Appendix Glossary of Terms Baked Core: A core which has been A heated for a sufficient time and temperature Abrasion: The displacement and/or to produce the desired physical properties. detachment of metallic particles from a Baked Strength: Compressive, shear, surface as a consequence of being exposed to tensile or transverse strength of a molded flowing solids, fluids or gases. sand mixture when baked at a temperature Aging: A change in properties of metals above 230 oF (110 oC) and then cooled to and alloys that occurs slowly at room room temperature. temperature and will proceed rapidly at Base Plate: A plate to which the pattern higher temperatures. The change in properties assemblies are attached and to which a flask is often, but not always, due to a phase is subsequently attached to form the mold change (precipitation), but never involves a container. change in chemical composition of the metal Blow Holes: 1) Holes in the head plate or or alloy. blow plate of a core-blowing machine Alloy: A substance having metallic through which sand is blown from the properties and composed of two or more reservoir into the core box. 2) Irregular chemical elements of which at least one is shaped cavities with smooth walls produced metal. Usually possesses qualities different in a casting when gas is entrapped during from those of the components. mold filling. The gas sources may be air, Angle Testing (UT): A method of binder decomposition products or gases ultrasonic testing using shear waves dissolved in the molten steel. introduced from the surface of the material at Blow Plate: The plate containing the core approximately 45 degrees. sand entrance holes or blow holes used in Apparent Contraction: The net open-face core boxes. contraction of a casting dimension due to true Blower, Core or Mold: A device using air metal contraction, mold wall movement, and pressure to fill a core box or flask with sand. restraint during solidification and cooling. Boss: A projection of circular cross- As Cast: Referring to metal which has not section on a casting. Usually intended for received finishing (beyond gate removal or drilling and tapping for attaching parts. sandblasting), or treatment of any kind Bracket: Strengthening strip, rib, or including heat treatment after casting. (See projection on a casting. Usually used to Finishing). prevent hot tearing. Breakoff Notch: A thinner section of a B gate or riser to facilitate clean breaking-off Backing Board (backing plate): A second during the cleaning process. bottom board on which molds are opened. 143 144 Rapid Tooling Guidelines For Sand Casting Brinell Hardness: The value of hardness Casting Layout: A check of dimensions of a metal on an arbitrary scale representing against applicable drawings and kg/mm2, determined by measuring the specifications. diameter of the impression made by a ball of Chaplet: Metal support that holds a core given diameter applied under a known load. in place within a mold; molten metal Values are expressed in Brinell Hardness solidifies around the chaplet and fuses it into Numbers, BHN the finished casting. Buckle: 1) Bulging of a large flat face of Cheek: The intermediate section of a a casting; in investment casting, caused by flask that is used between the cope and the dip coat peeling from the pattern. 2) An drag when molding a shape requires more indentation in a casting, resulting from than one parting plane. expansion of the sand, may be termed the Chill (External): Metal, graphite, or start of an expansion defect. carbon blocks that are incorporated into the Burnishing: Developing a smooth finish mold or core to locally increase the rate of on a metal by tumbling or rubbing with a heat removal during solidification and reduce polishing tool. shrinkage defects. Chill (Internal): A metallic device/insert C in molds or cores at the surface of a casting or CAD: Computer Aided Design. within the mold to increase the rate of heat CAE: Computer Aided Engineering. removal, induce directional solidification and CAM: Computer Aided Manufacturing. reduce shrinkage defects. The internal chill CNC: Computer numerical control. may then become a part of the casting. Carbide: A compound of carbon with one Cleaning: The removal of gates, runners, or more metallic elements. and risers from the rough casting, This term Carbon: Element occurring as diamond also involves any hand finishing such as and as graphite. Carbon reduces many metals grinding or blasting. from their oxides when heated with the latter, CMM: Coordinate Measuring Machine. and small amounts of carbon greatly affect CNC Machine Tools: Computer the properties of iron. Numerical Controlled Machine Tools. Carbon Dioxide Process (Silicate Cold-Box Process: 1) Any core binder Process, Schmidt-Philipp Process): A process process that uses a gas or vaporized catalyst for hardening molds or cores in which carbon to cure a coated sand while it is in contact