Device for controlling repeated precision of mold clamping force of injection molding machine

Abstract

The utility model relates to an injection molding machine clamping force repetition precision control device, which relates to the injection molding machine field, and comprises a mainboard, the mainboard comprises a setting module, a detection module, a difference value module, a control module and an execution module, the setting module is used for setting a reference clamping force and outputting a reference clamping force signal, and the detection module is used for detecting the reference clamping force; the detection module is used for detecting an actual mold clamping force physical quantity and converting the actual mold clamping force physical quantity into an actual mold clamping force signal, the difference value module is connected with the setting module and the detection module to receive a reference mold clamping force signal and the actual mold clamping force signal and output a difference value signal, and the control module is connected with the difference value module to receive the difference value signal and output a control signal. And the execution module is connected with the control module to receive the control signal and respond to the control signal to control the driving speed of the motor. The utility model has the effects of improving the injection molding precision of the injection molding machine and enhancing the control on the mold clamping force of the injection molding machine.

Description

Technical Field

[0001] This utility model relates to the field of injection molding machines, and in particular to a device for controlling the repeatability accuracy of clamping force in injection molding machines. Background Technology

[0002] Injection molding machines are the main molding equipment used to make various shapes of plastic products from thermoplastic or thermosetting plastics using plastic molding dies.

[0003] In existing technology, injection molding machines include a fixed mold plate, a moving mold plate, and a linkage mechanism for driving the moving mold plate. Generally, a motor drives the linkage mechanism, thereby driving the moving mold plate closer to or away from the fixed mold plate. During injection molding, the linkage mechanism needs to have a certain clamping force. The clamping force refers to the locking force applied to the mold by the injection machine to overcome the expansion force of the melt in the cavity on the mold during injection.

[0004] The linkage mechanism has a complex shape and many joints. The clamping force is greatly affected by the angle of the linkage and is not easy to control precisely. This leads to a decrease in the repeatability of the clamping force of the injection molding machine, which in turn leads to a decrease in the injection molding accuracy. Utility Model Content

[0005] In order to improve the injection accuracy of injection molding machines and enhance the control of the clamping force of injection molding machines, this utility model provides a device for controlling the repeatability accuracy of clamping force of injection molding machines.

[0006] The present invention provides a device for controlling the repeatability accuracy of clamping force in injection molding machines, which adopts the following technical solution:

[0007] A device for controlling the repeatability accuracy of clamping force in an injection molding machine includes a main board. The main board includes a setting module, a detection module, a difference module, a control module, and an execution module. The setting module is used to set a reference clamping force and output a reference clamping force signal. The detection module is used to detect the actual clamping force physical quantity and convert it into an actual clamping force signal. The difference module is connected to the setting module and the detection module to receive the reference clamping force signal and the actual clamping force signal and output a difference signal. The control module is connected to the difference module to receive the difference signal and output a control signal. The execution module is connected to the control module to receive the control signal and respond to the control signal to control the drive speed of the motor.

[0008] When the actual clamping force is less than the reference clamping force, the difference module outputs a high-level difference signal, the control module receives the high-level difference signal and outputs a high-level control signal, and the execution module receives the high-level control signal and controls the motor to increase the clamping speed.

[0009] When the actual clamping force is not less than the reference clamping force, the difference module outputs a low-level difference signal, the control module receives the low-level difference signal and outputs a low-level control signal, and the execution module receives the low-level control signal and controls the motor to complete the mold closing at a preset speed.

[0010] By adopting the above technical solution, a reference clamping force is set by a setting module, and the actual clamping force is detected by a difference module. The reference clamping force is subtracted from the actual clamping force to obtain the clamping force difference. Thus, when the actual clamping force is small and the clamping force difference is large, the motor is started to increase the clamping force, thereby improving the injection accuracy of the injection molding machine and enhancing the control of the clamping force of the injection molding machine.

[0011] Optionally, the setting module includes a fixed unit and an adjustable unit, wherein the adjustable unit is used to adjust the magnitude of the output reference clamping force signal.

[0012] By adopting the above technical solution, the magnitude of the reference clamping force signal can be adjusted by the adjustable unit, thereby adjusting the starting limit of the clamping force repeatability control device of the injection molding machine according to the actual situation, thus improving the ease of use of the clamping force repeatability control device of the injection molding machine.

