JPH07329124A - Control of disk molding machine - Google Patents

Abstract

PURPOSE:To prevent the damage to male and female cutters at the time of the clogging of a nozzle by prohibiting the supply of a current to an electromagnetic direction changeover valve for the advance driving of the mile cutter when a screw position does not arive at an injection holding pressure changeover position at a time when the elapse of the set time of an injection filling time setting device is completed during injection filling. CONSTITUTION:Hydraulic oil is selectively supplied to a hydraulic piston 15 by a hydraulic pump 19 and, when an electromagnetic direction changeover valve 16 is excited, the hydraulic piston 15 moves to the right and a male cutter 10 advances and, when an electromagnetic direction changeover valve 17 is excited, the male cutter 10 retreats. A control unit 25 outputs an excitation signal to the electromagnetic direction changeover valves 16, 17 and an injection filling time setting device 26 prescribing the completion of injection filling is provided. When the clogging of a nozzle is generated, unless a screw does not arrive at the set position of an injection holding pressure changeover position setting device 27 within the set time of the injection filling time setting device 26, the circuit of the electromagnetic direction changeover valve 16 for the male cutter is turned off to prohibit the advance of the male cutter.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to control of a molding machine for a disk molded product having a center opening, and more particularly, to prevent damage to the male cutter and the mescatter for punching the center opening inside the mold during abnormal molding. Control method for prevention.

[0002]

2. Description of the Related Art In FIG. 1, the center opening is punched by the male cutter 10 and the mescutter 6 in a mold closed state after the injection is completed. However, when the molding machine is in the automatic operation, the conventional method is performed at a predetermined time after the injection is completed. In all cases, the male cutter always moved forward.

[0003]

In the recent disk molding, in order to avoid the so-called stringing phenomenon between the sprue and the nozzle, the temperature of the nozzle is lowered to a necessary minimum or the nozzle hole is narrowed. Further, in order to save unnecessary resin and shorten the molding cycle, it was necessary to lengthen the nozzle in order to make the sprue as small as possible. These causes a decrease in resin temperature in the nozzle portion, and so-called nozzle clogging occurs in which the nozzle hole is blocked by the solidified resin.

When nozzle clogging occurs, the molten resin does not reach the sprue hole 5 and the gate portion 13 and the screw 2
No. 3 cannot advance to the normal injection advance position. In this state, there is no molten resin around the gate portion 13,
When the male cutter 10 advances to punch the central opening and its edge portion 10a fits with the edge portion 6a of the mescutter 6, there is no lubrication action by the molten resin, so that the mescatter and the male cutter contact with each other and the cutter is damaged. Become.

The mess cutter is mounted on the fixed side mold 1 and the male cutter is mounted on the movable side mold 7, respectively, and the molds are closed to form a cutter. In addition, thermal expansion due to dimensional error and temperature difference of these components is caused. Since a difference or the like cannot be avoided, damage to the cutter cannot be avoided unless the edge portion 10a and the edge portion 6a make excessive metal contact with each other and there is no lubricating action by the molten resin.

[0006]

SUMMARY OF THE INVENTION Therefore, a mold provided with an male cutter and a mesh cutter for punching a central opening in a disk, a position detector for detecting a screw position in an injection device, an injection filling time setting device and an injection device. In a disk molding machine having a control device including a holding pressure switching position setting device and an electromagnetic directional switching valve for selectively switching pressure oil to a hydraulic piston driving the male cutter, a set time of the injection filling time setting device When the screw position has not reached the injection holding pressure switching position after the passage of, the energization of the electromagnetic directional switching valve for forward drive of the male cutter is prohibited.

[0007]

[Function] The state in which there is no molten resin and no lubricating action is detected by the fact that the screw has not reached the predetermined screw position within the predetermined time, and the forward movement of the male cutter is prohibited, so damage to the cutter is prevented in advance. You can do it.

[0008]

The present invention will be described in detail with reference to the accompanying drawings. FIG. 1 shows a schematic cross section of a main part of a mold for molding an optical disc, a part of an injection device, and an outline of a control device for punching a central opening of the disc. In FIG. 1, reference numeral 1 is a fixed-side die, which is composed of a fixed-side mirror surface plate 2, a fixed-side mirror surface plate mounting plate 3, a sprue bush 4, a mescutter 6 into which the sprue bush is inserted, and 5 is a sprue bushing. 4 is the sprue hole. Reference numeral 7 denotes a movable-side mold, which includes a movable-side mirror surface plate 8, a movable-side mirror surface plate mounting plate 9, a male cutter 10, a sprue projecting pin 11, a male cutter actuating hydraulic piston 15, and the like. Reference numeral 12 is a cavity formed when the fixed-side mold 1 and the movable-side mold 7 are in close contact with each other on the mold matching surface 14, and 13 is a gate which is also formed. It is needless to say that the illustrated mold device is shown in a simplified manner for the purpose of explaining the present invention, and various concrete structures are available within a known range.

