Powder compacting equipment is used to shape powders as part of a forming process as well as to compress a wide range of materials into compact shapes for ease of transportation and ease of handling. Materials compressed by powder compacting equipment include powdered metals, ceramics, carbides, composites, pharmaceuticals, carbon/graphite, ferrites, explosives, chemicals, foods, nuclear fuel or other materials into compact shapes. Metal or ceramic powder compacts require additional processing such as sintering or forging to provide a finished part.
There are seven main configurations of powder compacting equipment (although custom varieties are available). These types are defined either by the shape of the product they produce or the technology used to process materials.
Briquetters turn fine, powdered materials into briquettes or chunks, to improve handling, transportation, scrap disposal, storage or secondary processing. Briquetters often consist of a roll compactor with a serrated roll or a smooth roll combined with a granulator / chopper. Briquetters that form discrete cylindrical compacts also exist. Some briquetters are used for fluid extraction and recovery.
Cold isostatic presses (CIP) use a chamber to compact the powder or material placed in a sealed tool, bag or other flexible tooling. Cold isostatic presses use an oil-water mixture pressurized up to 100,000 psi. Flexible rubber or plastic tooling and steel mandrels are used in CIPing to produce performs with more complex shapes. CIP applications include refractory nozzles, blocks, and crucibles; cemented carbides, isotropic graphite, ceramic insulators, tubes for special chemical applications, ferrites, metal filters, preforms, and plastic tubes and rods.
Hot isostatic presses (HIP) use an argon atmosphere or other gas mixtures heated up to 3000º F and pressurized up to 100,000 psi. Evacuated steel or metal cans or a sintered surface are used to contain and maintain a seal during HIPing. HIPs are used for densifying high performance ceramics, ferrites and cemented carbides, net-shape forming of nickel-base superalloy and titanium powders, compacting of high-speed tool steel, diffusion bonding of similar and dissimilar materials, and eliminating voids in aerospace castings or creep damaged blades.
Pellet mills compress or extrude particles or fibrous materials into a cavity or die to form uniform cylindrical pellets. Compacted pellets are also formed using briquetters or tableting presses. Extruding pelletizers generate discrete and uniformly sized particles from a melt or a polymer (reclaimed scrap, post consumer or virgin plastic), liquid-solid pastes with a binder or other meltable materials. The melt or paste is extruded through a die with multiple orifices. The pellet is sheared off or chopped after cooling / drying. Several types of pelletizers are available such as hot face, air, and cold cutting and underwater.
Roll compactors with smooth rolls compact a powdered material into a sheet for the continuous production of ceramic or metal powder sheet or strip for filter applications or for clad / bimetal production.
Rotary and multi-station tableting presses have multiple stations or punches for compacting pharmaceuticals into tablets or metal powders into simple flat or multilevel shaped parts like gears, cams, or fittings. Rotary types have a series of stations or tool sets (dies and punches) arranged in a ring in a rotary turret. As the turret rotates, a series of cams and press rolls control filling, pressing and ejection. Pharmaceutical tablet and high volume metal part production facilities often use high-speed automatic rotary presses.
Single station presses are a type of powder compacting equipment that use a single action rams press with a die on both upper and lower punches. Single station powder compacting presses are available in several types basic types such as cam, toggle / knuckle and eccentric / rank presses with varying capabilities such as single action, double action, floating die, movable platen, opposed ram, screw, impact, hot pressing, coining or sizing.
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