Select the first letter of the word from the list above to jump to the appropriate section of our glossary.
– A –

ADCI — The American Die Casting Institute, which offers statistical, marketing, technical and training programs for die casting. In 1989 the ADCI was merged with the Die Casting Society of Engineers to form the current die casting organization, NADCA which stands for North American Die Casting Association.

Aging Change — Changes to metallurgical structure, mechanical properties, physical properties or other phenomena over time.

Alignment System — The system of pins, bushings, blocks and wear plates utilized to align two die halves correctly.

Alloy — A substance made of two or more metals or a metal and a nonmetal. Most die castings are composed of alloys.

Aluminum — A light, silver-colored metal that frequently appears in die casting alloys.

Anodize — To use electric current in a solution to create a protective hard oxide surface on a part. A form of plating a part.

As-Cast — A die casting after the flash, runners and overflows have been trimmed but before surface finishing, machining or coating has taken place.

Auto-Ladle — A metal feeding delivery device generally attached to a cold chamber die casting machine. One may also be part of a furnace system.

Automatic Operation — A die casting machine that does not need an operator to initiate a cycle, ladle metal or remove the casting.

– B –

Benching — Finishing die cavity surfaces by hand.

Biscuit — The leftover ladled metal in the shot sleeve on a cold chamber die casting machine. Removed from the die with the casting.

Blister — A casting defect caused by gas expansion that presents as a bump on the casting surface with a hole inside the casing underneath.

Blowholes — Holes found in heavy sections that usually occur because of trapped gas or shrinkage during the solidification process.

Boss — A die casting protrusion from the main casting, looks like a “tower” or “column” rising from a surface.

– C –

Castability — How well molten metal flows through a casting die.

Casting — The result of solidifying molten metal in a die or cavity formed by plaster, sand, or other materials.

Casting Cycle — The sequence of events that make up the casting process. Usually solidification time, machine movement and operator manual movements.

Casting Surface — The surfaces of the die casting as cast.

Cast-to-Form — Screw threads cast in the die with the other part of the casting – usually formed as external threads.

Cavity — Sunken part of the die for forming the casting.

Cavity Insert — An additional component put in the die block to create an external feature.

Checking — Small cracks on a die surface caused by repeated heating by the injection of molten alloys. They can produce raised veins on the die castings. Also referred to as “heat checking”. The result of thermal fatigue of the die steel.

Clamping Force — The force the die casting applies to keep the die halves closed.

Cold Chamber Machine — A casting machine where one ladles the metal into the shot sleeve rather than submerging the metal injection system in molten metal.

Cold Shut — This defect mark appears if the melt in the cavity is not hot enough, or it flows together but does not melt into each other. Appears as a line on the surface of the part.

Core — A part of the die casting separate from the cavity block that forms an internal feature, usually a hole in the casting for fasteners. It can be fixed relative to the cavity or actuated by movement when the die is opened.

Core Actuating Mechanism — The parts of the die and mounting that controls the core’s movement when it is necessary to form a hole in the casting that is perpendicular to the die open/close direction. Can include angled pins, slides, hydraulic cylinders and detents.

Core Pin — A hot work tool steel pin, typically H-13, that one uses to make a cored hole.

Cored Hole — A hole made in a fixed or movable core casting with a core pin.

Creep — Plastic deformation of metals that occurs when they are held at stresses below yield strength for a long period of time.

– D –

Deburring Work — Trimming flash, runners and other excess from the casting after removing it from the machine.

Defects — Any of a variety of casting failures, including cold shuts, cracks, porosity, blisters, checking and solder.

Density — The unit mass of material, by pounds per cubic inch or kilograms per cubic meter.

Die — More specifically, the die casting die, the tool one uses to make the casting, consisting of two matching steel blocks with cavities that shape molten metal until it solidifies. The steel blocks are an ejector die or moving die, and a stationary die or cover die. The die casting die is typically made up of multiple steel alloys and must be made to resist extremely high temperatures over repeated castings. The die is at the heart of the die casting process. Each die casting die is made specifically to conform to the machine it’s going to be used for and the parts it will be used to make.

Die Block — This large steel block is the base for one-half of the casting die, with the other components of the die mounted onto it.

Die Blow — Dimensional growth of casting in the direction of slide movements or across the parting line.

Die Casting — The process of injecting a molten metal alloy into the die to form a die cast part. This part may also be referred to as a die casting.

