(English) Die Casting Definitions
Glossary of Die Casting Industry Definitions
The Die Casting industry has many unique terms and phrases that can be confusing to newcomers to our field. As the leading die casting machinery expert, Beta Die Casting Equipment has the knowledge and the technical experience to guide you through any project. Below is a list of definitions explained in an easy-to-understand format.
Die Casting Industry Definitions (A to Z)
- Alloy: A metallic solid created by combining two or more metals or adding a non-metal to a metal for the purpose of enhancing its properties for the end use.
- Aluminum Castings: Aluminum is a silvery-white, ductile metallic element. As the most abundant metal in nature, it is extensively used for castings and foundry patterns, and is also utilized as a deoxidizer in iron and steel making.
- Automation: Industry term commonly used to describe the mechanization of various aspects of the die casting process.
- Biscuit: Excess of ladled metal remaining in the shot sleeve of a cold chamber die casting machine. It is part of the cast shot and is removed from the die with the casting.
- Blister:
A surface bubble caused by gas expansion (usually from heating) which was trapped within the die casting or beneath the plating. - Blow holes: Voids or pores which may occur due to entrapped gas or shrinkage during solidification, usually evident in heavy sections (see porosity).
- Carbon Steel Casting: Cast, low carbon steels contain mainly carbon as the principal alloying element. Other elements are present in small quantities, including those added for de-oxidation. They are produced to a great variety of properties because composition and heat treatment can be selected to achieve specific combinations of properties, including hardness, strength, ductility, fatigue resistance, and toughness.
- Cast iron: A hard, brittle alloy of iron and carbon that can be readily cast in a mold and contains a higher proportion of carbon than steel does. It is firm and unchangeable.
- Casting: Casting is a manufacturing process for making complex shapes that is difficult or costly to make through other methods. Liquid metal is poured into a mold of the desired shape, and then allowed to solidify. The solid part is also called a casting and it is ejected from the mold once solidified.
- Casting Drawing: Contains all of the information for the foundry operations involved including machining allowances, tolerances and other specifications.
- Cavity: The recess or impressions in a die in which the casting is formed.
- Centrifugal Casting: A casting process performed by rotating the mold so as to produce a centrifugal force in the molten metal. The end product is often more reliable — free from gas and shrinkage porosity.
Checking: Fine cracks on the surface of a die which produce corresponding raised veins on die castings. Caused by repeated heating of the die surface by injected molten alloys.- Cold chamber machine: A type of casting machine in which the metal injection mechanism is not submerged in molten metal.
- Core: A separate piece (often made from molding sand) placed inside the mold to create openings and cavities, which cannot be made by the pattern alone. Every attempt should be made to eliminate or reduce the number of cores needed for a particular design, which proportionately reduces the cost of the casting.
- Core Box: A type of pattern into which sand is rammed or packed to form a core.
- Creep: Plastic deformation of metals held for long periods at stresses lower than yield strength.
- Degassing: A step in the casting process, usually necessary to reduce the amount of hydrogen dissolved in the liquid metal. If the hydrogen concentration in the melt is too high, the resulting casting will be porous as the hydrogen comes out of solution as the aluminum cools and solidifies. Porosity often seriously deteriorates the mechanical properties of the metal.
- Die Casting: A rapid, water-cooled permanent molding casting process that is quite limited to non-ferrous metals. The metal is melted, and then injected into a die. It is cooled rapidly to form the part. The die-cast part can then be taken through a number of finishing steps for a wide variety of end products.
- Die lubricant: Liquid formulations applied to the die to facilitate casting release and prevent soldering.
- Dimensional stability: Ability of a component to retain its shape and size over a long period in service.
- Dowel pin: A guide pin which assures registry between cavities in two die halves.
- Draft: The amount of taper (or the angle) which must be allowed on all vertical faces of a pattern to permit its removal from the sand mold without tearing the mold walls. Draft should be added to the design dimensions while maintaining minimum metal thickness.
