JP4836751B2 - Operation method of foamed resin molding machine - Google Patents

Description

The present invention relates to a method for operating a foamed resin molding machine for producing a foamed molded product.

  Conventionally, as disclosed in Patent Document 1, a foamed resin molding machine used in the field of foam molding is configured such that a movable die plate is moved closer to and away from a fixed die plate by driving a piston. There are many things that open and close. Specifically, there is an apparatus equipped with a mold opening and closing device 10 as shown in FIG. 5, which is configured by attaching a piston 51 to a movable die plate 2 having a movable mold 4 attached to the front surface. By driving 51 with a drive cylinder 52, the movable die 4 is brought close to and away from the fixed die 3 attached to the fixed die plate 1.

  In the foamed resin molding machine as described above, a predetermined cracking gap S is secured between the fixed mold 3 and the movable mold 4 and is temporarily stopped. After the raw material beads are filled in the cavity C, the mold is moved closer to the mold. It is configured to perform tightening. The cracking gap S is important as an air escape path when the raw material beads are introduced into the cavity C by the air flow.

  However, in a conventional foam resin molding machine using a hydraulic cylinder, the pressing force of the moving die plate 2 varies depending on the viscosity of the oil, the temperature, the speed of the moving die plate 2, and the weight of the moving die 4. There is a problem that the control of the stop position of the die plate 2 is unstable and the cracking gap S fluctuates and the molding conditions vary.

In order to solve the above problems, the applicant previously applied for a foamed resin molding machine including a toggle link and a ball screw as Japanese Patent Application No. 2006-56220. According to the present invention, the cracking gap can be set with high accuracy by the positioning accuracy of the toggle link and the ball screw. However, even in this foam molding machine, when wear has progressed after using the fixed mold 3 and the movable mold 4 for many years, the mold thickness of the mold (fixed when the fixed mold 3 and the movable mold 4 are brought into contact with each other) Since the distance between the die plate 1 and the movable die plate 2 fluctuates, there is a problem that a required clamping force cannot be secured when clamping is performed to the clamping limit. Excess or deficiency of the mold clamping force causes quality defects such as variations in the density of the foam molded product, and therefore it is necessary to keep the mold clamping force constant.
JP 05-154930 A

In view of the above-described conventional problems, the present invention is a method for operating a foamed resin molding machine capable of manufacturing a foamed molded article by controlling the cracking gap with high accuracy and always ensuring a predetermined clamping force. It is an issue to provide.

The operation method of the foamed resin molding machine according to the present invention made to solve the above problems is as follows:
A fixed die plate having a fixed mold, a movable die plate having a movable mold, and a mold opening and closing device for opening and closing the movable die plate with respect to the solid die plate;
The mold opening and closing device is composed of a toggle link disposed between the movable die plate and the mold clamping housing, and a ball screw that bends and stretches the toggle link through a crosshead. An operation method of a foamed resin molding machine connected to a mold clamping force adjusting mechanism for measuring a mold clamping force and adjusting the mold clamping force to a predetermined mold clamping force ,
A first step of extending the toggle link to perform clamping to the clamping limit and measuring the load torque of the electric motor as clamping force;
While performing mold opening, the controller determines whether the mold clamping force is within the target range, and if necessary, moves the mold clamping housing using the mold thickness adjusting means to set the mold clamping force within the predetermined range. A second step of
A third step in which mold clamping is started by extension of the toggle link and the mold clamping is stopped at a position where a cracking gap is left;
A fourth step in which the raw material is filled in the cavity and re-clamped to the mold clamping limit, and then the raw material is expanded and fixed by introduction of steam and injection of cooling water; and
At the same time as mold opening after molding or before mold opening, mold is opened while air is being poured into the fixed mold, the mold opening is stopped at the mold opening cracking position, and the molded product is floated with air and moved to the movable mold side. 5th process to deposit,
A sixth step in which the mold is clamped to the cracking position of the mold release mold while air is put into the movable mold, and the molded product is deposited in the fixed mold;
And a seventh step of extruding the molded product while opening the mold.

In the invention according to claim 1, when the mold clamping force is not within the range of the target value, the mold clamping force can be adjusted within a predetermined range by the mold clamping force adjusting mechanism.

Hereinafter, the present invention will be described in detail based on embodiments.
FIG. 1 is a schematic configuration diagram showing a foamed resin molding machine provided with a mold clamping force adjusting mechanism. In FIG. 1, a movable die plate 2 is disposed to face the fixed die plate 1, and a mold clamping housing 8 is disposed on the right side of the movable die plate 2 in the drawing.

