1. Filling of the cavity
BWall thickness influences the feedstock flow
inhomogeneous form filling,
recognizable from the timelines
homogeneous form filling due to
increased wall thickness towards
2. Selection of the gate position
A gate position close to thick-walled areas:
Due to the quick cooling of the feedstock,
3. Draft angles for ejectionMIM green parts exhibit less strength
and less shrinkage than usual polymers.
Thus they need large size ejectors and
large draft angles.
Draft angle > 1°
Ejectors: 4-6 times larger compared
to plastic injection moulding
4. Adjusting wall thicknessGoal:
Uniform wall thickness
for the complete part
max. 25 mm;
good: 1-10 mm;
better: 1-5 mm
5. Adjusting the wall thicknesSave money and take care to achieve
a consistent (thin) wall thickness.
This reduces the danger of:
■ Cavities and pores
■ Residual stress after injection moulding
■ Part distortion during sintering
Avoid large differences in wall thickness
as they lead to higher tolerances.
If unavoidable, use continuous transitions.
6. Keep in mind for sintering:Green and brown parts are not very strong
and shrink noticeably during sintering.
■ Design with sufficient contact
■ area to support
■ Flat or contoured support
■ Avoid projections
■ Use a smooth support with low friction
■ If necessary, use feedstock supports
■ that shrink with the part (have to be
■ removed after sintering)
■ Adequate ribbing prevents sagging