CN115255582B - Inverter type direct-current plasma double-air-valve cutting machine and control circuit - Google Patents
Inverter type direct-current plasma double-air-valve cutting machine and control circuit Download PDFInfo
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- CN115255582B CN115255582B CN202210919731.0A CN202210919731A CN115255582B CN 115255582 B CN115255582 B CN 115255582B CN 202210919731 A CN202210919731 A CN 202210919731A CN 115255582 B CN115255582 B CN 115255582B
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- 238000005520 cutting process Methods 0.000 title claims abstract description 80
- 238000001514 detection method Methods 0.000 claims abstract description 104
- 238000002955 isolation Methods 0.000 claims description 39
- 230000000087 stabilizing effect Effects 0.000 claims description 15
- 238000010891 electric arc Methods 0.000 claims description 11
- 238000012423 maintenance Methods 0.000 abstract description 4
- 239000003990 capacitor Substances 0.000 description 23
- 239000007789 gas Substances 0.000 description 17
- 238000010586 diagram Methods 0.000 description 7
- 235000014676 Phragmites communis Nutrition 0.000 description 5
- 230000002093 peripheral effect Effects 0.000 description 4
- 238000007664 blowing Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 235000006508 Nelumbo nucifera Nutrition 0.000 description 2
- 240000002853 Nelumbo nucifera Species 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- 238000003466 welding Methods 0.000 description 2
- 238000013459 approach Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015556 catabolic process Effects 0.000 description 1
- 238000010168 coupling process Methods 0.000 description 1
- 238000005859 coupling reaction Methods 0.000 description 1
- 230000001934 delay Effects 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 230000009977 dual effect Effects 0.000 description 1
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K10/00—Welding or cutting by means of a plasma
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K10/00—Welding or cutting by means of a plasma
- B23K10/006—Control circuits therefor
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Abstract
The application discloses an inversion type direct current plasma double-air-valve cutting machine and a control circuit, wherein the double-air-valve cutting machine comprises an air source, a main air valve, an auxiliary air valve and a double-air-valve control circuit, one end of the main air valve is connected with the air source, the other end of the main air valve is connected with the main air passage and the auxiliary air passage, the main air passage is directly used for conveying air to the cutting machine, the auxiliary air valve is arranged on the auxiliary air passage, the air flow size conveyed to the cutting machine is controlled through the auxiliary air valve, and the double-air-valve control circuit is respectively connected with the main air valve and the auxiliary air valve and is used for controlling the actions of the main air valve and the auxiliary air valve; the control circuit comprises a main loop current detection circuit, an output detection control circuit, a main air valve control circuit, an auxiliary air valve control circuit and an idle load detection control circuit; according to gun switching signals, idle signals and main loop current signals, the opening or closing of the main air valve and the auxiliary air valve is controlled, so that strong arc continuity is ensured during arc maintenance, and arc interruption is avoided; the nozzle and the electrode of the cutting gun are prevented from being damaged, and the success rate of arc striking is improved.
Description
Technical Field
The application relates to the technical field of cutter control, in particular to an inversion type direct-current plasma double-air-valve cutter and a control circuit.
Background
Cutting, generally refers to cutting of metal. The working principle of the DC plasma cutting machine is as follows: cutting method using extremely fine and high temperature plasma arc to melt local metal rapidly and then blowing away the melted metal with air current.
At present, a conventional inverter type direct current plasma double-air-valve cutting machine is provided with only one air valve, an air valve control circuit only needs to control a single air valve, the cutting machine is provided with compressed air flow in an arc maintenance function and a cutting function, the problems of arc interruption and small arc interruption in the arc maintenance state often occur in the control, and meanwhile, the arc striking success rate is low in the arc maintenance cutting process; the plasma arc is smaller, so that the electrode loss of the nozzle of the cutting gun is increased, and the use cost is increased.
Therefore, controlling the gases in different states of the cutting machine is a problem to be solved.
Disclosure of Invention
The application aims to provide an inversion type direct current plasma double-air-valve cutting machine and a control circuit, which are used for detecting the current of a main circuit, opening a main air valve and an auxiliary air valve in a pilot arc state, supplying matched small-flow gas to the pilot arc, ensuring strong electric arc continuity in the pilot arc function and avoiding the occurrence of an arc breakage phenomenon; in the cutting state, the main air valve and the auxiliary air valve are controlled to be switched, so that the nozzle and the electrode of the cutting gun are prevented from being damaged due to discontinuous or small plasma arc, and the success rate of arc striking is improved.
