The injection molding design
process typically
consists of two phases: Definition and Validation.
Definition Phase
During the Definition phase, you define the proper process settings
and validate the runner system design. These settings depend on the selected
material and the part’s thickness distribution. Typical settings include:
- Mold and melt temperature
- Injection speed
- Fill / Pack switch point
- Pack and cool time
Validation Phase
During the Validation phase, you check:
- Whether the defined process settings can fill the part with
the specified machine pressure.
- Whether the part shows fill defects such as burn marks, weld
lines, hot spots, or sink marks.
You also need to evaluate:
- The freezing time of the gate to get the packing time.
- The freezing time of the part to get the cooling time.
- The part deformation for shrinkage and warpage
caused
by
residual stresses as the part cools.
During the Validation phase, you identify any part defects and make
changes to the process parameters or geometry to improve the product quality. Once
the machine ejects the part, you can only evaluate surface part defects that are
visible.
You might still need to evaluate the structural properties of the
part. For example, if you use a fiber-filled material and your injection speed is
too high, it might cause shear effects that cut the fiber length and result in
reduced
part
stiffness.