Draft angle(Fig. 2. 1)is critical in workpiece design since this directly affects how easily ar object can be ejected from a mold but without be damaged. A slight angle is recommended for all thermoplastics to facilitate workpiece ejection if the workpiece can be ejected in integrity. The draft angle is determined by several factors such as plastic material selected, geometry of workpiece, and ejection system. 1" draft angle in per side is Draft angle=I'/Side used for most thermoplastic workpieces, and 0.5 draft angle in per side Is minimum value. Some plastic materials can require up to as much as 2 per side, such as stvrene-acvilonitrile SAN). The guideline above is recommended for those untextured surface of workpieces
For textured part surfaces such as grained surfaces, an additional 1° of draft is added for every 0.025mm depth of texture, to eject the part and avoid drag marks from forming on the part.
