Principle for the injection speed selected in the plastic part molding processing

​Since the plastic part shape is complex, melt resin need follow and fill into runner, gate and cavity. Each section for them to follow is different and change every moment. So what principle we need keep when we select injection speed.

• To make perfect plastic parts and less internal stress, for injection speed most important condition is to keep the front flow in constant velocity when cross every different sections. That is to say, the front flow velocity=constant

If we can obey this principle, the part could be better and not easy to appear shrink mark, short shot etc defect, and get better cosmetic part surfaces.