Die Casting Glossary -Technical Terms Explained

Reference for engineers, buyers, and quality professionals working with die casting.

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Process Terms

As-cast: The condition immediately after ejection, before secondary operations.

Cavity: Space within the die filled with metal to produce the casting. Single or multi-cavity dies are common.

Cold chamber: Process with injection cylinder separate from holding furnace. Metal is ladled each cycle. Used for aluminum, magnesium, copper.

Clamping force: Force holding die halves closed during injection, in tonnes. Must exceed separating force (injection pressure x projected area).

Cover half: Stationary die half, mounted to fixed platen. Gate typically enters here.

Cycle time: Total time from die close to die close -injection + solidification + ejection + die preparation.

Draft angle: Taper on surfaces parallel to die-opening direction, enabling clean ejection. Measured in degrees.

Ejector half: Moving die half containing ejector pins.

Ejector pin: Hardened steel pin pushing the solidified casting from the die cavity on die opening.

Fast shot: Second, high-velocity injection phase filling the die cavity.

Gate: Restricted opening where metal enters the cavity from the runner. Gate velocity is metal speed at this point.

Hot chamber: Process with injection system submerged in molten metal. Used for zinc and low-melting-point alloys.

Intensification: High-pressure phase after cavity filling, compressing semi-solid metal to reduce shrinkage porosity.

Overflow well: Small supplementary cavity at the end of metal flow, capturing cold metal and air.

Parting line: Plane at which die halves separate. Leaves a visible mark on the casting.

Projected area: Cavity area projected perpendicular to die-opening direction. Used to calculate separating force.

Runner: Channel directing metal from sprue to gate(s).

Shot: One complete injection cycle producing one or more castings.

Shot sleeve: Cold-chamber cylinder into which metal is ladled before injection.

Slow shot: Low-velocity initial injection filling the shot sleeve without air entrainment.

Sprue: Initial channel from machine nozzle into the runner system.

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Quality Terms

Blister: Surface bubble from gas porosity expansion during heat treatment.

Cold shut: Seam where two flow fronts met but did not fuse due to partial solidification.

Cpk: Process capability index. Cpk >=1.33 typical minimum; >=1.67 required for automotive critical characteristics.

CT grade: Casting Tolerance grade per ISO 8062. Die casting achieves CT3-CT6.

FAI: First Article Inspection -dimensional verification of first production parts.

Flash: Thin unwanted metal fin at parting line, slides, or ejector pin locations.

Gas porosity: Internal voids from gas entrapment during injection or dissolved gas rejection during solidification.

Misrun (short shot): Incomplete die fill -cavity portion not filled before solidification.

PPAP: Production Part Approval Process -automotive quality submission before production start.

Shrinkage porosity: Internal voids in thick sections from insufficient liquid metal feeding during solidification.

Soldering: Metal bonding to die surface, causing surface tearing at ejection. Also called die erosion.

SPC: Statistical Process Control -real-time monitoring with control charts.

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Tooling Terms

H13: Hot work tool steel hardened to 44-48 HRC. Standard for production aluminum/magnesium dies.

P20: Pre-hardened tool steel, 28-32 HRC. Used for prototype dies and short-run zinc dies.

Core: Steel projection forming internal features (holes, passages, pockets).

Insert: Replaceable die component. Worn inserts replaced without replacing the entire die.

Mold flow simulation: Computer simulation of fill, solidification, and stress before tooling is cut.

Slide (side action): Die component moving perpendicular to die opening to form undercuts.

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Alloy Terms

ADC12: JIS H5302 aluminum alloy -9.6-2% silicon. Japanese standard, equivalent to A383.

A380: ASTM B85 aluminum -8.5% Si, 3.5% Cu. Most widely produced die casting alloy globally.

A413: ASTM B85 near-eutectic aluminum -12% Si. Best pressure tightness and thermal conductivity.

AZ91D: High-purity magnesium -9% aluminum. Most widely produced magnesium die casting alloy.

Eutectic: Alloy composition solidifying at a single temperature. For Al-Si: 12.6% silicon.

HRB: Rockwell B hardness scale. A380 >=80 HRB; Zamak 5 >=91 HRB; A390 >=120 HRB.

SHG zinc: Special High Grade zinc, 99.99% minimum purity. Required for Zamak alloys to prevent zinc pest.

T5: Aluminum temper -artificially aged only. Moderate strength improvement.

T6: Aluminum temper -solution treated, quenched, artificially aged. Maximum strength.

Zamak: Family of zinc-aluminum die casting alloys (Zamak 2, 3, 5, 7).

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Commercial Terms

DDP: Delivered Duty Paid -seller delivers to named destination, pays all duties.

FOB: Free on Board -seller responsible until goods loaded on vessel.

IMDS: International Material Data System -automotive material declaration database.

MOQ: Minimum Order Quantity.

RFQ: Request for Quotation.

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This glossary is updated periodically. For undefined terms, contact KastMfg's engineering team.

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