Appendix Glossary of Terms - Springer978-1-4419-5731-3/1.pdf · gate or riser to facilitate clean breaking ... A separate part of the mold, made of sand and cured, which is used to

Appendix Glossary of Terms

A Abrasion: The displacement and/or

detachment of metallic particles from a surface as a consequence of being exposed to flowing solids, fluids or gases.

Aging: A change in properties of metals and alloys that occurs slowly at room temperature and will proceed rapidly at higher temperatures. The change in properties is often, but not always, due to a phase change (precipitation), but never involves a change in chemical composition of the metal or alloy.

Alloy: A substance having metallic properties and composed of two or more chemical elements of which at least one is metal. Usually possesses qualities different from those of the components.

Angle Testing (UT): A method of ultrasonic testing using shear waves introduced from the surface of the material at approximately 45 degrees.

Apparent Contraction: The net contraction of a casting dimension due to true metal contraction, mold wall movement, and restraint during solidification and cooling.

As Cast: Referring to metal which has not received finishing (beyond gate removal or sandblasting), or treatment of any kind including heat treatment after casting. (See Finishing).

B Backing Board (backing plate): A second

bottom board on which molds are opened.

Baked Core: A core which has been heated for a sufficient time and temperature to produce the desired physical properties.

Baked Strength: Compressive, shear, tensile or transverse strength of a molded sand mixture when baked at a temperature above 230 oF (110 oC) and then cooled to room temperature.

Base Plate: A plate to which the pattern assemblies are attached and to which a flask is subsequently attached to form the mold container.

Blow Holes: 1) Holes in the head plate or blow plate of a core-blowing machine through which sand is blown from the reservoir into the core box. 2) Irregular shaped cavities with smooth walls produced in a casting when gas is entrapped during mold filling. The gas sources may be air, binder decomposition products or gases dissolved in the molten steel.

Blow Plate: The plate containing the core sand entrance holes or blow holes used in open-face core boxes.

Blower, Core or Mold: A device using air pressure to fill a core box or flask with sand.

Boss: A projection of circular cross-section on a casting. Usually intended for drilling and tapping for attaching parts.

Bracket: Strengthening strip, rib, or projection on a casting. Usually used to prevent hot tearing.

Breakoff Notch: A thinner section of a gate or riser to facilitate clean breaking-off during the cleaning process.

143

Brinell Hardness: The value of hardness of a metal on an arbitrary scale representing kg/mm2, determined by measuring the diameter of the impression made by a ball of given diameter applied under a known load. Values are expressed in Brinell Hardness Numbers, BHN

Buckle: 1) Bulging of a large flat face of a casting; in investment casting, caused by dip coat peeling from the pattern. 2) An indentation in a casting, resulting from expansion of the sand, may be termed the start of an expansion defect.

Burnishing: Developing a smooth finish on a metal by tumbling or rubbing with a polishing tool.

C CAD: Computer Aided Design. CAE: Computer Aided Engineering. CAM: Computer Aided Manufacturing. CNC: Computer numerical control. Carbide: A compound of carbon with one

or more metallic elements. Carbon: Element occurring as diamond

and as graphite. Carbon reduces many metals from their oxides when heated with the latter, and small amounts of carbon greatly affect the properties of iron.

Carbon Dioxide Process (Silicate Process, Schmidt-Philipp Process): A process for hardening molds or cores in which carbon dioxide gas is blown through dry clay-free silica sand to precipitate silica in the form of a gel from the sodium silicate binder.

Carburizing: A form of case hardening that produces a carbon gradient inward from the surface, enabling the surface layer to be hardened by either quenching directly from the carburizing temperature or by cooling to room temperature, then reaustenitizing and quenching.

Casting: The metal shape, exclusive of gates and risers, that is obtained as a result of pouring metal into a mold.

Casting Layout: A check of dimensions against applicable drawings and specifications.

