A narrow pulse discharge drive circuit for wire-cut electric discharge machine tools

Abstract

The present invention provides a narrow pulse discharge drive circuit for an electric spark wire cutting machine tool, which is applied to the technical field of electric spark wire cutting processing, and is used to turn off the output signal through logic transformation according to the breakdown time of the narrow pulse, so as to improve the effective discharge rate. The drive circuit includes an input signal and an output signal, and the input signal includes a drive signal and a feedback signal. The drive circuit includes: a first part, which is used to receive the drive signal and the feedback signal, and output the output signal through logic transformation; and a second part, which is used to receive the output signal, and output the feedback signal after comparing the output signal with a comparator. The drive circuit outputs the feedback signal by comparing the output signal with a set value, thereby relying on the logic transformation of the drive circuit to turn off the output signal in time, so that the output signal can be turned off immediately after the breakdown is completed, thereby improving the effective discharge rate.

Description

Technical Field

[0001] The invention belongs to the technical field of electric spark wire cutting processing, and in particular relates to a narrow pulse discharge driving circuit for an electric spark wire cutting machine tool. Background Art

[0002] Wire EDM is also called wire cutting. Its basic working principle is to use a continuously moving thin metal wire (called electrode wire) as an electrode to perform pulse spark discharge to erode metal and cut the workpiece into shape.

[0003] Wire EDM technology is a special processing technology. It is different from traditional processing technology that needs mechanical force and mechanical energy to cut. It mainly uses electrical energy to process materials. Therefore, wire EDM technology is not limited by material properties and can process any hardness, strength, and brittle materials. It occupies a very important position in the current mechanical processing.

[0004] At present, the narrow pulse signal of existing EDM wire cutting is a small pulse width square wave signal directly generated by the controller to drive the power tube to discharge, so that the system outputs a narrow pulse. However, during the EDM wire cutting process, the fixed pulse voltage applied to the workpiece and the molybdenum wire cannot discharge immediately, and a breakdown time is required, and the breakdown time is also variable, so the effective discharge rate is relatively low, that is, most of the pulses are invalid pulses.

[0005] Therefore, it is necessary to design a driving circuit that can obtain a real narrow pulse current signal to improve the effective discharge rate. Summary of the invention

[0006] In view of the above problems in the prior art, the purpose of the present invention is to provide a narrow pulse discharge drive circuit for an electric spark wire cutting machine tool, which outputs a feedback signal by comparing the output signal with the set value, thereby relying on the logic transformation of the drive circuit to shut down the output signal in time, so that the output signal can be shut down immediately after the breakdown is completed, thereby improving the effective discharge rate.

[0007] A narrow pulse discharge drive circuit for an electric spark wire cutting machine tool is used to turn off an output signal through logic transformation according to the breakdown time of a narrow pulse to improve an effective discharge rate. The drive circuit includes an input signal and an output signal. The input signal includes a drive signal and a feedback signal. The drive circuit includes:

[0008] The first part is used to receive the driving signal and the feedback signal, and output the output signal through logical transformation;

[0009] The second part is used to receive the output signal, compare the output signal with the comparator and then output a feedback signal;

[0010] The first part includes a loop formed by resistor 1, switch 1, switch 2, and resistor 2 connected in series in sequence, and the circuit between switch 1 and switch 2 is connected with NAND gate 1, NAND gate 2, NAND gate 3, and NAND gate 4 in sequence, the signal output by NAND gate 3 is used to control the state of switch 1, and the signal output by NAND gate 4 is used to control the state of switch 2, and the circuit between resistor 1 and switch 1 is connected with NAND gate 5 and NAND gate 6 in sequence, the output end of NAND gate 6 is electrically connected to the second part, and NAND gate 6 is connected to NAND gate 1 and NAND gate 2 respectively;

[0011] The driving signal is input to the circuit between the resistor 1 and the switch 1, and the driving signal input is connected to two input terminals of the NAND gate 5;

[0012] The feedback signal is input to the circuit between the second resistor and the second switch.

