JPH08164546A - Method and apparatus for controlling injection of injection molding machine - Google Patents

Abstract

PURPOSE: To control the injection of an injection molding machine so as to hold the amt. of the resin charged in a mold at every shot to a constant level without taking labor even when the back flow of the resin is generated by the abrasion of a screw or cylinder. CONSTITUTION: A mold internal pressure sensor 3, a measuring device 5 displaying a mold internal pressure waveform, a setting device 7 having a setting table presetting the reference value of mold internal pressure and the tolerance value of a mold internal pressure change and setting the alteration of a weighing completion position or injection stroke according to the shift degree of the tolerance value and a controller 6 comparing the mold internal pressure detected by the mold internal pressure sensor 3 with a set value are provided and the weighing completion position or injection stroke is altered on the basis of the signal of the controller 6.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection control method and apparatus for an injection molding machine.

[0002]

2. Description of the Related Art Conventionally, injection molding in which a molding material (hereinafter referred to as resin) obtained by adding metal powder, glass fiber, carbon fiber, ceramics, etc. to a resin is plasticized and melted, measured, and injected into a mold. When the operation is repeated,
Cylinder wear and screw wear due to extremely hard resin,
There is a problem in that the backflow prevention ring is worn, and when shot from the same measurement completion position, a short shot occurs in the molded product due to the backflow of the resin. Therefore, by taking advantage of the fact that the amount of residual resin (the gap between 0 and SO in Fig. 4) decreases as the backflow of resin increases, the next shot is measured when the residual amount becomes zero or less than a predetermined amount. The molding completion position was moved by an arbitrary amount in the direction of increasing the amount, and the molding was continued so that a predetermined amount of the remaining amount could be secured. Also, by utilizing the fact that the mold internal pressure decreases as the amount of resin filled in the mold decreases, if it is found that the mold internal pressure has been detected and it has become lower than the set value of the mold internal pressure, Each time, the molding conditions such as increasing the measurement completion position in the direction of increasing the injection amount by hand were changed. Next, a more detailed description will be given with reference to the drawings.

FIG. 4 is a diagram showing injection / measurement positions when the cylinder is not worn. That is, screw 2
It shows that the measurement completion position or the position S1 immediately before injection advances to the position S0 by the injection operation, and the remaining amount is secured between the origin 0 of the screw position and SO. Also,
The mold internal pressure detected by the mold internal pressure sensor 3 is displayed as a mold internal pressure waveform on the measuring instrument 5 via the amplifier 4 every shot.

FIG. 5 shows the injection when the cylinder is worn.
It is a figure which shows a measurement position. That is, the reverse flow rate of resin at the time of injection increases due to the worn portion 10 of the cylinder 1, and the screw position SO at the time of completion of injection is infinitely 0.
It means that the remaining amount cannot be secured due to approaching to.

FIG. 6 is a diagram showing injection / measurement positions when the measurement completion position is increased. That is, because the remaining amount cannot be secured, the measurement completion position S1 for the next shot is increased to S2 (> S1), and the screw position SO at the completion of injection becomes sufficiently larger than the origin 0 of the screw position. It shows that the quantity was secured.

[0006]

However, the fact that the remaining amount becomes less than or equal to the predetermined amount can be detected by using the alarm device of the injection molding machine, but the measurement completion position is moved so that the remaining amount can be secured by the predetermined amount. However, it is necessary to manually perform the operation to increase the injection amount each time, which is a cause of cost increase, which is contrary to labor saving. Also, when detecting the mold internal pressure and changing the molding conditions, it is necessary to always manually perform the same.
The present invention has been made in view of such problems of the conventional technology, and an object of the present invention is to perform manual intervention even when backflow of resin occurs due to wear of a screw, a cylinder, or the like. It is another object of the present invention to provide an injection control method and apparatus for an injection molding machine, which can maintain the amount of resin filled in each shot mold at a constant level.

[0007]

According to the injection control method for an injection molding machine of the present invention, a reference value of mold internal pressure and a permissible value of change in mold internal pressure are set in advance, and measurement is completed depending on the degree of deviation from the permissible value. A setting table configured by setting the changed amount of the position or the injection stroke is stored in a memory device, and when the mold internal pressure deviates from the set value in any molding shot, the next table is automatically set according to the setting table. It is characterized in that the measurement completion position of the shot or the injection stroke is changed.

