JP2002120265A - Injection molding machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a circuit constitution on the side of a main control unit and the wiring of the main control unit with each sensor part and each control part, to make a noise-resisting performance excellent and also to facilitate an extension of the sensor part and the control part. SOLUTION: Serial communication means provided at a position sensor part, a pressure sensor part, a temperature control part and servo control parts for injection, metering, mold opening and closure and ejection are connected respectively to the serial communication means of the main control unit.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric in-line screw type injection molding machine, and more particularly to a technique relating to a communication connection method between a main control unit and each sensor unit or each servo control unit in the injection molding machine. About.

[0002]

2. Description of the Related Art In an electric injection molding machine, a main control device for controlling the entire machine (injection molding machine) operates based on various preset operation control programs and set values.
Control each servo control unit while referring to the actual measurement value of each sensor to execute weighing, injection, mold opening and closing, and eject operation, or control the band heater driver to execute temperature control control of each unit It is made to let.

FIG. 2 is a block diagram showing the configuration of a main part of a conventional electric injection molding machine. In FIG. 2, reference numeral 100 denotes a main controller that controls the entire machine, 110 denotes a position sensor unit, 120 denotes a pressure sensor unit, 130 denotes a temperature control unit, and 14 denotes a temperature control unit.
0A to 140D are servo control units, and 150A to 150D are servo motors.

Although only one position sensor unit 110 is shown in FIG. 2, in actuality, the position of a movable die plate (or a crosshead of a toggle link mechanism for driving the screw) is detected for detecting the position of a screw. And three position sensors 110 for detecting the position of the eject member. Each position sensor unit 110 has the same configuration, and a position detection unit 1 composed of a rotation pulse encoder.
11 and a signal processing unit 112 for appropriately processing the output of the detection unit 111. The signal processing unit 112 sends out A-phase and B-phase detection pulse signals to the counter 102 of the main controller 110. You. The arithmetic control means 101 of the main control device 100 recognizes the position of the measured object based on the output from the counter 102.

FIG. 2 shows only one pressure sensor section 120. However, actually, two pressure sensor sections 120 are provided for detecting an injection pressure and for detecting a mold opening / closing pressure. Each pressure sensor unit 120 has a similar configuration, and includes a pressure detection unit 121 using a strain gauge or the like.
And a signal processing unit 1 for appropriately processing the output of the detection unit 121
22. From the signal processing unit 122, the pressure detection data as an analog signal is transmitted to the A / D
It is sent to conversion section 103. The arithmetic and control unit 101 of the main control device 100 detects the pressure of the object to be measured based on the signal converted into a digital signal by the A / D converter 103.

Although only one temperature control unit 130 is shown in FIG. 2, four to seven temperature control units 130 are actually provided corresponding to a plurality of locations of a heating cylinder incorporating a screw and a nozzle at the tip of the heating cylinder. Degrees are provided. Each of the temperature control units 130 has the same configuration, and includes a detection unit 131 for detecting the temperature of the controlled target portion, a signal processing unit 132 for appropriately processing the output of the detection portion 131, and a distribution for the controlled target portion. And an output section (heater driver section) 133 for driving and controlling the provided heater. From the signal processing unit 132,
The temperature detection data is sent to the A / D converter 104 of the main controller 100 as an analog signal. The arithmetic and control unit 101 of the main control device 100 detects the temperature of the controlled part based on the signal converted into a digital signal by the A / D converter 104. The arithmetic control unit 101 controls the output unit 133 via the digital interface 105 while referring to the output (actually measured temperature value) of the A / D conversion unit 104 based on a preset temperature control program and a set value. (The power supply rate to the heater by the output unit 133 is controlled).