[0013] In order to determine whether the output signal has completed breakdown, the second part includes a MOS tube and a comparator, the output signal is electrically connected to the gate of the MOS tube, the drain and source of the MOS tube are respectively connected to resistor four and resistor three, the other end of the resistor four is electrically connected to the LDC, the other end of the resistor three is grounded, the source of the MOS tube is also connected to the inverting input end of the comparator, the non-inverting input end of the comparator is grounded through resistor five, and the signal output by the comparator is a feedback signal.

[0014] The process of the driving circuit shutting down the output signal includes four stages, and the four stages include:

[0015] In the first stage, there is no pulse input, the drive signal and the feedback signal are both high level, at this time, switch 1 is open, switch 2 is closed, the output signal is high level, and the feedback signal output after the output signal is compared by the comparator is high level;

[0016] The second stage, in which there is a pulse input, the drive signal is low level, and the feedback signal is high level. At this time, switch 1 is disconnected, switch 2 is closed, the output signal is low level, and the feedback signal output after the output signal is compared by the comparator is low level;

[0017] The third stage, in which there is a pulse input, the drive signal is at a low level, and the feedback signal is at a low level. At this time, the switch 1 is closed, the switch 2 is open, the output signal is at a high level, and the feedback signal output after the output signal is compared by the comparator is at a high level;

[0018] In the fourth stage, there is a pulse input, the drive signal is at a low level, and the feedback signal is at a high level. At this time, switch 1 is closed, switch 2 is open, and the output signal is at a high level.

[0019] In order to provide a feedback signal to the first part, the output signal is compared with a comparator. If the output signal does not exceed the set value, the feedback signal output by the comparator is a high level. If the output signal exceeds the set value, the feedback signal output by the comparator is a low level.

[0020] In order to influence the output signal through the driving signal and the feedback signal, the output terminal of the NAND gate five is connected to one input terminal of the NAND gate six, and the other input terminal of the NAND gate six is ​​connected to two input terminals of the NAND gate one.

[0021] In order to shut off the output signal through logical transformation, the two input ends of the NAND gate 1 are connected to the circuit between switch 1 and switch 2, the output end of the NAND gate 1 is connected to one input end of the NAND gate 2, the other input end of the NAND gate 2 is connected to the input end of the NAND gate 6, the output end of the NAND gate 2 is connected to the two input ends of the NAND gate 3, the output end of the NAND gate 3 is connected to the two input ends of the NAND gate 4, the output end of the NAND gate 4 is electrically connected to switch 2, and the output end of the NAND gate 3 is also electrically connected to switch 1.

[0022] The beneficial effects of the present invention are as follows: the narrow pulse discharge drive circuit for an electric spark wire cutting machine tool compares the output signal with a set value through a comparator to output a feedback signal, and the level of the feedback signal is affected by the current change of the output signal. According to the logic transformation of the drive circuit, the output signal is turned off through the feedback signal, so that the output can be turned off after the output signal completes the breakdown. On the basis of ensuring the effective discharge time, the output time of the output signal is reduced, thereby improving the effective discharge rate. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The accompanying drawings are used to provide a further understanding of the present invention and constitute a part of the specification. Together with the embodiments of the present invention, they are used to explain the present invention and do not constitute a limitation of the present invention. In the accompanying drawings:

[0024] Figure 1 is a circuit diagram of the present invention;

[0025] Figure 2 It is a waveform diagram of each signal in the circuit of the present invention;

[0026] Figure 3 It is a flow chart of the driving process of the present invention.

[0027] The markings in the figure are: 1, NAND gate one; 2, NAND gate two; 3, NAND gate three; 4, NAND gate four; 5, NAND gate five; 6, NAND gate six. DETAILED DESCRIPTION

[0028] Embodiment 1

[0029] like Figure 1As shown, a narrow pulse discharge drive circuit for an electric spark wire cutting machine tool is used to shut down the output signal through logic transformation according to the breakdown time of the narrow pulse to improve the effective discharge rate. The drive circuit includes an input signal and an output signal, and the input signal includes a drive signal and a feedback signal. The drive circuit includes a first part for receiving the drive signal and the feedback signal and outputting the output signal through logic transformation and a second part for receiving the output signal and outputting the feedback signal after comparing the output signal with a comparator.

