(1) Poor mold design
The arc radius at the corner is too small, so the radius of the transition arc should be increased.
(2) The heating temperature of the sheet is too high or too low
When the temperature is too high, the heating time should be appropriately reduced, the heating temperature should be lowered, and the heating should be uniform and slow, and the compressed air slightly cooled sheet should be used;
When the temperature is too low, the heating time should be appropriately extended, the heating temperature should be increased, and the sheet should be preheated for uniform heating.
