Step 1
The first stage involves mixing fine powdered metal with a wax/polymer binder to produce a compound suitable for injection moulding. The powder-metal particles used for MIM are much finer and more spherical than those used for the conventional sintered metal process.

Step 2
The compound is injected under pressure into a die, using similar equipment and techniques as those used in plastic injection moulding. The MIM part is produced oversize to allow for contraction in the next stages.

Step 3
The injected part in its ‘green state’ is placed in an oven to vapourise and remove the binder, leaving the part in its ‘brown state’. During this stage, support plates may be required to prevent distortion.

Step 4
The final stage is a high temperature sintering treatment which releases surface energy stored in the fine powder and fuses the metal particles together. This results in a high density, high strength MIM part.