Inverter multifunctional cold welding machine

Abstract

The utility model relates to an inversion multifunctional cold welding machine which can realize four different welding methods of argon arc welding, pulsed argon arc welding, cold welding and manual arc welding and can select, adjust and control welding parameters, control modes and the like under different methods. During cold welding, the welding time is extremely short and millisecond level, the welding heat input quantity is low, welding of thin plates and materials with high heat sensitivity is facilitated, and workpieces do not deform after welding; the problems which cannot be solved by a common argon arc welding machine in some occasions with special requirements are solved; when a welding method, a welding gun switch operation mode, welding parameters and the like are selected, corresponding indicator lamps are lightened for indication, meanwhile, selected numerical values can be displayed through a nixie tube, and the parameters can be set or adjusted through an encoder. By applying the technical scheme, the performance of the welding machine can be remarkably improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of inverter multifunctional cold welding machine, using the inverter multifunctional argon arc welding of microprocessor control can be made, belong to inverter welding machine technical field. BACKGROUND

[0002] On the market, the vast majority of general inverter argon arc welding machine is the welding machine of high-frequency arc-starting direct-current constant-current output, among them, in addition to this direct-current argon arc welding (DC TIG), there are also many welding machines with manual arc welding (MMA) function, in addition, there is also the function of pulse argon arc welding (Pulse TIG). In recent years, the optional item VRD (low idle voltage output) function when manual arc welding, because the output idle voltage of welding machine is very low when VRD function is opened, only ten or so volts, therefore, compared with the high idle voltage of 60~90 volts output when general manual welding, it has higher use safety, so it is welcomed by users, users hope that welding machine has VRD function when manual welding, it is convenient to use. In addition, although pulse argon arc welding has many advantages compared with direct-current argon arc welding, for example, current waveform is not constant current, but has pulse peak current, pulse base current stage control, therefore, heat input during welding is much lower than that of direct-current argon arc welding, and workpiece deformation after welding is small; furthermore, because it has strong electromagnetic stirring effect, therefore, weld grain is small, and the mechanical properties of weld are good, and welding joint is not easy to produce porosity and other welding defects. Therefore, pulse argon arc welding has obtained rapid development, and gradually becomes the main function of inverter argon arc welding machine. However, even if it has pulse argon arc welding, direct-current argon arc welding and manual arc welding functions, it still has some deficiencies. The reason is that in some special application occasions, for example, the thickness of the workpiece to be welded is thin, if manual arc welding and direct-current argon arc welding are used, the workpiece will be inevitably burned through, even if pulse argon arc welding with good performance is used, it cannot solve the welding of such workpiece; some thin plate materials with strong heat sensitivity also face the same problem. Therefore, in order to solve the above problems, a new welding technology, i.e. cold welding technology, emerges as the times require. Cold welding is a welding method with very low heat input, and the duration of large current stage during welding (i.e. welding time) is extremely short, which is millisecond level, much smaller than the large current duration of second level during pulse argon arc welding; in addition, it has a long interval of second level, and the current is small. The output mode of such current waveform is significantly different from that of general pulse argon arc welding. Because of this, cold welding technology has obtained good application in special welding processing occasions, such as workpiece with thin thickness and some materials with strong heat sensitivity. To realize cold welding, it is necessary to innovate in the function, control performance and other aspects of welding machine, so as to solve the problems existing in general argon arc welding and other methods. This is also a problem that many people in the electric welding machine industry are concerned about or need to solve.

[0003] The utility model relates to a kind of control solutions of inverter multifunctional cold welding machine, by the connection of the power supply circuit of general IGBT inverter argon arc welding machine, cooling fan, argon arc welding torch switch, IGBT in inverter main circuit, the output of the current transformer of argon arc welding transformer primary current detection, the voltage detection circuit of the output of Hall current sensor and output two ends of welding machine output loop detection current, high-frequency arc starting control circuit, just can obtain the performance superior to general inverter argon arc welding machine, that is, realize the argon arc welding of welding machine, pulse argon arc welding, cold welding, four kinds of welding methods of manual electric arc welding, and, welding time is extremely short during cold welding, just millisecond level, welding heat input quantity is much lower than when pulse argon arc welding, therefore, it is more favorable to the welding of thin plate, heat-sensitive material, and workpiece is not deformed after welding;Realize the VRD function of manual electric arc welding, and the selection and adjustment of hot arc starting (or hot start) current, welding current, arc thrust or thrust current welding parameter;Realize the 2T, 4T torch switch operating mode selection and control of gas shielded welding (including argon arc welding etc.);Realize the selection and adjustment of advance gas feeding time, welding current, arc current, lagging gas closing time welding parameter of argon arc welding;Realize the selection and adjustment of peak current, base current, arc current of pulse argon arc welding, of course, there is advance gas feeding time, lagging gas closing time welding parameter selection and adjustment;Realize the selection and adjustment of advance gas feeding time, welding time, interval time, lagging gas closing time welding parameter of cold welding;Realize the control of welding machine cooling fan;Realize the overheat, overcurrent protection control of welding machine;Realize the output control of high-frequency arc starting, electromagnetic gas valve control signal of gas shielded welding;Realize the output control of welding machine PWM pulse width modulation signal, and the drive control of IGBT in inverter main circuit, finally realize the control of welding current, voltage parameter.Welding method, torch switch operating mode or VRD function, welding parameter selection under different welding methods, there is corresponding indicating lamp lighting corresponding parameter, and simultaneously, the value of selection can be shown by nixie tube, so simultaneously, the above-mentioned parameter can be set or adjusted using encoder. Utility model content

[0004] The utility model relates to a kind of inverter multifunctional cold welding machine, by with the +15V of ordinary IGBT inverter argon arc welding machine, -15V and +24V power circuit, cooling fan, argon arc welding torch switch, IGBT in inverter main circuit, the output of the current transformer of argon arc welding torch switch, the output of the voltage detection circuit of the current sensor of welding machine output loop detection current and two ends, the connection of high-frequency arc starting control circuit, just can obtain the performance of general IGBT inverter argon arc welding machine, i. e. realize the argon arc welding of welding machine, pulse argon arc welding, cold welding, manual arc welding four welding methods, and, welding time is extremely short during cold welding, just millisecond level, welding heat input quantity is much lower than when pulse argon arc welding, therefore, it is more favorable to the welding of thin plate, heat-sensitive material, and workpiece is not deformed after welding;Realize the VRD function when manual arc welding, and the selection and adjustment of hot arc starting (or hot start) current, welding current, arc thrust or thrust current welding parameter;Realize the 2T of gas shielded welding (including argon arc welding etc.), 4T torch switch operating mode selection and control when;Realize the selection and adjustment of advance gas feeding time, welding current, arc current, lagging gas closing time welding parameter when argon arc welding;Realize the selection and adjustment of peak current, base current, arc current when pulse argon arc welding, of course, there is advance gas feeding time, lagging gas closing time welding parameter;Realize the selection and adjustment of advance gas feeding time, welding time, interval time, lagging gas closing time welding parameter when cold welding;Realize the control of welding machine cooling fan;Realize the overheat, overcurrent protection control of welding machine;Realize the output control of high-frequency arc, electromagnetic gas valve control signal when gas shielded welding;Realize the output control of welding machine PWM pulse width modulation signal, and the drive control of IGBT in inverter main circuit, finally realize the control of welding current, voltage parameter.Welding method, torch switch operating mode or VRD function, welding parameter selection under different welding methods, there is corresponding indicating lamp lighting corresponding parameter, and simultaneously, the value of selection is shown by nixie tube, so simultaneously, the above-mentioned parameter can be set or adjusted using encoder.

[0005] The utility model discloses, its control circuit board design is two pieces, and different circuit boards bear different function. One piece of circuit board is operation and display control panel, and another piece of circuit board is main control panel, and the former is connected to the latter through the connecting line of socket and its plug, and main control panel still is equipped with: the socket of welding machine + 24V power connection, the socket of welding machine output current detection's hall sensor connection, the socket of welding machine cooling's direct current 24V cooling fan connection, the socket of welding machine normally closed type temperature controller connection, the socket of welding machine output end connection, the socket of welding machine's + 15V, - 15V power, IGBT pipe drive control end, the current transformer output end of inverting main transformer primary current detection connection, the socket of welding machine's electromagnetic air valve, + 24V power, high frequency arc control end, argon arc welding's welding gun switch connection. Through these sockets and the connection of welding machine, can constitute a complete whole and control system, and finally realize the control function and control performance of each aforementioned.

