Plastic parts are more and more widely used, from simple tableware,
kitchenware to complex mechanical parts, electronic product shells
and so on. However, for plastic parts with high precision, such as
electronic product shells, attention should be paid to their
precision requirements from the beginning of injection moulding
manufacturing.
What factors determine the accuracy of plastic parts during
injection molding? How can we improve the precision of thin-walled
injection moulding parts?
1. Closing pressure: In principle, it should be greater than the
total pressure of plastic injection into the mold, based on no
burr.
2. Pressure and speed have a part of the same relationship. The
purpose of acting on the die is to make the material enter the die
evenly, thoroughly and properly to fill all corners. Too low will
shoot short, shrink, too high with hair, too full, viscous mold,
burning, vulnerable mold and high internal stress bad phenomenon.
3. The speed determines the condition of raw materials in the
runner of the die and the finished products. If the raw materials
are burred, saturated, burnt, and slow down, short shot, shrinkage,
poor combination and easy to break will occur.
4. Temperature: Different raw materials, different temperatures,
too low melt opacity and lead to uneven color, the internal stress
of finished products increased. Because the temperature is too low
and the pressure is too high, it may cause the screw to break, too
high, the product has hairy edges, and the temperature difference
caused by cooling, causing shrinkage. Raw materials will decompose,
yellowing, discoloration, easy to fracture. The longer the cooling
time, the gas is not easy to discharge.