  A fixed die 3 is attached to the fixed die plate 1, and a movable die 4 is attached to the movable die plate 2. A cavity C is formed between the fixed die 3 and the movable die 4. The fixed die 3 is provided with a raw material supply device and an eject pin for extruding a molded product (not shown) penetrating the fixed die plate 1. Further, the fixed mold 3 and the movable mold 4 are provided with pipes for introducing water, steam, air, etc. (not shown).

  Four tie bars 14 are disposed through the movable die plate 2 and the mold clamping housing 8, and the mold clamping housing 8 is positioned by an adjusting nut 11 screwed into an end portion of the tie bar 14. A small gear 31 is provided coaxially with the adjustment nut 11, and a chain 35 is bridged over the small gears 31 of the four tie bars 14.

  Between the mold clamping housing 8 and the movable die plate 2, toggle links 5 constituting the mold opening / closing device 10 are arranged, and these toggle links 5 are connected to the crosshead 6. A ball nut 15 is fixed to the cross head 6, and a ball screw 7 is screwed into the ball nut 15. The ball screw 7 is screwed through the clamping housing 8 in a rotatable state. An electric motor 12 for rotating the ball screw is connected to the end of the ball screw 7 opposite to the cross head 6. That is, the mold opening / closing device 10 includes a toggle link 5 and a ball screw 7 that bends and stretches the toggle link 5 via the cross head 6.

  The mold opening / closing device 10 is connected to a mold clamping force adjusting mechanism 20. The mold clamping force adjusting mechanism 20 includes a torque sensor 21 serving as a torque detection unit as a mold clamping force measuring unit, and a mold thickness for adjusting the mold thickness of the mold clamped by moving the mold clamping housing 8. The adjusting means 9 and a controller 50 for instructing the die thickness adjusting means 9 to correct the measured deviation of the clamping force. In place of the torque sensor 21, an elongation detecting means such as a strain gauge attached to the tie bar can be used.

  The mold thickness adjusting means 9 includes a mold thickness adjusting motor 91 and a rotary encoder 92 that detects the position of the movable die plate 2, and the chain 35 is mounted on a drive gear 93 mounted on the rotation shaft of the mold thickness adjusting motor 91. Has been passed. The rotary encoder 92 can detect the position of the movable die plate 2 by detecting the rotational speed of the mold thickness adjusting motor 91. In the mold pressure adjusting means 9, when the mold thickness adjusting motor 91 is operated, the rotation of the drive gear 93 is transmitted to the chain 35, and the small gears 31 are integrally rotated simultaneously. Since each adjusting nut 11 moves forward and backward along the threaded portion of each tie bar 14, the movable die plate 2 also moves forward and backward, and the position in the front-rear direction, that is, the mold thickness can be adjusted.

  The controller 50 includes a CPU 56 and a memory 51 for storing a system program and a user program. The CPU 56 is connected to a monitor screen 52 for displaying the operating state of the molding machine main body such as liquid crystal and a touch panel 53 including a keyboard. The torque sensor 21 is connected to the CPU 56 via the interface 54, and the CPU 56 is connected to the mold thickness adjusting means 9 via the interface 55.

  By configuring the mold clamping force adjusting mechanism 20 as described above, the torque sensor 21 can measure the load torque at the time of mold clamping as the mold clamping force, and mold thickness adjusting means based on a command from the controller 50 based on the result. 9 can finely adjust the position of the mold clamping housing 8 back and forth to adjust the clamping force.

  That is, as shown in FIG. 2, mold clamping is performed by pressing a button on the touch panel 53, and it is determined whether or not the mold clamping force is lower than a target upper limit value. As a result, when the upper limit value is exceeded, the toggle link 5 is opened, and the die thickness adjusting means 9 moves the moving die plate 2 backward to increase the die thickness. Thereafter, the mold clamping is performed again to measure the mold clamping force. If the value is below the upper limit value, it is determined whether the value is above the lower limit value. If it is below the lower limit value, the toggle link 5 is opened and the die thickness adjusting means 9 moves the moving die plate 2 forward to narrow the die thickness. When the operation as described above is repeated and the mold clamping force is between the target upper and lower limits, the mold clamping force adjustment operation is completed. Even when the mold is replaced with one having a different thickness, the clamping force can be adjusted in the same manner.

The set value of the clamping force is preferably 30 to 70% of the clamping force at the time of actual molding.
This is because during actual molding, the mold clamping force increases due to expansion of the mold by steam and pressurization by blown air. If it is less than 30%, the clamping force is insufficient during actual production, and if it exceeds 70%, the clamping force becomes excessive.

