JP2599063Y2 - Injection molding machine pressurization completion control device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for controlling completion of pressurization of a mold of an injection molding machine.

[0002]

2. Description of the Related Art In an injection molding machine in which mold clamping is performed by hydraulic pressure, when the mold clamping cylinder reaches a preset pressure, the pressurizing oil acting on the cylinder is cut off. However, if the timing of unloading the booster pump that sends the pressurized oil to the mold clamping cylinder is bad, the pressure control valve will overshoot, and the mold clamping force exceeding the set pressure will be lost. Hang on the mold.

[0003]

[Problems to be Solved by the Invention] As a result of applying a mold clamping force higher than a set pressure to the mold, the mold is damaged or its life is shortened. Also, the machine is initially adjusted to use the rated clamping force at the timing of unloading the booster pump, but setting the clamping pressure low,
It may not be possible to adjust properly if it changes delicately due to disturbances such as oil temperature.In such cases, the setting time of the timer differs depending on the person because the setting time of the timer had to be changed manually by experience and intuition. However, there is a disadvantage that an optimum mold clamping force cannot be obtained and a defective product is formed.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a mold clamping pressurization completion control device which eliminates the above-mentioned disadvantages, eliminates damage to a mold, and can obtain the best clamping force.

In order to achieve the above-mentioned object, the present invention relates to a mold-clamping-completion completion control device for transmitting a mold-clamping-completion completion signal at the completion of a mold-clamping process of an injection molding machine that performs mold clamping by hydraulic pressure. A pressure sensor for detecting a pressure waveform at the time of a mold clamping process provided in the cylinder, a setting device for setting a pressure for generating a preset maximum clamping force and an allowable range thereof, and a pressure value detected by the pressure sensor Is activated by a signal transmitted when a preset value set in the setting device is reached, and cuts off the action of the pressure oil acting on the mold clamping cylinder on the mold clamping cylinder when a preset time has elapsed. A timer for cutting off the pressure of the booster pump is compared with the pressure value detected by the pressure sensor and the pressure set in the setting device and its allowable range, and the maximum pressure value detected by the pressure sensor is set in the setting device. A learning circuit that sets the timer to a shorter time if the maximum pressure value is higher than the allowable pressure range and sets a longer time to the timer if the maximum pressure value is lower than the allowable pressure range so as to fall within the allowable pressure range. A mold clamping pressurization completion control device comprising a comparison arithmetic device having

[0006]

When the maximum pressure value detected by the pressure sensor is higher than the allowable pressure range, the set time of the timer is shortened. When the maximum pressure value is lower than the allowable pressure range, the learning circuit of the timer is used. By setting a long setting time, the best clamping force can be obtained.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described with reference to FIGS. 1 to 5. Reference numeral 1 denotes a mold clamping cylinder in which a mold clamping ram 3 having a movable die 2 mounted therein is slidably inserted. Reference numeral 4 denotes an electromagnetic switching valve that causes the pressure oil from a hydraulic pump 5 to act on the mold clamping cylinder 1 and controls the mold clamping ram 3 to move forward and backward.

Reference numeral 6 denotes a pressure P1 set in a pressure setting device 7 for setting a pressure for obtaining a maximum mold clamping force by an electromagnetic relief valve.
In addition, the pressure in the mold clamping cylinder 1 is automatically controlled by the allowable value ± △ P. 8 is the mold clamping cylinder 1
Is a pressure detecting device for detecting the pressure inside the mold-clamping-side oil chamber 9.

Reference numeral 10 denotes a comparison operation device which compares the pressure detected by the pressure detection device 8 with the pressure P1 set in the pressure setting device 7, and starts the operation of the timer 11 when the detected pressure value exceeds the set pressure P1. When the timer 11 elapses a preset time ΔT1, an electric signal acts on the electromagnetic switching valve 4, the electromagnetic switching valve 4 is brought to the position shown in the figure, and the hydraulic oil of the hydraulic pump 5 does not act on the mold clamping cylinder 1. At the same time, a boost completion signal is transmitted.

