiring of the injection molding machine, it causes inconveniences such as short-circuiting of the heater and failure of the electric control system. This is also undesirable for the safety of workers.

Therefore, in order to accurately attach the mold,
Traditionally, alignment pins and the like have been used. But,
Since the mold is attached to the mold mounting plate with bolts, the mounting accuracy between the mold mounting plate and the mold is poor, and there is a limit to the accuracy with which the positioning pins can be fitted, and resin leakage often occurs. Had occurred.

The present invention focuses on the above problems,
Further, it is an object of the present invention to provide a mold that can be easily and accurately replaced with the progress of mechanization and automation of mold replacement.

[0011]

The present invention has been made in order to achieve the above-mentioned object, and a mold is provided with a cylindrical ring (hereinafter referred to as a locate ring) having a resin inlet port as a center. It is provided so that it can move forward and backward freely, and a taper portion and a parallel portion are provided at the tip of this locate ring,
And the spring is attached to the base.

Since this locate ring is provided for the purpose of accurately determining the position of the resin inflow port, the center of the resin inflow port and the center of this ring must coincide with each other. Further, since the outer diameter of the parallel portion of the tip of the locate ring is to be fitted into the inner diameter of the fixed side die plate circular hole, the gap between the two must be made small.

The locate ring according to the present invention is cylindrical and can move forward and backward in the axial direction thereof. However, since the spring is attached to the base, the tip of the ring normally projects outside the mold mounting plate. When the tip portion is pressed in the axial direction, it resists the pressure of the spring and retracts inside the mold mounting plate. The tapered portion at the tip of the locate ring is for guiding the parallel portion provided adjacent to it to the circular hole of the die plate.

[0014]

When the die of the present invention is attached to the horizontal-insertion type injection molding apparatus, first, the moving side die plate is retracted, and the die attached to the die mounting plate is moved by the carriage or the carry-in machine. , Load it into the equipment from the side. At that time, insert the protruding locate ring tip end portion while pressing it against the fixed side die plate surface. Since the locating ring is pressed, it moves back into the mold against the pressure of the spring at the base. Further insertion, when the tip of the locate ring reaches the position of the circular hole provided near the center of the die plate, the tapered portion of the locate ring is first fitted into the circular hole by the pressure of the spring, While advancing inward while contacting the inner surface, finally, the adjacent parallel part,
Fully fit the inner surface of the circular hole. In this state, the center line of the circular hole of the die plate and the center line of the resin inflow port of the mold coincide with each other.

Next, the moving die plate is moved forward by the force of the hydraulic cylinder to bring the die mounting plate into close contact with the fixed die plate, and then the die mounting plate is fixed to the die plate with a clamp.

When removing the die, the movable die plate is slightly retracted after the clamp is removed. Next, the die is held by a trolley or a carry-in machine, and unloading is started toward the side. At that time, the slope of the taper part of the tip of the locate ring that was fitted in the die plate was pressed against the inner surface of the circular hole of the die plate, and the locate ring retracted into the die to move and carry out the die. It won't hurt.

Incidentally, it is difficult to move the mold laterally in the state where the parallel portion as well as the taper portion at the tip portion of the locate ring is fitted in the circular hole of the die plate, but the clamp is removed, Retreat the moving die plate,
When the pressure between the die plate and the mold mounting plate is released, the repulsive force of the cushion between the die plate and the mold mounting plate and the recoil that tightly binds both the die plate and the mold mounting plate. There is no gap between the mounting plate and the parallel part of the locate ring, which is outside the circular hole of the die plate.

[0018]

EXAMPLES The mold of the present invention will be described with reference to examples. FIG. 1 is a cross-sectional view showing a state in which the tip portion of the locate ring is fitted into the circular hole of the die plate, and FIG. 2 is a cross-section showing a state in which the locate ring is retracted into the mold by the pressure of the die plate surface. FIG. 3 and FIG. 3 are cross-sectional views showing a state where the taper portion of the locate ring has started to be fitted into the die plate circular hole.

2 is a fixed die plate, 11 is a circular hole provided in the die plate, 16 is a heating cylinder nozzle of the injection molding machine (shown by a broken line), 12A is a fixed side mold mounting plate.
13 is a circular hole provided in the mounting plate, 3 is a fixed side mold, 18 is a locate ring, 19 is a taper portion provided at the tip portion thereof, 20 is a parallel portion provided at the rear portion thereof, 21 is a base portion of the locate ring. The attached spring, 17 is the resin inflow port of the mold, and 22 is the cushion provided on the mounting plate.