Chaplet: Metal support that holds a core in place within a mold; molten metal solidifies around the chaplet and fuses it into the finished casting.

Cheek: The intermediate section of a flask that is used between the cope and the drag when molding a shape requires more than one parting plane.

Chill (External): Metal, graphite, or carbon blocks that are incorporated into the mold or core to locally increase the rate of heat removal during solidification and reduce shrinkage defects.

Chill (Internal): A metallic device/insert in molds or cores at the surface of a casting or within the mold to increase the rate of heat removal, induce directional solidification and reduce shrinkage defects. The internal chill may then become a part of the casting.

Cleaning: The removal of gates, runners, and risers from the rough casting, This term also involves any hand finishing such as grinding or blasting.

CMM: Coordinate Measuring Machine. CNC Machine Tools: Computer

Numerical Controlled Machine Tools. Cold-Box Process: 1) Any core binder

process that uses a gas or vaporized catalyst to cure a coated sand while it is in contact with the core box at room temperature.

Collapsibility: The requirement that a sand mixture break down under the pressures and temperatures developed during casting, in order to avoid hot tears or facilitate the separation of the sand and the casting.

Compressive Strength (Yield): The maximum stress in compression that can be withstood without plastic deformation or failure.

Conductivity (Thermal): The quantity of heat that flows through a material measured in heat units per unit time per unit of cross-

144 Rapid Tooling Guidelines For Sand Casting

sectioned area per unit of length, (electrical) the quantity of electricity that is transferred through a material of known cross-section and length.

Contraction: The volume change occurring in metals and alloys on solidification and cooling to room temperature.

Convection: The motion in a fluid resulting from the differences in density. In heat transmission, this meaning has been extended to include both forced and natural motion or circulation.

Cooling Curve: A curve showing the relationship between time and temperature during the solidification and cooling of a metal sample. Since most phase changes involve evolution or absorption of heat, there may be abrupt changes in the slope of the curve.

Conduction: The transmission of heat, sound, etc., by the transferring of energy from one particle to another.

Cope: Upper or topmost section of a flask, mold, or pattern.

Coping Out: The extension of sand of the cope downward into the drag, where it takes an impression of a pattern.

Core: A separate part of the mold, made of sand and cured, which is used to create openings and various shaped cavities in the casting.

Core Assembly: Putting together a core made of a number of sections.

Core Arbor: An iron framework embedded in a large core to stiffen it and for convenience in handling.

Core Extruder: A special shell-core-making machine that produces a continuous length of cores, usually of cylindrical cross-section.

Core Filler: Material used in place of sand in the interiors of large cores--coke, cinder, sawdust, etc., usually added to aid collapsibility.

Core Float: A casting defect caused by core movement towards the cope surface of the mold, as a result of core buoyancy in liquid steel, resulting in a deviation from the intended wall thickness.

Core Prints: Portions of a pattern that locate and anchor the core in the proper position in the mold.

Core Rod: A wire or rod of steel used to reinforce and stiffen the core.

Core Setting Jig/Gage: A device used to help position a core in the mold.

Core Shooter: A device using low air pressure to fluidize the sand mix which is released quickly in such a way as to force it into a core box.

Core Vents: 1) Holes made in the core for the escape of gas. 2) A metal screen or slotted piece used to form the vent passage in the core box employed in a core-blowing machine. 3) A wax product, round or oval in form, used to form the vent passage in a core.

Corrosion: 1) Gradual chemical or electrochemical attack on a metal by atmosphere, moisture, or other agents. 2) Chemical attack of furnace linings by gases, slags, ashes, or other fluxes occurring in various melting practices.

Cover Core: A core set in place during the ramming of a mold to cover and complete a cavity partly formed by the withdrawal of a loose part of the pattern. Also used to form part or all of the cope surface of the mold cavity. A core placed over another core to create a flat parting fine.

Cracking Strip: A fin of metal molded on the surface of a casting to prevent hot tearing.