dioxide gas is blown through dry clay-free with the core box at room temperature. silica sand to precipitate silica in the form of Collapsibility: The requirement that a a gel from the sodium silicate binder. sand mixture break down under the pressures Carburizing: A form of case hardening and temperatures developed during casting, in that produces a carbon gradient inward from order to avoid hot tears or facilitate the the surface, enabling the surface layer to be separation of the sand and the casting. hardened by either quenching directly from Compressive Strength (Yield): The the carburizing temperature or by cooling to maximum stress in compression that can be room temperature, then reaustenitizing and withstood without plastic deformation or quenching. failure. Casting: The metal shape, exclusive of Conductivity (Thermal): The quantity of gates and risers, that is obtained as a result of heat that flows through a material measured pouring metal into a mold. in heat units per unit time per unit of cross- Appendix Glossary of Terms 145 sectioned area per unit of length, (electrical) Core Float: A casting defect caused by the quantity of electricity that is transferred core movement towards the cope surface of through a material of known cross-section the mold, as a result of core buoyancy in and length. liquid steel, resulting in a deviation from the Contraction: The volume change intended wall thickness. occurring in metals and alloys on Core Prints: Portions of a pattern that solidification and cooling to room locate and anchor the core in the proper temperature. position in the mold. Convection: The motion in a fluid Core Rod: A wire or rod of steel used to resulting from the differences in density. In reinforce and stiffen the core. heat transmission, this meaning has been Core Setting Jig/Gage: A device used to extended to include both forced and natural help position a core in the mold. motion or circulation. Core Shooter: A device using low air Cooling Curve: A curve showing the pressure to fluidize the sand mix which is relationship between time and temperature released quickly in such a way as to force it during the solidification and cooling of a into a core box. metal sample. Since most phase changes Core Vents: 1) Holes made in the core for involve evolution or absorption of heat, there the escape of gas. 2) A metal screen or slotted may be abrupt changes in the slope of the piece used to form the vent passage in the curve. core box employed in a core-blowing Conduction: The transmission of heat, machine. 3) A wax product, round or oval in sound, etc., by the transferring of energy from form, used to form the vent passage in a core. one particle to another. Corrosion: 1) Gradual chemical or Cope: Upper or topmost section of a electrochemical attack on a metal by flask, mold, or pattern. atmosphere, moisture, or other agents. 2) Coping Out: The extension of sand of the Chemical attack of furnace linings by gases, cope downward into the drag, where it takes slags, ashes, or other fluxes occurring in an impression of a pattern. various melting practices. Core: A separate part of the mold, made Cover Core: A core set in place during of sand and cured, which is used to create the ramming of a mold to cover and complete openings and various shaped cavities in the a cavity partly formed by the withdrawal of a casting. loose part of the pattern. Also used to form Core Assembly: Putting together a core part or all of the cope surface of the mold made of a number of sections. cavity. A core placed over another core to Core Arbor: An iron framework create a flat parting fine. embedded in a large core to stiffen it and for Cracking Strip: A fin of metal molded on convenience in handling. the surface of a casting to prevent hot tearing. Core Extruder: A special shell-core- Critical Cooling Rate: minimum rate of making machine that produces a continuous continuous cooling just enough to prevent length of cores, usually of cylindrical cross- undesired transformations. section. Crystallization: The formation of crystals Core Filler: Material used in place of by the atoms assuming definite positions in sand in the interiors of large cores--coke, the crystal lattice, e.g. when a metal cinder, sawdust, etc., usually added to aid solidifies. collapsibility. 146 Rapid Tooling Guidelines For Sand Casting D ways: bilateral tolerance, unilateral tolerance Datum Plane: In layout and machining and limit dimensions. operations, the reference plane from which Direct AIM™ (ACES Injection dimensions are measured in the perpendicular Molding): This is a new "soft/bridge tooling" direction. process which quickly and inexpensively Datum Points: In layout and machining builds prototype parts using a variety of operations, the reference points that define engineering thermoplastics in a very short the datum plane from which dimensions are time without the need for production tooling.