In a first aspect, the above object of the present application is achieved by the following technical solutions:
the inversion type direct current plasma double-air-valve cutting machine comprises an air source, a main air valve, an auxiliary air valve and a double-air-valve control circuit, wherein one end of the main air valve is connected with the air source, the other end of the main air valve is connected with the main air passage and the auxiliary air passage, the main air passage is directly used for conveying air to the cutting machine, the auxiliary air valve is arranged on the auxiliary air passage, the air flow size conveyed to the cutting machine is controlled through the auxiliary air valve, and the double-air-valve control circuit is respectively connected with the main air valve and the auxiliary air valve and is used for controlling the action of the main air valve and the auxiliary air valve.
The application is further provided with: the double-air valve control circuit detects the current of the main loop, judges the state of the circuit and controls the opening or closing of the double-air valve, and in the cutting state, the current of the main loop flows back to the negative electrode of the power supply from the positive electrode of the power supply through the workpiece and the electrode, an electric arc is established between the electrode and the workpiece, and the main air valve is opened; in the pilot arc state, the output of the inverter flows back to the negative electrode of the power supply from the positive electrode through the idle circuit, the nozzle and the electrode, the electric arc is established between the electrode and the nozzle, the main air valve and the auxiliary air valve are simultaneously opened, and the auxiliary air valve shunts the air in the air pipe; in the idle state, idle current is detected, the main air valve is closed, the auxiliary air valve is opened, and the air in the air pipe is discharged.
The application is further provided with: when a switch of a cutting machine gun is pressed down, the double air valve control circuit detects that the main loop has voltage output, controls the main air path to supply air, and controls the electric arc between the electrode and the nozzle to pull up, and after the electric arc is pulled up, the double air valve control circuit controls the auxiliary air valve to be sucked in, so that the air flow of the cutting machine is split; when the cutting gun is close to a workpiece, the small arc is changed into a large arc, the double-air valve control circuit detects that current exists in the main loop, the auxiliary air valve is closed, and the exhaust is stopped; when the switch of the cutting machine gun is loosened, the inverter does not work, the main air valve is still in a conducting state, and the electrode and the nozzle are in a disconnecting state; the cutting machine gun switch is pressed down again, the inverter works, the double-air valve control circuit detects an idle signal and controls the main air valve to be closed, the auxiliary air valve to be opened, residual air in the air pipe is discharged, and the electrode and the nozzle are accelerated to reset.
In a second aspect, the above object of the present application is achieved by the following technical solutions:
an inverter type direct current plasma double-air-valve cutting machine control circuit comprises a main loop current detection circuit, an output detection control circuit, a main air-valve control circuit and an auxiliary air-valve control circuit; the output detection control circuit is respectively connected with the main air valve control circuit and the auxiliary air valve control circuit and is used for outputting a third signal S3 to the auxiliary air valve control circuit and outputting a fourth signal S4 to the main air valve control circuit according to the output voltage; the main air valve control circuit is used for controlling the switching state of the main air valve according to the cutting machine gun switching signal S and the fourth signal S4; the main loop current detection circuit is connected with the auxiliary valve control circuit, and outputs a fifth signal S5 to the auxiliary valve control circuit according to whether current flows through the main loop or not; the auxiliary air valve control circuit is used for controlling the on-off state of the auxiliary air valve according to the cutting machine gun on-off signal S, the third signal S3 and the fifth signal S5.
The application is further provided with: the system also comprises an idle load detection control circuit which is respectively connected with the main loop current detection circuit and the output detection control circuit and is used for detecting whether the main loop is in an idle load state or not, outputting a first signal S1 to the main loop current detection circuit and outputting a second signal S2 to the output detection control circuit according to the detection result; the main loop current detection circuit is used for outputting a fifth signal S5 and the auxiliary air valve control circuit according to whether current flows through the main loop or not and the first signal S1; the output detection control circuit is used for outputting a third signal S3 to the auxiliary valve control circuit and outputting a fourth signal S4 to the main valve control circuit according to the magnitude of the output voltage and the second signal S2.
The application is further provided with: the output detection control circuit comprises a voltage control circuit, a first isolation circuit, a first inversion circuit and a first switch circuit which are sequentially connected, wherein the voltage control circuit controls whether the first isolation circuit is isolated and conducted according to the output voltage and the second signal S2, the first isolation circuit is used for isolating an output power supply from a control power supply, the first inversion circuit inverts the output signal of the first isolation circuit and controls the switch state of the first switch circuit, and the first switch circuit outputs a third signal S3 to the auxiliary air valve control circuit and a fourth signal S4 to the main air valve control circuit.
The application is further provided with: the no-load detection control circuit comprises a no-load voltage detection circuit, a voltage stabilizing circuit, a second isolation circuit and a second inverting circuit which are connected in sequence; the voltage stabilizing circuit is used for stabilizing the no-load voltage or the output voltage to give a voltage signal conforming to the second isolation circuit, the second isolation circuit is used for isolating the output power supply from the control power supply, and the second inverting circuit outputs the first signal S1.