Critical Cooling Rate: minimum rate of continuous cooling just enough to prevent undesired transformations.

Crystallization: The formation of crystals by the atoms assuming definite positions in the crystal lattice, e.g. when a metal solidifies.

145 Appendix Glossary of Terms

D Datum Plane: In layout and machining

operations, the reference plane from which dimensions are measured in the perpendicular direction.

Datum Points: In layout and machining operations, the reference points that define the datum plane from which dimensions are measured.

Decarburization: Loss of carbon from the surface of a ferrous alloy as a result of heating in a medium, usually oxygen, that reacts with carbon.

Defect: A discontinuity in the product whose severity is judged unacceptable in accordance with the applicable product specification.

Deformation Test: An AFS test using an instrument such as the Dietert Universal Sand-Strength Testing machine (with deformation accessory) to determine the amount, in inches, that the sand specimen is compressed before it ruptures.

Deoxidation: Removal of oxygen from molten metal, usually accomplished by adding materials with a high affinity for oxygen, the oxides of which are either gaseous or readily form slags.

Die Casting: A rapid, watercooled permanent mold casting process limited to non-ferrous metals.

Dilatometer: An instrument for measuring the length of a metal sample during heating and cooling.

Dimension: A dimension is a numerical value associated with an appropriate unit of measurement. It defines the size, shape and location of features.

Dimensional Tolerance: A tolerance is the permissible variation in size of a feature placed on the specified dimension. It is usually assigned to a dimension based on limitations inherent in production processes and equipment. It can be expressed in three

ways: bilateral tolerance, unilateral tolerance and limit dimensions.

Direct AIM™ (ACES Injection Molding): This is a new "soft/bridge tooling" process which quickly and inexpensively builds prototype parts using a variety of engineering thermoplastics in a very short time without the need for production tooling. The Direct AIM™ process utilizes core and cavity mold halves produced using the SLA process.

Direct Shell Production Casting (DSPC): DSPC produces the actual ceramic molds for metal castings directly from 3-D CAD designs using the Three Dimensional Printing (3DP) technology. No tooling or patterns are required.

Disruptive Strength: Maximum strength of a metal when subjected to three principal tensile stresses at right angles to one another and of equal magnitude.

Dowel: A wooden or metal pin used in the parting surface of patterns and core boxes to locate and hold them in position.

Downsprue (Sprue, Downgate): The first channel, usually vertical, which the molten metal enters.

Draft: Slight taper given to pattern to allow drawing from sand.

Drag: Lower or bottom section of a mold or pattern

Drawback: A part of the mold, made of green sand, which may be drawn back to clear overhanging portions of the pattern.

Drawing: Removing the pattern from the sand.

Draw Plate: A plate attached to a pattern to facilitate drawing of a pattern from the mold.

Dry and Baked Compression Test: A sand test to determine the maximum compressive stress that a baked sand mixture is capable of developing.

Dry Permeability: The property of a molded mass of sand bonded or unbonded,


dried at 220-230 oF (105~110 oC and cooled to room temperature that allows passage of gases resulting during pouring of molten metal into a mold.

E Elastic Limit: Maximum stress that a

material will withstand without permanent deformation. (See Yield Strength).

Elasticity: The property of recovering original shape and dimensions upon removal of a stress.

Elongation: Amount of permanent extension in the vicinity of the fractures in the tensile test; usually expressed as a percentage of original gage length.

Embrittlement: Loss of ductility of a metal due to a chemical or physical change.

EPC (Expendable Pattern Casting): See Lost Foam Process.

Erosion: Abrasion of metal or other material by liquid or gas.

Etchant: A solution for the chemical etching of the polished surface of a metal specimen to reveal macro- or microstructures.

Evaporative Pattern Casting/Expendable Pattern Casting/EPC: See Lost Foam Process.

Epoxy: Containing oxygen attached to two different atoms already connected to a ring. A word often used by itself for epoxy resin.

