JPH04261821A - Monitor circuit for injection molding machine - Google Patents

Abstract

PURPOSE:To make it possible to detect, to display and to monitor a relation between screw position and pressure by means of a control apparatus controlling and injection molding machine. CONSTITUTION:A pulse output from a position detector 28 fitted on a servo motor driving a screw 29 is counted by means of a counter 15 to obtain a screw position, which is input in a memory 16. In addition, a pressure detected by means of a pressure sensor is input in a memory 18. An address generator generates successively addresses after injection is started to store the screw position and the pressure in the same address of each memory. An address switching circuit 21 is switched to the read-out side by a command of a monitor to read out data stored in the memories 16 and 18 on each address and they are displayed on a displaying apparatus.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention 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 a screw in the axial direction, and during the injection stroke, the position of the screw is detected by a potentiometer, etc., and the resin pressure inside the mold is detected by a sensor. However, it is possible to monitor the relationship between the screw position and resin pressure using a monitor device that is separate from the control device that controls the injection molding machine, and use it as a reference for changing injection conditions such as the injection speed for the next injection. It was commonly practiced.

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 to perform injection, and further includes a position detector for detecting the position of the screw and a pressure sensor for detecting pressure. , a control device that controls the injection molding machine includes a counter that counts pulses from the position detector, a first memory that stores the value of the counter, and a pressure signal detected by the pressure sensor that is converted into a digital signal. An address is transmitted through an analog-to-digital converter for conversion, a second memory for storing the output of the analog-to-digital converter, and an address switching circuit for switching addresses for accessing the first and second memories. An address generator for outputting and a graphic display device are provided, the first and second memories and the display device are connected to the processor of the control device by a bus, and during injection, the first and second memories sequentially specified by the address generator are connected to the processor of the control device. , the value of the counter and the output of the analog-to-digital converter are stored moment by moment in the address of the second memory, the values stored in the first and second memories are read by a monitor command, and the screw is displayed on the display device. The relationship between position and pressure is now displayed graphically.

[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 is sequentially read out for each address, and the relationship between the screw position and pressure is graphically displayed on the graphic display device based on the read data.

[0006]

[Embodiment] The figure is a block diagram showing an embodiment of the present invention.
Reference numeral 10 denotes a numerical control device for controlling the injection molding machine, and the configuration of the numerical control device 10 is described only with respect to the configuration related to the present invention. 11 is a processor, and memory (
The injection molding machine is controlled according to a control program stored in a computer (not shown). 12 is a CRT control circuit, which CR controls the relationship between the screw position and resin pressure, which will be described later.
This is to be displayed on the T-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 controls the position and speed of the servo motor 27, that is, the screw 29, in response to feedback pulses from a position detector 28 such as a pulse coder provided on the servo motor 27.

A pulse counter 15 is cleared by a command from the CPU 11 via the output circuit 14, and thereafter counts pulses from the detector 28. 20 is an address generator which is cleared by a command from the CPU 11 via the output circuit 19 and outputs addresses sequentially starting from address 0; The data is input to the memories 16 and 18 via an address switching circuit. Also, 1
Reference numeral 7 denotes an analog-to-digital converter (hereinafter referred to as A/D converter), which 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. .

With the above structure, 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 pulse counter value at that time. The pressure value will be stored. Note that 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.

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 to drive the servo motor 27 to advance the screw 29 and start injection. , 19, the pulse counter 15 and address generator 20 are cleared. 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 situation)
). In addition, the pulse counter 15
sequentially counts pulses from the detector 28 and outputs them to the memory 16, and the A/D converter 17 converts the pressure from the mold pressure sensor 31 into a digital signal and outputs it to the memory 18.
It is output to. As a result, each time an address is sequentially designated from the address generator 20, the memory 1 is placed at the address location.
6 stores the value of the pulse counter 15 at that time, that is, the position of the screw, and the memory 18 stores the value of the A/D converter at that time, that is, the value of the resin pressure. Then, during injection, the above operations are sequentially repeated.

Next, when monitoring, when a monitor command is input from the manual input device 24, the CPU 11 switches the address switching circuit 21 to the CPU side (reading) and accesses the 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 graphically on the screen 25.

[0011]

The present invention provides an injection molding machine in which injection is performed by moving a screw in the axial direction, and the control device of the injection molding machine constantly stores the screw position and pressure moment by moment during injection. Therefore, whenever you want to know the relationship between screw position and pressure, you can conveniently 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. Furthermore, 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 the drawing]

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

[Explanation of symbols]

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

Claims (3)

[Claims] Claim 1: An injection molding machine that performs injection by moving a screw in the axial direction, comprising a position detector for detecting the screw position and a pressure sensor for detecting pressure,
A control device that controls the injection molding machine includes a counter that counts pulses from the position detector, a first memory that stores the value of the counter, and converts the pressure signal detected by the pressure sensor into a digital signal. outputting an address via an analog-to-digital converter, a second memory for storing the output of the analog-to-digital converter, and an address switching circuit for switching addresses for accessing the first and second memories. an address generator and a graphic display device, the first and second memories and the display device being connected to a processor of the control device by a bus, and at the time of injection, the first and second memories sequentially specified by the address generator; The value of the counter and the output of the analog-to-digital converter are stored moment by moment in the address of the second memory, and the values stored in the first and second memories are read by a monitor command, and the screw position is displayed on the display device. A monitor circuit for an injection molding machine, characterized in that the relationship between pressure and pressure is displayed graphically. 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.