Firstly, the repair process is determined according to the body structure.
1, body modification and repair. For the pull-out index correction of the car body, the car body must be fixed, otherwise the overall displacement will occur under the tension, and the purpose of index correction will not be achieved.
2. Physical correction procedures
● Understand the performance of equipment and measures for safe use.
● Analyze and judge the car body damage and determine the traction scheme.
● Fixed point of preliminary correction foundation
● Modify the anchor point, check the correction effect, and pull the correction as planned.
3. Before traction correction, the inside and outside of the car body shall be protected as follows.
● Try to take out internal components, such as seats, instrument panels, car mats, etc.
● When welding, cover the glass, seat, dashboard and other parts with heat insulation materials to prevent burns.
● Remove the external parts of the car body, and protect the car body with cotton cloth or protective tape to prevent scratches.
● If there are scratches on the paint surface, they must be repaired to prevent corrosion.
4. Repair of the front end damage of the car body
● The damage of the front end of the car body is mainly caused by the collision of the front end (such as rear-end collision). The damaged parts include the fender on one side of the front cross member, the side member and the front fender on the other side.
● The renovation of the front end should start from the side member of the front fender. First of all, the supporting structure should be repaired, and the side beam should be pulled first by selecting the side that needs to be replaced.
5. Repair the damage at the rear of the car body
● During calibration, connect the fixture or hook to the rear of the rear longitudinal beam, the rear floor or the rear roof, and the rear end of the side panel, and measure the dimensions of each part under the car body while pulling, and observe the fit clearance of the car body panels to determine the necessary repair degree.
● When the rear side member seriously collides and the deformation switch of the rear door frame is not good, the stress of the rear roof side plate can be relieved by pulling the side member.
Second, determine the repair process according to the damage degree of the car body surface.
1, concave-convex surface renovation
● Plastic surgery of local small lump: stick a pad iron on the back of the lump and compress the lump to its original shape with a hammer. During operation, it is required that the hammering force should be light, impact continuously at a frequency of 2 times per second, and the hammering points should be evenly distributed.
● Shaping of local depression: unlike the trimming of bumps, the hammering point is not above the top surface of the pad, but at the iron bump. Stick the gasket to the lowest position, and hit the nearby bump with a hammer.
● Lever up the depression and trim the depression with a leveling knife. There is a depression somewhere on the surface of the car door. Use a leveling knife as a cushion, and the concave part can be repaired by hitting the convex part of the surface.
2. Surface shrinkage molding
● Shrinkage of deformed parts on metal plate
Heat the most convex or concave point (stretching center) with torch flame, without cherry red. The amount of heating is related to the degree of stretching.
After heating, quickly pat the periphery of the flushing area and gradually surround the center of the heating point. Metal structure shrinks. When knocking, use a pad iron on the back of the component, knock with a wooden hammer, and then gently knock with a hammer after cooling.
If a little shrinkage can't achieve the purpose of leveling, you can shrink around the point in the same way, but the heating range is smaller at this time.
After all the contraction points have cooled down, make a comprehensive tap, and the tapping force should be light.
Thirdly, the repair process is determined according to the corrosion degree.
The repair methods of sheet metal are different with the different corrosion degree of car body surface.
1, the bulge of the surface paint layer is caused by the rust on the metal surface. The paint layer here should be cleaned to expose the metal layer, derusted with rust remover, then treated according to the painting requirements and repainted.
2, penetrating corrosion, generally will make the paint surface uplift in a large area, at this time, this part of the rusty metal should be completely removed, repair welding a piece of metal after renovation, and then according to the requirements of painting for processing, repainting.
3. Scratching the surface paint layer is a common damage. The paint layer near the scraped part should be polished with special sandpaper until the metal is exposed, and then the metal surface should be treated and repainted according to the painting requirements.