Core Pulling Structure Of Injection Mould

- Oct 18, 2017-

Plastic hook like distance tensioning mechanism generally used in mold cavity or core pulling demoulding two times, because of this kind of mechanism in the two side of the mould design, the action must be synchronized, i.e. clamping and buckles, opening to a certain position and hook. Once out of sync, it will cause the injection mold template or scratch skew and damage, the structure design of the parts require a higher stiffness and wear resistance, it is very difficult to adjust, mechanism of short life, try to avoid the use of, can use other structural design.

The core pulling was relatively small in case of auxiliary ejection method using spring core pulling action requires the use of movable mold core sliding backwards, to complete the mold structure into the core pulling, in large mold can be used on an oil cylinder. Damage of inclined pin slide type core pulling mechanism. This kind of organization often appears the trouble mostly is not processing in place and the material is too small, mainly has the following two questions.

The angle of inclined pin is A, and the advantage is that larger core pulling distance can be produced in shorter injection mold opening stroke. However, taking too large inclination angle A, when the pulling force F is a certain value, in the core pulling process, the bending force P=F/COSA of the inclined pin is bigger, and the inclined pin deformation and inclined hole wear are prone to occur. At the same time, the oblique pin produces upward thrust to the slider, and the greater the N=FTGA, the force increases the positive pressure of the guide surface in the guide groove, thereby increasing the friction resistance of the slider sliding. Easy to cause slippage, guide groove wear. According to the experience, the angle A should not be greater than 2.

Some die because the template size limit, slot length is too small, a guide groove outside the slider in the core pulling action is finished, so in the core stage and closing stage reduction are easy to cause the slider tilt, especially in the mold, the slider reset is not smooth, so that the slide damage, even bending failure. According to the experience, the length of the slider left in the chute should not be less than 2/3 of the length of the guide groove after the core pulling action is completed.