As shown in FIG. 2, the comparison operation device 10 is set so that the maximum pressure value P detected by the pressure detection device falls within the allowable pressure range set by the setting device, that is, (P1- △
P) ≦ P ≦ (P1 + ΔP) When the maximum pressure value P is higher than the allowable pressure range, that is, when (P1 + ΔP) <P, the time set for the timer is shortened, and the maximum pressure value becomes the allowable pressure. When the value is lower than the range, that is, when P <(P1− △ P), there is provided a learning circuit for setting a longer set time of the timer.

The learning circuit will be described with reference to the flowchart of FIG. 5. In 1 STEP, the maximum pressure value P is monitored. In 2 STEP, it is determined whether or not the maximum pressure value P is within an allowable range set in the setting device.

When P <(P1- △ P) in 2 STEP,
That is, as shown by the solid line in FIG. 4, when the set time of the timer 11 is too short and the maximum pressure value P falls below the allowable range, the process goes to 3 STEP, and the set time of the timer 11 in the next cycle is changed from the time T1. The time of the timer 11 is reset so that the maximum pressure value P falls within the allowable range as shown by the broken line diagram as long Δt1. Also, when the maximum pressure value P is within the allowable range in 2 STEPs, that is, when the diagram shown in FIG. 2 is reached, the operation proceeds to 4 STEPs and the operation is continued in the next cycle for the set time ΔT1 as it is.

In 2 STEP, the maximum pressure value P is (P1 + △
P) <P, that is, as shown by the solid line in FIG.
If the maximum pressure value P exceeds the permissible range because the set time of 1 is longer than ΔT1 and the maximum pressure value P exceeds the allowable range, the process goes to 5 STEP, and the set time of the timer 11 in the next cycle is set as Δt2 shorter than ΔT1, as indicated by the broken line diagram. The time of the timer 11 is reset so that the maximum pressure value P falls within the allowable range.

[0014] From the above 3 to 5 STEP, 1S again
Returning to the TEP, the monitoring of whether the maximum pressure value P is repeatedly within the allowable range is continued.

[0015]

According to the present invention, since the learning circuit constantly monitors the maximum pressure value P so as to be within the allowable range, an excessive force is applied to the mold so that the mold is not damaged. Instead, the maximum pressure value P falls below the allowable range, and troubles such as defective products being formed without obtaining the optimum mold clamping force can be avoided.

[Brief description of the drawings]

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

FIG. 2 is a pressure diagram when a maximum pressure value P is within an allowable range.

FIG. 3 is a pressure diagram when the maximum pressure value P exceeds an allowable range.

FIG. 4 is a pressure diagram when the maximum pressure value P falls below an allowable range.

FIG. 5 is a flowchart of a learning circuit.

[Description of Signs] 1 Mold clamping cylinder 2 Moving die 3 Mold clamping ram 4 Electromagnetic switching valve 5 Hydraulic pump 6 Electromagnetic relief valve 7 Pressure setting device 8 Pressure detection device 9 Mold clamping side oil chamber 10 Comparison operation device 11 Timer

Claims (1)

(57) [Scope of request for utility model registration] 1. A mold-clamping press-up completion control device configured to transmit a mold-clamping boosting completion signal when a mold-clamping process of an injection molding machine that performs mold-clamping by hydraulic pressure is completed. A pressure sensor that detects the pressure waveform of the pressure, a setting device that sets a pressure for generating a preset maximum mold clamping force and an allowable range thereof, and a pressure value detected by the pressure sensor is set in the setting device in advance. A pressure pump pumping cut-off timer that is activated by a signal transmitted when the set value is reached, and that cuts off the action of the pressure oil that was acting on the mold clamping cylinder on the mold clamping cylinder when a preset time has elapsed. And comparing the pressure value detected by the pressure sensor with the pressure set in the setting device and its allowable range, and the maximum pressure value detected by the pressure sensor falls within the allowable pressure range set in the setting device. Thus, when the maximum pressure value is higher than the allowable pressure range, the set time of the timer is shortened, and when the maximum pressure value is lower than the allowable pressure range, the comparison operation device having a learning circuit for setting the timer time longer is provided. Mold clamping pressurization completion control device.