[0006] The operation and display control panel part circuit includes the driving chip U1 of the nixie tube display, the nixie tube U2, the cold welding indicator lamp L1, the manual welding or manual arc welding indicator lamp L2, the argon arc welding indicator lamp L3, the pulse argon arc welding indicator lamp L4, the 2T welding gun switch operation mode indicator lamp L5, the 4T welding gun switch operation mode indicator lamp L6, the VRD function indicator lamp L7 during manual welding, the overheat or overcurrent protection indicator lamp L8, the advance gas feeding time indicator lamp L9, the welding current or peak current indicator lamp L12, the base current indicator lamp L14 of the pulse argon arc welding, the arc collecting current indicator lamp L16, the lagging gas closing time indicator lamp L17, the pulse frequency indicator lamp L18 during the pulse argon arc welding, the hot ignition current of manual welding or the welding time indicator lamp L19 during cold welding, the arc thrust of manual welding or the interval time indicator lamp L20 of the thrust current or the cold welding, the power supply indicator lamp L29, the welding parameter adjustment encoder BMQ, the selection button of the welding parameter, the selection button SW1 of manual welding / argon arc welding / pulse argon arc welding / cold welding, the selection button SW2 of 2T / 4T / VRD, the socket CN8 connected with the main control circuit of the operation and display control part circuit, the capacitors C1-C4 and C7-C8, the resistors R1, R4-R7, the +5V power supply, the 1 pin of U1 connected with the 3 pin of the socket CN8, the 3 pin of U1 connected with the 1 pin of the socket CN8, the 2 pin of U1 connected with the 2 pin of the socket CN8, the control circuit of the operation and display part connected with the CN8 socket and the main control circuit through the CN8 socket, the 6 pin of U1 connected with +5V, the 22 pin of U1 connected with ground, the +5V from the 4 pin of the CN8 socket, the +5V connected with the capacitors C1-C4, the 5 pin of the CN8 socket connected with ground, the 7 pin of U1 connected with the 11 pin of U2 and the anodes of L17, L9 and L1, the 8 pin of U1 connected with the 5 pin of U2 and the anodes of L18 and L2, the 9 pin of U1 connected with the 4 pin of U2 and the anodes of L19 and L3, the 10 pin of U1 connected with the 3 pin of U2 and the anodes of L20, L12 and L4, the 11 pin of U1 connected with the 2 pin of U2 and the anode of L5, the 12 pin of U1 connected with the 1 pin of U2 and the anodes of L14 and L6, the 13 pin of U1 connected with the 10 pin of U2 and the anode of L7, the 14 pin of U1 connected with the 7 pin of U2 and the anodes of L16 and L8, the 15 pin and 16 pin of U1 not connected, the 24 pin of U1 connected with the 12 pin of U2, the 23 pin of U1 connected with the 9 pin of U2, the 21 pin of U1 connected with the 8 pin of U2, the 20 pin of U1 connected with the cathodes of L17, L18, L19 and L20, the 19 pin of U1 connected with the cathodes of L9, L12, L14 and L16, the 18 pin of U1 connected with the cathodes of L1, L2, L3, L4, L5, L6, L7 and L8, the 17 pin of U1 not connected, the nixie tube U2 used for displaying parameters, one end of R1 connected with +5V, the other end of R1 connected with the anode of the light emitting diode L29, the cathode of the light emitting diode connected with ground.Pin 5 of the built-in button of the encoder BMQ is connected to the K3 end, and K3 is also connected to the 8th pin of CN8; pin 4 of the built-in button of the encoder BMQ is grounded; pin 1 of the encoder BMQ is connected to R4, R6, C7 and pin 6 of CN8, the other end of R4 is connected to +5V, and the other ends of R6 and C7 are grounded; pin 2 of the encoder BMQ is grounded; pin 3 of the encoder BMQ is connected to R5, R7, C8 and pin 7 of CN8, the other end of R5 is connected to +5V, and the other ends of R7 and C8 are grounded; pin 4 of the SW1 selection button is grounded, and its pin 3 K1 end is connected to the 10th pin of CN8; pin 3 of the SW2 selection button is grounded, and its pin 4 K2 end is connected to the 9th pin of CN8; using the above-mentioned circuit of the operation and display part, under the joint action of the circuit of the main control board, the operation and display functions of the welding machine can be realized. For the operation and display control panel, a digital tube display is provided above the operation interface of the control panel and to the right of the POWER indicator light, which is used to display parameters; to the right of the digital tube display, there is a yellow OH protection indicator light; below the digital tube display, there are indicators of welding parameters from left to right, at different high and low positions, which correspond to or correspond to the control timing of different stages. These welding parameters include: advance gas supply time (Preg) during argon arc welding (TIG), pulse argon arc welding (Pulse TIG), or cold welding (COLD); welding current or peak current (I; W or I F ); Base current of pulsed argon arc welding (I B ); Pulse frequency (Pulse FQ) in pulsed argon arc welding; Hot arc ignition (or hot start) current (HOT START) in manual welding or welding time (HJ Time) in cold welding; Arc force or thrust current (Arc Force) in manual welding or interval time (JG Time) in cold welding; Arc ending current (I E ); Post-gas holding time (Posg). Different welding methods have different welding parameters. For example, when manual welding is selected, there are hot arc (or hot start) current (HOT START), welding current (I W ), arc thrust or thrust current (Arc Force); when selecting argon arc welding (TIG), there are pre-gas supply time (Preg), welding current (I W )、the arc ending current(I E ), post-hold time (Posg); when pulse TIG welding is selected, there is a peak current (I W or I F ), base current (I B )、the arc ending current(I E), and of course, the pre-gas time (Preg), the post-gas time (Posg); when the cold welding is selected, there are the welding time (HJ Time), the interval time (JG Time), etc. In the case of selecting the welding method, the corresponding welding parameters can be selected by operating the keys of the encoder, and when the parameters are selected, the corresponding parameter indicator light will be lit to give a prompt, and the parameter data will be displayed in the display table composed of the digital tube at the same time. At this time, the parameters can be adjusted by using the encoder. On the right side of the operation and display control panel, there is an encoder with keys, and the keys are used to select the welding parameters under different welding methods. After the corresponding selection of the welding parameter indicator light is lit, the parameters can be adjusted by rotating the encoder. Counterclockwise rotation is for reduction, and clockwise adjustment is for increase. On the left side of the encoder, from top to bottom, there are the manual arc welding or MMA indicator light, the argon arc welding (TIG) indicator light, the cold welding (COLD) indicator light, and the pulse argon arc welding (Pulse TIG) indicator light. On the left side of these indicator lights, there are the welding method selection keys. When the keys are operated, the welding method can be selected, and when the keys are selected, the corresponding indicator light will be lit to give an indication. Above the welding method selection keys, there is the mode selection key, and on the right side of the key, there are the 2T, 4T, and VRD mode indicator lights. By operating the mode selection key, different modes can be selected. For example, the VRD mode for manual welding; the 2T or 4T mode for argon arc welding, and when the keys are selected, the corresponding indicator light will be lit to give an indication.

[0007] For the operation and display part, when the welding machine is working, the required welding method can be selected by pressing the welding method selection button, i.e. MMA, TIG, Pulse TIG or COLD. When the welding method selection button is pressed in turn, the indicator light corresponding to different welding method will light up in turn and change cyclically. For example, when the MMA indicator light is on, it means that the MMA method is selected; when the TIG indicator light is on, it means that the TIG method is selected; when the Pulse TIG indicator light is on, it means that the Pulse TIG method is selected; when the COLD indicator light is on, it means that the COLD method is selected. In the case of selecting MMA, the user can select whether to use the VRD function by pressing the mode selection button. If the VRD indicator light is on, it means that the VRD mode is selected, otherwise, the VRD function is not selected. In the case of selecting TIG or Pulse TIG, the user can select the welding gun switch operation mode by pressing the mode selection button. The indicator light of the selected operation mode will light up, indicating that the operation mode corresponding to the lit indicator light is selected. For example, when the 2T indicator light is on, it means that the 2T (two-step) welding gun switch operation mode is selected, i.e. the welding starts when the welding gun switch is pressed, and the welding stops when the welding gun switch is released; when the 4T indicator light is on, it means that the 4T (four-step) welding gun switch operation mode is selected, i.e. the welding starts when the welding gun switch is pressed, the welding continues when the welding gun switch is released, the welding stops when the welding gun switch is pressed again, and the welding is controlled to stop when the welding gun switch is released.

[0008] For the operation and display part, when the welding machine is working, the required welding method can be selected by pressing the welding method selection button, i.e. MMA, TIG, Pulse TIG or COLD. When the welding method selection button is pressed in turn, the indicator light corresponding to different welding method will light up in turn and change cyclically. For example, when the MMA indicator light is on, it means that the MMA method is selected; when the TIG indicator light is on, it means that the TIG method is selected; when the Pulse TIG indicator light is on, it means that the Pulse TIG method is selected; when the COLD indicator light is on, it means that the COLD method is selected. In the case of selecting MMA, the user can select whether to use the VRD function by pressing the mode selection button. If the VRD indicator light is on, it means that the VRD mode is selected, otherwise, the VRD function is not selected. In the case of selecting TIG or Pulse TIG, the user can select the welding gun switch operation mode by pressing the mode selection button. The indicator light of the selected operation mode will light up, indicating that the operation mode corresponding to the lit indicator light is selected. For example, when the 2T indicator light is on, it means that the 2T (two-step) welding gun switch operation mode is selected, i.e. the welding starts when the welding gun switch is pressed, and the welding stops when the welding gun switch is released; when the 4T indicator light is on, it means that the 4T (four-step) welding gun switch operation mode is selected, i.e. the welding starts when the welding gun switch is pressed, the welding continues when the welding gun switch is released, the welding stops when the welding gun switch is pressed again, and the welding is controlled to stop when the welding gun switch is released.

[0009] The driving control circuit part includes resistors R8-R15, electrolytic capacitor C9, capacitors C10 and C11, U4 driving chip, N / P channel enhancement field effect transistor chips U5 and U6, diodes D4-D7, +15V power supply; the 1st and 8th pins of U4 are connected to +15V, the 4th and 6th pins of U4 are grounded, the 2nd pin of U4 is connected to R8, the other end of R8 is connected to the 19th pin of microprocessor U3; the 3rd pin of U4 is connected to R9, the other end of R9 is connected to the 18th pin of microprocessor U3; the 7th pin of U4 is connected to R10, R11, the anode of D4 and the cathode of D5, the cathode of D4 and the other end of R10 are connected to the 4th pin of U5, the anode of D5 and the other end of R11 are connected to the 2nd pin of U5; the 5th pin of U4 is connected to R12, R13, the anode of D6 and the cathode of D7, the cathode of D6 and the other end of R12 are connected to the 4th pin of U6, the anode of D7 and the other end of R13 are connected to the 2nd pin of U6; the 3rd pin of U5 and the 3rd pin of U6 are connected to R14, the other end of R14 is connected to +15V and the positive pole of C9, the other end of C9 is grounded; the 5th-8th pins of U5 are connected to one end of R15, C10 and C11, the other end of R15, C10 and C11, i.e. DRVA, is the output IGBT driving control signal, the 5th-8th pins of U6 are connected to the other end, i.e. DRVB, which is another output IGBT driving control signal; the PWMA and PWMB signals output by microprocessor U3 are output as two groups of IGBT driving control signals DRVA and DRVB after passing through the driving control circuit, to control the working state of IGBT in the welding machine inverter circuit; the PWMA and PWMB signals output by microprocessor U3 are signals for determining the output current and voltage of the welding machine inverter main circuit, and whether the welding machine has output, while the PWM pulse width modulation signals are determined by current regulation given signals and current negative feedback signals, whether there is overheating and overcurrent phenomenon, and whether VRD function control is selected during manual welding.

[0010] The overheat signal detection and protection control circuit includes a CN6 socket CN6, a capacitor C12, resistors R16~R18, +5V and +24V power supplies, an optocoupler U7, an NPN transistor Q1, a diode D8, and an overheat detection protector or thermostat WKQ; +5V is connected to the collector of the output transistor in R16 and U7, and the other end of R16 or the Over Heat control signal end is connected to the collector of Q1. The Heat overheat control signal end is connected to pin 28 of the microprocessor U3, the emitter of Q1 is grounded, the base of Q1 is connected to R17 and the emitter of the output transistor in U7, and the other end of R17 is grounded; the anode of the light-emitting diode in U7 is connected to the cathode of R18 and D8, the other end of R18 is connected to +24V, the anode of D8 is connected to the cathode of the light-emitting diode in U7, C12, and pin 1 of CN6, the other end of C12 is grounded, and pin 2 of CN6 is connected to the +24V ground; the connection line of the normally closed WKQ overheat detection protector or thermostat is connected to the CN6 socket CN6 through a plug, and WKQ is installed close to the radiator of the IGBT of the inverter welding machine; the microprocessor U3 detects the high and low levels of its pin 28 to know whether overheating occurs. If overheating is confirmed, overheating protection control is performed.

