Resistance welding
This method is used to weld thin metal parts. The workpieces are clamped between two electrodes, and a high current is passed through them to melt the contact surfaces of the electrodes. This process is achieved through resistance heating of the workpieces. The workpieces are susceptible to deformation. Resistance welding welds both sides of the joint, while laser welding only welds from one side. Resistance welding electrodes require frequent maintenance to remove oxides and metal adhering to the workpieces. Laser welding thin lap joints does not contact the workpieces. Furthermore, the beam can reach areas difficult to reach with conventional welding, resulting in faster welding speeds.
Argon arc welding
Using a non-consumable electrode and shielding gas, it is often used to weld thin workpieces. However, the welding speed is slower, and the heat input is much greater than that of laser welding, which can easily cause deformation.
Plasma arc welding
Similar to argon arc welding, the torch produces a compressed arc to increase arc temperature and energy density. It is faster and has deeper penetration than argon arc welding, but inferior to laser welding. Electron beam welding relies on a beam of accelerated, high-energy-density electrons striking the workpiece, generating intense heat within a small, dense area on the workpiece surface, creating a "pinhole" effect and achieving deep penetration welding. The main disadvantages of electron beam welding are the requirement for a high vacuum environment to prevent electron scattering, the complexity of the equipment, the limitations of the size and shape of the welded parts on the vacuum chamber, and the stringent quality requirements for weld assembly. Non-vacuum electron beam welding can also be performed, but electron scattering can lead to poor focusing, which can affect the weld quality. Electron beam welding also presents magnetic offset and X-ray issues. Since electrons are charged, they are affected by magnetic field deflection, requiring pre-weld demagnetization of the workpiece. X-rays are particularly strong at high voltages, requiring operator protection. Laser welding, on the other hand, does not require a vacuum chamber or pre-weld demagnetization of the workpiece. It can be performed in the atmosphere and does not pose X-ray protection issues, allowing it to be operated in-line within a production line and capable of welding magnetic materials.
