Reflow soldering machine, also known as reflow soldering machine, is a welding technology that has developed with the emergence of miniaturized electronic products and is mainly used for soldering various surface-mounted components. The solder used in this welding technology is solder paste. A suitable amount and form of solder paste are pre-coated on the solder pads of the circuit board, and then SMT components are placed in the corresponding positions; the solder paste has a certain viscosity to fix the components. The circuit board with the components mounted is then passed into the reflow soldering equipment. The transmission system drives the circuit board through various temperature zones set in the equipment, and the solder paste undergoes drying, preheating, melting, wetting, and cooling processes to solder the components onto the printed board. The core of reflow soldering is to use an external heat source to heat the solder, causing it to melt and flow again to complete the soldering process of the circuit board.
The resistance welding machine has several welding methods, mainly including spot welding, seam welding, projection welding, and butt welding.
Spot Welding: Spot welding is a resistance welding method in which the welded parts are assembled into overlapped joints and pressed tightly between two cylindrical electrodes, using resistance heat to melt the base metal and form the welded spot. Spot welding is mainly used for welding thin plates.
The process of spot welding:
1 Pre-pressure to ensure good contact between the workpieces.
2 Power on to form a molten core and plastic ring at the weld.
3 De-energize and forge under pressure, allowing the molten core to cool and crystallize under continued pressure, forming a dense, pore-free, and crack-free welded spot.
Seam Welding: The process of seam welding is similar to spot welding, except that rotating disc-shaped roller electrodes replace cylindrical electrodes. The welded parts are assembled into overlapping or butt joints and placed between the two roller electrodes, which press and rotate the workpiece, and continuous or intermittent current is passed to form a continuous seam welding method.
Seam welding is mainly used for welding structures with relatively regular seams and requiring sealing, and the plate thickness is generally below 3mm.
Butt Welding: Butt welding is a resistance welding method that welds the workpieces along the entire contact surface.