[0011] The electromagnetic valve DF control circuit is characterized in that: the circuit consists of a socket CN3, an electromagnetic valve DCF connected to the CN3 socket, a field effect tube Q4, an optical coupler U11, a voltage regulator tube Z3, a diode D11, resistors R27~R30, and power supplies +5V and +24V; the 21-pin Gas of the microprocessor The control signal terminal is connected to the cathode of the light-emitting diode in U11, the anode of the light-emitting diode is connected to R27, and the other end of R27 is connected to +5V; the collector of the output-stage transistor in U11 is connected to R28, and the other end of R28 is connected to +24V; the emitter of the output-stage transistor in U11 is connected to R29, and the other end of R29 is connected to R30, the cathode of the voltage-stabilizing diode Z3, and the gate G end of the field-effect transistor Q4. The other end of R30, the anode of Z3, and the S end of Q4 are grounded; the D end of Q4 is connected to DCF or pin 8 of CN3, the cathode of D10, and the anode of D11 is connected to +24V; pin 7 of CN3 is connected to the positive terminal of the solenoid valve, and pin 8 of CN3 is connected to the negative terminal of the solenoid valve; during gas shielded welding, the microprocessor controls whether the light-emitting diode in the optocoupler U11 emits light through the output level of its pin 21, thereby controlling the conduction state of the field-effect transistor Q4, and ultimately determining whether the solenoid valve operates, thus realizing the control of the solenoid valve.

[0012] The utility model adopts microprocessor software and hardware control technology, has greatly improved the performance of control system. Digital control system is outstandingly superior to analog control circuit, has improved the integration of system, not only has reduced the volume of control circuit board, has reduced the cost, moreover, a variety of protection circuit, can also improve the work reliability of welding machine. The utility model has its own unique place in circuit principle, circuit board design. The content of the utility model patent application protection is just to protect this circuit design. BRIEF DESCRIPTION OF DRAWINGS

[0013] ATTACHMENT Figure 1 It is the schematic diagram of the control panel operation interface of an example welding machine made by the utility model

[0014] ATTACHMENT Figure 2 It is the circuit principle block diagram of the control panel of the utility model

[0015] ATTACHMENT Figure 3 It is the circuit principle diagram of the operation and display part in the control panel of the utility model

[0016] ATTACHMENT Figure 4 It is the circuit principle diagram of the main control panel part in the control panel of the utility model DETAILED DESCRIPTION

[0017] The utility model relates to a kind of control solutions of inverter multifunctional cold welding machine, by the connection of the output of the current transformer of the primary current detection of cooling fan, argon arc welding torch switch, IGBT in inverter main circuit, inverter transformer, the current of the output loop detection of welding machine, the voltage detection circuit of Hall current sensor and output two ends of +15V, -15V and +24V power supply circuit of general IGBT inverter argon arc welding machine, high-frequency arc starting control circuit, the performance of general IGBT inverter argon arc welding machine can be obtained, i. e. realize the argon arc welding of welding machine, pulse argon arc welding, cold welding, manual arc welding four welding methods, and, welding time is extremely short during cold welding, just millisecond level, welding heat input is much lower than when pulse argon arc welding, therefore, it is more conducive to the welding of thin plate, heat-sensitive material, and workpiece is not deformed after welding;Realize the VRD function when manual arc welding, and the selection and adjustment of hot arc starting (or hot start) current, welding current, arc thrust or thrust current welding parameter;Realize the 2T, 4T torch switch operating mode selection and control when gas shielded welding (including argon arc welding etc.);Realize the selection and adjustment of advance gas feeding time, welding current, arc current, lagging gas closing time welding parameter when argon arc welding;Realize the selection and adjustment of peak current, base current, arc current when pulse argon arc welding, of course, there is advance gas feeding time, lagging gas closing time welding parameter;Realize the selection and adjustment of advance gas feeding time, welding time, interval time, lagging gas closing time welding parameter when cold welding;Realize the control of welding machine cooling fan;Realize the overheat, overcurrent protection control of welding machine;Realize the output control of high-frequency arc starting, electromagnetic gas valve control signal when gas shielded welding;Realize the output control of welding machine PWM pulse width modulation signal, and the drive control of IGBT in inverter main circuit, finally realize the control of welding current, voltage parameter.Welding method, torch switch operating mode or VRD function, welding parameter selection under different welding methods, there is corresponding indicating lamp lighting corresponding parameter, and simultaneously, the value of selection is displayed by nixie tube, so simultaneously, the above-mentioned parameter can be set or adjusted by encoder.

[0018] The utility model discloses, its control circuit board design is two pieces, and different circuit boards bear different function. One of the circuit boards is operation and display control panel, and the other circuit board is main control panel, and the former is connected to the latter through the connecting line of socket and its plug, and the main control panel still is equipped with: the socket that is connected with the welding machine + 24V power supply, the socket that is connected with the welding machine output current detection's hall sensor, the socket that is connected with the welding machine cooling's direct current 24V cooling fan, the socket that is connected with the welding machine normally closed type temperature controller, the socket that is connected with the welding machine output end, the socket that is connected with the welding machine's + 15V, - 15V power supply, IGBT pipe drive control end, the current transformer output end of inversion main transformer primary current detection, the socket that is connected with the welding machine's electromagnetic air valve, + 24V power supply, high frequency arc starting control end, argon arc welding's welding gun switch. Through the connection of these sockets and the welding machine, a complete whole and control system can be constituted, and finally realizes the control function and control performance of each aforementioned.

[0019] The connection relationship between the two circuit boards of the utility model, the connection relationship with other parts of the welding machine, and the related functions and working principles are described as follows:

[0020] The control panel operation interface of the example welding machine made by the utility model is shown in the attached Figure 1 The upper part of the control panel operation interface, right of the POWER power supply indicator light, is provided with a digital tube display table for displaying parameters. Right of the digital tube display table, a yellow O.H protection indicator light is provided. Below the digital tube display table, from left to right, different height positions, and different stages of control time sequence corresponding or corresponding indicator lights of welding parameters are provided. These welding parameters include: argon arc welding (TIG), or pulse argon arc welding (Pulse TIG), or cold welding (COLD) pre-gas time (Preg); welding current or peak current (I W or I F ); pulse argon arc welding base current (I B ); pulse frequency (Pulse FQ) of pulse argon arc welding; hot arc starting (or hot start) current (HOT START) of manual welding or welding time (HJTime) of cold welding; arc thrust or thrust current (Arc Force) of manual welding or interval time (JG Time) of cold welding; arc current (I E ); lagging gas closing time (Posg). Different welding methods have different welding parameters. For example, when manual welding is selected, hot arc starting (or hot start) current (HOT START), welding current (I W ), and arc thrust or thrust current (Arc Force) are needed. When argon arc welding (TIG) is selected, pre-gas time (Preg), welding current (I W), post-arc current (I E ), post-gas time (Posg); when pulse TIG is selected, there are peak current (I W or I F ), base current (I B ), post-arc current (I E ), and of course, pre-gas time (Preg), post-gas time (Posg); when cold welding is selected, there are welding time (HJ Time), interval time (JG Time), etc. When the welding method is selected, the corresponding welding parameters can be selected by operating the key of the encoder, and the corresponding parameter indicator will light up to prompt, and the parameter data will be displayed on the display table composed of the digital tube at the same time. At this time, the encoder can be used for parameter adjustment; on the right side of the operation and display control panel, there is an encoder with keys, the keys of which are used to select the welding parameters under different welding methods, and after the corresponding selection of welding parameters is turned on, the parameter can be adjusted by rotating the encoder. Counterclockwise rotation is to reduce, clockwise adjustment is to increase; on the left side of the encoder, there are MMA indicator, TIG indicator, COLD indicator, Pulse TIG indicator from top to bottom, and on the left side of these indicators, there are welding method selection buttons. When this button is operated, the welding method can be selected, and the corresponding indicator will light up to indicate when selected. Above the welding method selection button, there is a mode selection button, and on the right side of the button, there are 2T, 4T and VRD mode indicator lights. By operating the mode selection button, different modes can be selected. For example, VRD mode for manual welding; 2T or 4T mode for TIG welding, and the corresponding indicator will light up to indicate when selected.

[0021] For the operation and display part, when the welding machine is working, the required welding method can be selected by pressing the welding method selection button, i.e. MMA, TIG, Pulse TIG or COLD. When the welding method selection button is pressed in turn, the indicator light corresponding to different welding method will light up in turn and change cyclically. For example, when the MMA indicator light is on, it means that the MMA method is selected; when the TIG indicator light is on, it means that the TIG method is selected; when the Pulse TIG indicator light is on, it means that the Pulse TIG method is selected; when the COLD indicator light is on, it means that the COLD method is selected. In the case of selecting MMA, the user can select whether to use the VRD function by pressing the mode selection button. If the VRD indicator light is on, it means that the VRD mode is selected, otherwise, the VRD function is not selected. In the case of selecting TIG or Pulse TIG, the user can select the welding gun switch operation mode by pressing the mode selection button. The indicator light of the selected operation mode will light up, indicating that the operation mode corresponding to the lit indicator light is selected. For example, when the 2T indicator light is on, it means that the 2T (two-step) welding gun switch operation mode is selected, i.e. the welding starts when the welding gun switch is pressed, and the welding stops when the welding gun switch is released; when the 4T indicator light is on, it means that the 4T (four-step) welding gun switch operation mode is selected, i.e. the welding starts when the welding gun switch is pressed, the welding continues when the welding gun switch is released, the welding stops when the welding gun switch is pressed again, and the welding is controlled to stop when the welding gun switch is released.

[0022] For the operation and display part, when the welding machine is working, the required welding method can be selected by pressing the welding method selection button, i.e. MMA, TIG, Pulse TIG or COLD. When the welding method selection button is pressed in turn, the indicator light corresponding to different welding method will light up in turn and change cyclically. For example, when the MMA indicator light is on, it means that the MMA method is selected; when the TIG indicator light is on, it means that the TIG method is selected; when the Pulse TIG indicator light is on, it means that the Pulse TIG method is selected; when the COLD indicator light is on, it means that the COLD method is selected. In the case of selecting MMA, the user can select whether to use the VRD function by pressing the mode selection button. If the VRD indicator light is on, it means that the VRD mode is selected, otherwise, the VRD function is not selected. In the case of selecting TIG or Pulse TIG, the user can select the welding gun switch operation mode by pressing the mode selection button. The indicator light of the selected operation mode will light up, indicating that the operation mode corresponding to the lit indicator light is selected. For example, when the 2T indicator light is on, it means that the 2T (two-step) welding gun switch operation mode is selected, i.e. the welding starts when the welding gun switch is pressed, and the welding stops when the welding gun switch is released; when the 4T indicator light is on, it means that the 4T (four-step) welding gun switch operation mode is selected, i.e. the welding starts when the welding gun switch is pressed, the welding continues when the welding gun switch is released, the welding stops when the welding gun switch is pressed again, and the welding is controlled to stop when the welding gun switch is released.

