● When the damaged parts may affect the safety and performance of the vehicle after repair, they should be replaced; However, if the maintenance can meet the corresponding technical requirements and standards, from the conventional and technical point of view, it is not necessary to replace the jerseys, and the principle of focusing on maintenance should be adhered to.
Second, the metal plate (iron) damage and repair principles
● Slight damage: the parts are elastically deformed, scratched or scraped, and the damage degree (area) is about 10%, so it is not necessary to disassemble or disassemble, and can be repaired by hand or setting machine;
● Moderate damage: the parts have large concave-convex deformation and folds, or the local deformation is small but there are dead folds, and the damage degree (area) is about 30%, which is not difficult to repair after disassembly or disintegration;
● Serious damage: the parts are severely twisted and broken, or the parts are partially missing or torn by more than 20cm, or the parts have lost their basic shape, and the damaged area is more than 50% and the bending degree is more than 30, so it is difficult to repair.
● Replacement: If the parts are seriously damaged and close to scrapping, replacement can be considered. However, the degree of loss is between serious damage and replacement, and if the customer insists on replacement, the proportion of not less than 20% shall be determined according to the specific situation.
Iii. Damage and repair principles of sheet metal (aluminum)
● If the deformation area is not large, it can be restored by tapping, stretching and other plastic methods and riveting and bonding processes, and it should be repaired;
● If the deformation area is large or there are tears, fractures, dead folds, etc. , can only be repaired by welding process, or although it can be repaired by riveting, it can be considered to be replaced because there are too many riveted parts, which seriously affect its appearance.
Four, plastic parts damage and repair principles
● Automotive plastics are divided into thermoplastics and thermosetting plastics according to their physical and chemical properties. There are two basic repair methods for plastic parts: chemical bonding and plastic welding.
● Usually, scratches, tears, perforations and depressions of plastic parts can be repaired;
● The overall rolling of plastic parts should be mainly based on replacement;
● Parts with low value and convenient replacement can be considered for replacement;
● Stress concentrated parts (such as tailgate hinge and pillar lock) should be replaced;
● Larger basic parts are damaged by scratches, tears, scratches or perforations. These parts are troublesome to disassemble, have high replacement cost or are out of stock, and should be mainly maintained;
● For plastic parts with high requirements for surface polishing, if there are obvious marks after the deep scratch table is repaired, it can not be roughly restored to its original appearance, so it can be considered to be replaced.
Five, safety parts damage and repair principle
● Components that may be related to driving safety are referred to as safety components for short, mainly including: brake system components (brake pads, brake pumps, pipelines and.