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What are the repair methods for the damage of automobile body sheet metal parts?
2022-08-09 16:49:12

Most of the sheet metal parts of the automobile body are produced in batch, and the forming process is completed on the mechanical equipment. Most manual operations are auxiliary processing, but single piece processing or repair are mainly manual operations. The common manual processes of sheet metal manufacturing include bending, edge closing, edge setting, edge pulling, arching and curling, seam biting and correction, etc. at the same time, welding, willow joint and other methods are used to realize the permanent connection between various sheet metal parts.

[damage type of automobile sheet metal parts]

Various damages will occur to the sheet metal parts of the automobile body during the use of the vehicle. Common are: wear, corrosion, fracture, concavo convex or tear of metal plate surface, fold, bend and skew. The damage during vehicle operation includes: wear, corrosion, crack, etc; Mechanical damage includes concavo convex, tear, wrinkled skirt, bending and skew caused by accidents; Sometimes due to design reasons, such as insufficient structural strength and unreasonable process design, sheet metal parts will also be damaged.

When automobile sheet metal parts are damaged, there is often more than one kind of damage. Therefore, during repair, observation and analysis should be made, and different repair methods and sequences should be adopted according to different damage conditions to obtain satisfactory results.

[repair of wrinkles and irregularities]

Folds and irregularities caused by impact or extrusion of external force, such as slight damage and no extension of metal, belong to elastic deformation. The heavier, the metal will stretch, belonging to plastic deformation. When the impact or extrusion is particularly serious, tearing will occur. The exposed parts of body sheet metal parts may have wrinkles and concavo convex damage.

Finishing of convex surfaces:

For the repair of the convex surface with large curvature, see. For the concave convex damage, the hammering method or the jacking method can be used. For minor concave and convex damage, the sizing block can be placed on the back of the low part of the recess, and the position of the sizing block can be changed accordingly.

When the convex part is basically flattened, the concave part will recover mostly due to the reaction force of the sizing block. Then, observe the overall smoothness of the plate surface, and make some targeted minor repairs to repair the uneven damage.


Automobile sheet metal parts


Large depressions:

The backing plate can be used to pad the back of the concave part, and the jacking tool can be used to directly jack up.

In order to reduce the jacking force, the concave part can be heated to dark red if necessary. Springback shall be taken into account during ejection to avoid "over correction". If the surface has a large ductile protrusion, the metal at the extension can be properly shrunk. If it is difficult to put the sizing block into the damaged part, the holes can be drilled in the concave part. The number of holes should be as small as possible, and the hole diameter should be as small as possible. Then, the iron wire should be folded into a hook shape, fastened from the hole, and then stretched by external force. When the requirements are met, the iron wire should be pulled out, welded and ground flat.

Repair of fold damage

For fold damage, an external force (opposite to the direction of impact force) can be applied at the fold to make the fold unfold and turn into concave convex damage. Then, the concavo convex damage repair method was used for repair. The repair tool can be a manual hoist. One end is fixed at the fold of the sheet metal part, and the other end is fixed on the solid column and wall. Tighten the guide chain, and the fold will unfold gradually. The extension degree should be observed at any time to avoid tearing.

[repair of bending and skew]

There are many reasons for bending and twisting caused by impact or extrusion of external force, and the common one is damage caused by accident. Generally speaking, the bending and skew deformation near the impact or extrusion center are relatively serious and easy to find. For slight deformation, the degree of deformation is determined by means of inspection tools and comparison with the design dimension data. Sometimes it can also be judged by observing the relative positions of the adjacent parts of the sheet metal.

The deformation of the body frame, beam and column can be corrected by bracing and pulling method. The direction of bracing and pulling force shall be opposite to the direction of deformation force. If the right front corner of the roof collapses after being impacted, resulting in deformation of the right front corner of the right door frame and the windshield frame, and the door cannot be closed, the deformation of the car frame is mainly at the upper right corner of the door frame. Use the ejector to push between the upper right corner and the lower left corner of the door frame, and rotate the handle to extend the screws at both ends. With the extension of the screw rod of the ejector, the upper right corner of the roof will gradually rise, the windshield frame will be reset accordingly, and the door frame can also be gradually restored. If the left side of the car is impacted, causing the center column between the two doors on the left side to be concave, at this time, a manual hoist can be used. One end is fixed at the damaged part of the center column, and the other end is fixed on the solid column and wall. Pull the guide chain to shorten the iron chain, and the concave part of the center column will gradually reset.

When correcting the frame, beam and column of the vehicle body with the bracing and pulling method, the pad shall be placed at the contact between the body sheet metal parts and the bracing and pulling tools to avoid new damage.

[repair of tear]

The tearing caused by the impact and extrusion of external forces is accompanied by the extension of the sheet metal and the loss of part of the sheet metal, commonly known as "lack of meat".

In case of minor damage, repair the tear part smoothly first, and then conduct welding. If conditions permit, CO2 gas shielded welding shall be used, and the weld crater shall be repaired. Then measure whether there is ductile protrusion. If necessary, repair with concave convex damage repair method. In case of serious damage and "lack of meat", it shall be considered to repair or replace with new parts according to its degree and shape.

If it needs to be patched, the "missing meat" shall be excavated into a simple geometry as far as possible, and then the size of the cavity shall be measured, and the plate with the same material and thickness as the original shall be used for filling. During blanking, there are generally no more than 1mm weld craters around, which can be used for CO2 gas shielded welding, which can reduce the deformation of the workpiece after welding and has strong rust resistance. In addition, due to the low hydrogen content of the welding wire, it has good crack resistance and high structural strength after welding.


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Auto Body Parts,Sheet Metal Body Parts,Auto Parts Manufacturer

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