[0023] Attached Figure 2The utility model discloses a control panel's circuit principle block diagram, which is shown. The control panel circuit includes two parts, one is operation and display control panel (SXB PCB), and the other is main control panel (Main Control PCB). The operation and display control panel (SXB PCB) part is connected with the main control panel (Main Control PCB) part through the plug of CN8 socket and its control line; the main control panel (Main Control PCB) part is additionally provided with: 1) CN9 socket, which is connected with the +24V power supply of the welding machine through its plug and its control line; 2) CN6 socket, which is connected with the normally closed temperature controller WKQ of the welding machine through its plug and its control line, and the temperature controller is installed close to the surface of the aluminum radiator of the inverter welding machine IGBT tube, and is used for the overheat protection control of the welding machine; 3) CN5 socket, which is connected with the DC 24V cooling fan of the welding machine through its plug and its control line; 4) CN2 socket, which is connected with the Hall current sensor HECGQ for detecting the output current of the welding machine through its plug and its control line, and the -15V and +15V power supply of the sensor comes from the main control panel circuit, and the detected welding machine output current signal is transmitted to the output current sampling signal processing circuit of the main control panel part; 5) CN4 socket, which is connected with the output ends of the welding machine through its plug and its control line, and the detected welding machine output voltage signal is transmitted to the output voltage sampling signal processing circuit of the main control panel part; 6) CN3 socket, which is connected with the following parts through its plug and its control line: the 7th and 8th pins of CN3 are connected with the electromagnetic air valve DCF of the welding machine; the 5th pin of CN3 is connected with the +24V power supply of the welding machine; the 4th pin of CN3 is connected with the ground of the +24V power supply of the welding machine; the 3rd pin of CN3 outputs the HF Control control signal to control the high-frequency arc starting circuit or the arc starting plate of the welding machine; the 2nd and 1st pins of CN3 are connected with the control line of the argon arc welding gun switch of the welding machine; 7) CN1 socket, which is connected with the following parts through its plug and its control line: the 6th and 7th pins of CN1 socket CN1 are connected with the mutual inductor output OC1 and OC2 of the inverter main circuit of the welding machine for detecting the primary current of the inverter transformer; the 4th and 5th pins of CN1 socket CN1 are connected with the IGBT tube part in the inverter main circuit of the welding machine to realize the driving control of the IGBT tube; the 3rd, 4th and 5th pins of CN1 socket CN1 are respectively connected with the -15V, ground and +15V power supply parts of the welding machine. Figure 1 The operation and display circuit part is controlled, and the control of different welding methods such as argon arc welding, pulse argon arc welding, cold welding and manual arc welding and the control of the welding parameters of the methods are realized, so that good welding performance is finally obtained.

[0024] ​Figure 3 This is the circuit diagram of the operation and display part of the control panel of the utility model. Figure 2 The circuit of the operation and display control panel (SXB PCB). This part of the circuit consists of the digital tube display driver chip U1 (SM1668), U2 (CPS5631AG) digital tube, cold welding (COLD) indicator L1, manual welding or manual arc welding (MMA) indicator L2, argon arc welding (TIG) indicator L3, pulse argon arc welding (Pulse TIG) indicator L4, 2T welding gun switch operation mode (2T) indicator L5, 4T welding gun switch operation mode (4T) indicator L6, VRD (low (no-load) voltage output) function indicator L7 during manual welding, overheating or overcurrent protection (OH) indicator L8, advance gas supply time (Preg) indicator L9, welding current or peak current (I W or I F ) indicator light L12, pulse argon arc welding base current (I B ) indicator light L14, arc current (I E) indicator L16, lagging gas closing time (Posg) indicator L17, pulse frequency (Pulse FQ) during pulse argon arc welding, hot start current (HOT START) during manual welding or welding time (HJ Time) during cold welding indicator L19, arc thrust or thrust current (Arc Force) during manual welding or interval time (JG Time) during cold welding indicator L20, power supply indicator L29, welding parameter adjustment encoder BMQ, selection key of welding parameters (Note: BMQ encoder is provided with a key for selecting parameters), selection key SW1 of manual welding / argon arc welding / pulse argon arc welding / cold welding (MMA / TIG / Pulse TIG / COLD), selection key SW2 of operating mode of welding gun switch and VRD function (2T / 4T / VRD) during manual welding, socket CN8 connected with control circuit of operating and display part and main control circuit, capacitors C1-C4 and C7-C8, resistors R1, R4-R7, +5V power supply; pin 1 (DI / O) of U1 is connected with pin 3 of socket CN8, which is data input / output interface; pin 3 (STB) of U1 is connected with pin 1 of socket CN8, which is chip selection signal control end; pin 2 (CLK) of U1 is connected with pin 2 of socket CN8, which is clock signal; control circuit of operating and display part is connected with CN8 socket and main control circuit through CN8 socket interface to realize exchange of control information and data; pin 6 of U1 is connected with +5V; pin 22 of U1 is connected with ground; +5V is from pin 4 of CN8 socket, and C1-C4 capacitors are connected between +5V and ground; pin 5 of CN8 socket is connected with ground; pin 7 of U1 is connected with pin 11 of U2 and anodes of L17, L9 and L1; pin 8 of U1 is connected with pin 5 of U2 and anodes of L18 and L2; pin 9 of U1 is connected with pin 4 of U2 and anodes of L19 and L3; pin 10 of U1 is connected with pin 3 of U2 and anodes of L20, L12 and L4; pin 11 of U1 is connected with pin 2 of U2 and anode of L5; pin 12 of U1 is connected with pin 1 of U2 and anodes of L14 and L6; pin 13 of U1 is connected with pin 10 of U2 and anode of L7; pin 14 of U1 is connected with pin 7 of U2 and anodes of L16 and L8; pins 15 and 16 of U1 are not connected; pin 24 of U1 is connected with pin 12 of U2; pin 23 of U1 is connected with pin 9 of U2; pin 21 of U1 is connected with pin 8 of U2; pin 20 of U1 is connected with cathodes of L17, L18, L19 and L20; pin 19 of U1 is connected with cathodes of L9, L12, L14 and L16; pin 18 of U1 is connected with cathodes of L1, L2, L3, L4, L5, L6, L7 and L8; pin 17 of U1 is not connected; digital tube U2 is used for displaying parameters; one end of R1 is connected with +5V, and the other end is connected with anode of L29 light emitting diode, cathode of which is connected with ground;The one end of the self-contained button of the encoder BMQ (5 pin of BMQ) is connected with K3 end, and K3 is also connected with 8 pin of CN8; the other end of the self-contained button of the encoder BMQ (4 pin of BMQ) is grounded; 1 pin of the encoder BMQ is connected with R4, R6, C7 and 6 pin of CN8, the other end of R4 is connected with +5V, the other end of R6 and C7 is grounded; 2 pin of the encoder BMQ is grounded; 3 pin of the encoder BMQ is connected with R5, R7, C8 and 7 pin of CN8, the other end of R5 is connected with +5V, the other end of R7 and C8 is grounded; 4 pin of the SW1 selection button is grounded, and 3 pin K1 end is connected with 10 pin of CN8; 3 pin of the SW2 selection button is grounded, and 4 pin K2 end is connected with 9 pin of CN8. Figure 1 The operation and display control interface shown in the figure can be realized by the above-mentioned operation and display part circuit, and under the joint action of the main control board part circuit, the operation and display part of each operation function and display can be realized.

[0025] The circuit in the figure is the circuit principle diagram of the main control board part in the control board of the utility model. Figure 4 The circuit in the figure is the circuit principle diagram of the main control board part in the control board of the utility model. Figure 4 The circuit in the figure is the circuit principle diagram of the main control board part in the control board of the utility model. Figure 4 The circuit working principle of the operation and display part is further described as follows:

[0026] 1) U15 integrated voltage regulator, C33 filter capacitor, and C34, C1~C3 capacitor constitute a voltage stabilizing circuit, see the figure Figure 4 This part of the circuit obtains +5V power supply by connecting +15V power supply, using U15 and capacitor to constitute a voltage stabilizing and filtering circuit, and supplies the control circuit.

[0027] 2) MCU microprocessor, see the figure Figure 4The circuit part is mainly composed of U3 microprocessor, resistors R1~R3, socket CN7, capacitor C4, +5V power supply. The control program is written into the microprocessor through the program writing interface. U3 microprocessor is the core of the control circuit. U3 microprocessor system, through the control signal output circuit of the operation and display control board composed of CN8 socket and the like, that is, through the circuit of this part, the DI / O, CLK, STB, A-CODE and B-CODE ends in the microprocessor system circuit realize the information exchange and control between the operation and display control circuit part, and finally realize the corresponding operation control and information display. For example, which welding method is selected by the user among the direct current argon arc welding, pulse argon arc welding, cold welding or manual arc welding? Which welding gun switch operation mode is selected among 2T and 4T? When manual welding, whether the VRD function is selected? Under different welding methods, which welding parameters are selected, and what parameters are set, etc. After obtaining the corresponding information, U3 microprocessor can complete the corresponding control and display according to the control program; U3 microprocessor system can control the working state of the cooling fan; when gas shielded welding, the welding gun switch operation state can be detected, the working state of high-frequency arc starting can be controlled, the action state of electromagnetic gas valve can be controlled according to the welding operation requirement, the control of advance gas supply and lagging gas closing is realized; the output voltage of the welding machine can be sampled, the obtained voltage sampling signal is input to U3 microprocessor, which is used for control in the welding process, for example, when manual arc welding, according to the control requirement, the thrust current and hot arc current control is realized; whether the welding machine appears overheating or overcurrent phenomenon can be detected, and the control signal is output through U3 microprocessor, so as to realize the overheat or overcurrent protection control of the welding machine. Of course, the above is only a simple description, the actual control process is far from such simple description, which involves the time sequence control of different welding methods and the control of output parameters and time. This will be further described in the introduction of the working principle of the related circuit, which will not be described here.

