Injection molding: defection possibility and rules of design

Defection possibility of injection molding

Defect	Causes
Streak/Flash	Infusion weight too highBrace compel too low
Distorting/Warping	Non-uniform cooling rate
Air pockets/bubbling	Infusion temperature too highAn excessive amount of dampness in material Non-uniform cooling rate
Unfilled areas	Deficient shot volumeStream rate of material too low
Sink marks	Infusion weight too lowNon-uniform cooling rate
Ejector marks	Cooling time too shortDischarge constrain too high

A considerable lot of the above deformities are caused by a non-uniform cooling rate. A variety in the cooling rate can be caused by non-uniform divider thickness or non-uniform mold temperature.

Rules of design in injection molding

Most extreme divider thickness

Lessening the most extreme divider thickness of a section to abbreviate the process duration (infusion time and cooling time particularly) and diminish the part volume

Part with thick walls -incorrect way

Part with thin walls – correct

Uniform divider thickness will guarantee uniform cooling and lessen absconds

Non-uniform wall thickness (t1 ≠ t2)

Uniform wall thickness (t1 = t2)

Corners

Round corners to lessen pressure focuses and break

Internal range ought to be at any rate the thickness of the dividers

Sharp corner

Round corner