Fig 2.35 illustrates another design point taht is often overlooked by engineers is the low cost of molding that can be affected if a side hole is extended to the top of the workpiece.

Side holes may be molded automatically by using the cam action in the mold or with hydraulic or pneumatic actuators as shown in Fig. 2.34a. Fig. 2.34b illustrates a side hole that can be molded withou

The biggest problem of using removing the workpiece from the mold is to avoid the distortion of workpiece. Sometimes the depth short and the plastic material is in high flexibility or flexural modulus

it is undercuts in a molded plastic workpiece which can be produced by using a removable ejector bar. Usually undercuts should be avoided whenever possible, as they increase mold costs and workpieces

Whenever the axis of a hole is not parallel to the draw of mold, either the forming core or pin that make the hole must be removed from the workpiece before the workpiece is retracted from the mold or

​An undercut is an indentation or projection on a workpiece usually means that the core moving direction is not parallel to the draw direction of mold, so that the molded workpiece makes ejection from

For blind hole, if the wall at the bottom of the holeis less than 1/6 the diameter of the hole, the bottom will tend to bulge after molding as shown in Fig.2.27b and can not to obtain a desired design

Deep holes may be molded by building the holes up in steps as shown in Fig. 2. 24a. It shows the solution of that the pins used in molding butt holes should be in different radius by at least 0.38mm t

Fig 2.23 illustrates the recess pin which make through holes is supported at both ends, but the recess may usually contain a small particle of flash prior to a new molding cycle. If the pin entering t