Reference numerals 16 and 17 are electromagnetic directional control valves,
The hydraulic oil in the hydraulic oil tank 20 is discharged by the hydraulic pump 19, and the high-pressure oil whose pressure becomes equal to or lower than a predetermined pressure by the relief valve 18 is selectively supplied to the hydraulic piston 15. Electromagnetic directional control valve 16
Is excited, the hydraulic piston 15 moves to the right and the male cutter 10 advances. When the electromagnetic directional control valve 17 is excited, the male cutter 10 moves backward.

Nozzle 21, heating cylinder 22 and screw 2
3 constitutes a part of the injection device, the nozzle 21 touches the sprue bush 4 at the time of injection, and the screw 23
The molten resin accumulated in the front of is passed through the sprue hole 5 and the gate portion 13 by the screw 23 and is filled in the cavity 12.

A screw position detector 24 is an encoder or potentiometer for electrically detecting the screw position by synchronously displacing the reciprocating movement of the screw by a device such as a pinion in which the screw 23 is rotatably inserted and engaged with a rack. Etc. Reference numeral 25 is a control device including a microcomputer for controlling the molding machine, which inputs a signal from the screw position detector 24 and outputs an excitation signal to the electromagnetic directional control valves 16 and 17. Further, the control device 25 has an injection filling time setting device 26 that regulates the end of injection filling, and an injection holding pressure switching position setting device 27 that regulates the end of injection filling according to the screw position in parallel with the injection filling time setting device. ing. In addition, the control device 25 is connected with devices such as a setting device, a detector, and an electromagnetic directional control valve (not shown) associated with all molding controls, but they are illustrated only for those necessary for explaining the present invention.

Next, the operation will be described with reference to the flow chart shown in FIG. In step S1, when the injection starts, the screw 23 advances to fill the cavity 12 with the molten resin, and at the same time, the injection filling time timer in the control device 25 starts counting (step S2). During normal operation, that is, during injection filling without nozzle clogging, the injection filling time setting device is set so that the screw reaches the position set by the injection holding pressure switching position setting device within the time set by the injection filling time setting device. Is set to a time slightly longer than the actual filling time, the control process of injection molding proceeds from the filling process to the holding pressure process by setting the injection holding pressure switching position setting device.

At the time of abnormal injection, that is, when a nozzle is clogged, the screw does not reach the setting position of the injection holding pressure switching position setting device within the setting time of the injection filling time setting device, so that the time of the injection filling time timer is measured. The injection filling time set value is reached (step S3). In this case, the process proceeds to step S4, and it is compared whether or not the screw position has reached the injection holding pressure switching position set value, and if it has reached, the circuit of the electromagnetic direction switching valve for male cutter 16 is turned on (step S5), and it has reached. If not, turn off the circuit of the electromagnetic directional control valve 16 for the male cutter (step S6).
It prohibits the advance of Oscatta.

The processing in FIG. 2 is generally performed in the controller 25 by a program of a microcomputer, and the result of step S5 or S6 in the flow chart is fetched by the sequence controller of the controller 25. Then, the control circuit of the output electromagnetic directional control valve 16 for the male cutter is turned on or off.

[0015]

According to the control method of the present invention, it is possible to prevent the male cutter and the mescatter from being damaged due to the operation of the male cutter when the abnormal molding such as nozzle clogging is not performed by the molten resin.

[Brief description of drawings]

FIG. 1 is a diagram showing a schematic cross section of a main part of a mold for molding an optical disc, a part of an injection device, and an outline of a control device for punching a central opening of the disc.

FIG. 2 is a flowchart illustrating a control method of the present invention.

[Explanation of symbols]

 1 Fixed Side Mold 4 Sprue Bush 5 Sprue Hole 6 Mescatter 7 Movable Side Mold 10 Oscatter 12 Cavity 13 Gate Part 14 Mold Matching Surface 15 Hydraulic Piston 16, 17 Electromagnetic Directional Change Valve 18 Relief Valve 19 Hydraulic Pump 21 Nozzle 22 Heating Cylinder 23 screw 24 screw position detector 25 control device 26 injection filling time setting device 27 injection holding pressure switching position setting device

Claims (2)

[Claims] 1. A mold provided with an male cutter and a mesh cutter for punching a central opening in a disc, a position detector for detecting a screw position in an injection device, an injection filling time timer, an injection filling time setting device, and an injection holding. In a disk molding machine having a control device including a pressure switching position setting device and an electromagnetic directional switching valve for selectively switching pressure oil to a hydraulic piston driving the male cutter, the injection filling time setting device during injection filling When the screw position has not reached the injection holding pressure switching position when the set time has been completed, the energization to the electromagnetic directional switching valve for forward drive of the male cutter is prohibited. . 2. In a normal injection filling process, when the injection filling time timer is counting time and the timing does not reach the set value of the injection filling time setter, the screw holds the injection holding pressure switching position. The control method for a disk molding machine according to claim 1, wherein the injection filling time setting device and the injection holding pressure switching position setting device are set so as to reach the set value of the setting device.