[0028] 3) Cooling fan FAN control circuit, see attached Figure 4The circuit is composed of socket CN5, cooling fan FAN connected to socket CN5, field effect tube Q3 (IRFZ24N), photo-coupler U9 (817C), voltage stabilizer Z1, diode D10, resistors R22~R25, power supply +5V and +24V. The 26th pin of MCU microprocessor, i.e. FAN Control control signal end, is connected to the cathode of the light emitting diode in photo-coupler U9, the anode of which is connected to R22, the other end of which is connected to +5V. The collector of the output stage triode in U9 is connected to R23, the other end of which is connected to +24V; the emitter of the output stage triode in U9 is connected to R24, the other end of which is connected to R25, the cathode of voltage stabilizer Z1 and the gate G end of field effect tube Q3, the other end of R25, the anode of Z1 and the S end of Q3 are grounded; the D end of Q3 is connected to the 1st pin of CN5, the 3rd pin of CN5 is connected to the cathode of D10, the anode of D10 is connected to +24V. The 3rd pin of CN5 is connected to the positive pole of cooling fan FAN, and the 1st pin of CN5 is connected to the negative pole of cooling fan FAN. When the welding machine needs FAN to work, the 26th pin of MCU microprocessor outputs low level, the light emitting diode in photo-coupler U9 emits light, the output stage triode in U9 is turned on, the emitter level of the output stage triode in U9 is pulled to high level, field effect tube Q3 is turned on, and cooling fan FAN runs to deliver cold air to the inside of the welding machine. On the contrary, when the 26th pin of MCU microprocessor outputs high level, field effect tube Q3 is cut off, and cooling fan FAN does not run. The output level of the 26th pin or FAN Control control signal end of MCU microprocessor control system is controlled according to the control requirements to realize the control requirements of cooling fan FAN. This realizes the control of FAN.

[0029] 4) The control circuit of electromagnetic air valve DF is shown in the attached Figure 4The circuit is composed of socket CN3, electromagnetic air valve DCF connected to socket CN3, field effect tube Q4 (IRFZ24N), photo-coupler U11 (817C), voltage stabilizing tube Z3, diode D11, resistors R27~R30, power supply +5V and +24V; the 21st pin of MCU microprocessor, i.e. Gas Control control signal end, is connected to the cathode of the light emitting diode in photo-coupler U11, the anode of the light emitting diode is connected to R27, the other end of R27 is connected to +5V. The collector of the output stage transistor in U11 is connected to R28, the other end of R28 is connected to +24V; the emitter of the output stage transistor in U11 is connected to R29, the other end of R29 is connected to R30, the cathode of voltage stabilizing tube Z3 and the gate G end of field effect tube Q4, the other end of R30, the anode of Z3 and the S end of Q4 are grounded; the D end of Q4 is connected to the cathode of D10 and the 8th pin of CN3, the anode of D11 is connected to +24V. The 7th pin (+24V) of CN3 is connected to the positive pole of electromagnetic air valve, the 8th pin of CN3 is connected to the negative pole of electromagnetic air valve. When the 21st pin of MCU microprocessor outputs low level, the light emitting diode in photo-coupler U11 emits light, the output stage transistor in U11 is turned on, the emitter level of the output stage transistor in U11 is pulled to high level, field effect tube Q4 is turned on, electromagnetic air valve is actuated to deliver protective gas to the welding area during gas shielded welding; on the contrary, when the 21st pin of MCU microprocessor outputs high level, field effect tube Q4 is cut off, electromagnetic air valve cannot be actuated to deliver protective gas to the welding area; the output level of the 21st pin or Gas Control control signal end of MCU microprocessor control system is controlled according to the requirements of gas shielded welding control timing to realize the control requirements of advance gas delivery and lag gas closing. For example, when the welding torch switch is detected to be closed during argon arc welding, the electromagnetic air valve is first connected, the protective gas is first delivered to the welding area, a delay time (the time is determined by the set advance gas delivery time parameter) is delayed, the electric arc is ignited by high frequency or contact arc ignition, and the welding is started, which realizes the advance gas delivery control; when the welding operation is detected to be ended, the control circuit stops the welding machine output current to extinguish the electric arc, then a delay time (the time is determined by the set lag gas closing time parameter) is delayed, and the electromagnetic air valve is closed, which realizes the lag gas closing control.

[0030] 5) The detection and output signal control circuit of welding torch switch signal is shown in the attached Figure 4The circuit is composed of U8 optocoupler, 2-pin (ON / OFF) of socket CN3 connected with welding torch switch QK and 1-pin ground of CN3, capacitor C13, resistors R19-R21, +5V and +24V power supply, diode D9 and NPN triode Q2. The anode of light emitting diode in U8 optocoupler is connected with the cathode of R21 and D9, the other end of R21 is connected with +24V, the anode of D9 is connected with 2-pin (ON / OFF) of CN3, C13 and the cathode of light emitting diode in U8 optocoupler, the other end of C13 is grounded. 2-pin (ON / OFF) of CN3 and 1-pin ground of CN3 are connected with welding torch switch QK through the plug of CN3 and its control line. The collector of output stage triode in U8 optocoupler is connected with +5V, its emitter is connected with R20 and the base of Q2, the other end of R20 and the emitter of Q2 are grounded. The collector of Q2, that is, the detection output control signal Torch Switch ON / OFF Control of welding torch switch is connected with R19, the other end of R19 is connected with +5V. When the welding torch switch is closed during gas shielded welding, the light emitting diode in U8 emits light, the triode in U8 is turned on, and the 25-pin of U3 microprocessor, that is, Torch Switch Control welding torch switch control signal is low level; on the contrary, when the welding torch switch is not closed, the light emitting diode in U8 does not emit light, the triode in U8 is turned off, and Torch Switch Control welding torch switch control signal is high level. U3 microprocessor can know whether the welding torch switch is closed or in open state by detecting the level state of its 25-pin. According to the operation control of welding torch switch and the selection state of user through welding torch switch operation mode on front panel, such as 2T and 4T mode, under the action of microprocessor control software, the output current of welding machine and related states can be controlled according to the corresponding mode control requirements.

[0031] 6) High frequency arc striking control circuit, see attached Figure 4This circuit consists of the U10 optocoupler, resistor R26, +5V and +24V power supplies, the HF control terminal (pin 3) and ground terminal (pin 4) of the CN3 socket, and the HF Control signal. The anode of the LED in the U10 optocoupler is connected to R26, and the other end of R26 is connected to +5V. The cathode of the LED in the U10 optocoupler is connected to the HFControl signal, which is connected to pin 17 of the microprocessor U3. The collector of the output-stage transistor in U10 is connected to +24V, and the emitter of the output-stage transistor is connected to the HF control terminal (pin 3) of the CN3 socket. This control signal terminal and its ground terminal (pin 4) of the CN3 socket are used to connect to the inverter welder's high-frequency arc ignition control circuit or high-frequency arc ignition control circuit board. For argon arc welding, pulsed argon arc welding, and cold welding, if high-frequency arc ignition is used, the inverter welder will have a corresponding high-frequency arc ignition control circuit or circuit board. During operation, when the welding gun switch is closed, it will be detected by the microprocessor U3 circuit, so the 17th pin output control signal HF Control of the microprocessor U3 is low, making the light-emitting diode in the U10 optocoupler light up, and the transistor in U10 is turned on, so that the HF signal end can obtain a +24V high level to control the high-frequency arc control circuit of the inverter welding machine or the circuit of the high-frequency arc control circuit board, generate high-frequency arc, and finally realize high-frequency arc in welding; on the contrary, when the welding gun switch is not closed, the light-emitting diode in U10 will not light up, the transistor in U10 will be cut off, and the 17th pin output control signal of the microprocessor U3 is high, then the high-frequency arc operation control will not be performed. It can be seen that the attached Figure 4 The microprocessor U3 control system in the controller will control the start signal of the high-frequency arc ignition control board according to the control requirements, and ultimately achieve the control requirements of the high-frequency arc ignition.

[0032] 7) The welding machine’s output voltage sampling signal processing circuit is shown in the attached Figure 4The circuit is composed of socket CN4, U14 (U14C in U14) operational amplifier, optocoupler U12 (817C), voltage stabilizing tube Z2, adjustable potentiometer Wvf, capacitors C18~C20, resistors R32~R37, and +5V power supply. The plug of socket CN4 and its control line are connected to the output end of the welding machine. The 2-pin of CN4 is connected to the positive polarity output end of the welding machine, and the 1-pin of CN4 is connected to the negative polarity output end of the welding machine. The function is to sample the output voltage of the welding machine and process the signal. The series-connected resistors R32~R34 form a voltage dividing circuit, and the C18 capacitor performs signal filtering to prevent interference. U12 is a linear optocoupler used for voltage conversion signal isolation and transmission. The series-connected resistors R35, adjustable potentiometer Wvf, and R37 are connected in parallel across Z2 and R36 to form a voltage dividing circuit. The midpoint sliding terminal of the adjustable potentiometer Wvf obtains a voltage dividing signal input to the positive polarity input end of the U14C synchronous follower. The output end of U14C obtains a sampling signal Ufu of the welding machine output voltage. Then, the Ufu signal is input to the 7-pin of the MCU microprocessor to complete sampling and A / D conversion by the microprocessor. The obtained digital welding machine output voltage feedback signal participates in the control of the welding machine.

[0033] 8) The output current sampling signal processing circuit of the welding machine is also the output current detection and current feedback control circuit of the inverter welding machine Hall sensor. See the attached Figure 4The circuit is composed of Hall sensor HECGQ, socket CN2, U14 (including U14A and U14D) operational amplifier, +15V and -15V and +5V power supply, filter capacitors C15, C16, C28-C31, C39-C41, double diode device D18, and resistors R55-R60. After the Hall sensor HECGQ is inserted into the welding cable line or connected metal sheet, it is connected in series in the output circuit of the welding machine inverter, that is, the output circuit of the welding machine, and functions to detect the size of the welding machine output current. The working power supply of the Hall sensor HECGQ is +15V and -15V, the 1 pin of the Hall current sensor HECGQ is connected to +15V, the 2 pin is connected to -15V, the 4 pin is connected to ground, and the 3 pin outputs a current detection signal. The connection line of the Hall sensor HECGQ and its plug are connected to the corresponding socket CN2 of the main control board. Through the detection of the Hall current sensor HECGQ, the welding machine output current detection signal is obtained, which is connected to the voltage division circuit of resistors R55 and R56, and capacitor C38 is connected in parallel across R56 for signal filtering, and output to the non-inverting input terminal (3 pin) of U14A. The working power supply of U14 is +15V and -15V, and the two power supplies are connected to C16 and C15 filter capacitors between the ground terminals. C39 and R58 are connected in parallel and between the inverting input terminal (2 pin) and the output terminal (1 pin) of U14A. R57 is connected between the inverting input terminal and the ground terminal of U14A. The output terminal of U14A is connected to R59, the other end of R59 is connected to the non-inverting input terminal of U14D, the other end of C40 is connected to the ground, the inverting input terminal of U14D is connected to its output terminal, and a synchronous follower is formed, the output terminal of U14D is connected to R60, the other end of R60 is connected to the middle connection point of D18 double diode and C41, the other two ends of D18 double diode are connected to +5V and ground, respectively, and the diode in D18 is used for clamping. The other end of C41 is connected to the ground. The welding machine output current detection feedback signal Ufi is obtained across C41. Then, the Ufi signal is input to the 8 pin of the MCU microprocessor, and the digital welding machine output current negative feedback signal obtained by the microprocessor through sampling and A / D conversion is used for welding machine control.