The application is further provided with: the main air valve control circuit comprises a delay circuit and a second switch circuit which are connected in sequence, and after a switch of the cutting machine gun is pressed down, the switch is delayed by the delay circuit, and the second switch circuit is controlled to be turned on or off independently or in combination with a fourth signal.
The application is further provided with: the main loop current detection circuit comprises a magnetic current detection element and two unidirectional current elements, one end of the first unidirectional current element is connected with the output of the no-load detection control circuit, the other end of the first unidirectional current element is connected with one end of the magnetic current detection element, and the other end of the magnetic current detection element is connected with the power supply ground; one end of the second unidirectional current element is connected with the output of the no-load detection control circuit, and the other end of the second unidirectional current element is connected with the output end of a fifth signal S5 of the output detection control circuit; when the magnetic current detection element detects that current flows in the main loop, the main loop current detection circuit outputs a low level; when the magnetic current detecting element detects that no current flows in the main loop, the output of the main loop current detecting circuit is the same as the first signal.
The application is further provided with: the auxiliary air valve control circuit comprises an auxiliary air valve first control circuit and an auxiliary air valve second control circuit which are connected with each other; the second control circuit of the auxiliary air valve outputs a sixth signal S6 to the first control circuit of the auxiliary air valve according to the third signal S3 and the fifth signal S5; the first control circuit of the auxiliary air valve is used for controlling the on-off state of the auxiliary air valve according to the cutting machine gun on-off signal S and the sixth signal S6.
Compared with the prior art, the application has the beneficial technical effects that:
1. according to the application, by arranging the double-gas and control circuit, the current of the main loop is detected, the magnitude of the gas flow is controlled according to the current state of the main loop, the continuous arc is ensured, and the success rate of arc striking is improved;
2. further, the current detection coil is arranged in the main loop, and when current is detected, the current detection coil controls the atmospheric flow to ensure cutting and blowing; when no current exists, controlling small air flow to ensure pilot arc;
3. further, the control circuit controls the opening or closing of the main air valve and the auxiliary air valve according to the current, the output voltage and the gun switching state of the main loop, so that the control of the air flow of the cutting machine in different states is realized, the effect of the cutting machine is improved, and the cost is reduced.
Drawings
FIG. 1 is a schematic diagram of a dual valve cutter gas circuit configuration according to one embodiment of the present application;
FIG. 2 is a schematic flow diagram of a double valve cutter according to an embodiment of the present application;
FIG. 3 is a block diagram of a control circuit according to an embodiment of the present application;
FIG. 4 is a schematic diagram of an output detection control circuit according to an embodiment of the present application;
FIG. 5 is a schematic diagram of an idle detection control circuit according to an embodiment of the present application;
FIG. 6 is a schematic diagram of a main valve control circuit according to an embodiment of the present application;
fig. 7 is a schematic diagram of a control circuit structure according to an embodiment of the present application.
Detailed Description
The present application will be described in further detail with reference to the accompanying drawings.
The application discloses an air circuit structure of an inversion type direct-current plasma double-air-valve cutting machine, which is shown in figure 1 and comprises an air source, a pressure reducing valve, a main air valve, an auxiliary air valve and a double-air-valve control circuit, wherein the air source, the pressure reducing valve, the main air valve and the auxiliary air valve are sequentially connected, and the double-air-valve control circuit is respectively connected with the main air valve and the auxiliary air valve and is used for controlling the opening or closing of the main air valve and the auxiliary air valve.
The main gas path and the auxiliary gas path are from the main gas valve, wherein the main gas path is directly used for conveying gas to the cutting machine, the auxiliary gas valve is arranged on the auxiliary gas path, and the size of the gas flow conveyed to the cutting machine is controlled through the auxiliary gas valve.
When the switch of the cutting machine gun is pressed down, a high-level signal is output, the double-air-valve control circuit detects that the main loop has voltage output and controls the main air valve to be opened, an electric arc between the electrode of the cutting machine and the nozzle is pulled up, at the moment, the double-air-valve control circuit detects the current between the electrode and the nozzle, and the auxiliary air valve is opened to split the air flow of the cutting machine.
When the cutting gun is close to a workpiece, the small arc is changed into the large arc, the double-air valve control circuit detects that the main loop has current flow, and the auxiliary air valve is controlled to be disconnected, so that the exhaust is stopped.
When the hand switch is released, the inverter does not work, the welding machine does not output, when the main air valve is in an open state, the electrode and the nozzle are in a disconnected state, the hand switch is pressed down again, the inversion works, the double air valve control circuit detects no-load voltage signals, the main air valve is closed, the auxiliary air valve is opened, residual air in the air pipe is discharged, and the electrode and the nozzle are accelerated to reset.
