1.Shape and size deviations of metal stamp deep drawing parts

The main reasons for the mismatch between shape and size of metal stamping deep drawing parts include material springback and inaccurate positioning. In addition to taking technological measures to reduce springback, the stability and accuracy of the blank positioning should also be enhanced.

2. Surface scratches on the metal stamp deep drawing parts

Surface scratch problems are usually caused by the following factors: improper material selection, insufficient hardness during heat treatment, rough mold surface, fillet wear of the die, poor surface quality of the blank, excessive thickness deviation of the material, unreasonable process plan and insufficient lubrication, etc.

3. Bending cracks in metal stamp deep drawing parts

The specific causes of bending cracks include:

(1) The Angle between the bending line and the rolling pattern direction of the sheet metal is incorrect - when bending in a unidirectional V shape, the bending line should be perpendicular to the rolling pattern direction; when bending in both directions, it is recommended to form a 45° Angle with the rolling pattern direction.

(2) The material itself has insufficient plasticity;

(3) The bending radius is too small, or the quality of pickling treatment is poor;

(4) Insufficient lubrication leads to excessive frictional resistance;

(5) The fillet wear or the gap between the punch and the die is too small, increasing the feeding resistance.

(6) The quality of the sheared or punched surface of the blank is poor, with defects such as burrs and cracks.

(7) The material thickness is seriously out of tolerance, causing difficulties in feeding.

4.Solution

(1) The shape of metal stamping deep drawing parts should be as simple and symmetrical as possible, and one-time deep drawing forming should be given priority.

(2) For parts formed by multiple deep drawing processes, under the premise of ensuring the basic appearance requirements, traces produced during the drawing process may be allowed.

(3) On the basis of meeting the assembly requirements, the side walls of the stretched parts are allowed to have a certain slope.

(4) The distance from the edge of the hole on the bottom or flange of the drawn part to the side wall should be reasonably designed.

(5) The fillet radii at the bottom and side walls of the drawn part, the flange and side walls, as well as the four corners of the rectangular part should be appropriately set.

(6) When marking the dimensions of metal stamping and drawing parts, it is necessary to avoid marking both the internal and external dimensions simultaneously.