Each of the servo control units 140A to 140D has an input / output control unit 141A to 141D, and these input / output control units 141A to 141D correspond to the corresponding input / output control units 106A to 106A of the main control unit 100. It is connected to 106D so as to transmit and receive signals by digital signals. The arithmetic control means 101 of the main control device 100
Based on various preset operation control programs and set values, each servo control unit 140A to 1A is referred to while referring to actual measurement values from each position sensor unit 110 and each pressure sensor unit 120.
40D is controlled to drive and control each of the servomotors 150A to 150D, thereby executing the weighing, injection, mold opening / closing, and ejecting operations.

[0008]

In a conventional injection molding machine having a structure as shown in FIG.
Since digital signals and analog signals are mixed in the communication between 0 and each part of the machine, there is a possibility that noise on the digital side goes around to the analog side, so a filter is required to prevent adverse effects due to the noise, This is a factor that increases the number of circuit components. In addition, since digital processing and analog processing are mixed on the main controller 100 side, it has been pointed out that it is difficult to achieve uniform control processing on the main controller 100 side and the design is cumbersome. Further, main controller 10
On the 0 side, a counter 10 is provided for the position sensor unit 110.
2 for the pressure sensor unit 120 and the A / D conversion unit 10
3 to the A / D converter 104 for the temperature controller 130.
And a digital interface 105 for each of the servo controllers 140A to 140D.
A to 106D must be prepared individually, and therefore, there is a problem that the circuit scale on the main control device 100 side is increased.
When the number is increased, the A / D converter 104 and the digital interface 105 have to be added correspondingly.

Japanese Patent Application Laid-Open No. HEI 8-118442 discloses a configuration in which first communication means of a main controller is connected to second communication means provided for each of four axis controllers. This prior application does not disclose a position sensor, a pressure sensor, or a temperature controller.

[0010] The present invention has been made in view of the above points,
The purpose of the injection molding machine is to simplify the circuit configuration of the main control device, to simplify the wiring between the main control device and each sensor or control unit, and to further excel in noise resistance. Is to provide. It is another object of the present invention to provide an injection molding machine that can easily cope with an increase in the number of sensors and control units connected to a main control device.

[0011]

In order to achieve the above-mentioned object, an injection molding machine according to the present invention is provided with a serial communication means in a main controller for controlling each part of the injection molding machine. Serial communication means provided in the position sensor unit for detecting the position of the object to be measured and outputting this as a digital signal, and a pressure sensor unit for detecting the pressure of the object to be measured and outputting this as a digital signal. And a temperature control unit that detects the temperature of the controlled part and outputs it as a digital signal, and controls the temperature of the controlled part based on a command from the main controller. Control the serial communication means and the injection servomotor for driving the screw back and forth, and control the injection servomotor controlled by digital signal input. Serial communication means provided in a servo control motor for measuring and rotating a screw, and a serial communication means provided in a servo control unit for measurement controlled by a digital signal input; and a movable die. To control the drive of a mold opening and closing servomotor for driving the plate back and forth, and to drive the ejector member forward and backward by serial communication means provided in the mold opening and closing servo control unit controlled by digital signal input. And a serial communication means provided in an ejection servo control unit controlled by a digital signal input.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram illustrating a main configuration of an injection molding machine according to an embodiment of the present invention.

In FIG. 1, reference numeral 1 denotes a machine (injection molding machine)
Main controller for overall control, 10A to 10C are position sensor units, 20A and 20B are pressure sensor units, 30A to 30
E is a temperature control unit, 40A to 40D are servo control units, 50
A to 5OD are servo motors.

Reference numeral 2 denotes an arithmetic control unit in the main control unit 1, and 3 denotes a serial communication unit in the main control unit 1. In this embodiment, a single serial communication unit 3 in the main control unit 1 The serial communication means provided in the sensor section and the control section of each section of the machine are connected in a daisy chain connection format. Then, under the control of the communication control by the arithmetic and control unit 2, the serial communication unit 3 of the main control device 1 is time-divisionally connected to the serial communication unit of each sensor unit or control unit in accordance with a predetermined serial communication protocol. Communication is performed individually.

