What is the Working Principle of An Argon Arc Welding Machine?
04. 17, 2021
The arc starting of argon arc welding adopts the arc starting method of high
voltage breakdown. First, high frequency and high voltage is applied between the
electrode needle (tungsten needle) and the workpiece to break down the argon gas
to make it conductive, and then supply a continuous current to ensure the arc
160V TIG Welding Machines
The working principle of the argon arc welding machine in the main circuit, auxiliary power supply, drive circuit, protection circuit, etc. is the same as that of the manual arc welding machine. No more description here, but focus on the unique control function and arc starting circuit function of the argon arc welding machine.
Hand switch control
The argon arc welding machine requires the argon gas to come first, and the current to go first (relatively speaking), this is achieved by hand switch control.
When the main switch of the welding machine is closed, the auxiliary power supply works and provides 24V direct current to the control circuit. When the hand switch is not closed, the 24V direct current passes through the resistor R5 to make Q2 turn on, and the 8 pins of the CW3525 chip are short-circuited to the ground through the T-shaped filter (composed of L5 and C5, for anti-interference). At this time, the CW3525 is in the wave-sealing state. The circuit has no output; when the hand switch is closed, the 24V direct current passes through the resistors R4 and R8 to turn on Q1, and the base of Q2 is pulled low to turn off. The 24V direct current passes through the resistors R6 and R7 to make Q3 turn on and the relay J3A pulls in to control it. The solenoid valve of the gas supply operates to supply gas to the welding. The 8-pin potential increases slowly due to the slow-start resistance and the capacitance. After a certain period of time, the CW3525 starts to work and the circuit starts to output power. In this way, the current is more than the gas delay supply delay time is determined by the slow-start dynamic resistance and capacitance).
The solenoid valve is a gas supply control device. When the relay J3A is closed, the inductance coil in the solenoid valve obtains current to generate magnetic energy to suck the iron block away from the gas pipe orifice, and the gas is supplied for welding through the solenoid valve.
In the hand switch control circuit, the inductance coils L1~L4 and C1, C2 play a role in preventing the hand switch from being turned on by interference.
1. When the hand switch is closed, the solenoid valve opens for air supply because the Q3 conduction relay J3A is closed. The auxiliary power supply charges the capacitor C17. However, due to the current limiting of the thermistors RT4 and RT5, the hand switch is less likely to be damaged due to excessive current;
2. After the welding is over, after the hand switch is turned off, Q2 is turned on, the voltage of pin 8 of CW3525 is pulled down, the circuit stops outputting, and C17 is still charged with electric energy, it discharges through R6, R7 and supplies Q3 to conduct, keeping the solenoid valve On-delay air supply. Realize the welding control requirements for current and gas.
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