Powder metallurgy is a manufacturing process where various powder metals such as stainless steel, brass, copper, iron and bronze are compressed and then sintered (heated) to metallurgically bond the particles. Material blending allows for a certain amount of customization of material properties to produce desired characteristics suitable for a particular application.
The part is formed by compressing the powder metal, or blended metal powders, in accurately formed dies and punches in special types of hydraulic presses. The compressed pieces are then sintered in an atmosphere controlled furnace at high temperatures, causing the metal powder particles to be metallurgically bonded together. This remarkably “green” and environmentally friendly process uses 99% of the material that’s in the mold, producing harmless bi-products of nitrogen and hydrogen.
Supplementary heat treatments may also be employed to increase material strength. Other optional finishing steps include milling & machining, drilling & tapping, reaming & other hole sizing, plating, and Cu, plastic or oil impregnating. The result is high density parts comparable to wrought products of the same composition and surpassing plastic and die cast material properties. Lower density will, of course, result in lower physical properties; however, these parts can be used in filter or air flow applications.
MANUFACTURING ADVANTAGES OF POWDER METALLURGY
- Cost Savings of up to 70% over other part manufacturing processes.
- Provides Close Dimensional Tolerances.
- Requires Minimal Machining.
- Results in Good Surface Finish.
- Excellent part to part reproducibility (Repetitive Accuracy).
- Often only process that produces parts with irregular curves, eccentrics, radial projections.
- Easily Produces parts requiring irregular holes, key-ways, flat sides, splines, or square holes.
- Easily Produces tapers and counter bores.
- Easily Produces slots, grooves, and bosses of varying depths.
- Axial projections possible but size depends on powder flowing into die recesses.
- Greater Customization Possible over other processes.
- Stronger Material Properties over plastics & dies casting.
- Greater Control of Material through sintering process, which is particularly important when working with stainless steel.
- Tailor material to be Ductile or Hard.
- Blend Materials to gain Desirable Material Properties.
- Corrosion Resistant.