The position sensor 10A is provided for detecting the position of the screw, the position sensor 10B is provided for detecting the position of the movable die plate, and the position sensor 10C is provided for detecting the position of the eject member. Each of the position sensors 10A to 10C has the same configuration. Each of the position sensor units 10A to 10C includes a detection unit 11 (a magnetostrictive linear position detection sensor) including a magnetostrictive linear position detection sensor that performs position detection using ultrasonic vibration propagating in a solid at a constant speed. Is described in Japanese Patent Application No. 2000-31532 previously proposed by the present applicant, if necessary.
1), an output of the detection unit 11 is appropriately calculated and converted to output an absolute position signal (a signal indicating a distance from the origin), and a signal process for controlling the measurement operation of the detection unit 11 It has a unit 12 and a serial communication unit 13 connected to the serial communication unit 3 of the main control device 1.
The detection output by the detection unit 11 controlled by the signal processing unit 12 is converted into an absolute position detection signal by the signal processing unit 12, which is transmitted from the serial communication unit 13 to the serial communication unit 3 of the main control device 1 as serial communication data. Sent out. The arithmetic and control unit 2 of the main control device 1 recognizes the position of the measured object based on the output from the serial communication unit 3.

The pressure sensor 20A is provided for detecting the injection pressure (and the back pressure at the time of measurement).
Reference numeral 0B is provided for detecting a mold opening / closing pressure (mold clamping pressure), and the two pressure sensor units 20A and 20B have the same configuration. Each of the pressure sensor units 20A and 20B generates a detection signal by appropriately processing the output of the pressure detection unit 21 using a strain gauge or the like, and converts the detection signal from an analog signal to a digital signal. And a serial communication unit 23 connected to the serial communication unit 3 of the main control device 1. The digitized pressure detection signal output from the signal processing & A / D conversion unit 22 is sent from the serial communication unit 23 to the serial communication unit 3 of the main control device 1 as serial communication data. The arithmetic and control unit 2 of the main control device 1 recognizes the pressure of the measured object from the output from the serial communication unit 3. In this embodiment, the pressure sensor unit 20B for detecting the mold opening / closing pressure (mold clamping pressure).
However, the pressure sensor section 20B may be omitted.

The temperature control unit 30A is provided for controlling the temperature of the nozzle at the tip of the heating cylinder.
B to 30E are provided for controlling the temperature of each of the four divided areas of the heating cylinder, and the respective temperature controllers 30A to 30E are provided.
Has a similar configuration. Each temperature control unit 30A-30
E is a detection unit 31 that detects the temperature of the controlled object part,
A signal processing & A / D conversion unit 32 for converting the detection signal from an analog signal to a digital signal while connecting the output of the detection unit 31 to an appropriate signal to generate a detection signal, and the serial communication unit 3 of the main control device 1 Serial communication means 33
And an output section (heater driver section) 34 for driving and controlling a heater disposed in the controlled object portion. The digitized temperature detection signal output from the signal processing & A / D conversion unit 32 is converted into serial communication data from the serial communication unit 33 as serial communication unit 3 of the main control device 1.
Sent to. The arithmetic and control unit 2 of the main control device 1 recognizes the temperature of the controlled object part based on the output from the serial communication unit 3. Then, the arithmetic control unit 2 refers to the actually measured temperature value output from the temperature control unit based on the preset temperature control program and the set value, and communicates with the temperature control unit via the serial communication units 3 and 33. Of the output unit (heater driver unit) 3
Reference numeral 4 controls the duty ratio of the corresponding heater to control the temperature of the control target portion. In this embodiment, an example in which five temperature control units are provided has been described. However, any number of temperature control units may be provided. It is also possible.