According to the circuit structure of the inverter type direct current plasma double-air-valve cutting machine, as shown in fig. 2, the secondary side current of a transformer T of the inverter type direct current circuit is converted into direct current through a full-bridge rectifying circuit, and a current sensor detects whether the inverter circuit has current flowing.
When the main loop has current flowing, the coil L1 generates a magnetic field, the main loop current detection circuit detects that the main loop has current flowing, the current of the main loop flows back to the negative electrode of the power supply from the positive electrode of the power supply through the workpiece and the electrode, and an electric arc is established between the electrode and the workpiece. The control circuit judges the state of the circuit by collecting the switch signal of the current detection device and controls the double air valves to be opened or closed.
In the pilot arc state, the main loop current detection circuit detects that no current flows through the main loop, the no-load detection control circuit detects that current flows through the main loop, the inverter circuit outputs and flows back to the negative electrode of the power supply from the positive electrode of the power supply through the no-load detection control circuit, the nozzle and the electrode, and an arc is established between the electrode and the nozzle.
The control circuit of the inverter type direct current plasma double-air-valve cutting machine disclosed by the application, as shown in fig. 3, comprises an idle load detection control circuit, a main loop current detection circuit, an output detection control circuit, a main air-valve control circuit and an auxiliary air-valve control circuit.
The auxiliary air valve control circuit comprises an auxiliary air valve first control circuit and an auxiliary air valve second control circuit which are connected with each other.
The no-load detection control circuit is respectively connected with the main loop current detection circuit and the output detection control circuit and is used for detecting whether the main loop is in a no-load state or not, outputting a first signal S1 to the main loop current detection circuit and outputting a second signal S2 to the output detection control circuit according to the detection result.
The output detection control circuit is respectively connected with the no-load detection control circuit, the main air valve control circuit and the auxiliary air valve second control circuit, and outputs a third signal S3 to the auxiliary air valve second control circuit and a fourth signal S4 to the main air valve control circuit according to the output voltage.
The main air valve control circuit controls the switching state of the main air valve according to the cutting machine gun switching signal S and the fourth signal S4.
The main loop current detection circuit is respectively connected with the no-load detection control circuit and the secondary air valve second control circuit, and outputs a fifth signal S5 to the secondary air valve second control circuit according to whether current flows through the main loop and the first signal S1.
The auxiliary valve second control circuit outputs a sixth signal S6 to the auxiliary valve first control circuit according to the third signal S3 and the fifth signal S5.
The auxiliary air valve controls the on-off state of the auxiliary air valve according to the cutting machine gun on-off signal S and the sixth signal S6.
The output detection control circuit, as shown in fig. 4, comprises a voltage-controlled circuit, a first isolation circuit, a first inverting circuit and a first switch circuit which are sequentially connected, wherein the voltage-controlled circuit outputs a first one-to-one signal S11 to the first isolation circuit according to the output voltage and the second signal S2, the first isolation circuit is used for isolating an output power supply from a control power supply, the first inverting circuit inverts a first two-signal S12 output by the first isolation circuit, a first three-signal S13 is output to control the switch state of the first switch circuit, and the first switch circuit outputs a third signal S3 to a secondary air valve second control circuit and a fourth signal S4 to a main air valve control circuit.
The output voltage is the voltage between the CP3 terminal and the CP5 terminal.
The voltage-controlled circuit is conducted when the voltage is set at a value equal to or less than the set value.
The first isolation circuit includes a photo-isolation element. The first inverting circuit includes an inverting device. The first switching circuit includes a triode switching circuit.
The no-load detection control circuit, as shown in fig. 5, includes a no-load voltage detection circuit, a voltage stabilizing circuit, a second isolation circuit, and a second inverter circuit, which are sequentially connected.
The no-load voltage detection circuit comprises no-load detection resistors and is used for collecting no-load voltage.
The voltage stabilizing circuit is used for stabilizing the no-load voltage or the output voltage to give a voltage signal S21 conforming to the second isolating circuit, the second isolating circuit is used for isolating the output power supply from the control power supply, and outputting a second signal S22 to the second inverting circuit, and the second inverting circuit outputs a first signal S1.
The no-load voltage is determined by the input at the a/B terminal.
The main air valve control circuit, as shown in fig. 6, comprises a delay circuit and a second switch circuit which are sequentially connected, and the main air valve controller adopts a relay.
When the cutting machine gun switch is turned on, the delay circuit delays for a set time, and outputs a third signal S31 to the second switch circuit for controlling the action of the main air valve relay.
The first control circuit of the auxiliary air valve comprises a third switch circuit which is used for outputting a sixth signal S6 according to a switch signal of the cutting machine gun.