Die Casting Alloy — The metal alloy used to make the die casting. Aluminum is very popular for this purpose with zinc, magnesium, and copper alloys much less used.

Die Casting Machine — The hydraulic press that closes the die, injects the metal, opens the die and ejects the casting. die casting machines come in different sizes, rated by closing tonnage. A die casting machine with very high closing tonnage can make much larger parts. However, their large cylinders and the high volumes of molten metal required to make such parts means a much longer casting cycle than for smaller die casting machines.

Die Cast Injection — The process of forcing the molten metal into the die casting die.

Die Close System — The mechanism for closing or opening the die.

Die, Cover — Of the two halves of the die casting die, the half that is attached to the stationary platen of the die casting machine.

Die, Ejector — Of the two halves of the die casting die, the half that is attached to the moving platen of the casting machine and contains the ejection system.

Die, Fixed — Another name for the cover die.

Die Locking Force — The force required to lock up the die.

Die Lubricant — A lubricant applied to prevent soldering and make casting release easier.

Die, Movable — Another name for the ejector die.

Die, Trim — A trim die cuts the runners, overflows and flash off the die casing. It is usually found in a power press.

Die, Unit — A unit die allows for fast changing of cavity blocks while still in the holder or die block.

Dimension, Critical — A dimension on a part that you must hold within a specified tolerance for it to function properly.

Dimensional Stability — How well a component retains its shape and size over a long period in service.

Dimensional Tolerance — Relates to casting tolerance requirements set by the North American Die Casting Association in its Product Standards book.

Dowel pin — A guide pin designed to ensure registry between the two die-half cavities.

Draft — In order to remove the casting from the die, you need positive draft, which is a taper to the walls, cores or other parts of the die cavity to allow ejection of the casing without damaging the casting.

– E –

Eject — Push the solidified casting out of the moving die cavity.

Ejector — The mechanism you use to eject the die casting.

Ejector marks — Marks left by the ejector pins on the die casting.

Ejector Pins — The moving pins you use to eject the die casting from the moving half of the die.

Ejector Plate— A plate that actuates the ejector pins to push the die casting out of the moving half of the die.

– F –

Fillet — A curved junction of two walls.

Finishing — Processes like painting, machining or thread-tapping performed on the casting after the trim process so the casting conforms to the customer’s needs.

Finishing Allowance — The amount of machining stock allowance for finishing on a die casting exterior.

Flash — A fin of metal that juts out of the casting well into die parting plane clearances or around cores. Usually trimmed after casting.

Flow Line — Defect that occurs on the casting when the melt solidifies prematurely (see cold shuts).

– G –

Gate — Passage for the molten metal connecting the runner with the die cavity. May also refer to the complete ejected content of the die, casting, runners, sprue, flash and all.

Gooseneck — A spout that connects a metal pot with a sprue hole or nozzle and a passage through which the molten metal is injected into the die. Part of a hot chamber injection machine.

Growth — Unwanted casting expansion due to factors such as intergranular corrosion or aging.

– H –

H-13 Steel — A fine-grain, air-hardening, hot-work tool steel used for making die casting dies for casting zinc, magnesium and aluminum alloys.

Hot Chamber Machines— In a hot chamber machine, the plunger and gooseneck are immersed in molten metal in the holding surface to form the casting.

– I –

Impact Strength — Tested ability to withstand shock.

Impression — Another name for the die cavity where the alloy touches the cavity surface, or a mark left by a hardness tester.

Ingot — Metal shaped for convenient storage, shipping or melting.

Injection — A critical part of the die casting process, in which one forces molten metal into the die casting die with an injection unit.

Insert — A piece of metal placed in the die before a shot that becomes an integral part of the die casting when the molten metal is cast around it – called “insert molding”.

Intergranular Corrosion — A corrosion which primarily attacks grain boundaries of alloys, causing deep penetration and weakness of the alloy/part.

– J –


– K –


– L –

Ladle — A tool for pouring molten metal into the cold chamber of a cold chamber die casting machine.

Light Alloy Castings — Castings made from low-gravity alloys like aluminum and magnesium.

Loose Piece — Also called a knockout, a core that forms undercuts that is not fastened to the die but is ejected with the casting then removed from the casting after ejection from the die.

Low-Pressure Casting — A casting process that uses low pressures to force the molten metal into the die.

– M –

Magnesium— A popular metal used in alloys, it is a low-gravity, silvery white metal.

