In order to facilitate the forming parts successfully plastic parts, plastic parts must be in the inner and outer surface along the parting direction design has sufficient slope, slope of plastic parts size plastic parts and plastic shrinkage rate, shape, structure, wall thickness and processing conditions have a certain relationship. Plastic pieces angle selection should follow the following principles:
1.plastic shrinkage is greater, more wall thickness, inclination should take a larger value, the smaller value.
2.plastic parts of the structure is complex, along the parting direction with holes, grooves or patterns to release the resistance is large, should choose draft larger.
3.when the plastic height, can not set up the slope, forming the core of the long or the cavity depth, inclination to small values, but usually in order to facilitate the release, in order to meet the use and size tolerance requirements of the value of the slope, and some. 4 in general, plastic slope value Kobe the outside surface of the inner surface of the small, sometimes according to the position of plastic parts to determine the workpiece surface inclination. 5 the thermosetting plastic shrinkage is generally thermoplastics are smaller, the draft also take some small. In general, the draft is not included in the tolerance range of the plastic parts.