Tonnage

Where it comes up

• Metal stampingShort- to medium-run stampings: brackets, clips, shields, and plates cut and formed from sheet or coil in a press.
• Plastic injection moldingMolten thermoplastic injected into a steel or aluminum mold. Lowest piece price for plastic parts at 5,000+ a year.
• Zinc and aluminum die castingMolten zinc or aluminum injected into steel dies at high pressure. Thin walls and net shape at 2,500+ parts a year.
• Powdered metalNet-shape gears, bushings, and structural parts pressed from metal powder and sintered, with little or no machining.

Related terms

Progressive die

A progressive die is a stamping die with a series of stations that pierce, form, and cut a part in sequence as a metal strip feeds through the press. One finished part drops with each stroke. It is the lowest piece-price option for high-volume small and medium stampings.

Coining

Coining is a stamping operation that squeezes metal under very high pressure so it flows into fine die detail or reaches a precise thickness. It is used for sharp embossed features, flattening, and sizing critical dimensions. Coining needs far more tonnage than bending or blanking the same part.

Flash

Flash is excess material that escapes past the parting line or between die halves and hardens as a thin fin on the part. In molding and die casting it signals worn tooling, low clamp force, or excess pressure. In forging, flash is designed in on purpose, then trimmed off.

Shot size

Shot size is the volume or weight of material injected into a mold in one cycle, including parts and runners. Molders typically want a shot to use about 20–80% of a press's barrel capacity to avoid degraded resin or inconsistent fill. In die casting, shot size drives machine and shot sleeve selection.