[0034] The output current negative feedback signal from the Hall sensor output current detection and its current feedback control circuit participates in the output current negative feedback control of the welding machine inverter circuit; the current given Ig signal is sampled from the U3 microprocessor, and of course, the current given Ig signal is determined by the welding parameters given by the operation panel part of the welding machine of the utility model. The current given Ig signal is the current given signal of different welding methods and different stages. For example, in the case of direct current argon arc welding, it is the welding current given signal; in the case of pulse argon arc welding, it may be the peak current given signal, or the base current given signal; in the case of manual arc welding, it may be the hot arc starting current given signal, or the welding current given signal, or the thrust current given signal. Here, it will not be expanded.

[0035] 9) Control signal output circuit of operation and display control board, see attached Figure 4 The circuit is composed of CN8 socket, microprocessor U3 and +5V power supply; the 1 pin STB of CN8 is connected with the 22 pin of U3, the 2 pin CLK of CN8 is connected with the 30 pin of U3, the 3 pin DI / O of CN8 is connected with the 29 pin of U3, the 4 pin STB of CN8 is connected with +5V, the 5 pin of CN8 is connected with the ground of +5V, the 6 pin A-CODE of CN8 is connected with the 14 pin of U3, the 7 pin B-CODE of CN8 is connected with the 15 pin of U3, the 8 pin K3 of CN8 is connected with the 3 pin of U3, the 9 pin K2 of CN8 is connected with the 2 pin of U3, and the 10 pin K1 of CN8 is connected with the 1 pin of U3. Through the circuit of this part, the information exchange and control between the DI / O, CLK, STB, A-CODE and B-CODE end of the MCU microprocessor system circuit and the operation and display control circuit part are realized, and the corresponding operation control and information display are realized. Figure 4

[0036] 10) Overheating signal detection and protection control circuit, see attached Figure 4 ​The circuit is composed of socket CN6, capacitor C12, resistors R16-R18, +5V and +24V power supply, optocoupler U7, NPN triode Q1, diode D8, overheat detection protector or temperature controller WKQ. +5V is connected to the collector of the output triode of R16. The other end of R16, which is also the Over Heat control signal end, is connected to the collector of triode Q1. The Over Heat control signal end is connected to pin 28 of microprocessor U3. The emitter of Q1 is grounded. The base of Q1 is connected to the emitter of the output triode of U7. The other end of R17 is grounded. The anode of the light emitting diode of U7 is connected to the cathode of D8. The other end of R18 is connected to +24V. The anode of D8 is connected to the cathode of the light emitting diode of U7, C12 and pin 1 of CN6. The other end of C12 is grounded. Pin 2 of CN6 is connected to the ground of +24V. The connection line of the overheat detection protector or temperature controller WKQ, which is of normally closed type, is connected to socket CN6 by a plug. WKQ is installed close to the heat sink of IGBT of the inverter welder. The microprocessor detects the high and low level of pin 28, and thus knows whether overheat phenomenon occurs. If it is confirmed that overheat phenomenon occurs, overheat protection control is performed. For example, during the output of the welder, when overheat phenomenon occurs in the heat sink of IGBT, the overheat detection protector or temperature controller WKQ is disconnected, the light emitting diode of U7 emits light, the output triode of U7 is turned on, the Over Heat control signal is at low level, the microprocessor control system detects this level signal, and sends a control command. On the one hand, the O.H indicator is lighted under the control of the operation and display circuit, showing the overheat state. On the other hand, the microprocessor control system sends a control command to shut down the PWM signal, and finally shuts down the current output of the welder. Under the action of the cooling fan, when the overheat phenomenon is eliminated, the control system automatically recovers, and the overheat O.H indicator of the operation and display circuit is extinguished, allowing the welder to perform welding operation again. Thus, overheat protection of the welder is realized. Of course, if it is in the state of argon arc welding or other gas shielded welding, the control system will also shut down the electromagnetic gas valve to stop the delivery of protective gas to the welding torch.

[0037] 11) Inverter primary side overcurrent signal detection and protection control circuit, see attached Figure 4 The primary circuit of the inverter transformer in the welder inverter circuit is provided with a bus current transformer for primary current detection. The bus current transformer can electrically isolate the high and low voltage circuits, which is beneficial to the reliability of the welder control circuit. The secondary output detection signals OC1 and OC2 of the bus current transformer are connected to the attached Figure 4The 7th pin and 6th pin of the socket CN1, the secondary output detection signals OC1 and OC2 pass through a full-wave rectifier circuit composed of four diodes D13~D16, and are converted into DC signals. The output of the full-wave rectifier circuit is connected in parallel with R43~R46 to the ground, and finally the primary inverter primary current detection signal is obtained , The signal passes through the rear stage circuit, i.e. a circuit composed of capacitors C24 and C25, resistors R47~R50, a double diode D17, and an operational amplifier U14B (one of U14), and a Ufo overcurrent protection detection control signal is obtained at the rear end. The signal is transmitted to the Figure 4 The 6th pin of the microprocessor U3 is used to participate in the overcurrent protection control of the welding machine. When the microprocessor U3 detects an excessive Ufo overcurrent protection detection control signal, it is determined that an overcurrent phenomenon occurs. At this time, the microprocessor control system will issue a control command. On the one hand, under the control of the operation and display circuit, the O.H indicator light is lit to show that there is an abnormal state. On the other hand, the microprocessor control system will issue a control command to close the PWM signal, and finally the current output of the welding machine is turned off. Of course, if it is in the state of argon arc welding and other gas shielded welding, the control system will also turn off the electromagnetic gas valve to stop the delivery of protective gas to the welding gun. When the overcurrent phenomenon is eliminated, the control system will automatically recover, and at the same time, the O.H indicator light of the operation and display circuit will be extinguished, allowing the welding machine to perform welding operation again. This realizes the overcurrent protection of the welding machine.

[0038] 12) Drive control circuit, see attached Figure 4The circuit part is composed of resistors 8~R15, electrolytic capacitor C9, capacitors C10, C11, U4 driving chip (EG2132), N / P channel enhancement field effect transistor chip U5 and U6 (SVD1055SA), diodes D4~D7, +15V power supply. The 1 and 8 pins of U4 are connected to +15V, the 4 pin and 6 pin of U4 are grounded, the 2 pin of U4 is connected to R8, the other end of R8 is connected to the 19 pin (PWMA) of microprocessor U3; the 3 pin of U4 is connected to R9, the other end of R9 is connected to the 18 pin (PWMB) of microprocessor U3; the 7 pin of U4 is connected to R10, R11, the anode of D4, the cathode of D5, the cathode of D4 and the other end of R10 are connected to the 4 pin of U5, the anode of D5 and the other end of R11 are connected to the 2 pin of U5; the 5 pin of U4 is connected to R12, R13, the anode of D6, the cathode of D7, the cathode of D6 and the other end of R12 are connected to the 4 pin of U6, the anode of D7 and the other end of R13 are connected to the 2 pin of U6; the 3 pin of U5 and the 3 pin of U6 are connected to R14, the other end of R14 is connected to +15V and the positive pole of C9, the other end of C9 is grounded; the 5 pin~8 pin of U5 is connected to R15, one end of C10 and C11, the other end of R15, C10 and C11, namely DRVA, is the output IGBT drive control signal, the 5 pin~8 pin of U6 is also connected to one end, which is DRVB, namely the other output IGBT drive control signal. The PWMA and PWMB signals output by the microprocessor U3 are output as two groups of IGBT drive control signals DRVA and DRVB after passing through the drive control circuit, to control the working state of the IGBT tube in the welding machine inverter circuit. For example, if overheat protection, overcurrent protection control and other phenomena occur, the microprocessor U3 can stop outputting the PWM signal, so as to stop the output of the welding machine; through the negative feedback control of the current, the PWM signal output by the microprocessor U3 is changed, that is, the duty cycle of the two groups of square wave pulse signals output by the U3 chip PWMA and PWMB is changed, and finally the output current of the welding machine is changed. The working frequency and dead time of the two groups of square wave pulse signals PWMA and PWMB are determined by the parameter setting of the U3 chip. As for how to determine it, the relevant use materials or instructions of U3 need to be consulted, which will not be repeated here. The PWMA and PWMB signals output by the microprocessor U3 are the signals that determine the output current and voltage of the welding machine inverter main circuit, and whether the welding machine has output, while the PWM pulse width modulation signals are controlled by the current regulation given signal and the current negative feedback signal, whether there is overheat, overcurrent phenomenon, whether the VRD function is selected during manual welding, and other control influencing factors.

[0039] By the way, if the control system detects that the welding machine is overheating or overcurrent, at this time, the U3 microprocessor control system will issue control instructions, on the one hand, under the control of the operation and display circuit, the O.H indicator light is on; on the other hand, through the U3 microprocessor to close the output of PWM, eventually close the output of the welding machine; when the overheating or overcurrent phenomenon is eliminated, the control circuit can continue to output the PWM control signal, at the same time, the O.H indicator light of the operation and display circuit is turned off, allowing the welding machine to perform welding operation again. If it is in the state of argon arc welding and other gas protection, the electromagnetic gas valve will also be closed to stop the delivery of protective gas to the welding gun. Many of the above contents have been described in the relevant part, which will not be expanded here.

