How to design the demoulding mechanism with threaded parts
Many pieces have threads on them, and there are two main types of threads: inner and outer threads.The surface of the thread is grooved, so the demoulding method is different from that of the general plastic parts, which requires special demoulding mechanism (figure 3-8).
(1) problems that should be paid attention to in designing the demoulding mechanism of threaded plastic parts
1) due to the requirement of plastic thread fluted surface, so the internal thread must be threaded core, external thread must be threaded ring forming, and demoulding must from the threaded core or turn the threaded ring out, both of the "must make relative rotation between ff, therefore, the appearance of plastic parts or end shall be prevent rotation pattern or design, or difficult to emerge.
The plastic parts of the mould should not rotate according to the demands of the mould, and the mould should be ensured by corresponding anti-rotating measures.
(2) demoulding mode of threaded plastic parts
Manual demultipation is the use of hand or simple tools to spin the core or ring out of the parts after the parts are formed and moulded.This kind of mold structure is simple, easy to manufacture, but labor intensity is big, production efficiency is low.
This is to make use of the elastic or core of plastic parts, so that plastic parts or cores and threads produce axial movement, and to force the core or plastic parts out of the thread.This kind of mould structure is also simple, mainly used for the parts with low precision and easy thread shape.
Torque motor demultipation is the use of the linear motion when the die is opened, through the transmission of rack gear or lead screw, to drive the screw core to make rotary motion so that the thread demultipation.This kind of mould structure is more complex, but save labor, high efficiency and good quality.
Valves with flaps or flaps with flaps or flaps for demoulding.This demoulding method is simple to manufacture, but there are fractal lines in the thread part, and it is easy to produce flanges.