MIM or CIM (for ceramics) is a micro-technical parts shaping method based on plastic injection moulding and powder metallurgy.
It allows to design and manufacture metallic parts with the same concepts in design and the same productivity as plastic injection moulding.
Engineering in collaboration with the customer to define together the best possible MiM product, with a view to its integration into the final assembly. A part delivered by Alliance-MiM is not a product in itself. It is a component of a larger whole and must interface perfectly with the other parts of the whole. As such, we consider that a product does not exist until its control plan is perfectly defined. A dedicated project manager for each customer is in charge of defining this control plan. The resulting specifications serve as starting point for the design and production of the required tooling.
The injection tooling and all peripherals are designed and built in-house. The use of simulation software allows us to quickly evaluate critical points and to carry out rapid developments.
The base material, called feedstock, is a mixture of ultra-fine powder (20 μm) and polymers. This is the starting point of the technology. The following steps transform this material into products that can be used by our customers.
The first process stage consists in shaping the feedstock into parts though a standard plastic injection moulding machine. The injected part is called a green part. Possible additional operations on the green part.
Moulding does not allow for all types of shaping and is not always suitable for multi-versioning. In order to control costs as much as possible, Alliance-MiM works on the green part before the rest of the process. For example, the injection points can be engraved, micro-drilled or milled at this stage with great efficiency and without burrs.
Placing the parts and building up the loads for the rest of the process. Qualified operators check and deburr the moulded parts and arrange them on special supports in the most appropriate way. This is a stage where attention to detail is of the utmost importance and ensures the compliance of edges and surface finishing to requirements.
Binder is only a vector to shape the powder. Once parts are moulded, the binder needs to be eliminated, it is the de-binding step. After this operation we get a “brown” part which is metallic but porous and without any strength.
Once parts are debounded, they are densified by diffusion bonding using special sintering furnaces. This high temperature operation is linked to a controlled isotropic shrinkage.
After being fired at high temperature, the parts are often slightly deformed. A recalibration step may be necessary to guarantee the geometries and tolerances typical of the micromechanical industry.
The parts can also be completely finished, as Alliance-MiM has in-house control of all the classic complementary operations (multi-axis milling, tapping, turning, polishing, welding, gluing, lacquering) with the exception of heat treatments and surface coating processes.
Depending on specifications Alliance-mim make all kind of tests and reports from the most simple to a full metallurgical study or 3D scanning.
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