The auxiliary valve second control circuit comprises a fourth switch circuit and is used for controlling the action of the auxiliary valve relay according to the third signal S3, the sixth signal S6 and the fifth signal.
The main loop current detection circuit comprises a magnetic current detection element and two unidirectional current elements, and in one specific embodiment of the application, the magnetic current detection element adopts a reed switch.
One end of the first unidirectional current element is connected with the output of the no-load detection control circuit, the other end of the first unidirectional current element is connected with one end of the magnetic current detection element, and the other end of the magnetic current detection element is connected with the power ground.
One end of the second unidirectional current element is connected with the output of the no-load detection control circuit, and the other end of the second unidirectional current element is connected with the output end of a fifth signal S5 of the output detection control circuit.
When the magnetic current detection element detects that current flows in the main loop, two ends of the magnetic current detection element are connected, and the main loop current detection circuit outputs a low level.
When the magnetic current detecting element detects that no current flows in the main loop, the output of the main loop current detecting circuit is the same as the first signal.
In one embodiment of the present application, an inverter type DC plasma double air valve cutter control circuit is shown in FIG. 7.
The voltage-controlled circuit comprises a voltage-controlled resistor RV1, when the output voltage is higher than a set voltage value or the no-load voltage is higher than the set voltage value, the voltage-controlled resistor RV1 is conducted, otherwise, the voltage-controlled resistor RV1 is not conducted.
The first isolation circuit comprises a photoelectric isolation element U5, wherein the positive end of the input side of the photoelectric isolation element U5 is connected with the output of the voltage-controlled circuit through a resistor R44, a diode D29 and a capacitor C21 are connected in parallel between the positive end and the negative end of the input side, and the negative end of the diode D29 is connected with the positive end of the input side.
The positive end of the output side of the photoelectric isolation element U5 is connected with a control circuit power supply VDD through a resistor R38; the negative end of the output side is connected with the input end of the first inverting circuit through a resistor R40 and is connected with the control power ground through a resistor R39.
At both ends of the resistor R40, a diode D22 is connected in parallel, and the positive end of the diode D22 is connected to the input end of the first inverter circuit.
The input end of the first inverting circuit is connected with the control power supply ground through a capacitor C15.
The first inverter circuit includes an inverter U3F having a schmitt trigger function.
The first switching circuit comprises an NPN triode switching circuit, wherein the base electrode of the NPN triode Q1 is connected to the output of the first inverting circuit through a resistor R19, is connected with control power supply ground through a resistor R2, and is connected with control power supply ground through a capacitor C4.
The resistor R19 and the resistor R2 divide the output of the first inverting circuit to obtain the base voltage of the NPN triode Q1.
The emitter of NPN triode Q1 is connected with control power supply ground, its collector is connected with fourth signal S4 end of main air valve control circuit, and through series combination of diode D15 and resistor R15, third signal S3 is outputted to auxiliary air valve second control circuit. The positive terminal of the diode D15 is connected to the collector.
The no-load detection resistance is a resistance of 1 ohm.
The voltage stabilizing circuit comprises a voltage stabilizing tube D28, wherein the negative electrode of the voltage stabilizing tube D28 is connected with one end of the no-load detection circuit and the voltage output end, the positive electrode of the voltage stabilizing tube D is connected with the first input end of the second isolation circuit, and the second input end of the second isolation circuit is connected with the other end of the no-load detection circuit. The no-load voltage or the output voltage is applied to two input ends of the second isolation circuit after passing through the voltage stabilizing circuit.
The second isolation circuit comprises a photoelectric isolation element U4 and a peripheral circuit thereof, wherein a first input end of the input side of the photoelectric isolation element U4 is used as a first input end of the second isolation circuit, the positive electrode of the voltage stabilizing tube D28, the negative electrode of the diode D27 and one end of the capacitor C20 are connected, a second input end of the input side is connected with the positive electrode of the diode D27, the other end of the capacitor C20 and one end of the resistor R43, and the other end of the resistor R43 is used as a second input end of the second isolation circuit.
The input end of the output side of the photoelectric isolation element U4 is connected with the input end of the second inverting circuit, one end of a resistor R37 and one end of a capacitor C16, the other end of the resistor R37 is connected with a control power supply VDD, and the output end of the output side of the resistor R37 and the other end of the capacitor C16 are connected with a control power supply ground.
The second inverting circuit comprises an inverter U3E with a Schmitt trigger function and a resistor R31, wherein the input end of the inverter U3E is connected with the input end of the output side of the photoelectric isolation circuit, the output end of the inverter U is connected with one end of the resistor R31, and the other end of the resistor R31 is used as the output end of the second inverting circuit.