Below, the operation method of a foamed resin molding machine is demonstrated easily with the process flowchart of FIG.
First, the position of the mold clamping housing 8 is adjusted in advance by driving the mold thickness adjusting motor 91 so as to match the mold thickness T of the attached mold. Then, the toggle link 5 is extended to perform mold clamping to the mold clamping limit, and the load torque of the electric motor 12 is measured as the mold clamping force. Thereafter, the mold is opened once. At this time, the controller 50 determines whether or not the mold clamping force is within a target range. If there is an excess or deficiency in the clamping force, the clamping housing 8 is finely adjusted in the front-rear direction to adjust the clamping force.

  When the mold clamping force is within the target range, mold clamping is started by extension of the toggle link 5, and the mold clamping is stopped at a position where a cracking interval S of about 0.1 to 10 mm is left. After the movable die 4 is stopped at the cracking position, filling of the raw material beads into the cavity C is started by the raw material supply device, and the filling of the raw material is ended by counting out a timer provided in the raw material supply device.

  Next, after re-clamping to the mold clamping limit, steam is introduced into the fixed mold 3 and the movable mold 4 from the steam pipe. Then, the introduction of the steam is stopped by counting out the timer for introducing the steam. The raw material in the cavity C is expanded and fused. Thereafter, cooling water is injected into the fixed mold 3 and the movable mold 4 from the water supply pipe, and the injection is stopped when the water injection timer counts out. The expanded raw material is cooled and fixed to complete the molding.

  After molding, mold opening starts at a low initial speed, and shifts to medium speed mold opening at a position 2 to 3 mm away from the mold clamping limit. Open the mold while putting in, stop the mold opening at the cracking position of the mold release, and float the molded product with air and deposit it on the movable mold 4 side. Next, the medium mold is clamped to a cracking position for mold clamping while air is being introduced into the movable mold 4, the mold clamping is stopped, and the molded product is deposited in the fixed mold 3. Thereafter, the molded product can be dropped and removed by extruding the molded product with an eject pin while opening the mold at a high speed.

  As described above, the molding of the molded product of one cycle is completed. When the same molded product is subsequently formed, the mold opening for filling the raw material can be started after the mold opening is performed to the mold opening limit or partway.

As described above, the operation method of the foamed resin molding machine of the present invention adjusts the mold clamping force adjustment mechanism to an appropriate range even when the mold wear progresses and the mold clamping force fluctuates. As a result, there is an effect that a product defect does not occur.

It is a schematic diagram of a foamed resin molding machine. It is a flowchart of a mold clamping force adjustment process. It is a process flow figure which manufactures a foaming molding article. It is a schematic block diagram of the conventional foaming resin molding machine.

  1 fixed die plate, 2 moving die plate, 3 fixed type, 4 moving type, 5 toggle link, 6 cross head, 7 ball screw, 8 mold clamping housing, 20 mold clamping force adjustment mechanism

Claims (1)

A fixed die plate having a fixed mold, a movable die plate having a movable mold, and a mold opening and closing device for opening and closing the movable die plate with respect to the solid die plate;
The mold opening and closing device is composed of a toggle link disposed between the movable die plate and the mold clamping housing, and a ball screw that bends and stretches the toggle link through a crosshead. An operation method of a foamed resin molding machine connected to a mold clamping force adjusting mechanism for measuring a mold clamping force and adjusting the mold clamping force to a predetermined mold clamping force ,
A first step of extending the toggle link to perform clamping to the clamping limit and measuring the load torque of the electric motor as clamping force;
While performing mold opening, the controller determines whether the mold clamping force is within the target range, and if necessary, moves the mold clamping housing using the mold thickness adjusting means to set the mold clamping force within the predetermined range. A second step of
A third step in which mold clamping is started by extension of the toggle link and the mold clamping is stopped at a position where a cracking gap is left;
A fourth step in which the raw material is filled in the cavity and re-clamped to the mold clamping limit, and then the raw material is expanded and fixed by introduction of steam and injection of cooling water; and
At the same time as mold opening after molding or before mold opening, mold is opened while air is being poured into the fixed mold, the mold opening is stopped at the mold opening cracking position, and the molded product is floated with air and moved to the movable mold side. 5th process to deposit,
A sixth step in which the mold is clamped to the cracking position of the mold release mold while air is put into the movable mold, and the molded product is deposited in the fixed mold;
And a seventh step of extruding the molded product while opening the mold.

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