[0040] The brief control process of different welding methods is briefly described as follows:

[0041] If it is to be manual welding (MMA), connect the required welding electrode holder and its welding cable, workpiece welding cable. By operating and display control circuit welding method selection button, you can choose "MMA" or "manual welding". Then, by pressing the encoder BMQ button, you can select the hot start current, welding current, thrust current parameters under manual welding. After completing the settings, you can proceed with the manual arc welding operation. Under the action of the control circuit, the PWM pulse width control signal output by U3 microprocessor makes the drive circuit of IGBT work, and finally makes the inverter main circuit of the welding machine output a high no-load voltage. If the user selects the VRD function when manual welding, the control result is different from the above, and a high no-load voltage will not be generated, but a low no-load voltage of a few dozen volts will be output. Then, the operator can use the welding electrode to weld. When welding, once the electrode and the workpiece are short-circuited, the welding machine will output a large hot start current to ignite the arc, and moving the electrode will start to form a weld. During welding, the Hall sensor of the inverter output circuit will feed back the detected current signal to the microprocessor in real time through the circuit system. Through the PI (proportional integral) operation control of the current given signal and the current negative feedback, the output PWM signal will change in real time, and through the IGBT drive circuit, the output characteristics of the inverter main circuit can meet the requirements of manual welding. Within a certain range where the output voltage of the inverter main circuit is higher than 16V, the output current of the inverter main circuit is constant current output; when the output voltage is below 16V, the current given signal involved in the welding current output control will increase with the decrease of the welding machine output voltage, that is, thrust current control is performed. In this way, the output characteristics of the welding machine are controlled to be constant current with a descending characteristic outside. The control in the constant current stage is current cutoff negative feedback control, that is, feedback control that only works when the current reaches the set value of the welding current. During the constant current output current control process, the output voltage decreases with the increase of the current because, when the welding current given signal remains unchanged, the difference between the welding current given signal and the current negative feedback control signal will decrease with the increase of the current, and after PI operation control, the pulse width or duty cycle of U3 chip will decrease, so the output voltage of the welding machine will decrease. Because the feedback coefficient of PI operation control is large, when the current increases slightly, the output voltage will decrease a lot; when the welding machine output voltage decreases to below 16V, with the decrease of the voltage, the control circuit can increase the PWM pulse width or duty cycle of microprocessor U3, so that the welding current is controlled according to the set current parameters plus the increment of thrust current, and finally the output current increases a lot. In addition, when the welding current given signal changes, the current cutoff negative feedback set value is different, and the other control processes are similar. In this way, between the minimum and maximum set by the encoder, you can obtain countless descending characteristic curves.The setting of the arc force current (ARC FORCE) is changed, that is, the slope of the outer drag portion of the outer characteristic curve is changed to obtain different outer drag stage currents. Such control also meets the basic requirements of manual arc welding.

[0042] If argon arc welding is to be performed, the welding torch (including the connection of the welding torch switch plug), the shielding gas, the workpiece connection cable, the welding torch connection to the negative polarity output quick connector of the welding machine, and the workpiece welding cable connector connection to the positive polarity output quick connector of the welding machine are connected. The shielding gas is connected to the gas outlet of the argon gas flowmeter of the gas supply system through a gas pipe, and the other end of the gas pipe is connected to the gas input interface or gas inlet nozzle at the rear of the welding machine. The atmosphere switch of the argon gas cylinder is opened, the flow rate of the argon gas flowmeter is adjusted, and the requirements for argon arc welding are met. Then, the welding method button of the operation and display control circuit is pressed to select "argon arc welding" or "TIG"; according to the welding operation requirements, the 2T or 4T welding torch switch operation mode is selected by pressing the selection button. The corresponding indicator lights of the pre-gas sending time (Preg), welding current (I W ), arc collecting current (I E ), and post-gas closing time (Posg) parameters can be selected by pressing the button of the encoder BMQ. When one of the indicator lights is on, the corresponding welding parameter can be set or adjusted by the encoder BMQ. After the setting is completed, argon arc welding can be performed. Due to the "high-frequency arc starting" control (non-contact arc starting mode), the distance between the welding torch tungsten needle and the workpiece should be kept small, about a few millimeters, without contact. When the welding torch switch is pressed, the control system detects that the welding torch switch is closed, at which time the control system first controls the electromagnetic gas valve according to the pre-set pre-gas sending time, that is, as soon as the welding torch switch is closed, the electromagnetic gas valve starts to work immediately to deliver shielding gas to the welding area. After the pre-gas sending time (Preg) delay control stage is completed, the high-frequency arc starting control process is performed under the action of the control circuit, then the electric arc is ignited, and the welding stage control is entered, and the welding current is controlled according to the set welding current (I W ) parameter. When it is detected that the welding torch switch is finally released and the welding is ready to be completed, the arc collecting stage and the arc collecting current (I E ) control are entered, and finally the post-gas closing time (Posg) stage control is performed. In addition, the control of the 2T and 4T modes is different, mainly in terms of the different welding torch switch operation modes. The time sequence and logic control of the above-mentioned different stages are realized by the control system of the present application. The above control process also meets the basic requirements of argon arc welding.

[0043] If pulse argon arc welding is to be performed, the connections of the welding gun, workpiece, and shielding gas are the same as those for argon arc welding. The difference is that "pulse argon arc welding" or "pulse TIG" is selected by operating and displaying the welding method button of the control circuit; according to the welding operation requirements, the 2T or 4T welding gun switch operation mode is selected by selecting the button. The peak current (I W or I F ), base current (I B )、the arc ending current(I E ), of course, there are also parameters such as advance gas supply time (Preg) and delayed gas holding time (Posg). When the indicator light corresponding to one of the parameters is on, the encoder BMQ can be used to set or adjust the corresponding welding parameters. After completing the settings, pulse argon arc welding can be performed. The arc striking method is the same as the aforementioned argon arc welding, "high-frequency arc striking" control or non-contact arc striking method. When the welding gun switch is pressed, the control system detects that the welding gun switch is closed. At this time, the control system first controls the electromagnetic valve according to the advance gas supply time set on the circuit board, that is, as soon as the welding gun switch is closed, the electromagnetic valve is immediately started to supply protective gas to the welding area. After the delay control stage of the advance gas supply time (Preg) is completed, the high-frequency arc striking control process is carried out under the action of the control circuit. After that, the arc is ignited and the control enters the alternating stage of welding peak current and base current. The current size of the welding peak current stage is based on the set peak current (I W or I F ) parameter, the current size of the welding base current stage is controlled by the set base current (I B ) parameters. When the welding gun switch is released and welding is about to end, the arc extinguishing stage and arc extinguishing current (I E ) and finally the control of the post-gas holding time (Posg). The rest of the control is similar to that of argon arc welding.

[0044] If it is to be cold welding, welding gun, workpiece, the connection of protective gas, etc. are consistent with argon arc welding or pulse argon arc welding. The difference is that the welding method key of the operation and display control circuit is selected "cold welding" or "COLD"; according to the welding operation needs, through the selection of the key, select 2T or 4T welding gun switch operation mode. The welding time (HJ Time, millisecond level), interval time (JG Time) and other parameters can be selected by pressing the encoder BMQ key. When the corresponding indicator light of a certain parameter is on, the corresponding welding parameter can be set or adjusted by the encoder BMQ. After the setting is completed, the cold welding operation can be carried out. The arc striking method is the same as the above-mentioned argon arc welding, "high-frequency arc striking" control or non-contact arc striking mode. When the welding gun switch is pressed, the control system detects that the welding gun switch is closed. At this time, the control system first controls the electromagnetic gas valve according to the pre-set gas delivery time on the circuit board, that is, as soon as the welding gun switch is closed, the electromagnetic gas valve starts to work immediately, and the protective gas is delivered to the welding area. After the pre-delivery time (Preg) delay control stage is completed, the high-frequency arc striking control process is carried out under the action of the control circuit, and then the arc is ignited, and the cold welding stage control is entered. The welding time and interval time stages will be alternately carried out. Since the welding time is very short, millisecond level, the heat input of welding is very low. The control of cold welding is controlled according to the set cold welding parameters. Other controls are similar to the control of argon arc welding.

Claims

1. An inverter multi-functional cold welder characterized by comprising: The cold welding machine comprises two control circuit boards, one of which is an operation and display control panel and the other is a main control panel; the operation and display control panel is connected with the main control panel through the plug of the CN8 socket and control lines thereof; the main control panel is provided with, in addition to the socket CN8, 1) a CN9 socket which is connected with the +24V power supply of the welding machine through the plug thereof and control lines thereof; 2) a CN6 socket which is connected with a normally closed temperature controller WKQ of the welding machine through the plug thereof and control lines thereof, the temperature controller being installed close to the surface of an aluminum radiator of an IGBT tube of the inverter welding machine and being used for overheat protection control of the welding machine; 3) a CN5 socket which is connected with a DC 24V cooling fan of the welding machine through the plug thereof and control lines thereof; and 4) a CN2 socket which is connected with a Hall current sensor HECGQ for detecting the output current of the welding machine through the plug thereof and control lines thereof, the -15V and +15V power supplies of the sensor being from the main control panel circuit, and the detected output current signal of the welding machine being transmitted to the main control panel; 5) CN4 socket Socket CN4, which is connected to the output of the welding machine through its plug and its control line, transmits the detected welding machine output voltage signal to the main control board; 6) CN3 socket Socket CN3, which is connected to the following parts through its plug and its control line: the 7th and 8th pins of the CN3 socket CN3 are connected to the electromagnetic gas valve DCF of the welding machine; the 5th pin of the CN3 socket CN3 is connected to the +24V power supply of the welding machine; the 4th pin of the CN3 socket CN3 is connected to the ground of the +24V power supply of the welding machine; the 3rd pin of the CN3 socket CN3 outputs the HF Control control signal to control the high-frequency arc starting circuit or the arc starting board of the welding machine; the 2nd and 1st pins of the CN3 socket CN3 are connected to the control line of the argon arc welding gun switch of the welding machine; 7) CN1 socket Socket CN1, which is connected to the following parts through its plug and its control line: the 6th and 7th pins of the CN1 socket CN1 are connected to the output OC1 and OC2 of the current transformer for detecting the primary current of the inverter transformer in the inverter main circuit of the welding machine; the 4th and 5th pins of the CN1 socket CN1 are connected to the IGBT tube part in the inverter main circuit of the welding machine to realize the driving control of the IGBT tube; the 3rd, 4th and 5th pins of the CN1 socket CN1 are respectively connected to the -15V, ground and +15V power supply parts of the welding machine; the main control board part is installed on the front panel of the welding machine, and through the above connection, the control of the welding machine can be realized; for the operation and display part, there are power indicator, digital tube display table, protection indicator, encoder with keys; there are indicator lights for manual arc welding, argon arc welding, cold welding, pulse argon arc welding, and selection keys for these welding methods; there are 2T, 4T and VRD mode indicator lights, and selection keys for these modes; there are indicator lights for the advance gas delivery time and the lagging gas closing time when gas protection, welding current or peak current, base current for pulse argon arc welding, pulse frequency, welding time for hot arc starting current or cold welding, interval time for arc thrust or thrust current or cold welding, and arc current; under the condition of selecting the welding method, the corresponding welding parameters can be selected by operating the keys of the encoder, the corresponding parameter indicator will light up, and the parameter data will be displayed in the digital tube display table at the same time, and the parameter can be adjusted using the encoder; the circuit of the main control board part is composed of integrated voltage stabilizer U15, filter capacitor C33, voltage stabilizing circuit composed of capacitors C34, C1~C3, microprocessor U3, cooling fan FAN control circuit, electromagnetic gas valve DF control circuit, welding gun switch signal detection and output signal control circuit, high-frequency arc starting control circuit, welding machine output current sampling signal processing circuit, welding machine output voltage sampling signal processing circuit, overheat signal detection and protection control circuit, inverter primary side overcurrent signal detection and protection control circuit, drive control circuit and control signal output circuit of operation and display control board;Under the joint action of the main control board circuit, operation and display control circuit and the welding machine circuit board connected with the main control board, a complete whole can be formed to realize the control of the above four welding methods, different operation modes and different welding parameters and obtain good control effect.