The main loop current detection circuit comprises a diode D26, a diode D21, a magnetic current sensing element, a resistor R42 and a capacitor C17. After being combined in series, the resistor R42 and the capacitor C17 are connected in parallel to two ends of the magnetic current sensing element, the anode of the diode D26 and the anode of the diode D21 are connected together, and the output end of the second inverting circuit is connected; the cathode of the diode D26 is connected with one end C of the magnetic current sensing element, and the other end D of the magnetic current sensing element is connected with the control power supply ground; the negative electrode of the diode D21 is used as the output end of the main loop current detection circuit and is connected with the input end of the secondary air valve second control circuit.
In one embodiment of the application, the magnetic current sensing element adopts a reed switch, and when current flows in the main circuit, the reed switch is closed and is turned on, and when no current flows, the reed switch is turned off.
When the second inverter circuit outputs a low level, the output of the main loop current detection circuit is low level regardless of whether or not a current flows through the main loop; when the second inverter circuit outputs a high level, the output of the main loop current detection circuit is high level when a current flows in the main loop, and when no current flows in the main loop, the output of the main loop current detection circuit is low level.
In the main air valve control circuit, a delay circuit comprises a diode D5 and a capacitor C5, wherein the anode of the diode D5 is connected to the output end of a cutting machine gun switching signal, the cathode of the diode D5 is connected with one end of the capacitor C5, one end of a resistor R3, one end of the capacitor C3 and the control electrode of a power tube Q2, and the other end of the capacitor C5, the other end of the resistor R3 and the other end of the capacitor C3 are connected with a control power supply ground.
The second switch circuit comprises a power tube Q2 and a peripheral circuit thereof, wherein the input end of the power tube Q2 is connected with one end of a main air valve control element, the other end of the main air valve control element is connected with a power supply VSS, the output end of the power tube Q2 is connected with a fourth signal S4 end of the output detection control circuit and one end of a resistor R1, and the other end of the resistor R1 is connected with the power supply VSS.
In one embodiment of the present application, the main valve control element is a relay JD1A.
The high level of the cutting machine gun switching signal charges the capacitor C5 through the diode D5, when the capacitor C5 is charged to a certain voltage, the power tube Q2 is conducted, and whether the relay JD1A is conducted or not is determined according to the output voltage of the first output end of the output detection control circuit.
The auxiliary air valve first control circuit comprises a power tube Q6 and a peripheral circuit thereof, wherein the anode of a diode D6 is connected with the output end of a cutting machine gun switching signal, the cathode of the diode D6 is connected with one end of a resistor R6 and the control electrode of the power tube Q6, and the other end 6 of the resistor R6 is connected with a control power supply ground.
The input end of the power tube Q6 is connected with one end of the auxiliary air valve control element, the other end of the auxiliary air valve control element is connected with the power supply VSS, and the output end of the power tube Q6 is connected with the sixth signal S6 end of the auxiliary air valve first control circuit.
The secondary air valve second control circuit comprises an NPN triode Q7 and peripheral circuits thereof. The base electrode of the triode Q7 is connected with one end of a resistor R17, one end of a resistor R5 and one end of a capacitor C8, the other end of the resistor R17 is connected with the output end of a third signal S3 of the output detection control circuit and the output end of a fifth signal S5 of the main loop current detection circuit, the other end of the resistor R5, the other end of the capacitor C8 and the emitting electrode of the triode Q7 are connected with a control power supply ground, and the collecting electrode of the triode Q7 outputs a sixth signal S6 to the first control circuit of the auxiliary air valve.
When Q1 is turned on, the fourth signal S4 is at a low level, if the cutter gun is turned off, the switch signal S is at a high level, and after the delay of the capacitor C5, the power tube Q2 is turned on, the main air valve is opened by suction, and the main air valve supplies air, at this time, Q7 is turned off, and the auxiliary air valve is not operated and is in a closed state.
Conversely, when Q1 is turned off, the fourth signal S4 is high, if the cutter gun is turned off, the switch signal S is high, the power tube Q2 is turned off after the delay of the capacitor C5, the main gas valve is not operated, and at this time, Q7 is turned on, and the auxiliary gas valve is operated to supply gas.
The implementation principle of the embodiment is as follows:
when the gun switch of the cutting machine is pressed, the control part sends a control signal, the inverter works, the main loop has voltage output, and current is generated between the electrode and the nozzle (the characteristic of gun structure, the electrode and the nozzle are in a short circuit state under the state of no air flow). Meanwhile, a high-level signal of 11.5V is generated at the gun switch signal S, so that the control electrode of the power tube Q6 is at a high potential, meanwhile, the high-level signal charges the capacitor C5 through the diode D5, when the charging potential of the capacitor C5 reaches 2.5V, at the moment, the voltage between the output voltage ends CP3 and CP5 is very low and cannot break through the voltage-controlled resistor RV1 due to the fact that the electrode and the nozzle are in a short circuit state, the light-coupling U5 of the first isolation circuit does not emit light, the input end of the inverter U3F is at a low potential, the output end of the first isolation circuit is at a high potential (VDD), the triode Q1 in the output control circuit is conducted, the power tube Q2 in the main air valve control circuit begins to conduct, the main air valve relay JD1A is closed, the main air circuit is opened for supplying air, the electrode of the cutter moves backwards under the action of air flow, and an arc between the electrode and the nozzle is pulled up.