[0013] Optionally, the detection module includes a detection unit and a comparison unit. The detection unit is used to detect the actual clamping force physical quantity and convert it into a detection signal. The comparison unit is used to compare it with the detection unit to output the actual clamping force signal.

[0014] By adopting the above technical solution, the clamping force is converted into an electrical signal by the detection unit and compared with the comparison unit as a benchmark, thereby obtaining the actual clamping force signal corresponding to the actual clamping force, thus improving the ease of use of the injection molding machine clamping force repeatability accuracy control device.

[0015] Optionally, the difference module includes a minuend unit, a subtrahend unit, and a calculation unit. The minuend unit is connected to the setting module to receive a reference clamping force signal and output a minuend signal. The subtrahend unit is connected to the detection module to receive an actual clamping force signal and output a subtrahend signal. The calculation unit is connected to the minuend unit and the subtrahend unit to receive the minuend signal and the subtrahend signal and output a difference signal.

[0016] By adopting the above technical solution, the difference between the reference clamping force signal and the actual clamping force signal is calculated by the difference module and defined as the difference signal. The difference signal reflects the gap between the actual clamping force and the reference clamping force, and then the motor is controlled to start and stop based on the difference signal.

[0017] Optionally, the subtraction unit includes resistors R5 and R6, and the calculation unit includes operational amplifier N1. Resistor R6 and operational amplifier N1 form a negative feedback loop.

[0018] By adopting the above technical solution, a subtraction circuit is formed by the negative feedback loop composed of resistor R6 and operational amplifier N1, thereby calculating the difference between the reference clamping force signal and the actual clamping force signal, and controlling the magnitude of the output difference signal by controlling the ratio of resistor R5 and resistor R6.

[0019] Optionally, the motherboard further includes a reference module and a subtraction module. The reference module is used to provide a reference signal, and the subtraction module is connected to the difference module and the reference module to receive the difference signal and the reference signal and output a subtraction signal to the control module.

[0020] When the difference signal is greater than the reference signal, the subtraction module outputs a high-level subtraction signal, and the control module receives the high-level subtraction signal and outputs a high-level control signal.

[0021] When the difference signal is not greater than the reference signal, the subtraction module outputs a low-level subtraction signal, and the control module receives the low-level subtraction signal and outputs a low-level control signal.

[0022] By adopting the above technical solution, the reference signal provided by the reference module is used as the reference value of the difference signal, and the difference between the reference value and the actual value of the difference signal is obtained by the subtraction module, and the start and stop of the motor are controlled according to the difference.

[0023] Optionally, the motherboard further includes an adjustment module, which is connected to the control module to receive control signals and output adjustment signals, and the execution module receives the adjustment signals and responds to the adjustment signals to adjust the speed of the motor.

[0024] By adopting the above technical solution, the control signal is converted into an adjustment signal through the adjustment module, so that the motor can control the speed according to the difference between the reference value and the actual value of the difference signal, thereby achieving the effect of stepless speed change and improving the ease of use of the injection molding machine clamping force repeatability accuracy control device.

[0025] Optionally, the adjustment module includes a protection unit and a transmission unit. The protection unit is used to protect the transmission unit, and the transmission unit is connected to the control module to receive control signals and output corresponding adjustment signals to the execution module.

[0026] By adopting the above technical solution, the transmission unit is reduced from burning out due to overcurrent through the protection unit, thereby improving the stability of the transmission unit's operation and thus improving the stability of the injection molding machine's clamping force repeatability control device.

[0027] Optionally, the transmission unit includes an optocoupler U1, which outputs an adjustment signal of a corresponding magnitude according to the magnitude of the control signal.

[0028] By adopting the above technical solution, the control signal is converted into light in real time through the optocoupler U1, and then the light is converted into an adjustment signal and output to the execution module. This reduces the possibility of interference during the conversion process causing errors in the adjustment signal and improves the accuracy of the adjustment signal.

[0029] Optionally, the protection unit includes resistor R13 and resistor R14, wherein resistor R13 is used to protect the input terminal of optocoupler U1 and resistor R14 is used to protect the output terminal of optocoupler U1.

[0030] By adopting the above technical solution, resistors R13 and R14 protect the input and output terminals of optocoupler U1 respectively, thereby reducing the possibility of excessive current in the input optocoupler causing breakdown and improving the stability of optocoupler U1.