As shown in FIG. 1, a circular groove is provided in the mold 3, a cylindrical locate ring 18 is provided in the mold 3, a tip thereof is tapered 19, and a parallel portion 20 is provided at the rear thereof. A spring 21 is attached to the base portion of the locate ring 18, and the tip end portion of the locate ring 18 normally projects outward from the fixed-side die mounting plate 12A.
However, in order to prevent the locate ring 18 from coming out and to regulate the length of the parallel portion 20, the die mounting plate 12A
Hold down with.

The center of the locate ring 18 and the center of the resin inflow port 17 must be aligned, while the center of the circular hole 11 of the die plate 2 and the center axis of the tip nozzle 16 of the injection molding machine must be aligned. I won't.

When the die according to the present invention is attached to the die plate, the block in which the die mounting plates 12A and 12B and the die 3 are integrated is held by a carry-in machine, and as shown in FIG.
Insert it from the side while pressing it against the die plate 2.
The locate ring 18 is retracted into the mold while countering the pressure of the spring 21. As shown in FIG. 3, the tip portion of the locate ring 18 has a circular hole 1 in the die plate 2.
When the position 1 is reached, the tapered portion 19 moves along the inner surface of the circular hole 11, and the locate ring 18 starts to project. As shown in FIG. 1, when the tapered portion 19 is completely fitted in the circular hole 11, the movement of the carry-in machine is stopped.

Next, the movable die plate is moved forward, and the die mounting plate 12A is pressed against the die plate 2. At this time, the parallel part 20 is fitted to the inner surface of the circular hole 11, and the position of the mold 3 is finely adjusted for accurate positioning. After that, the die mounting plates 12A and 12B are fixed to the die plates 2 and 4 by the clamps, respectively. To remove it, reverse the above procedure.

[0024]

As described above, when the mold of the present invention is used, it is easy to operate when mounting the mold, and the mold and the die plate circular hole are directly connected to each other without using the mounting plate. Since the positioning is performed, it can be accurately fixed without using a positioning pin or the like. As a result, the problem of resin leakage was reduced, and defects such as short shots and mechanical failures could be reduced.

Further, according to the present invention, since the locate ring can be moved forward and backward by the spring, the locate ring is automatically protruded when the mold comes to a predetermined position by simply inserting the mold from the side by the carry-in machine, and the positioning is performed. No auxiliary equipment, such as mold alignment pins, is required as it can. This has a great effect on facilitating mechanization and automation of equipment.

[Brief description of drawings]

FIG. 1 is a sectional view showing a main part of a mold of the present invention, showing a state in which a tip end portion of a locate ring is fitted into a circular hole of a die plate.

FIG. 2 is likewise a sectional view showing a state in which the locate ring is retracted inside the die due to the pressure on the die plate surface.

FIG. 3 is also a cross-sectional view showing a state where the tapered portion of the locate ring has started to be fitted into the circular hole of the die plate, similarly.

FIG. 4 is a perspective view showing a configuration of a horizontal insertion type injection molding facility.

FIG. 5 is a perspective view showing a mounting state of a die according to a horizontal loading method.

FIG. 6 is a view taken in the direction of arrow A in FIG.

[Explanation of symbols]

 1 injection molding machine 2 fixed side die plate 3A mold (fixed side) 3B mold (moving side) 4 moving side die plate 5 hydraulic cylinder for clamping 6 spare mold 7 mold carriage 8 tie bar 9 clamp 10 safety door 11 Circular hole of fixed side die plate 12A Mold mounting plate (fixed side) 12B Mold mounting plate (moving side) 13 Circular hole of fixed side mold mounting plate 14 Mold positioning pin 15 Fitting of fixed side mold mounting plate Mating concave portion 16 Nozzle of heating cylinder of injection molding machine 17 Resin inlet of mold 18 Locate ring 19 Tapered portion of locate ring 20 Parallel portion of locate ring 21 Spring

Claims (1)

[Claims] 1. A mold for injection molding having a cylindrical locate ring centered on a resin inlet, wherein the locate ring has a taper portion at a tip and a parallel portion at a rear portion, and a base portion. A mold for injection molding, which is equipped with a spring and is movable back and forth in the axial direction.