After pulling up, 15-20A current flows through 1R no-load resistor, A/B terminal no-load voltage U AB The light lotus root U4 of the second isolation circuit emits light, the inverter U3E outputs high potential (VDD), the triode Q7 in the auxiliary air valve second control circuit is conducted, the auxiliary air valve relay JD2A is sucked and conducted, and the air flow of the cutting machine gun is split.
When the cutting gun approaches the workpiece, the small arc is changed into a large arc, the reed pipe is closed, the detection end C, D in the main loop current detection circuit is connected to generate a signal with 0 potential difference, the positive electrode of the diode D26 is pulled down to 0.7V, correspondingly, the negative electrode of the diode Q21 is also at 0 potential, the Q7 is cut off, the auxiliary air valve JD2A is disconnected, and the exhaust is stopped.
The output voltage terminals CP3, CP5 detect the effect of the signal: when the cutting machine gun switch is in a back blowing state, the inverter is not operated, the welding machine does not output, but stored charges are stored in a capacitor C5, a power tube Q2 in a main air valve control circuit is still in a conducting state, the main air valve is in a conducting state, an electrode and a nozzle are in a disconnecting state, the cutting machine gun switch is pressed down again, the inverter works, a 350V no-load voltage signal is detected between output voltage ends CP3 and CP5, a breakdown voltage-controlled resistor RV1 is broken, a light lotus root U5 in a first isolation circuit emits light, a first inverter U3F outputs low potential (0V), a triode Q1 in the first switch circuit is cut off, a main air valve is closed, simultaneously, a power source VSS (+24V) supplies a high level to a triode Q7 base in a secondary air valve second control circuit, the secondary air valve 2A is conducted, residual air in the air tube is discharged, and the electrode and the nozzle are reset. After that, the next pilot arc process is started.
The embodiments of the present application are all preferred embodiments of the present application, and are not intended to limit the scope of the present application in this way, therefore: all equivalent changes in structure, shape and principle of the application should be covered in the scope of protection of the application.
Claims (8)
1. The inversion type direct current plasma double-air-valve cutting machine is characterized by comprising an air source, a main air valve, an auxiliary air valve and a double-air-valve cutting machine control circuit, wherein one end of the main air valve is connected with the air source, the other end of the main air valve is connected with the main air passage and the auxiliary air passage, the main air passage is directly used for conveying air to the cutting machine, the auxiliary air valve is arranged on the auxiliary air passage, the air flow size conveyed to the cutting machine is controlled by the auxiliary air valve, the double-air-valve control circuit is respectively connected with the main air valve and the auxiliary air valve and is used for controlling the action of the main air valve and the auxiliary air valve, and the double-air-valve cutting machine control circuit comprises a main loop current detection circuit, an output detection control circuit, a main air-valve control circuit and an auxiliary air-valve control circuit; the output detection control circuit is respectively connected with the main air valve control circuit and the auxiliary air valve control circuit and is used for outputting a third signal S3 to the auxiliary air valve control circuit and outputting a fourth signal S4 to the main air valve control circuit according to the output voltage; the main air valve control circuit is used for controlling the switching state of the main air valve according to the cutting machine gun switching signal S and the fourth signal S4; the main loop current detection circuit is connected with the auxiliary valve control circuit, and outputs a fifth signal S5 to the auxiliary valve control circuit according to whether current flows through the main loop or not; the auxiliary air valve control circuit is used for controlling the on-off state of the auxiliary air valve according to the cutting machine gun on-off signal S, the third signal S3 and the fifth signal S5; the main loop current detection circuit comprises a magnetic current detection element and two unidirectional current elements, one end of the first unidirectional current element is connected with the output of the no-load detection control circuit, the other end of the first unidirectional current element is connected with one end of the magnetic current detection element, and the other end of the magnetic current detection element is connected with the power supply ground; one end of the second unidirectional current element is connected with the output of the no-load detection control circuit, and the other end of the second unidirectional current element is connected with the output end of a fifth signal S5 of the output detection control circuit; when the magnetic current detection element detects that current flows in the main loop, the main loop current detection circuit outputs a low level; when the magnetic current detecting element detects that no current flows in the main loop, the output of the main loop current detecting circuit is the same as the first signal.
