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1. The main reason for the discrepancy between the shape and scale of the metal stamping and stretching parts is due to rebound and positioning prohibition. In addition to taking measures to reduce rebound, the reliability of blank positioning should also be improved.

2. The surface damage of metal stamping and stretching parts is caused by improper material selection, low heat treatment hardness, poor smoothness, wear of concave die corners, poor surface quality of curved blanks, excessive thickness of data, unreasonable selection of process plans, and short and smooth surface.

3. Metal stamping and stretching parts with tortuous cracks

(1) When the angle between the zigzag line and the direction of the rolling grain does not comply with the regular layout, and when the unidirectional V-shaped zigzag is used, the zigzag line should be perpendicular to the direction of the rolling grain; When winding in both directions, it is best to form a 45 degree angle between the zigzag line and the rolling direction.

(2) The plasticity of the stretched part data is poor.

(3) The curvature radius is too small, resulting in poor pickling quality.

(4) Insufficient smoothness - high friction.

(5) The radius of the convex and concave die fillet is worn or the gap is too small - the feed resistance increases.

(6) The quality of the shear and punching sections of the drawn parts is poor - burrs and cracks.

(7) The material thickness scale is severe and out of tolerance - difficult to feed

Solution to problems with metal stamping and stretching parts:

1. The processing shape of metal stamping and stretching should be as simple and symmetrical as possible, and it should be formed by one deep drawing as much as possible;

2. Parts that require multiple stretches should be allowed to have traces that can occur during the stretching process on the inner and outer surfaces, while ensuring the necessary surface quality;

3. On the premise of ensuring device requirements, a certain slope should be allowed on the side wall of the stretching part;

4. The spacing between the hole edge on the bottom or flange of the stretched part and the side wall should be appropriate;

5. The rounded radii of the bottom to wall, flange to wall, and four corners of the rectangular part of the stretched part should be appropriate;

6. The dimensions of metal stamping and stretching parts cannot be indicated together with the internal and external dimensions.