More specifically, when the internal pressure of the mold is lower than the set value in any molding shot, the metering completion position or the injection stroke of the next shot is automatically increased according to the setting table. Is characterized by.

More specifically, in any molding shot, when the mold internal pressure rises above the set value, the metering completion position or injection stroke of the next shot is automatically reduced according to the setting table. Is characterized by.

According to the injection control method of the injection molding machine of the present invention, when the mold internal pressure is detected and the mold internal pressure is lower than the set value of the mold internal pressure, the injection filling amount increases in the direction where the injection filling amount increases or When the injection stroke is increased and the mold internal pressure rises above the mold internal pressure setting value, the injection control method that changes the metering completion position or the injection stroke in the direction in which the injection filling amount decreases decreases the molding condition in advance. The reference value of the mold internal pressure and the allowable value of the mold internal pressure change are set, and a setting table in which the increment / decrement of the measurement completion position or the increase / decrease of the injection stroke is set according to the degree of deviation from the allowable value is stored in the storage device. , In any molding shot, when the mold internal pressure deviates from the set value, the metering completion position or injection stroke is automatically increased or decreased for the next shot according to the setting table. It is characterized in.

The injection control method of the injection molding machine according to the present invention is characterized in that the above-mentioned mold internal pressure is replaced with the remaining amount.

The injection control method of the injection molding machine according to the present invention is characterized in that the injection load pressure is used in place of the mold internal pressure.

An injection control device for an injection molding machine according to the present invention sets a mold internal pressure sensor, a measuring instrument for displaying a mold internal pressure waveform, a reference value of the mold internal pressure and an allowable value of change in the mold internal pressure in advance. , Comparing the set value with a setter having a setting table that sets a change amount of the measurement completion position or the injection stroke according to the degree of deviation from the allowable value, and the set value with the mold internal pressure detected by the mold internal pressure sensor It is characterized in that the metering completion position or the injection stroke is changed based on a signal from the controller.

[0014]

In the injection control method and apparatus according to the present invention, the amount of increase / decrease in the measurement completion position when the mold internal pressure falls below or rises above the set value of the mold internal pressure is determined, and the setting table is stored in the storage device. The memory is stored, and the metering completion position of the next shot or the injection stroke is automatically increased or decreased according to the table, and the mold internal pressure is constantly controlled within the predetermined allowable decrease ΔP of the mold internal pressure. The mold internal pressure may be controlled instead of the remaining amount or the injection load pressure.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing changes in the mold internal pressure waveform due to the progress of cylinder wear. The Max value of the mold internal pressure, P0 (reference value), is P1 due to resin backflow due to the worn portion 10 of the cylinder 1. (<P0) and wear part 10
Indicates that the Max value of the mold internal pressure has decreased to P2 (<P1 <P0).

FIG. 3 is a diagram in which the Max value of the mold internal pressure and the rule for the increase of the measurement completion position are defined, and the Max of the mold internal pressure is Max.
When the value decreases from P0 to P1 by ΔP, the weighing completion position S1
Is increased to S2 to ΔS, and the Max value of the mold internal pressure is P0.
From P2 to P2, the weighing complete position S1 up to S3 2 △
It shows that S is increased.

In FIG. 1, the mold internal pressure detected by the mold internal pressure sensor 3 and amplified by the amplifier 4 is displayed on the measuring instrument 5 and input to the controller 6. Setting device 7
Setting table in which the Max value P0 of the mold internal pressure and the allowable value of the mold internal pressure change are set in the storage device and the increment of the measurement completion position or the injection stroke is set according to the degree of deviation from the allowable value (Fig. 3) is stored in memory. The setting table may be stored in the controller. Then, in any molding shot, the detected value of the mold internal pressure and the set value are compared by the controller 6, and if the set value is not more than the set value P1 (= P0-ΔP), for example, the rule defined in FIG. Accordingly, the weighing completion position is increased by ΔS. After that, as the mold internal pressure further decreases and decreases from the Max value P0 of the mold internal pressure to 2ΔP, 3ΔP, the controller 6 automatically indicates the measurement completion position as 2ΔS, 3ΔS. Calculate and increase. The signal from the controller 6 is amplified by the amplifier 8 and input to the drive device 9 to increase the measurement completion position. The above-mentioned device and its arrangement can be arbitrarily selected within the range in which the function of each device is not lost, and can be replaced with a device or a part having the same function.

