JPS60179216A - Injection compression mold and injection compression molding method making use of mold - Google Patents

Abstract

PURPOSE:To enable to obtain a stabilized injection compression-molded article always, by changing over to a compression process from a filling process when a filled state arrives at the predetermined filled state in the inside of a mold cavity by detecting the state of filled resin within the mold cavity. CONSTITUTION:An electric signal is set by a filled state setting device 29 through resin pressure, a resin temperature or a mold opening quantity to be detected by a pressure sensor 24, a temperature sensor 26 or a mold opening quantity detector 32 respectively. A comparator 30 compares a value set by the setting device 29 with values to be detected by both the sensors 24, 26 or a sensor 32 and when the set value and the detected values coincide with each other, sends out a signal, controls a solenoid relief valve 28 and changes over hydraulic pressure of a closing cylinder 12 to closing pressure for a compression process. With this construction, when filling of resin is performed, the filled state in the inside of a mold cavity is detected by the filled state setting device 29 such as the pressure sensor 24 or the temperature sensor 26 or the mold opening quantity detector 32 and when the state arrives at completion terms of a predetermined filling process, the process is changed over to the next compression process.

Description

[Detailed Description of the Invention] A method of filling a mold cavity with resin by keeping it open by a certain amount, and then increasing the mold clamping pressure to close the opening amount;
Alternatively, the mold joint surface is initially closed, the joint surface is opened by a predetermined amount by the pressure of the resin filled in the mold gap, and after filling is completed, the opened joint surface is returned to its original state as the filled resin contracts. There are two ways to close the mold, and in either method, after filling the mold cavity with resin, the mold is opened by a predetermined amount of compression, and then the clamping force is increased to open the mold. This method compresses the joint surfaces until they close.

However, in the conventional method, during the compression process after resin filling, the communication between the injection nozzle that supplies resin into the mold cavity and the mold cavity is cut off with a push-off valve, and then compression is performed. 191 is activated at the start of the compression process by the time-out signal of the timer that operates at the same time as the start of resin filling, or by the injection completion signal that is sent at the same time as the filling is completed.
It will be done.

Therefore, regardless of the amount of resin filled into the mold cavity, the injection process is switched to the compression process after a set time has elapsed. Once the compression process is switched to a, there is no flow of resin between the injection nozzle and the mold cavity (
It is not possible to correct excess or insufficient filling of resin in the mold cavity.

As a result, very strict metrological boundaries are required. If the measurement is incorrect for each shot, the amount filled into the mold cavity will also differ, and the method using the mold to always obtain a stable injection compression molded product even if the actual compression amount varies slightly The mold for injection compression molding is provided with a detection device that detects the oil temperature or the opening amount of the mold, and switches from the filling process to the compression process when the detection device reaches a preset filling condition in the mold cavity. (Fixed plate with a movable mold fixed to a movable plate 14 integrally attached to a mold clamping ram 13 that moves forward and backward in the pressure oil of the molds) 1
When the molds 11 and 16 are closed during filling with molten resin, they cooperate with a cavity plate 17 to form a mold cavity 18. The cavity plate 17 is attached to the movable mold 11 so that it can move forward and backward by a predetermined compression amount δ, and when it comes into contact with the mold bartending surface A, a predetermined compression amount δ is ensured. The movable mold u22 that is pushed from the back side of the mold bartending surface A by the piston rod 2J of the mold closing cylinder 20 provided in the mold 1 is a gate cut sill, and the piston rod 23 Mold compression (lower half of Figure 1 is shown)
During VC, the resin passage between the mold cavity 18 and the spool 18a leading to a resin supply nozzle (not shown) is blocked. A pressure sensor 24 detects the resin pressure within the mold cavity 18, and is configured to detect the pressure via the bottles 2 and 5. 26 is a temperature sensor that detects the resin temperature in the mold cavity 18. u32 is a differential transformer 32a connected to a mold opening amount detector that comes into contact with the holder 32b and detects the amount of mold opening. It is. 27
is an electromagnetic switching valve for opening and closing the mold, and its switching controls the forward and backward movement of the mold clamping ram 13. 28 is electromagnetic +71
J-) The set pressure in the control circuit is changed in proportion to the strength of the voltage acting on the valve. Reference numeral 29 denotes a filling state setting device which sets the resin pressure, resin temperature, or mold opening amount detected by the pressure sensor 25, temperature sensor 26, or mold opening amount detector 32 as an electrical signal such as a voltage. A comparator 30 compares the value set in the setting position 29 with the value generated by both the sensors 24, 26 or 32, and when the set value and the detected value match, a signal is generated, and the electromagnetic relief valve 28f: The hydraulic pressure of the mold clamping cylinder 12, which has been the mold clamping pressure for the filling process, is switched to the mold clamping pressure for the compression process. Here, in this example, an electromagnetic relief valve was used to set the mold clamping pressure, but this
Not only LC, but also multiple IJs with different set pressures.
It is obvious that there is no problem even if the J-F valve is switched by the coincidence signal.

31 is a changeover switch for selecting the sensor 24, 26 or 32. In addition, if resin filling is performed in the same process using both sensors 24, 26 and 32 without using the changeover switch 31, the pressure sensor, temperature sensor, or filling state detection device such as mold opening amount detection will not work properly. The filling state in the mold cavity is detected, and when a preset filling process completion condition, such as resin pressure or resin temperature, is reached, the next process, the compression process, is started.

Therefore, as mentioned at the beginning, the drawback of the conventional method of switching from the filling process to the compression process after a preset time has elapsed, regardless of the filling state in the mold cavity, is eliminated.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a mold according to the present invention. FIG. 2 is a diagram showing a control circuit of a mold clamping device using gold mk according to the present invention. 1]...Moving mold, 16...Fixed mold, 17...
Cavity plate, 10... Mold cavity, 20
...Mold closing cylinder 1-122...Gate cut cylinder 124...Pressure sensor, 26...Temperature sensor,
28...Electromagnetic relief valve, 29...Filling state setting device, 30...Comparator, J! -・-TA'NO f'J3 quantity もE1 flea.

Claims (1)

[Claims] 1. A mold cavity formed by joining a fixed mold and a movable mold, and a mold joint surface that is compressed to a predetermined mold compression amount when filling of resin into the mold cavity is completed. a mold compression amount setting device for maintaining, a gate cutting device for disconnecting the communication between the mold cavity and the mold gate after completion of filling the resin into the mold cavity, and a resin pressure in the mold cavity; Injection consists of a filling state detection device that detects the filling state such as temperature and mold opening amount, and when a predetermined state is reached, increases the mold clamping pressure and sends a signal to the mold clamping control circuit to compress the filled resin in the mold cavity. Mold for compression molding. 2. A mold cavity formed by joining a fixed mold and a movable mold, and a mold compression amount setting device that maintains the mold joint surface at a predetermined mold compression amount when filling of resin into the mold cavity is completed. and a gate cutting device that cuts off communication between the mold cavity and the mold gate after the resin filling into the mold cavity is completed, and a gate cut device that controls the resin pressure, temperature, mold opening amount, etc. in the mold cavity. Using a mold consisting of a filling state detection device that detects the filling state and sends a signal to the mold clamping control circuit to increase mold clamping pressure when a predetermined state is reached and compress the filled resin in the mold cavity, An injection compression molding method in which, when the filling of resin into the mold cavity is completed, the mold joint surface, which is maintained at a predetermined mold compression amount, is closed and the filled resin in the mold cavity is pressed.