- Ductile iron: A cast iron that has been treated while molten with an element such as magnesium or cerium to induce the formation of free graphite as nodules or spherulites. This imparts a measurable degree of ductility (easily manipulated) to the cast metal. The ductile iron family offers the design engineer a unique combination of strength, wear resistance, fatigue resistance, and toughness, as well as excellent ductility characteristics.
- Ejector marks: Marks left on castings by ejector pins.
- Ejector plate: A plate to which ejector pins are attached and which actuates them.
- Ferrous Alloys: Alloys with iron as its main constituent.
- Fillet: Curved junction of two surfaces, e.g., walls which would meet at a sharp angle.
- Flash:
A thin web or fin of metal on a casting which occurs at die partings, vents and around moveable cores. This excess metal is due to working and operating clearances in a die. - Foundry: A facility engaged in the manufacture of numerous types of castings using various casting processes.
- Gate: Passage for molten metal which connects runner with die cavity. Also, the entire ejected content of a die, including castings, gates, runners, sprue (or biscuit) and flash.
- Gooseneck: Spout connecting a metal pot or chamber with a nozzle or sprue hole in the die and containing a passage through which molten metal is forced on its way to the die. It is the metal injection mechanism in a hot chamber type of die casting machine.
- Growth: Expansion of a casting as a result of aging or of intergranular corrosion, or both.
- Heat checking: (See checking)
- Hot chamber machines: Die casting machines which have the plunger, gooseneck (metal pressure chamber) immersed in molten metal in the holding furnace.
- Hot short: Term used to describe an alloy which is brittle or lacks strength at elevated temperatures.
- Impact strength: Ability to resist shock, as measured by a suitable testing machine.
- Impression: Cavity in a die. Also, the mark or recess left by a ball, or penetrator of a hardness tester.
- Ingot: Metal or alloy cast in a convenient shape for storage, shipping and remelting.
- Injection: The process of forcing molten metal into a die.
- Insert: A piece of material, usually metal, which is placed in a die before each shot. When molten metal is cast around it, it becomes an integral part of the die casting.
- Intergranular corrosion: A type of corrosion which preferentially attacks grain boundaries of metals or alloys, resulting in deep penetration.
Investment Casting: Often thought of as the ultimate technique for low weight, precision steel casting production; investment casting is used to make parts that cannot be produced by normal manufacturing techniques. It is done by casting metal into a mold produced by surrounding, or investing, an expendable pattern with a refractory slurry coating that sets at room temperature, after which the wax or plastic pattern is removed through the use of heat prior to filling the mold with liquid metal. It is also called precision casting or lost wax process.- Loose Pattern: The cheapest pattern to make, has the shape of the casting without forms for sprues, risers, etc. attached. May be made in one or more pieces.
- Loose piece, knockout: A type of core (which forms undercuts) which is positioned in, but not fastened to a die. It is so arranged as to be ejected with the casting and from which it is removed. It is used repeatedly for the same purpose.
- Machining: Process such as abrading, cutting, drilling, forming, grinding, and/or shaping of a piece of metal or other material performed by machine tools such as lathes, power saws, and presses. In casting, the supplier foundry is responsible for giving the designer a cast product that is capable of being transformed by machining to meet the specific requirements intended for the function of the part.
- Machining Allowance: The amount by which dimensions of a casting are made oversize to provide excess stock for machining.
- Metal saver: Core used primarily to reduce amount of metal in a casting and to avoid sections of excessive thickness.
- Minimum Section Thickness: The minimum thickness to which a section can be designed. In custom cast work, the specifications in the bid should include this information. A minimum thickness of 0.25 in (6 mm) is suggested for design use when conventional steel casting techniques are employed. Wall thicknesses of 0.060 in (1.5 mm) are common for investment castings and sections tapering down to 0.030 in (0.76 mm) can readily be achieved.
- Mounted Pattern: A pattern that is fastened permanently to a board or match plate. Mounted patterns cost more than loose patterns: but when many castings are to be made from a pattern, the time saved in operation warrants the cost of mounting it. Mounted patterns have the shape of the casting often with forms for sprues, risers, etc. attached.
- Multiple cavity die: A die having more than one duplicate impression.
