of auto covering parts is the main mould for manufacturing automobile. The design of stamping mould for auto covering parts should follow the following principles:
1. Pressing direction should be rational
Rational design of pressing direction for auto covering parts determines whether stretching satisfying covering parts or not. Besides, it also has direct influences on quantity of process supplement, form of binder surface, hardness and service life of mold.
2. The shape of binder surface should be effective
The shape of binder surface for stretch forming covering parts is the primary condition that prevents materials from fracturing so that materials can take shape smoothly during stretching. To realize the goal, binder surface should form definite slant angle to reduce the depth of stretching, meanwhile, form flat binder surface to realize the best swaging effectiveness. A definite geometrical relationship is maintained by lower binder and the shape of die punch so that the materials are always under pressure and cling on die punch during stretching. Redundant materials are not allowed to cause wrinkles and maintain the best swaging effectiveness. To maintain smooth binder surface so that wollens can flow into cavity of upper draw die, the binder surface should have partial swell, pit and sag. If the binder surface is flange of drawn parts and it has bulge or sag, the reshaping procedures should be increased. If the included angle between binder surface of press direction is larger than 90 degrees, feeding resistance will grow. That is unacceptable.
3. Addendum should be sufficient
Addendum is not only the condition for realizing stretching, but also the condition for enhancing deformation extent and rigidity of parts. It will has direct impact on drawing molding, trimming deflashing, coning, turnup and other following processes.
4. The design of mold should be overall planned
The design of stamping mold for auto covering parts should be combined with the future technologies and overall planned. Design plan of multi-grading mould should be adopted. Under the precondition that maintains deformation bounce capacity and surface quality of products, reduce the times of grading to help enterprise reduce the cost of mold manufacturing and maintenance, improving production efficiency.