JPH0582284B2 - - Google Patents

Description

[Detailed description of the invention]

[0001]

TECHNICAL FIELD The present invention relates to a monitor circuit for monitoring the relationship between screw position and pressure in an injection molding machine.

[0002]

[Prior Art] In a conventional injection molding machine, injection is performed by moving the screw in the axial direction, and during the injection stroke, the position of the screw is detected with a potentiometer, etc., and the resin pressure inside the mold is detected with a sensor. The relationship between the screw position and resin pressure is monitored by a monitor device that is separate from the control device that controls the injection molding machine, and can be used as a reference for changing detection conditions such as the injection speed for the next injection. It was common practice to do so.

【0003】

SUMMARY OF THE INVENTION An object of the present invention is to enable the above-mentioned monitoring function to be performed by the control device itself that controls the injection molding machine.

[0004]

[Means for Solving the Problems] The present invention provides an injection molding machine that moves a screw in the axial direction using a servo motor to perform injection, including a position detector for detecting the screw position and a pressure sensor for detecting pressure. A control device for controlling the injection molding machine further includes a counter for counting pulses from the position detector, a first memory for storing the value of the counter, and a pressure detected by the pressure sensor. An analog-digital converter that converts a signal into a digital signal, a second memory that stores the output of the analog-digital converter, and an address switching circuit that switches addresses for accessing the first and second memories. and a graphic display device, the first and second memories and the display device are connected to the processor of the control device via a bus, and the address generator sequentially outputs addresses during injection. The value of the counter and the output of the analog-to-digital converter are momentarily stored in designated addresses of the first and second memories, and the values stored in the first and second memories are read by a monitor command; The relationship between screw position and pressure is displayed graphically on the display device.

[0005]

[Operation] During injection, the first memory momentarily stores the value of the detector, that is, the screw position, at the address position specified by the address generator, and the second memory stores the value of the analog-to-digital converter. The output, that is, the pressure is stored moment by moment, and this action is repeated sequentially during injection. When a monitor command is input, the control device switches the address switching circuit to the reading side, and the pressure is stored in the first and second memories. The data read out is read out sequentially for each address, and the relationship between screw position and pressure is graphically displayed on the graphic display device based on the read data.

[0006]

[Example] The figure is a block diagram of an embodiment of the present invention. 10 is a numerical control device for controlling an injection molding machine. The configuration of the numerical control device 10 is described only with respect to the configuration related to the present invention. has been done. 11
1 is a processor that controls the injection molding machine according to a control program stored in a memory (not shown). 12 is a CRT control circuit, which controls the relationship between the screw position and resin pressure, which will be described later.
It is displayed on the graphic display device 25. 13 is a pulse distributor that outputs pulses to the servo circuit 26 to drive the servo motor 27, moves the screw 29 of the injection molding machine in the axial direction, and injects the molding material in the heating cylinder 32 into the mold 30. It is. The servo circuit 26 receives feedback pulses from a position detector 28 such as a pulse coder provided on the servo motor 27 to control the position and speed of the servo motor 27, that is, the screw 29.

[0007] 15 is a pulse counter, and the output circuit 1
Cleared by command from CPU 11 via 4,
Thereafter, pulses from the detector 28 are counted. 2
0 is an address generator, which is output via the output circuit 19.
Cleared by command from CPU11, address 0
It outputs addresses sequentially from the address, and the output is sent to the memory 16,
The data is input to the memories 16 and 18 via an address switching circuit that switches the address to 18. Further, 17 is an analog-to-digital converter (hereinafter referred to as A/D converter) that converts an analog signal from an in-mold pressure sensor 31 that detects the resin pressure in the mold 30 into a digital signal and stores it in the memory 18. It is.

[0008] Since the configuration is as described above, the memories 16 and 18 store the pulse counter value at that time at the address position generated by the address generator 20, and the memory 18 stores the value of the pulse counter at that time. The pressure value will be stored. In addition, 22
is a data bus, and 23 is an address bus. Further, 24 is a manual input device provided on the operation panel or the like of the numerical control device 10.

[0009] Next, the operation of this embodiment will be explained. When the injection molding machine performs injection, the CPU 11 operates the servo circuit 26 via the pulse distributor 13, drives the servo motor 27, and rotates the screw 29.
The pulse counter 1 is advanced through the output circuits 14 and 19 to start injection.
5. Clear the address generator 20. After this, the address generator 20 outputs address addresses sequentially starting from address 0, and the addresses of the memories 16 and 18 are sent via the address switching circuit 21 (note that the address switching circuit 21 is currently on the address generator side (writing state). Also,
The pulse counter 15 sequentially counts the pulses from the detector 28 and outputs them to the memory 16.
The converter 17 converts the pressure from the in-mold pressure sensor 31 into a digital signal and outputs it to the memory 18. As a result, each time an address is sequentially designated by the address generator 20, the value of the pulse counter 15 at that time is stored in the memory 16 at the address location.
That is, the position of the screw and the value of the A/D converter at that time, that is, the value of the resin pressure, are respectively stored in the memory 18. Then, during injection, the above operations are sequentially repeated.

[0010] Next, when the motor is run, when a monitor command is input from the manual input device 24, the CPU
11 is the address switching circuit 21 on the CPU side (reading)
to access memory. Therefore, the pulse counter value stored in each address, that is, the screw position, is read out from the memory 16, and the resin pressure stored in each address is read out from the memory 18. The relationship between the screw position and the resin pressure will be displayed in a graph on the screen 25.

[0011]

Effects of the Invention The present invention provides an injection molding machine that moves a screw in the axial direction using a servo motor to perform injection, and the control device of the injection molding machine constantly stores the screw position and pressure moment by moment during injection. are doing. Therefore, whenever it is desired to know the relationship between screw position and pressure, it is convenient to be able to display this relationship by inputting a monitor command. Furthermore, since the control device that controls the injection molding machine is provided with this monitor circuit, no special monitor device is required. Therefore, an injection molding machine equipped with a monitor circuit can be made inexpensive and compact. Further, since the display device and the memory for storing the screw position and pressure are connected to the processor of the control device by bus, data can be transferred at high speed.

[Brief explanation of drawings]

FIG. 2 is a block diagram of an embodiment of the present invention.

[Figure 1]

[Explanation of symbols]

10... Numerical control device 14, 19...output circuit 22...Data bus 23...Address bus.

Claims (3)

[Claims] 1. In an injection molding machine that moves a screw in the axial direction using a servo motor to perform injection, a position detector that detects the screw position;
A control device for controlling the injection molding machine includes a pressure sensor for detecting pressure, a counter for counting pulses from the position detector, a first memory for storing the value of the counter, and a control device for controlling the injection molding machine. An analog-to-digital converter for converting a pressure signal detected by the sensor into a digital signal, a second memory for storing the output of the analog-to-digital converter, and switching an address for accessing the first and second memories. The first and second memories and the display device are connected to the processor of the control device via a bus, and the address generator outputs an address through an address switching circuit for injection, and a graphic display device. The value of the counter and the output of the analog-to-digital converter are momentarily stored in addresses of the first and second memories sequentially designated by the generator, and are stored in the first and second memories according to a monitor command. A monitor circuit for an injection molding machine, characterized in that the value is read and the relationship between screw position and pressure is displayed graphically on the display device. 2. A monitor circuit for an injection molding machine according to claim 1, wherein the detector for detecting the screw position is a position detector provided on a servo motor that moves the screw in the axial direction to perform injection. 3. The monitor circuit for an injection molding machine according to claim 1, wherein the monitor circuit is connected to a control device for controlling the injection molding machine via a bus and is built in the control device.