Design Of Thread In Plastic Mould- Taizhou Huangyan Aoxu Mould Technology Co., Ltd.

Design Of Thread In Plastic Mould

03-04-2023

When required, external and internal threads can be automatically molded into the part, eliminating the need for mechanical thread-forming operations.

External Threads

Parts with external threads can be molded in two ways. The least expensive way is to locate the parting line on the centerline of the thread, Figure 3.17. If this is not acceptable, or the axis of the thread is in the direction of mold-opening, the alternative is to equip the mold with an external, thread-unscrewing device.

Internal Threads

Internal threads are molded in parts by using automatic unscrewing devices or collapsible cores to produce partial threads. A third method is to use handloaded threaded inserts that are removed from the mold with the part.

Stripped Threads

When threaded parts are to be stripped from the mold, the thread must be of the roll or round type. The normal configuration is shown in Figure 3.18 where R = 0.288 ´ pitch. Requirements for thread stripping are similar to those for undercuts. Threaded parts with a ratio of diameter to wall thickness greater than 20 to 1 should be able to be stripped from a mold. Figures 3.19 and 3.20 show the method of ejection from the mold.