- No-Bake Molding / Sand Casting:
A versatile process for metal casting designers in which sand is mixed with a chemical binder/catalyst system and then molded around a pattern. It is an ideal option for production runs from 1: 5,000 castings / year. - Non-ferrous Alloys: Non-iron-based metals.
- Nozzle: Outlet end of a gooseneck or the tubular fitting which joins the gooseneck to the sprue hole.
- Overflow-well: A recess in a die connected to a die cavity by a gate to assist in proper venting.
- Parting Line: The line where parting surface meets with the casting surface of the mold. Patterns with straight parting lines (that is, with parting lines in one plane) can be produced more easily and at lower cost than those with irregular parting lines. Casting shapes, which are symmetrical about one centerline or plane readily suggest the parting line. Such casting design simplifies molding and coring, and should be used wherever possible. They should always be made as “split patterns” (separate cope and drag) which require a minimum of handwork in the mold, improve casting finish, and reduce costs.
- Pattern: A replica of the object to be cast, used to prepare the cavity into which molten material will be poured during the casting process.
- Plunger: Ram or piston which forces molten metal into a die.
- Porosity: Voids or pores resulting from trapped gas, or shrinkage during solidification.
- Port: Opening through which molten metal enters the injection cylinder.
- Process control: Where parameters of a process are studied and correctly applied in the manufacturing process to produce high quality parts.
- Runner: Die passage connecting sprue or plunger holes of a die to the gate where molten metal enters the cavity or cavities.
- Shot: That segment of the casting cycle in which molten metal is forced into the die.
- Shrink mark: A surface depression which sometimes occurs next to a heavy section that cools more slowly than adjacent areas.
- Shrinkage: Volumetric contraction that occurs as a steel casting begins to solidify. Testing should be done to ensure the end product will meet specifications in castings when the design is likely to result in shrinkage.
- Slide: The portion of the die arranged to move parallel to die parting. The inner end forms a part of the die cavity wall that involves one or more undercuts and sometimes includes a core or cores.
- Soldering: Adherence of molten metal to portions of the die.
- Soundness: In metal components, refers to the level of freedom from impurities and/or discontinuities such as sand inclusions, slag inclusions, macro porosity (pores greater than 50 nm in diameter), and shrinkage.
- Split gate: A gate of castings having the sprue or plunger axis in the die parting.
- Sprue: Metal that fills the conical passage (sprue hole) which connects the nozzle with runners.
- Sprue pin: A tapered pin with rounded end projecting into a sprue hole and acting as a core which deflects metal and aids in the removal of the sprue.
- Stainless Steel Casting: A casting made from stainless steel. Stainless steel is a steel alloy with a minimum of 10.5 or 11% chromium content by mass. Stainless steel does not stain, corrode, or rust as easily as ordinary steel (it stains less, but it is not stain-proof). There are different grades and surface finishes of stainless steel to suit the environment to which the material will be subjected in its lifetime.
- Steel Alloys: Steel that has been alloyed with other metals from 1.0% to 50% by weight to improve the mechanical properties of the steel. Alloy steels are broken down into two groups: low-alloy steels and high-alloy steels
- Steel Casting: A specialized form of casting that involves various types of carbon steel and alloy steels.
- Toggle: Linkage employed to mechanically multiply pressure when locking the dies of a casting machine.
- Tolerance: An allowance, given as a permissible range, in the nominal dimensions of a finished product. The acceptable dimensional tolerances must be indicated when a drawing is provided. Tolerances are normally decided by agreement between the supplier foundry and customer. Close cooperation between the customer’s design engineers and the supplier foundry is essential to optimize the casting design.
- Trim die: A die for shearing or shaving flash from a die casting.
- Undercut: Recess in the side wall or cored hole of a casting disposed so that a slide or special form of core (such as a knockout) is required to permit ejection of the casting from the die.
- Unit die: A die interchangeable with others in a common holder.
- Vent: Narrow passage at the die parting which permits air to escape from the die cavity as it is filled with molten metal.
- Void: A large pore or hole within the wall of a casting usually caused by entrapped gas. A blow hole.
- Waterline: A tube or passage through which water is circulated to cool a casting die.