[0030] like Figure 1 As shown, the driving signal is the Plus signal output by the controller, the driving signal is input to the circuit between the resistor 1 and the switch 1, and the driving signal input is connected to the two input terminals of the NAND gate 5; the feedback signal is the Current signal generated after the output signal is compared by the comparator, the feedback signal is input to the circuit between the resistor 2 and the switch 2, and the output signal is the Out signal output by the NAND gate 6.

[0031] Among them, the first part includes a loop formed by resistor 1, switch 1, switch 2, and resistor 2 connected in series in sequence, and the circuit between switch 1 and switch 2 is connected with NAND gate 1, NAND gate 2, NAND gate 3, and NAND gate 4 in sequence, and the circuit between resistor 1 and switch 1 is connected with NAND gate 5 5 and NAND gate 6 6 in sequence, the output end of NAND gate 6 6 is electrically connected to the second part, the output end of NAND gate 5 5 is connected to one input end of NAND gate 6 6, and the other input end of NAND gate 6 6 is connected to two input ends of NAND gate 1 1.

[0032] like Figure 1 As shown, the two input ends of NAND gate 1 are connected to the circuit between switch 1 and switch 2, the output end of NAND gate 1 is connected to one input end of NAND gate 2, the other input end of NAND gate 2 is connected to the input end of NAND gate 6, the output end of NAND gate 2 is connected to two input ends of NAND gate 3, the output end of NAND gate 3 is connected to two input ends of NAND gate 4, the output end of NAND gate 4 is electrically connected to switch 2, the output end of NAND gate 3 is also electrically connected to switch 1, the signal output by NAND gate 3 is used to control the state of switch 1, and the signal output by NAND gate 4 is used to control the state of switch 2.

[0033] like Figure 1 As shown, switch 1 and switch 2 are voltage-controlled analog switches. When point A is at a high level, switch 1 is closed and turned on, and when point A is at a low level, switch 1 is opened; similarly, when point B is at a high level, switch 2 is closed and turned on, and when point B is at a low level, switch 2 is opened.

[0034] The initial state of the driving circuit is: the driving signal is at a high level, the feedback signal is at a high level, the switch 1 is disconnected, and the switch 2 is closed and turned on.

[0035] The second part includes a MOS tube and a comparator, the output signal is electrically connected to the gate of the MOS tube, the drain and source of the MOS tube are respectively connected to resistor four and resistor three, the other end of the resistor four is electrically connected to the LDC, the other end of the resistor three is grounded, the source of the MOS tube is also connected to the inverting input end of the comparator, the non-inverting input end of the comparator is grounded through resistor five, and the signal output by the comparator is a feedback signal.

[0036] Resistor three is a sampling resistor, which is used to sample the output signal of the first part. The voltage signal on the sampling resistor is compared with the reference voltage signal on resistor five by a comparator to output a feedback signal, wherein the reference voltage signal on resistor five is adjustable.

[0037] like Figure 2 As shown, the Plus signal is converted into the Out signal, which can improve the effective discharge rate. The process of the driving circuit turning off the output signal includes four stages, which include:

[0038] In the first stage, there is no pulse input, the drive signal and the feedback signal are both high level, at this time, switch 1 is disconnected, switch 2 is closed, the output signal is high level, at this time the output signal does not exceed the set value, and the feedback signal output after the output signal is compared by the comparator is high level;

[0039] The second stage, in which there is a pulse input, the drive signal is low level, and the feedback signal is high level. At this time, switch one is disconnected, switch two is closed, and the output signal is low level. When the output signal completes breakdown and the current increases to exceed the set value, the feedback signal output after the output signal is compared by the comparator is low level;

[0040] The third stage, in which there is a pulse input, the drive signal is low level, and the feedback signal is low level. At this time, switch one is closed, switch two is opened, and the output signal that has completed the breakdown is turned off through the drive signal, the feedback signal and the logic transformation, and the output signal is high level. The feedback signal output after the output signal is compared by the comparator is high level;

[0041] In the fourth stage, there is a pulse input, the drive signal is at a low level, and the feedback signal is at a high level. At this time, switch 1 is closed, switch 2 is open, and the output signal is at a high level.

[0042] like Figure 1 and Figure 2 As shown, the output signal is compared with the comparator. If the output signal does not exceed the set value, the feedback signal output by the comparator is a high level. If the output signal exceeds the set value, the feedback signal output by the comparator is a low level.

