Research On The Pulse MIG Welding Machine Based On The ARM Controller

The pulsed MIG welding method has the advantages of small spatter,short arc length and good directivity,suitable for all position welding and low heat input in the welding process.It has been widely used in the welding of thin-walled materials and heat sensitive materials.With the development of welding machine towards digital direction,many foreign enterprises have launched the MIG welding machine with double pulse function,and through digital control,the welding machine has realized the external characteristics required by various welding methods through program control,which has truly realized the multi-function of one machine.Based on the research of welding machine at home and abroad,this paper uses ARM chip as the control core,designs a pulse MIG welding machine based on the control method of constant speed wire feeding and duty cycle adjusting to stabilize the arc length,which provides reference for exploring other waveform control technology of welding current and the integration of various welding functions.In this paper,the design of the main circuit and the selection of the device are first carried out.According to the requirements of welding technology,the soft switch full bridge inverter structure is selected in the main circuit.The main circuit design mainly includes the rectifier filter circuit,inverter voltage reduction circuit,full wave rectifier and filter output circuit.Soft switch full bridge inverter structure is used in the inverter circuit of the welding machine,which significantly reduces the switching loss of the main circuit during the inverter process.Secondly,this paper introduces the hardware and software design based on the ARM control system.The hardware circuit mainly includes the ARM minimum system design,current and voltage sampling circuit,pulse width modulation circuit and IGBT driving circuit design,welding parameter storage and display circuit,human-computer interface,air supply and wire supply circuit.The software program mainly includes main control program,pulse parameter realization program,parameter setting and display program,constant current control program,arc length control program,fault protection program,etc.Compared with the traditional single chip and the DSP as the control system of the main control chip,the main control chip STM32fF407 selected in this paper has rich on-chip resources.The control circuit only needs to do simple I/O expansion on the basis of the minimum system to meet the requirements,significantly reducing the difficulty of control circuit design and debugging,and reserving sufficient hardware resources for the control system transformation and upgrading,which is extremely high cost performance.Finally,the design of the pulsed MIG welding machine is debugged.The debugging process of welding machine includes independent test of each function of control system,no-load voltage test,external characteristics test of welding machine,wire feeding test and low-carbon steel welding test.The manual welding method is adopted in the pulse MIG welding process test.The welding current and arc length are stable,and the ability of anti-interference is strong.The transfer of droplet is uniform and the spatter is very small.Even if there is no arc swing,the uniform fish scale can be obtained,and the performance indexes of the welding machine reach the design target.