Process Design part 2

When bending, it is necessary to first determine the tool and tool groove for bending according to the size on the drawing and the material thickness. The key to the selection of upper die is to avoid the deformation caused by collision between the product and the tool (in the same product, different models of upper die may be used). The selection of lower die is determined according to the thickness of the plate. The second is to determine the sequence of bending. The general rule of bending is that the bending is from inside to outside, from small to large, and from special to ordinary. For the work-piece with dead edge to be pressed, first bend the work-piece to 30℃ – 40℃, and then use the leveling die to press the work-piece to death.
During riveting, the same and different moulds shall be selected according to the height of the stud, and then the pressure of the press shall be adjusted to ensure that the stud is flush with the surface of the workpiece, so as to avoid that the stud is not pressed firmly or pressed out beyond the surface of the workpiece, causing the workpiece to be scrapped.
Welding includes argon arc welding, spot welding, carbon dioxide shielded welding, manual arc welding, etc. For spot welding, the position of workpiece welding shall be considered first, and positioning tooling shall be considered during mass production to ensure accurate spot welding position.
In order to weld firmly, bump shall be made on the workpiece to be welded, which can make the bump contact with the flat plate evenly before power on welding to ensure that the heating of each point is consistent. At the same time, the welding position can also be determined. Similarly, to weld, the preloading time, pressure holding time, maintenance time and rest time shall be adjusted to ensure that the workpiece can be spot welded firmly. After spot welding, there will be welding scar on the workpiece surface, which shall be treated with a flat mill. Argon arc welding is mainly used when two workpieces are large and need to be connected together, or when one workpiece is corner treated, to achieve the flatness and smoothness of the workpiece surface. The heat generated during argon arc welding is easy to deform the workpiece. After welding, it needs to be treated with a grinder and a flat grinder, especially in terms of edges and corners.