[0043] like Figure 3As shown, when the drive circuit is in the first stage, the output is turned off if there is no pulse input, and then it is determined whether there is a pulse input. If so, it enters the second stage and the output is turned on. If not, it remains in the first stage. After entering the second stage, it is determined whether the output signal exceeds the set value. If so, it enters the third stage and the output is turned off. If not, it remains in the second stage and continues to output. After entering the third stage, it can enter the fourth stage and keep the output turned off.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A narrow pulse discharge drive circuit for an electric spark wire cutting machine tool, which is used to turn off the output signal through logical transformation according to the breakdown time of the narrow pulse to improve the effective discharge rate, characterized in that: The driving circuit includes an input signal and an output signal, wherein the input signal includes a driving signal and a feedback signal, and the driving circuit includes: The first part is used to receive the driving signal and the feedback signal, and output the output signal through logical transformation; The second part is used to receive the output signal, compare the output signal with the comparator and then output a feedback signal; The first part includes a loop formed by resistor 1, switch 1, switch 2, and resistor 2 connected in series in sequence, and the circuit between switch 1 and switch 2 is connected with NAND gate 1, NAND gate 2, NAND gate 3, and NAND gate 4 in sequence, the signal output by NAND gate 3 is used to control the state of switch 1, and the signal output by NAND gate 4 is used to control the state of switch 2, and the circuit between resistor 1 and switch 1 is connected with NAND gate 5 and NAND gate 6 in sequence, the output end of NAND gate 6 is electrically connected to the second part, and NAND gate 6 is connected to NAND gate 1 and NAND gate 2 respectively; The driving signal is input to the circuit between the resistor 1 and the switch 1, and the driving signal input is connected to two input terminals of the NAND gate 5; The feedback signal is input into the circuit between the resistor 2 and the switch 2; The second part includes a MOS tube and a comparator, the output signal is electrically connected to the gate of the MOS tube, the drain and source of the MOS tube are respectively connected to resistor 4 and resistor 3, the other end of the resistor 4 is electrically connected to the LDC, the other end of the resistor 3 is grounded, the source of the MOS tube is also connected to the inverting input end of the comparator, the non-inverting input end of the comparator is grounded through resistor 5, and the signal output by the comparator is a feedback signal; The process of the driving circuit shutting down the output signal includes four stages, and the four stages include: In the first stage, there is no pulse input, the drive signal and the feedback signal are both high level, at this time, switch 1 is open, switch 2 is closed, the output signal is high level, and the feedback signal output after the output signal is compared by the comparator is high level; The second stage, in which there is a pulse input, the drive signal is low level, and the feedback signal is high level. At this time, switch 1 is disconnected, switch 2 is closed, the output signal is low level, and the feedback signal output after the output signal is compared by the comparator is low level; The third stage, in which there is a pulse input, the drive signal is at a low level, and the feedback signal is at a low level. At this time, the switch 1 is closed, the switch 2 is open, the output signal is at a high level, and the feedback signal output after the output signal is compared by the comparator is at a high level; The fourth stage, in which there is a pulse input, the drive signal is at a low level, and the feedback signal is at a high level. At this time, the switch 1 is closed, the switch 2 is open, and the output signal is at a high level; The output signal is compared with the comparator. If the output signal does not exceed the set value, the feedback signal output by the comparator is a high level. If the output signal exceeds the set value, the feedback signal output by the comparator is a low level. The output end of the NAND gate 5 is connected to one input end of the NAND gate 6, and the other input end of the NAND gate 6 is connected to two input ends of the NAND gate 1; The two input ends of the NAND gate 1 are connected to the circuit between switch 1 and switch 2, the output end of the NAND gate 1 is connected to one input end of the NAND gate 2, the other input end of the NAND gate 2 is connected to the input end of the NAND gate 6, the output end of the NAND gate 2 is connected to the two input ends of the NAND gate 3, the output end of the NAND gate 3 is connected to the two input ends of the NAND gate 4, the output end of the NAND gate 4 is electrically connected to switch 2, and the output end of the NAND gate 3 is also electrically connected to switch 1.

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