[0031] In summary, this utility model has at least one of the following beneficial technical effects:

[0032] 1. The reference clamping force is set by the setting module, and the actual clamping force is detected by the difference module. The reference clamping force is subtracted from the actual clamping force to obtain the clamping force difference. When the actual clamping force is small and the clamping force difference is large, the motor is started to increase the clamping force, thereby improving the injection accuracy of the injection molding machine and enhancing the control of the clamping force of the injection molding machine.

[0033] 2. The reference signal provided by the reference module is used as the reference value of the difference signal, and the difference between the reference value and the actual value of the difference signal is obtained by the subtraction module. The motor is then controlled to start and stop based on the difference.

[0034] 3. The control signal is converted into an adjustment signal through the adjustment module, enabling the motor to control its speed according to the difference between the reference value and the actual value of the differential signal, thereby achieving stepless speed regulation and improving the ease of use of the injection molding machine clamping force repeatability accuracy control device. Attached Figure Description

[0035] Figure 1 This is a circuit diagram of a device for controlling the repeatability accuracy of clamping force in an injection molding machine.

[0036] The parts referred to by the numbers in the above attached diagrams are as follows: 1. Main board; 11. Setting module; 111. Fixed unit; 112. Adjustable unit; 12. Detection module; 121. Detection unit; 122. Comparison unit; 13. Difference module; 131. Subtrahend unit; 132. Subtrahend unit; 133. Calculation unit; 14. Control module; 15. Execution module; 16. Reference module; 17. Subtraction module; 18. Adjustment module; 181. Protection unit; 182. Transmission unit. Detailed Implementation

[0037] The present invention will now be described in further detail with reference to the accompanying drawings and embodiments.

[0038] Reference Figure 1 This utility model discloses a device for controlling the repeatability accuracy of clamping force in an injection molding machine, comprising a setting module 11, a detection module 12, a difference module 13, a reference module 16, a subtraction module 17, a control module 14, an adjustment module 18, and an execution module 15. The setting module 11 is used to set a reference value for the clamping force; the detection module 12 is used to detect the physical quantity of the clamping force; the difference module 13 is used to calculate the difference between the reference value and the actual value of the clamping force; the reference module 16 is used to provide a reference value for the clamping force difference; the subtraction module 17 is used to calculate the difference between the reference value and the actual value of the clamping force difference; the control module 14 is used to control the opening and closing of subsequent circuits based on the difference between the reference value and the actual value of the clamping force difference; the adjustment module 18 is used to enable the execution module 15 to continuously adjust its speed according to the difference between the reference value and the actual value of the clamping force difference; and the execution module 15 is used to drive the moving platen to enhance the clamping force.

[0039] The setting module 11 includes a fixed unit 111 and an adjustable unit 112. The setting module 11 is used to provide a reference clamping force signal. The fixed unit 111 includes a resistor R1, and the adjustable unit 112 includes a variable resistor RP. The magnitude of the output reference clamping force signal is adjusted by changing the resistance value of the resistor RP.

[0040] The detection module 12 includes a detection unit 121 and a comparison unit 122. The detection unit 121 is used to detect the physical quantity of clamping force and convert it into a detection signal. The comparison unit 122 is used to provide a reference value for the detection unit 121 and output the actual clamping force signal. The detection unit 121 includes a force-sensitive resistor RF with a negative coefficient, and the comparison unit 122 includes a resistor R2.

[0041] The difference module 13 includes a subtraction unit 131, a subtraction unit 132, and a calculation unit 133. The subtraction unit 131 is connected to the setting module 11 to receive the reference clamping force signal and output the subtraction signal. The subtraction unit 132 is connected to the detection module 12 to receive the actual clamping force signal and output the subtraction signal. The calculation unit 133 is connected to the subtraction unit 131 and the subtraction unit 132 to receive the subtraction signal and the subtraction signal and output the difference signal.

[0042] The subtraction unit 131 includes resistors R3 and R4, the subtraction unit 132 includes resistors R5 and R6, and the calculation unit 133 includes operational amplifier N1. Operational amplifier N1 is an LM158 type operational amplifier. R6 and operational amplifier N1 form a negative feedback loop to form a subtraction circuit. The ratio of resistors R3 and R4 is equal to the ratio of resistors R5 and R6. By controlling the ratio, the scaling ratio of the difference signal output by the operational amplifier is controlled.