Epoxy Resin: A plastic resin and hardener that sets or hardens itself as room temperature to form a new chemical, used as an adhesive or workable material.

Expended Polystyrene: A foamy plastic composed of bonded beads, density between 1 to 1.2 lb./per ft., compressive strength 13~15 psi.

Expended Polyurethane: A lightweight expanded plastic polymer whose foamed texture results from the trappings of CO2 evolved during production. In resin from it is used for coating and adhesive.

F Fabrication: The joining, usually by

welding, of two or more parts to produce a finished assembly The components of the assembly may be a combination of cast and wrought materials.

Fast Freeform Fabrication (FFFF): see Rapid prototyping.

Feature: A feature is any physical portion of an object, such as a hole, surface, or groove. It is a general term that is used to denote or refer to any part of an object.

Feeding: The process of supplying molten metal to compensate for volume shrinkage while a casting is solidifying.

Fillet: A concave comer piece used on foundry patterns, a radiused joint replacing sharp inside comers.

Fin: A thin projection on a casting due to an imperfect joint in the mold.

Finish Allowance: The amount of stock left on the surface of a casting for machining.

Finish Mark: A symbol (f, f1, f2, etc.) appearing on the line of a drawing that represents the edge of the surface of the casting to be machined or otherwise finished.

Finite Element Analysis (FEA): A computerized numerical analysis technique used for solving mechanical engineering problems relating to stress analysis, heat transfer, and so forth.

Flash: A thin section of metal formed at the mold, core or die joint, or parting in a casting due to the cope and drag not contacting completely, or where core and core print do not contact completely.

Flask: A metal frame used for making or holding a sand mold. The upper part is the cope and the bottom half is the drag.

Flask Bar: A reinforcing member attached within either half of a flask to assist in holding the rammed sand in position.

Flask Clamp: A device for holding together the cope, drag and cheek of a flask.


Flask Pins: Pins to fit corresponding sockets on the joint of a flask to permit separation.

Flask Pin Guides: Guides used to accurately align the match plate pattern in the flask and flask to flask location.

Flat Back: A pattern with a flat surface at the joint of the mold. It ties wholly within the drag, and the cope is a plane surface.

Floor Molding: Used where the pattern size prohibits the use of molding machines. The pattern is bolted to the floor and the assembled mold is moved by crane.

Fluidity: The ability of molten metal to flow. Common devices used to measure fluidity are spiral casting and the Chinese Puzzle.

Foam Plastics: Resinoids in spongy form, as polystyrene. The sponge maybe flexible or rigid, the cells closed or interconnected, with a density from that of the parent resin to, in a few cases, 2 lb/ft3.

Follow Board: A board shaped to the parting line of the mold.

Foundry Returns: Metal in the form of sprues, gates, runners, risers, and scrapped castings, with known chemical composition that are returned to the furnace for remelting. Sometimes referred to as "revert".

G Gage Length: The original length of that

portion of the specimen over which strain or change of length is determined.

Gage Marks: Reference marks; in tensile testing, the marks which indicate the gage length, used in determination of tensile elongation.

Gate: A channel through which the molten metal enters the casting cavity.

Gating System: The gating system is a channel, or network of channels, through which the molten metal flows into the cavity. It is typically composed of a pouring cup, sprue, and runner.

Geometry Driver: The critical features which may affect or determine the tooling path selection.

Grain Fineness Number: A system developed by AFS for expressing the average grain size of a given sand, It approximates the number of meshes per inch of that sieve that would just pass the sample if its grains were of uniform size.

Green Sand: A naturally bonded sand or a compounded molding sand mixture which has been tempered with water for use while still in the damp or wet condition.

Green Sand Core: One that is made of green sand but not baked.

Green Strength: The strength of a tempered sand mixture at room temperature.

H Hardness: Resistance of a material to

indentation as measured by such methods as Brinell, Rockwell, and Vickers. The term hardness also refers to the ability of the metal to resist scratching, abrasion, or cutting. It is related to yield strength and ultimate tensile strength.