2. The multi-functional cold welding machine of claim 1, wherein: The circuit of the operation and display control panel part comprises a driving chip U1 of a digital tube display, digital tubes U2, a cold welding indicating lamp L1, a manual welding or manual electric arc welding indicating lamp L2, an argon arc welding indicating lamp L3, a pulse argon arc welding indicating lamp L4, a 2T welding gun switch operation mode indicating lamp L5, a 4T welding gun switch operation mode indicating lamp L6, a VRD function indicating lamp L7 during manual welding, an overheat or overcurrent protection indicating lamp L8, an advance gas feeding time indicating lamp L9, a welding current or peak current indicating lamp L12, a base value current indicating lamp L14 of pulse argon arc welding, a collecting arc current indicating lamp L16, a lagging gas closing time indicating lamp L17, a pulse frequency indicating lamp L18 during pulse argon arc welding, a hot arc starting current during manual welding or welding time indicating lamp L19 during cold welding, an arc thrust or thrust current during manual welding or interval time indicating lamp L20 during cold welding, a power supply indicating lamp L29, a welding parameter adjustment encoder BMQ, a selection button of welding parameters, a selection button SW1 of manual welding / argon arc welding / pulse argon arc welding / cold welding, a selection button SW2 of 2T / 4T / VRD, a socket CN8 for connecting the control circuit of the operation and display part with the main control circuit, capacitors C1-C4 and C7-C8, resistors R1, R4-R7, a +5V power supply, the 1 pin of U1 being connected with the 3 pin of the socket CN8; the 3 pin of U1 being connected with the 1 pin of the socket CN8; the 2 pin of U1 being connected with the 2 pin of the socket CN8; the control circuit of the operation and display part is connected with the main control circuit through the CN8 socket interface, so as to realize the exchange of control information and data; the 6 pin of U1 being connected with +5V; the 22 pin of U1 being connected with ground; +5V being from the 4 pin of the CN8 socket, and the +5V to ground being connected with C1-C4 capacitors; the 5 pin of the CN8 socket being connected with ground; the 7 pin of U1 being connected with the 11 pin of U2, and the anodes of L17, L9 and L1; the 8 pin of U1 being connected with the 5 pin of U2, and the anodes of L18 and L2; The 9th pin of U1 is connected with the 4th pin of U2 and the anode of L19, L3; the 10th pin of U1 is connected with the 3rd pin of U2 and the anode of L20, L12, L4; The 11th pin of U1 is connected with the 2nd pin of U2 and the anode of L5; The 12th pin of U1 is connected with the 1st pin of U2 and the anode of L14, L6; the 13th pin of U1 is connected with the 10th pin of U2 and the anode of L7; The 14th pin of U1 is connected with the 7th pin of U2 and the anode of L16, L8; the 15th pin and the 16th pin of U1 are not connected; the 24th pin of U1 is connected with the 12th pin of U2; The 23rd pin of U1 is connected with the 9th pin of U2; The 21st pin of U1 is connected with the 8th pin of U2; the 20th pin of U1 is connected with the cathodes of L17, L18, L19 and L20; the 19th pin of U1 is connected with the cathodes of L9, L12, L14 and L16; the 18th pin of U1 is connected with the cathodes of L1, L2, L3, L4, L5, L6, L7 and L8; the 17th pin of U1 is not connected; the digital tube U2 is used for displaying parameters; one end of R1 is connected with +5V, the other end of R1 is connected with the anode of L29 LED, the cathode of the LED is connected with the ground; the 5th pin of the encoder BMQ is connected with the K3 end, K3 is also connected with the 8th pin of CN8; the 4th pin of the encoder BMQ is connected with the ground; the 1st pin of the encoder BMQ is connected with R4, R6, C7 and the 6th pin of CN8, the other end of R4 is connected with +5V, the other ends of R6, C7 are connected with the ground; the 2nd pin of the encoder BMQ is connected with the ground; the 3rd pin of the encoder BMQ is connected with R5, R7, C8 and the 7th pin of CN8, the other end of R5 is connected with +5V, the other ends of R7, C8 are connected with the ground; the 4th pin of SW1 selection button is connected with the ground, the 3rd pin of SW1 selection button is connected with the K1 end of CN8 10th pin; The 3rd pin of SW2 selection button is connected with the ground, the 4th pin of SW2 selection button is connected with the K2 end of CN8 9th pin; by using the above operation and display part circuit, under the common action of the main control board part circuit, the operation and display function of the welding machine can be realized.

3. The multi-functional cold welding machine of claim 1, wherein: The driving control circuit part includes resistors R8-R15, electrolytic capacitor C9, capacitors C10 and C11, U4 driving chip, N / P channel enhancement field effect transistor chips U5 and U6, diodes D4-D7, and +15V power supply; the 1st and 8th pins of U4 are connected to +15V, the 4th and 6th pins of U4 are grounded, the 2nd pin of U4 is connected to R8, the other end of R8 is connected to the 19th pin of microprocessor U3; the 3rd pin of U4 is connected to R9, the other end of R9 is connected to the 18th pin of microprocessor U3; the 7th pin of U4 is connected to R10, R11, the anode of D4, and the cathode of D5, the cathode of D4 and the other end of R10 are connected to the 4th pin of U5, the anode of D5 and the other end of R11 are connected to the 2nd pin of U5; the 5th pin of U4 is connected to R12, R13, the anode of D6, and the cathode of D7, the cathode of D6 and the other end of R12 are connected to the 4th pin of U6, the anode of D7 and the other end of R13 are connected to the 2nd pin of U6; the 3rd pin of U5 and the 3rd pin of U6 are connected to R14, the other end of R14 is connected to +15V and the positive pole of C9, the other end of C9 is grounded; the 5th-8th pins of U5 are connected to one end of R15, C10 and C11, the other end of R15, C10 and C11, i.e. DRVA, is the output IGBT driving control signal, the 5th-8th pins of U6 are connected to the other end, which is also DRVB, i.e. the other output IGBT driving control signal; the PWMA and PWMB signals output by microprocessor U3 are output as two groups of IGBT driving control signals DRVA and DRVB after passing through the driving control circuit, to control the working state of IGBT in the welding machine inverter circuit; the PWMA and PWMB signals output by microprocessor U3 are signals for determining the output current and voltage of the welding machine inverter main circuit, and whether the welding machine has output, and these PWM pulse width modulation signals are determined by the current regulation given signal and the current negative feedback signal, whether there is overheating and overcurrent phenomenon, and whether the VRD function control is selected during manual welding.

4. The multi-functional cold welding machine of claim 1, wherein: The overheat signal detection and protection control circuit comprises a CN6 socket, a capacitor C12, resistors R16-R18, +5V and +24V power supplies, an optical coupler U7, an NPN triode Q1, a diode D8, an overheat detection protector or temperature controller WKQ; the +5V is connected to the collector of the output triode of the U7 and the other end of the R16, or the overheat control signal end is connected to the collector of the NPN triode Q1, the overheat control signal end is connected to the 28th pin of the microprocessor U3, the emitter of the Q1 is grounded, the base of the Q1 is connected to the emitter of the output triode of the U7, and the other end of the R17 is grounded; the anode of the light emitting diode in the U7 is connected to the cathode of the D8, the other end of the R18 is connected to the +24V, the anode of the D8 is connected to the cathode of the light emitting diode in the U7, the C12 and the 1st pin of the CN6, the other end of the C12 is grounded, and the 2nd pin of the CN6 is connected to the ground of the +24V; the connection line of the normally closed WKQ overheat detection protector or temperature controller is connected to the CN6 socket through a plug, and the overheat detection protector or temperature controller WKQ is installed close to the heat sink of the IGBT of the inverter welder; The microprocessor U3 detects the high and low levels of the 28th pin, and can know whether the overheat phenomenon occurs; if it is confirmed that the overheat phenomenon occurs, overheat protection control is performed.

5. The multi-functional cold welding machine of claim 1, wherein: The electromagnetic gas valve DF control circuit is characterized in that the circuit comprises a socket CN3, an electromagnetic gas valve DCF connected to the socket CN3, a field effect tube Q4, an optical coupler U11, a voltage stabilizing tube Z3, a diode D11, resistors R27-R30, +5V and +24V power supplies; the 21st pin GasControl control signal end of the microprocessor is connected to the cathode of the light emitting diode in the U11, the anode of the light emitting diode is connected to the R27, and the other end of the R27 is connected to the +5V; the collector of the output stage triode in the U11 is connected to the R28, and the other end of the R28 is connected to the +24V; the emitter of the output stage triode in the U11 is connected to the R29, and the other end of the R29 is connected to the R30, the cathode of the voltage stabilizing tube Z3 and the gate G end of the field effect tube Q4, the other end of the R30, the anode of the Z3 and the S end of the Q4 are grounded; the D end of the Q4 is connected to the 8th pin of the electromagnetic gas valve DCFDCF or the cathode of the D10, the anode of the D11 is connected to the +24V; the 7th pin of the socket CN3 is connected to the positive electrode of the electromagnetic gas valve, and the 8th pin of the CN3 is connected to the negative electrode of the electromagnetic gas valve; during the gas shielded welding, the microprocessor controls whether the light emitting diode in the optical coupler U11 emits light through the output level of the 21st pin, and further controls the conduction state of the field effect tube Q4, and finally determines whether the electromagnetic gas valve operates, thereby realizing the control of the electromagnetic gas valve.

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