Precision Made Products LLC.
Powering Innovation in MIM
Through a series of rheological and physical studies, we have developed our own polymeric binder system. Because of this, the chemical components of our polymeric binder system are highly controlled and repeatability is easily guaranteed.
Using varying percentages of polymeric binder, mixed with our high quality pre-alloy powder allows precise control of the percentage of shrinkage (from 10-15%) and the flexibility of the sintered parts. Our mixing devices are equipped with an internal dispersion mixer and a co-rotating, intermeshing, twin-screw extruder.
Injection Molding Process (Green Stage)
By analyzing the information provided from the injection molding machine and our DAQ system, our production team performs design of experiment (DOE) to ensure that desired quality of moldings will be produced.
To ensure that each part meets the chemical and dimensional specification, our programs were fully developed for each alloy through DOE to optimize the sintering conditions. In addition, all temperature sensors used in the furnace are calibrated every three months by a qualified supplier to guarantee that there are no deviations in temperature.
Our metal injection molding machines are equipped with a data acquisition (DAQ) system. The plug-in DAQ system allows production control under a defined range of cavity parameters. In addition, the entire production period data is digitally documented and serves as a reference for the future production.
The metal injection molding process begins with the mixing of very fine metal powders (less than 20 microns) and our proprietary binder in a heated state to uniformly coat the metal powder with binder. The mixture is then pelletized to form a "feedstock".
The feedstock is then heated and fed into injection molding machines where it is pushed into the mold. Once the part is formed in the mold it is quickly cooled and then removed. The gates and excess material is removed and recycled eliminating all waste.
The next step is to remove a majority of the binder material in a process known as debinding. Conventional debinding consists of using hazardous chemicals, our process and propietary binder material completely eliminates the need for such chemicals. After the initial step, the parts are then thermally debinded to further remove binder material leaving just enough to keep the parts size and shape intact. The resulting part is now in the "brown stage" of the process.
The part is then placed into a sintering furnace which gradually heats the parts to within 85% of the metals melting temperature. The remaining binder is removed and the particles begin to fuse as the part shrinks isotropically. The resulting parts have very high density rates of up to 99.7%. Although the end result meets all dimensional requirements, the part can be enhanced further through heat treat, machining, polishing, etc.