High Pressure Mold: A strong high-density mold.

Hot Tear: A crack or fracture formed prior to completion of metal solidification as a result of hindered contraction. A hot tear is frequently open to the surface of the casting and is commonly associated with design limitations.

Hot Strength (Sand): (compressive, shear or transverse) Strength of a sand mixture determined at any temperature above room temperature.

I Impact Strength: The resistance to

impact loads; usually expressed as the foot pounds of energy absorbed in breaking a standard specimen.


Induction Furnace: An AC melting furnace which utilizes the heat of electrical induction.

Induction Hardening: A surface hardening process involving the localized use of pulsating magnetic currents to achieve heating above the austenite transformation temperature, AC3, followed by quenching.

Induction Heating: Process of heating by electrical resistance and hysteresis losses induced by subjecting a metal to the varying magnetic field surrounding a coil carrying an alternating current.

Ingates: See Gate. Insert: A part usually formed from metal,

which is placed in a mold and may become an integral part of the casting.

Internal Shrinkage: A void or network of voids within a casting caused by inadequate feeding of that section during solidification.

Internal Stresses (or Thermal Stresses): Generally stresses which occur during the cooling of a part.

Investment Casting: Casting produced in a mold obtained by investing an expendable pattern with a refractory to produce a shell. The expendable pattern may consist of wax, plastic, or other material, and is removed prior to filling the mold with metal.

Isocyanate Resin: A basic chemical component of the urethanes.

J Jarring Machine: A molding machine

that packs the sand by jarring. Jig: A device arranged to expedite a hand

or machine operation. Jolting Machine: See Jarring Machine. Jolt-Squeezer Machine: A combination

machine that employs a jolt action followed by a squeezing action to compact the sand around the pattern.

K

Keyhole Specimen: A type of notched impact test specimen, which has a hole-and-slot notch, shaped like a keyhole.

Kissing (Touching): Gating with minimum metal left at casting breakoff point, having a gate just "kiss" the surface.

Knockout Pins (Ejector Pins): Small diameter pins affixed to a pattern back-up plate for removing the cured mold in the shell-molding process.

L Layered Manufacturing (LM): see Rapid

prototyping. Layout: A full size drawing of pattern

showing its arrangement and structural features.

Loam Mold: A mold built up of brick, covered with a loam bud, and then baked before being poured.

Loose Molding: The molding process utilizing unmounted pattern. Gates and runners are usually cut by hand.

Loose Piece: Part of a pattern that remains in the mold and is taken out after the body of the pattern is removed. It can be indicated as 1) Core box: part of the core box which remains embedded in the core and is removed after lifting off the core box. 2) Pattern: laterally projecting pan of a pattern so attached that it remains in the mold until the body of the pattern is drawn. Back-draft is avoided by this means. 3) Permanent mold: part which remains on the casting and is removed after the casting is ejected from the mold.

Lost Foam Process: Casting process in which a foam pattern is removed from the cavity by the molten metal being poured.

M Machine Allowance: Stock added to the

part to permit machining to final dimensions. Machine Finish: Allowance of stock on

the surface of the pattern in order to permit


machining of the casting to the required dimensions.

Master Pattern: An original pattern made to produce metal castings that are then used for production.

Matchplate: A plate on which patterns and gating systems, split along the parting fine, are mounted. Matchplates are mounted back to back to form an integral piece.

Mechanical Properties: Properties of a material that reveal its strength and elastic behavior.

Metallurgy: The science and technology of metals. A broad field that includes but is not limited to the study of internal structures and properties of metals and the effects on them of various processing methods.

Microporosity: See Microshrinkage. Microshrinkage: Very finely divided

porosity resulting from interdendritic shrinkage resolved only by use of the microscope; may be visible on radiographic films as mottling. Etching shows they occur at intersections of convergent dendritic directions.

Misrun: Denotes an irregularity of the casting surface caused by incomplete filling of the mold.

