Powder Metallurgy - or PM – is a state of the art metal forming process used to produce net shape components. The PM manufacturing process entails starting with a raw material in the form of atomized metal powder. These highly engineered raw materials are controlled for particle size, particle shape, compressibility (hardness), particle distribution, flow rate and chemistry. (Note: ASCO does not make powder, it is purchased) These powders flow into a die cavity by gravity, assisted by a fluidized bed feed shoe, and are then compacted at room temperature. These compaction pressures may exceed (50) tons per square inch (689.5 MPa). The “green” preform is removed from the die, assisted by robotics and a floating die withdrawal press. Then, as a second separate operation, the green compact is processed thru an atmosphere controlled furnace. By atmosphere controlled we mean Hydrogen with a very low dew point (i.e. no water vapor). The term sintering is defined as "the reduction of Oxides in a reducing atmosphere". During sintering in the absence of oxygen, these metal particles are fused together. (Note: we do not melt materials but use a solid state diffusion bonding mechanism).
Once the part is out of the furnace it could be considered a finished part or it could be machined, heat treated for higher strength or plated.
The benefits of this process orient around capturing the final net shape (with the tooling) without expensive and time consuming secondary machining operations. Inherent in the process is eliminating material waste and scrap. Basically a “chip-less” metalworking process, PM typically uses more than 97% of the starting raw material in the finished part, conserving energy and materials.
|What is PM?|