In this process, custom-blended
metal powders are fed into a die, compacted into the desired shape, ejected
from the die, and then sintered (solid-state diffused) at a temperature below
the melting point of the base material in a controlled atmosphere furnace.
The compaction step requires the part to be removable from the die in the
vertical direction with no cross movements of the tool members. The sintering
step creates metallurgical bonds between the powder particles, imparting
the necessary mechanical and physical properties to the part.
Conventional PM offers many advantages over the other consolidation methods.
It offers the lowest manufacturing cost, including modest tooling costs.
It also produces the closest tolerances in the finished parts. Since it is
a net-shape processing technology, it yields parts requiring little or no
secondary machining operations. Lastly, it makes available to designers and
fabricators a wide variety of material systems from which to choose.
Parts produced through the press-and-sinter process are subject to certain
limitations as well. Tooling and the maximum press tonnage capabilities impose
size and shape constraints on parts that can be fabricated. Annual production
quantities dictate how quickly the costs of tool set-ups and maintenance
can be amortized. Finally, the presence of residual porosity in the parts
will cause certain physical and mechanical properties to be lower than those
of the wrought material.
Typical Press-and-Sinter Products—gears, sprockets, cams, ratchets,
levers, clutch plates, pressure plates, housings, pole pieces, bearings,
Typical Markets Using Press-and-Sinter Parts—automotive, appliances,
power tools, hydraulics, lawn and garden, agriculture, off-road equipment,
motors, firearms, recreational equipment, hardware, business equipment