[0043] One end of resistor R1 is connected to the power supply VCC. The other end of resistor R1 is connected to one end of variable resistor RP and then to one end of resistor R3. The other end of variable resistor RP is connected to ground GND. The other end of resistor R3 is connected to the positive input terminal of operational amplifier N1 and then to one end of resistor R4. The other end of resistor R4 is connected to ground GND. One end of force-sensitive resistor RF is connected to the power supply VCC. The other end of force-sensitive resistor RF is connected to one end of resistor R2 and then to one end of resistor R5. The other end of resistor R2 is connected to ground GND. The other end of resistor R5 is connected to the negative input terminal of operational amplifier N1 and then to one end of resistor R6.

[0044] The reference module 16 is used to provide a reference signal, and the reference module 16 includes resistors R7 and R8.

[0045] Subtraction module 17 is connected to reference module 16 and difference module 13 to receive reference signal and difference signal and output subtraction signal. Subtraction module 17 includes resistors R9, R10, R11, R12 and operational amplifier N2. Operational amplifier N2 is an LM158 operational amplifier. R12 and operational amplifier N1 form a negative feedback loop to form a subtraction circuit. The ratio of resistors R9 and R10 is equal to the ratio of resistors R11 and R12. By controlling the ratio, the scaling ratio of the subtraction signal output by the operational amplifier is controlled.

[0046] The other end of resistor R6 is connected to the output terminal of op-amp N1 and then to one end of resistor R9. The other end of resistor R9 is connected to one end of resistor R10 and then to the positive input terminal of op-amp N2. The other end of resistor R10 is connected to ground (GND). One end of resistor R7 is connected to the power supply (VCC). The other end of resistor R7 is connected to one end of resistor R11 and then to one end of resistor R8. The other end of resistor R8 is connected to ground (GND). The other end of resistor R11 is connected to the negative input terminal of op-amp N2 and then to one end of resistor R12.

[0047] The control module 14 is connected to the subtraction module 17 to receive the subtraction signal and output the control signal. The adjustment module 18 includes a protection unit 181 and a transmission unit 182. The transmission unit 182 is connected to the control module 14 to receive the control signal and convert it into a continuous adjustment signal. The protection unit 181 is used to protect the transmission unit 182. The execution unit is connected to the transmission unit 182 to receive the adjustment signal and respond to the adjustment signal to control the speed of the motor.

[0048] The control module 14 includes a transistor Q1, which is an NPN transistor of type 9013. The protection module includes resistors R13 and R14. The transmission unit 182 includes an optocoupler U1. The execution unit includes a motor M.

[0049] The other end of resistor R12 is connected to the output of operational amplifier N2 and then to the base of transistor Q1. The collector of transistor Q1 is connected to the negative input of optocoupler U1. The emitter of transistor Q1 is connected to ground GND. The positive input of optocoupler U1 is connected to one end of resistor R13. The other end of resistor R13 is connected to power supply VCC. The positive output of optocoupler U1 is connected to one end of resistor R14. The other end of resistor R14 is connected to power supply VCC. The negative output of optocoupler U1 is connected to one end of motor M. The other end of motor M is connected to ground GND.

[0050] Working principle:

[0051] When the actual clamping force is less than the reference clamping force, the difference module 13 outputs a high-level difference signal. When the difference signal is greater than the reference signal, the subtraction module 17 outputs a high-level subtraction signal. The control module 14 receives the high-level subtraction signal and outputs a high-level control signal. The adjustment module 18 is connected to the control module 14 to receive the control signal and output an adjustment signal. The execution module 15 receives the adjustment signal and responds to the adjustment signal to adjust the speed of the motor.

[0052] The above description is merely a preferred embodiment of this utility model. The protection scope of this utility model is not limited to the above embodiments. All technical solutions falling within the scope of this utility model's concept are protected. It should be noted that for those skilled in the art, any improvements and modifications made without departing from the principle of this utility model should also be considered within the protection scope of this utility model.