2. The inverter type direct current plasma double-air valve cutting machine according to claim 1, wherein the double-air valve control circuit detects the current of the main loop, judges the state of the circuit, controls the opening or closing of the double-air valve, and in the cutting state, the current of the main loop flows back to the negative electrode of the power supply from the positive electrode of the power supply through the workpiece and the electrode, an electric arc is established between the electrode and the workpiece, and the main air valve is opened; in the pilot arc state, the output of the inverter flows back to the negative electrode of the power supply from the positive electrode through the idle circuit, the nozzle and the electrode, the electric arc is established between the electrode and the nozzle, the main air valve and the auxiliary air valve are simultaneously opened, and the auxiliary air valve shunts the air in the air pipe; in the idle state, idle current is detected, the main air valve is closed, the auxiliary air valve is opened, and the air in the air pipe is discharged.
3. The inverter type direct current plasma double-air-valve cutting machine according to claim 1, wherein when a switch of a cutting machine gun is pressed, the double-air-valve control circuit detects that a main loop has voltage output and controls the main air path to supply air, an electric arc between an electrode and a nozzle is pulled up, and after the electric arc is pulled up, the double-air-valve control circuit controls an auxiliary air valve to be sucked up, and air flow of the cutting machine is split; when the cutting gun is close to a workpiece, the small arc is changed into a large arc, the double-air valve control circuit detects that current exists in the main loop, the auxiliary air valve is closed, and the exhaust is stopped; when the switch of the cutting machine gun is loosened, the inverter does not work, the main air valve is still in a conducting state, and the electrode and the nozzle are in a disconnecting state; the cutting machine gun switch is pressed down again, the inverter works, the double-air valve control circuit detects an idle signal and controls the main air valve to be closed, the auxiliary air valve to be opened, residual air in the air pipe is discharged, and the electrode and the nozzle are accelerated to reset.
4. The inverter type direct current plasma double-air valve cutting machine according to claim 1, further comprising an idle load detection control circuit, wherein the idle load detection control circuit is respectively connected with the main loop current detection circuit and the output detection control circuit and is used for detecting whether the main loop is in an idle load state or not, outputting a first signal S1 to the main loop current detection circuit and outputting a second signal S2 to the output detection control circuit according to a detection result; the main loop current detection circuit is used for outputting a fifth signal S5 and the auxiliary air valve control circuit according to whether current flows through the main loop or not and the first signal S1; the output detection control circuit is used for outputting a third signal S3 to the auxiliary valve control circuit and outputting a fourth signal S4 to the main valve control circuit according to the magnitude of the output voltage and the second signal S2.
5. The inverter type direct current plasma double-air-valve cutting machine according to claim 4, wherein the output detection control circuit comprises a voltage control circuit, a first isolation circuit, a first inversion circuit and a first switch circuit which are sequentially connected, the voltage control circuit controls whether the first isolation circuit is isolated and conducted according to the output voltage and the second signal S2, the first isolation circuit is used for isolating an output power supply from a control power supply, the first inversion circuit inverts the output signal of the first isolation circuit and controls the switch state of the first switch circuit, and the first switch circuit outputs a third signal S3 to the auxiliary air-valve control circuit and a fourth signal S4 to the main air-valve control circuit.
6. The inverter type direct current plasma double-air valve cutting machine according to claim 4, wherein the no-load detection control circuit comprises a no-load voltage detection circuit, a voltage stabilizing circuit, a second isolation circuit and a second inverting circuit which are connected in sequence; the voltage stabilizing circuit is used for stabilizing the no-load voltage or the output voltage to give a voltage signal conforming to the second isolation circuit, the second isolation circuit is used for isolating the output power supply from the control power supply, and the second inverting circuit outputs the first signal S1.
7. The inverter type direct current plasma double-air-valve cutting machine according to claim 1, wherein the main air-valve control circuit comprises a delay circuit and a second switch circuit which are sequentially connected, and after a gun switch of the cutting machine is pressed down, the second switch circuit is controlled to be turned on or off singly or in combination with a fourth signal through delay of the delay circuit.
8. The inverter type direct current plasma double-air-valve cutting machine according to claim 1, wherein the auxiliary air-valve control circuit comprises an auxiliary air-valve first control circuit and an auxiliary air-valve second control circuit which are connected with each other; the second control circuit of the auxiliary air valve outputs a sixth signal S6 to the first control circuit of the auxiliary air valve according to the third signal S3 and the fifth signal S5; the first control circuit of the auxiliary air valve is used for controlling the on-off state of the auxiliary air valve according to the cutting machine gun on-off signal S and the sixth signal S6.
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| CN202210919731.0A CN115255582B (en) | 2022-08-02 | 2022-08-02 | Inverter type direct-current plasma double-air-valve cutting machine and control circuit |
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| CN115255582A (en) | 2022-11-01 |
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