Machining— Machine operations performed on castings, like drilling, face milling and tapping.

Malleable Cast Iron— Castings made from pig iron and scraps, toughened by heat treatment.

Melt Flow— How the molten metal that is used in the die casting process flows, generally a function of its chemical composition.

Molten Metal— Melted metal, or melted alloy.

Mounting Jig— A setup for affixing work to a spot with guides or positioning for easy access.

Metal Saver — A core that is used to reduce the amount of metal in a casting, avoiding excess thickness.

Multiple Cavity Die — A die with multiple duplicate impressions or die cavities. The cavities do not need to be the same part (family mold).

– N –

Nozzle — Part of a gooseneck, the outlet end where the gooseneck meets the sprue hole.

– O –

Overflow — A small reservoir on the exterior of the die cavity that takes on impure or cold metal during the cavity filling. It can also generate additional die heat in the local area.

– P –

Parting Line — The line around the die casting where the two die halves come together.

Parting Plane — The plane where the die blocks meet that results in the parting line.

Permanent Mold Castings — Castings made from molten alloy using gravity to pour the metal into the die.

Platen — A thick flat steel plate, these are major parts of the die casting machine frame.

Plunger — An injection unit that forces the molten metal into the die.

Porosity — Any defect hole in the die casting, whether within the casting or on the surface, like blow holes and shrinkage pores.

Port — The opening where the molten metal goes into the injection cylinder.

Pressure Tightness — A measure that describes a die casting’s ability to contain a fluid under pressure.

Print — A design tool that points out feature tolerances and other important characteristics of a part that are critical to the die casting functioning properly.

Process Control — The study and application of process parameters in the manufacturing process, with the goal of producing the highest-quality parts.

– Q –


– R –

Rib — A reinforcement that enhances the sturdiness of the casting.

Runner — The channel in the die casting die allowing the molten metal to flow from the sprue or biscuit to the cavity when it is injected.

– S –

Shell-Mold Castings — Castings made out of resin sand molds.

Shot — The actual injection of the molten metal into the die casting die is called a shot. The term shot may also be used to refer to the solidified metal when it is extracted from the die, casting, flash, overflows, runners, biscuit or sprue and all.

Shot Sleeve — A steel tube that the plunger moves through to inject the molten metal into the die in a cold chamber die casting machine.

Shrinkage— A reduction in dimension that results from the freezing of the metal as it goes from molten to solid.

Shrink Mark— A defect that appears as a depression that may occur when a heavy section cools more slowly than the areas around it.

Shut-Off — A place in the die casting die where two surfaces are fitted together to prevent any flow of molten metal between them.

Slide — A die, tool or machine that moves in a straight line parallel to the die parting, and perpendicular to the die pull.

Soldering — A situation where the casting metal adheres to the die cavity or core pins, usually caused by high injection velocity or high temperatures.

Split Gate — A castings gate with the plunger or sprue axis in the die parting.

Sprue — A sprue is a hole in the die casting die that the molten metal enters first. It may also refer to the part of the cast shot formed by the sprue hole in the die. This term is used for zinc die casting.

Sprue Pin — A tapered pin with a round end that is used to facilitate the removal of the sprue. It projects into the sprue hole and serves as a core that deflects metal. This term is used for zinc die casting.

Statistical Quality Control — A way to make sure manufactured items like die casting are of acceptable quality. A few random items are inspected to estimate the overall quality level of all the items the die caster is manufacturing.

Steel Castings — These are castings made out of steel. They tend to be tougher and more resistant to impact than nonsteel castings.

– T –

Tie Bar — Typically round bars connecting the stationary platen to the moving platen on the die casting machine.

Toggle — Used for mechanically multiplying pressure when you lock the dies of the casting machine.

Trim— The process of removing the overflows, flash and runners from the die casting.

– U –

Undercut — A feature in the part design that makes it difficult to eject the casting without damage – an undercut in the part requires a moving slide system in the die.

– V –

Vent — A passage cut into the parting face of the die so air and gases can escape from the cavity when it fills up with molten metal.

Void — A large hole within the casting wall typically caused by entrapped gas (see blowholes).

– W –

Water Line — A channel in the die that water flows through in order to cool the die. Correct water line placement is critical to effective casting.

– X –


– Y –


– Z –

Zinc — The metal that comprises the majority of a zinc-base die casting alloy.