The first step in the MIM manufacturing process is the production of the feedstock that will be used. It begins with extensive characterization of very fine elemental or prealloyed metal powders (generally less than 20 μm).
In order to achieve the flow characteristics that will be required in the injection molding process, the powder is mixed together with thermoplastic polymers (known as the binder) in a hot state in order to form a mixture in which every metal particle is uniformly coated with the binder. Typically, binders comprise 40% by volume of the feedstock. Once cooled, this mixture is then granulated into pellets to form the feedstock for the injection molding machine.
The next step is the molding of the part in a conventional injection molding machine.Theoretically these machines are standard plastic injection molding equipments, but equipped with special screws, barrels, tools, etc.
The feedstock pellets are gravity fed from a hopper into the machine’s barrel where heaters melt the binder, bringing the feedstock to the consistency of toothpaste. A reciprocating screw forces the material into a two-part mold through openings called gates. Once cooled, the part is ejected from the mold with its highly complex geometry fully formed. The molded parts are called “Green parts” , which are usually placed on their special ceramic trays without human touch. These trays are used through the next steps until final quality check and inspection.
If necessary, additional design features not feasible during the molding process (undercuts or cross holes, for example) can be easily added at this stage by machining or another secondary operation.
This process step is a special chemical procedure to remove binder from the green parts.
The ejected as-molded partis still composed of the same proportion of metal and polymer binder that made up the feedstock, and is approximately 20% larger in all its dimensions than the finished part will be.
This stage is to remove most of the binder, leaving behind only enough to serve as a backbone holding the size and geometry of the part completely intact. This process, commonly referred to as “debinding,” may be performed chemically (catalytic debinding) or thermally, which in some cases may involve a solvent bath as the initial step. The choice of debinding method depends on the material being processed, required physical and metallurgical properties, and chemical composition. After debinding, the part is referred to as a “brown part.”
After debinding the parts are sintered in the vacuum furnace to reach their final size. As the parts are porous, this special step of vacuum sintering is needed to produce ready parts. The sintering takes 20 to 25 hours on a controlled temperature and atmosphere close to the melting point.
The remaining binder is removed in the early part of the cycle, followed by the elimination of pores and the fusing of the metal particles as the part shrinks (18-20%) isotropically to it’s design dimensions and transforms into a dense solid. The sintered density is approximately 98% of theoretical. The end result is a net-shape or near-net-shape metal component, with properties similar to those of one machined from bar stock. Of course, if necessary, post-sintering operations such as coining, machining, heat treating, coating, and others, may be performed on the part to achieve tighter tolerances or enhanced properties
In most technologies, the part is carved out of one workpiece, that results high material loss. In contrast, MIM technology uses nearly exactly as much raw materials as needed.
Alll in one place from tooling to manufacturing! Easily available european location.
All you need in one place!
We have our own fully equipped and annually audited quality lab, controlling the whoe prodcution proccess. We are IATF 16949 and ISO 9001 certified, so according to the highest automotive standards
material’s strength can be better, if molding the part in one piece than assembling it of 2/3 different items. You also need less parts to keep in inventory!.
have more parts with our 4 or 8 cavity tools at the same amount of time
Our plant and the work stations are fully developed for the MIM process. We pay special attention to the permanent technological development in terms of new materials and processing.
We are specialized for unique and complex geometries with tight tolerances! For us, the more complex your part is, the better. We can provide solutions even if other technologies do not work.
Our engineering team is here to assist and help you in the design phase of the product and anytime if you need support later on! We can also re-design you existing product to get a MIM –friendly only with few dimensional and/or feature modifications.
We compound our owr own feedstock to a variety of materials to meet customer requirements.
Free professional seminar for our clients and interested parties where we introduce the details, advantages and design guidelines of our technology.
As a European supplier, we are easily accessible and can even provide a personal presence / support to our customers in case of any problems.
With our special tools with 4 or even 8 cavities, we are ready to make thousands of parts before the tools are at the end of their life. With other technologies - becouse of the process, like at casting - tool life is much shorter.
Incomparison with investment casting wihich requires both curing of the mold and melting of the steel, less energy is consumed per piece.
In case of investment casting – for example – each part run has a separate, non- reusable mold. By MIM the „waste” material after molding is regrinded, so no need to throw away.
Due to the technological steps, MIM is a much cleaner technology compared to other processes. this not only makes the work environment better for those who work here, but they also don’t have to fear for their health.
Protecting our empolyees’ safety besides their health is also very important to us! A great advantage that MIM is a safer process and use less dangerous chemicals then the others – like investment casting!