Welding mechanism and welding method for PCB (printed circuit board)

The invention belongs to the field of welding and discloses a welding mechanism and a welding method for a PCB (printed circuit board) of a servo motor of an air door of a vehicle air conditioner. The welding mechanism comprises a board gripping mechanical arm, a tin scraping device, a transmission mechanism, a supporting mechanism and auxiliary devices. The board gripping mechanical arm comprises a connecting arm, a mechanical arm vertical cylinder, a telescopic cylinder and a gripper; the tin scraping device comprises a tin furnace, a tin disk, a tin scraper, a tin disk vertical propulsion cylinder, a tin disk lifting mechanism, a tin scraper vertical propulsion cylinder, a horizontal propulsion cylinder and a horizontal propulsion cylinder; the connecting arm is connected with the transmission mechanism, the mechanical arm vertical cylinder and the telescopic cylinder; the gripper is connected with the mechanical arm vertical cylinder and the telescopic cylinder; the tin scraper is propelled by the horizontal propulsion cylinder and the tin scraper vertical propulsion cylinder; the tin disk is propelled by the tin disk vertical propulsion cylinder. The invention also provides the welding method. The welding method comprises five steps. According to the welding mechanism and the welding method, accurate control is realized, and the influence of tin level change on dip soldering quality is avoided.