In the above embodiment, the internal pressure of the mold is detected to increase the measurement completion position. However, in addition to this, there is a gap between the origin 0 of the screw position and the screw position SO at the completion of injection. Needless to say, similar control can be performed by using the amount, the injection load pressure of the injection cylinder, and the like. Further, the injection stroke may be increased instead of increasing the measurement completion position. Further, in the above embodiment, the case where the mold internal pressure is reduced has been described.However, when the mold internal pressure is increased, conversely, the measurement completion position is decreased or the injection stroke is decreased to reduce the mold internal pressure. It goes without saying that the control can be performed within a predetermined allowable range. Also, if the mold internal pressure decreases due to gate clogging, etc.,
Since an abnormal increase in injection load pressure and the like is detected, it is safer and more effective when used in combination with a device that stops injection. In addition, the detailed configuration can be arbitrarily changed without departing from the scope of the present invention.

[0020]

Since the present invention is configured as described above, the effects as described below can be obtained. In other words, even if resin backflow occurs due to abrasion of the screw, cylinder, etc., the mold internal pressure, residual amount, or injection load pressure can be controlled within a predetermined allowable value without human intervention, so that each shot metal The amount of resin filled in the mold can be maintained at a constant level.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a diagram showing changes in a mold internal pressure waveform due to progress of cylinder wear.

FIG. 3 is a diagram in which rules for increasing the Max value of the mold internal pressure and the measurement completion position are determined.

FIG. 4 is a view showing an injection / measurement position when the cylinder is not worn.

FIG. 5 is a diagram showing injection / measurement positions when the cylinder is worn.

FIG. 6 is a diagram showing injection / measurement positions when the number of measurement completion positions is increased.

[Explanation of symbols]

 1 Cylinder 2 Screw 3 Mold pressure sensor 4, 8 Amplifier 5 Measuring instrument 6 Controller 7 Setting device 9 Drive device 10 Wear part

Claims (5)

[Claims] 1. A setting table in which a reference value of mold internal pressure and a permissible value of change in mold internal pressure are set in advance, and a measurement completion position or a change amount of an injection stroke is set according to the degree of deviation from the permissible value is stored. A memory is stored in the device, and when the mold internal pressure deviates from the set value in any molding shot, the measurement completion position or injection stroke of the next shot is automatically changed according to the setting table. And an injection control method for an injection molding machine. 2. When the mold internal pressure is detected and the mold internal pressure is lower than the set value of the mold internal pressure, the metering completion position or injection stroke is increased in the direction of increasing the injection filling amount to set the mold internal pressure. When the mold internal pressure rises above the value, in the injection control method that changes the molding condition so that the injection filling amount decreases and the metering completion position or the injection stroke decreases, the mold internal pressure reference value and the mold internal pressure change in advance. The setting table, which sets the allowable value of, and sets the increment / decrement of the metering completion position or the increment / decrement of the injection stroke according to the degree of deviation from the allowable value, is stored in the storage device, and the internal pressure of the mold is reduced at any molding shot. When the value deviates from the set value, the injection control method of the injection molding machine is characterized in that the metering completion position of the next shot or the injection stroke is automatically increased or decreased according to the setting table. Law. 3. An injection control method for an injection molding machine, wherein the mold internal pressure according to claim 1 or 2 is replaced with the remaining amount. 4. An injection control method for an injection molding machine, wherein an injection load pressure is used instead of the mold internal pressure according to claim 1. 5. A mold internal pressure sensor (3), a measuring instrument (5) for displaying a mold internal pressure waveform, a reference value of the mold internal pressure and an allowable value of change in the internal mold pressure are set in advance, and the allowable value is set. The setting device (7) having a setting table for setting the change amount of the measurement completion position or the injection stroke according to the degree of deviation from the value, the mold internal pressure detected by the mold internal pressure sensor (3) and the set value. An injection control device for an injection molding machine, comprising: a controller (6) for comparing the above-mentioned items, and changing a measurement completion position or an injection stroke based on a signal from the controller (6).