The temperature field in the welding area of the spot welder is the result of the heating and dissipation process. The heat deposited in the welding area cannot be used to melt the base material, and the effective heat of forming a large enough core of molten core only accounts for 10%-30% of the total heat, and most of the rest will be due to adjacent materials (including air), inside the plate, metal electrodes, radiation losses, etc. The dynamic heat balance of the welding process is formed so that the welding area of the spot welder maintains the proper temperature.
Factors affecting the effective heat of the spot welder are the specific heat capacity of the material, the melting temperature, the volume of the melting core, etc. Generally speaking, the heat conducted to the metal around the weld joint accounts for about 20% of the total heat, the heat conducted to the electrode accounts for 30% to 50% of the total heat, and the radiation convection from the surface of the electrode plate to the air medium, the heat loss accounts for about 5% of the total heat.
1. spot welding machine welding quality: AC welding machine adjustment cycle is long, the resolution of the 500Hz grid welding time adjustment is 20ms. Inverter DC spot welding machine resolution up to 00.25ms (4kHz inverter frequency), high control accuracy. The feedback control response of the inverter welder is significantly faster and the output stability is good. Due to the influence of current over zero, the thermal efficiency of the industrial frequency AC welder is low, and when the current percentage is too small, the impact is greater; the inverter DC spot welder output current is pulsating DC, with high thermal efficiency and stable welding heat input under continuous DC output.
2. Spot welder welding speed: Due to the current over zero, the heating time of the AC welding machine is longer. Inverter resistance spot welder is DC output, centralized heating, shorten the welding time.
3. Spot welder energy saving effect: the industrial frequency AC spot welder works at 50 dot Hz, the transformer loss is large, the welder power is low, and the circuit loss is large. Inverter welder transformer working at a higher frequency (1-4kHz), small loss, DC output to improve the power factor, energy saving effect is obvious.
4. The volume and weight of the spot welder equipment: the transformer of the AC welder has a larger iron core, and the equipment is larger in volume under the same power conditions. Inverter DC resistance spot welder transformer is greatly reduced, and the equipment is lighter.