Claims

1. A clamping force repeatability control device for an injection molding machine, comprising a main board (1), characterized in that: The mainboard (1) comprises a setting module (11), a detection module (12), a difference module (13), a control module (14) and an execution module (15), the setting module (11) is used for setting a reference locking force and outputting a reference locking force signal, the detection module (12) is used for detecting an actual locking force physical quantity and converting into an actual locking force signal, the difference module (13) is connected with the setting module (11) and the detection module (12) to receive the reference locking force signal and the actual locking force signal and output a difference signal, the control module (14) is connected with the difference module (13) to receive the difference signal and output a control signal, and the execution module (15) is connected with the control module (14) to receive the control signal and control the driving speed of the motor in response to the control signal. When the actual locking force is less than the reference locking force, the difference module (13) outputs a high-level difference signal, the control module (14) receives the high-level difference signal and outputs a high-level control signal, and the execution module (15) receives the high-level control signal and controls the motor to increase the clamping speed. When the actual locking force is not less than the reference locking force, the difference module (13) outputs a low-level difference signal, the control module (14) receives the low-level difference signal and outputs a low-level control signal, and the execution module (15) receives the low-level control signal and controls the motor to complete clamping at a preset speed.

2. The clamp tonnage repeatability control apparatus for an injection molding machine of claim 1 wherein: The setting module (11) comprises a fixed unit (111) and an adjustable unit (112), and the adjustable unit (112) is used for adjusting the size of the output reference locking force signal.

3. The clamp tonnage repeatability control apparatus of claim 1 wherein: The detection module (12) comprises a detection unit (121) and a comparison unit (122), the detection unit (121) is used for detecting an actual locking force physical quantity and converting into a detection signal, and the comparison unit (122) is used for comparing with the detection unit (121) to output an actual locking force signal.

4. The clamp tonnage repeatability control apparatus of claim 1 wherein: The difference module (13) comprises a subtracted unit (131), a subtraction unit (132) and a calculation unit (133), the subtracted unit (131) is connected with the setting module (11) to receive the reference locking force signal and output a subtracted signal, the subtraction unit (132) is connected with the detection module (12) to receive the actual locking force signal and output a subtraction signal, and the calculation unit (133) is connected with the subtracted unit (131) and the subtraction unit (132) to receive the subtracted signal and the subtraction signal and output a difference signal.

5. The clamp tonnage repeatability control apparatus of claim 4 wherein: The subtraction unit (132) comprises a resistor R5 and a resistor R6, the calculation unit (133) comprises an operational amplifier N1, and the resistor R6 and the operational amplifier N1 constitute a negative feedback loop.

6. The clamp tonnage repeatability control apparatus of claim 1 wherein: The mainboard (1) further comprises a reference module (16) and a subtraction module (17), the reference module (16) is used for providing a reference signal, and the subtraction module (17) is connected with the difference module (13) and the reference module (16) to receive the difference signal and the reference signal and output a subtraction signal to the control module (14). When the difference signal is greater than the reference signal, the subtraction module (17) outputs a high level subtraction signal, and the control module (14) receives the high level subtraction signal and outputs a high level control signal; When the difference signal is not greater than the reference signal, the subtraction module (17) outputs a low level subtraction signal, and the control module (14) receives the low level subtraction signal and outputs a low level control signal.

7. The clamp tonnage repeatability control apparatus of claim 1 wherein: The mainboard (1) further comprises an adjusting module (18), which is connected with the control module (14) to receive the control signal and output an adjusting signal, and the executing module (15) receives the adjusting signal and responds to the adjusting signal to adjust the rotating speed of the motor.

8. The clamp tonnage repeatability control apparatus of claim 7 wherein: The adjusting module (18) comprises a protection unit (181) and a transmission unit (182), the protection unit (181) is used for protecting the transmission unit (182), and the transmission unit (182) is connected with the control module (14) to receive the control signal and output a corresponding adjusting signal to the executing module (15).

9. The clamp tonnage repeatability control apparatus of claim 8 wherein: The transmission unit (182) comprises an optical coupler U1, which outputs an adjusting signal with a corresponding size according to the size of the control signal.

10. The clamp tonnage repeatability control apparatus of claim 9 wherein: The protection unit (181) comprises a resistor R13 and a resistor R14, the resistor R13 is used for protecting the input end of the optical coupler U1, and the resistor R14 is used for protecting the output end of the optical coupler U1.

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