With the rapid development of the 3C digital industry, 3C digital products are upgrading towards the direction of high integration and high precision. The internal components of the products are more and more compact, and the precision and electronic integration are higher and higher. Therefore, the appearance, deformation and pulling force of the internal structure are more and more demanding on the welding technology. Because of its high energy, high precision and high directional characteristics, laser products are widely used in the welding of 3C products.