ALFA mim-tech | metal injection moulding technologies

Design and tolerances

Design recommendations

LDesign rules are basically the same as those for thermoplastic injection, but there are some that are specific to any metal forming process.

  • Avoid accumulations of mass.
  • Eliminate material wherever possible.
  • Avoid sudden changes in thickness; aim for a uniform thickness.
  • Avoid sharp edges - use radii of 0.25mm.
  • Allow for adequate draft angles (0.5° to 2°).
  • Provide a flat surface to support the part.
  • Do not use tight tolerances on dimensions with interference in parting lines, injection points and ejectors.
  • Determine the location of the injection point, ejector marks and parting line.

Download design recommendations (pdf, 1.162 kb)

Unfavourable, Feasible and Ideal


The MIM process has a tolerance range of ±0.5%, depending on factors such as material, location of the injection point, thermal treatment and in general, the shape of the part:

Tighter tolerances can be discussed depending on the factors mentioned above and other operations such as straightening, machining, special controls on process, or high-precision adjustment of tools.

Download table of tolerances (pdf, 1.162 kb)

Tolerance recommendations

  • Tight tolerances should only be specified for functional dimensions.
  • Dimensions affected by parting lines, ejectors and injection points should not have tight tolerances.
  • Position dimensions must have higher tolerances.
< 6 mm. ≈0,05 0,10
6 -12 mm. ≈0,08 0,16
12 - 20 mm. ≈0,12 0,24
20 - 35 mm. ≈0,19 0,38
35 -50 mm. ≈0,26 0,52
> 50 mm. ≈0,5%
Alignment and concentricity