The servo control unit 40A drives and controls an injection servo motor 50A for driving the screw forward and backward, and the servo control unit 40B drives and controls a measuring servo motor 50B for rotating and driving the screw. The servo control unit 40C drives and controls a servomotor 50C for opening and closing the mold (for clamping) for driving the movable die plate forward and backward. The drive of the motor 50D is controlled. Each of the servo controllers 40A to 40D has the same configuration, and each of the servo motors 50A to 50D has the same configuration. Each of the servo control units 40A to 40D has a serial communication unit 41. Each of the serial communication units 41 is connected to the serial communication unit 3 of the main control device 1 so that signals are transmitted and received by serial communication. Has become. The arithmetic and control unit 2 of the main control device 1 controls each of the position sensor units 10A to 10C, each of the pressure sensor units 20A and 20A based on various preset operation control programs and set values.
0B, each servo control unit 40A
-40D to drive and control each of the servomotors 50A-50D, thereby executing the weighing, injection, mold opening / closing, and eject operations.

In this embodiment having the above-described configuration, communication between the main controller and each sensor and each controller connected to the main controller is entirely performed by digital signal communication. The noise performance is improved compared to the case where analog signal communication is mixed, the filter for noise removal required when digital and analog signals are mixed is not required, and the input and output of the main control unit is further reduced. Since all outputs are unified with digital signals, it becomes easy to design the main controller. In addition, since the main control device and each sensor and each control unit are connected to the serial communication means and perform serial data communication, the number of wires is smaller than that of the parallel data communication, and the main control device has Since only one serial communication means needs to be provided, the configuration of the main control device can be greatly simplified as compared with the related art. Furthermore, when adding sensors and control units to be connected to the main controller, simply connect them in a daisy chain and assign new identification data to the newly added sensor units and control units. Since it is good, it is possible to easily cope with an increase in the number of sensors and control units.

[0020]

As described above, according to the present invention, the circuit configuration on the main control device side can be simplified, and the wiring between the main control device and each sensor section and each control section can be simplified, and furthermore, the resistance can be improved. An injection molding machine having excellent noise performance can be realized. Further, it is possible to easily cope with an increase in the number of sensors and control units connected to the main control device.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a main configuration of an injection molding machine according to an embodiment of the present invention.

FIG. 2 is a block diagram showing a main configuration of an injection molding machine according to a conventional technique.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main control device 2 Arithmetic control means 3 Serial communication means 10A-10C Position sensor part 11 Detection part 12 Signal processing part 13 Serial communication means 20A, 20B Pressure sensor part 21 Detection part 22 Signal processing & A / D conversion part 23 Serial communication means 30A-30E Temperature control unit 31 Detecting unit 32 Signal processing & A / D conversion unit 33 Serial communication means 34 Output unit 40A-40D Servo control unit 41 Serial communication means 50A-5OD Servo motor

Claims (2)

[Claims] 1. A serial communication means provided in a main control device for controlling each part of an injection molding machine, a serial communication means provided in a position sensor unit for detecting a position of an object to be measured and outputting this as a digital signal. A serial communication means provided in a pressure sensor unit for detecting a pressure of a measured object and outputting the digital signal as a digital signal; detecting a temperature of a controlled object portion and outputting the digital signal as a digital signal; Serial communication means provided in the temperature control unit that controls the temperature of the controlled part based on commands from the device, and drive control of the injection servomotor for driving the screw back and forth, and control by digital signal input Serial communication means provided in a servo control unit for injection, and a drive control of a measuring servomotor for rotationally driving a screw and Serial communication means provided in the servo control unit for measurement controlled by digital signal input, and drive control of a die opening / closing servo motor for driving the movable die plate back and forth, and controlled by digital signal input A serial communication means provided in the servo control unit for opening and closing the mold, and a drive control of an ejection servo motor for driving the ejection member back and forth, and also provided in the servo control unit for ejection controlled by digital signal input. An injection molding machine, wherein the serial communication means are connected to each other. 2. The position sensor unit and the pressure sensor unit according to claim 1, wherein a plurality of the position sensor units are provided, a single or a plurality of the pressure sensor units are provided, and a plurality of the temperature control units are provided. An injection molding machine, wherein the serial communication means provided in each of the temperature controller and the temperature controller is connected to the serial communication means of the main controller.