JP2995369B2 - Mold protection device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for continuing or interrupting a mold closing operation in response to a change in sliding resistance of a guide pin due to a temperature difference between a fixed mold and a movable mold during molding. And a mold protection device.

[0002]

2. Description of the Related Art During a molding operation by an injection molding machine or the like, a mold closing load caused by mold clamping varies between mold opening / closing strokes S as shown in FIG. Usually this load is
In the case of hydraulic drive, it is based on the dynamic pressure (pressure value) of a mold clamping cylinder, but in an electric molding machine having a servomotor, it is based on a change in current value.

[0003] The mold closing load curve P has a peak at the start of mold closing, and after a lapse of a vertical fluctuation range, finishes the high-speed movement section B of the cylinder ram in a substantially gentle descending state.
In the low pressure mold closed section, which is the next mold protection section C, a tendency to gradually increase is shown.

In a mold protection section C from a position a at which the mold closing operation is switched to a low speed to a mold closing completion position b, the mold difference is caused by a temperature difference between the fixed mold and the movable mold, insufficient lubrication of the sliding portion and galling. The sliding resistance of the mold gradually increases, and the pressure value or the current value increases stepwise as indicated by a broken line.

[0005] For this reason, even if the mold protection pressure is set to the maximum value, the mold will not close or the guide pin will seize due to the fluctuation of the sliding resistance of the mold. This problem also occurs when an extreme temperature difference is applied between the fixed mold and the movable mold.

[0006]

SUMMARY OF THE INVENTION In view of such circumstances, the present invention informs an operator of an abnormality in the mold closing operation of a mold, and damages the mold or prevents the mold from being closed so that automatic operation cannot be performed. It is an object of the invention to provide a mold protection device which automatically allows an appropriate action to be taken before it is interrupted.

[0007]

To achieve the above object, the present invention provides a sensor for detecting a mold closing load value in a mold protection section, a sensor for detecting a mold opening / closing operation position, and a sampling interval. Number of shots or time to decide,
An operation setting section for presetting parameters such as an alarm output count value and a mold protection section, an input / output section for inputting / outputting an output signal from the sensor and parameter data from the operation setting section, and storing these data. And a central processing unit (CPU) that processes data from the input / output unit, the operation setting unit, and the memory according to a predetermined program, and outputs a result to the memory. The maximum load value Ai in the mold protection section is compared with the previous maximum load value Ap at the number of shots or the time interval, and when the maximum load value continuously increases by a predetermined count, a caution signal is displayed on the alarm display section. It is characterized by having a procedure for outputting.

[0008]

With such a configuration, the maximum load value Ai in the mold protection section is stored in the memory at a preset number of shots or at intervals of time, and whether or not this value is larger than the previous maximum load value Ap. Is determined. If the maximum load value Ai is large, 1 is added to the counter. Otherwise, the counter and the output terminal of the attention signal in the CPU are reset.

Next, it is determined whether or not the count value of the counter has reached a predetermined number, and if so, a caution signal is output; otherwise, the process is repeated until the predetermined number is reached. That is, when the maximum load value increases continuously,
When the number of consecutive increases reaches a predetermined number, a warning signal is issued. If the count does not increase even once during the counting of the number of times of increase, the count is reset.

According to the warning signal, a warning is output, and a message is output to a warning display section of the controller to give attention and instructions to the operator, and the low pressure type closed value is manually corrected upward according to the situation. Or check the mold.

[0011]

An embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a block diagram showing a schematic configuration of a controller in a mold protection device according to the present invention. The sensor 1 detects a mold closing load, and an analog signal from the sensor 1 is inputted and converted into a digital value. An input / output unit 2 for outputting
An operation setting unit 3 for presetting parameters such as the number of shots or time for determining a sampling interval, a count value for alarm output, and a mold protection section; and a memory 4 for storing a maximum load value or a count value. , An alarm display section 5 for outputting an alarm message, and a CPU 6 having a program for controlling the protection pressure of the mold to an optimum value.

The sensor 1 is provided with two types of a hydraulic sensor 7 or a current sensor 8 for detecting a mold closing load pressure, and a mold position sensor 9 for detecting a mold position. In this case, the hydraulic sensor 7 is used, and when the servo motor is driven, the current sensor 8 is used.

FIG. 2 is a flowchart showing a control procedure of the CPU 6 provided in the mold protection device of the present invention. The CPU 6 determines the number of shots or the time that determines the sampling interval set in advance by the operation setting unit 3, the alarm output count value, the parameters such as the mold protection section, and the signal from the sensor output to the input / output unit. The maximum load value Ai in the die protection section is sequentially stored in the memory 4 at a preset number of shots or at intervals of time.

Next, the current maximum load value Ai stored in the memory is compared with the previous maximum load value Ap, and Ai>
If Ap, 1 is added to the counter of the CPU 6 and this count value is stored in the memory 4. If not, the counter and the output terminal of the caution signal in the CPU 6 are reset.

After the count of the counter is incremented, the CPU 6 determines whether or not the count value of the counter has reached a predetermined set value, and if so, issues a caution signal to alert the operator to the alarm display section. 5 to cause the display unit 5 to output an alarm message.

As a result, the operator monitors and determines the fluctuation of the sliding resistance of the mold in which the controller is actually operating with respect to the mold protection pressure set by the operator, and furthermore, from the warning display unit. It can be read that the maximum load value is continuously increasing based on the preset count number (for example, 5 times) by the attention signal of (1).

[0017]

As is apparent from the above description,
According to the mold protection device of the present invention, the maximum load value is detected at a certain number of shots or at intervals of time, and when the maximum load value is continuously increased as compared with the previous value, the worker can be notified with an alarm. Therefore, it is possible to manually correct the low-pressure mold closing value to protect the mold by manual operation or check the mold according to the situation.

In particular, since the setting of parameters and the like can be freely changed in the apparatus of the present invention, the mold can be protected without interrupting the molding operation frequently in the initial stage of molding in which the sliding resistance of the mold fluctuates greatly. , Which can contribute to the promotion of the molding cycle.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of a controller of a mold protection device according to the present invention.

FIG. 2 is a flowchart of a CPU in the controller of FIG. 1;

FIG. 3 is an explanatory diagram showing output characteristics of a mold closing load indicating fluctuation of sliding resistance of a mold attached to a molding machine, corresponding to a mold closing stroke.

[Explanation of symbols]

 Reference Signs List 1 sensor 2 input / output unit 3 operation setting unit 4 memory 5 alarm display unit 6 CPU 7 oil pressure sensor 8 current sensor 9 type position sensor

Continued on the front page (58) Fields surveyed (Int.Cl. ⁶ , DB name) B29C 45/76-45/84 B29C 45/64-45/68 B29C 33/20-33/24 B22D 17/26

Claims (1)

(57) [Claims] A sensor for detecting a mold closing load value in a mold protection section; a sensor for detecting a mold opening / closing operation position;
An operation setting unit for presetting parameters such as the number of shots or time for determining a sampling interval, a count value for alarm output, and a mold protection section; and an input / output unit for inputting / outputting an output signal from the sensor and parameter data from the operation setting unit. An output unit, a memory for storing these data,
A central processing unit (CPU) that processes data from the input / output unit, the operation setting unit, and the memory according to a predetermined program, and outputs a result to the memory, wherein the program sets a predetermined number of shots or time. The maximum load value (Ai) in the mold protection section is compared with the previous maximum load value (Ap) at intervals of. When the maximum load value continuously increases by a predetermined count, a caution signal is displayed on the alarm display. A mold protection device having a procedure for outputting.