As the automotive industry moves towards lighter structures, materials such as aluminum and magnesium alloys are becoming candidates to replace galvanized steel. Since the body-in-white (BIW) accounts for about 27% of vehicle weight, using these lightweight materials can reduce the vehicle's overall weight. However, traditional resistance spot welding has many problems with these materials: long welding time, high electrode maintenance costs, and zinc coating adhesion to electronic products. Laser welding can overcome some of these issues. Besides BIW, laser welding is also used for engine parts, transmission parts, alternators, solenoids, fuel injectors, fuel filters, and fuel cells.