Mock-up: A full-size model built accurately for study, testing or display.

Model: A representative of an object; miniature or full size.

Modulus of Elasticity (E): In tension, it is the ratio of stress to the corresponding strain within the limit of elasticity (Yield Point) of a material. For carbon and low alloy steels of any composition and treatment, the value is approximately 30,000,000 psi.

Mold: A body of molding sand or other heat-resisting material containing a cavity which forms a casting when filled with molten metal.

Mold Blower: Molding equipment for blowing a sand mixture onto the pattern with

compressed air; allows for faster production than gravity rollover dump.

Mold Board (Follow Board): The board upon which the pattern is placed to make the mold.

Mold Cavity: The space in a mold which is filled with liquid metal to form the casting upon solidification.

Mold Clamps: Devices used to hold or lock cope and drag flask parts together.

Mold Coating (Mold Facing, Dressing): Coating to prevent surface defects on permanent mold castings and die castings. 2) Coating on sand molds to prevent metal penetration and improve metal finish.

Mold Jacket: A wooden or metal form slipped over a mold to support the sides during pouring.

Mold Shift: A casting discontinuity resulting from misalignment of the cope and drag halves.

Molding, Floor: Making sand molds from loose patterns of such size that they cannot be satisfactorily handled on a bench or molding machine, the equipment being located on the floor during the entire operation of making the mold.

Molding, Pit: Molding method in which die mold is made in a pit or hole in the floor.

Molding Sand: A sand which binds strongly without losing its permeability to air or gases.

Mulling and Tempering: The thorough mixing of sand with a binder, either natural or added, with lubricant of other fluid, as water,

N Non-destructive Testing (NDT): Testing

or inspection that does not destroy the object being tested or inspected.

Nucleation: 1) (Homogeneous). The initiation of solid crystals from the liquid stage, or a new phase within a solid without outside interference-rarely occurs. 2) (Heterogeneous). Foreign particles altering


the liquid-solid interface energy during phase changes usually occurs.

O Oil Sands: Sands bonded with such oils

as linseed and the synthetics. One-Piece Pattern: Solid pattern, not

necessarily made from one piece of material. May have one or more loose pieces.

Overheated: A term applied when, after exposure to an excessively high temperature, a metal develops an undesirable coarse grain structure, but is not necessarily damaged permanently. Unlike burned structure, the structure produced by overhearing can be corrected by suitable heat treatment, by mechanical work, or by a combination of the two.

Oxidation: Any reaction of an element with oxygen. In a narrow sense, oxidation means the taking on of oxygen by an element or compound, and on the basis of the electron theory, it is a process in which an element loses electrons.

Overhang: The extension on the vertical surface of a core print in order to provide clearance for closing the mold over the core, also known as “shingle”.

P Parted Pattern: A pattern made in two or

more parts. Parting: Joint where mold separates to

permit removal of pattern. Parting Line: A line on a pattern or

casting corresponding to the separation between the cope and drag portions of a sand mold.

Parting Sand: A bondless sand dusted on the parting surface to prevent the parts of the molds from adhering to each other.

Pattern: A form of wood, plastic, foam, metal, or other material around which molding material is placed to make a mold.

Pattern Draft: The taper on vertical elements in a pattern which allows easy separation of pattern from compacted sand mixture.

Pattern Layout: Full-sized drawing of a pattern showing its arrangement and structure features.

Permanent Mold: A metal mold of two or more parts; not an ingot mold. It is used repeatedly for the production of many castings of the same form.

Pilot Casting: Casting produced prior to the production run to verify correctness of procedures, materials, and process to be used in production.

Polymer: A compound of high molecular weight, in which the molecules are packed closely, with water, alcohol and the like eliminated.

Polymerization: The hardening or setting of plastic materials, as epoxy, urethane, when the resin and hardener are mixed together.

Polystyrene: A polymer of styrene used in making molding products. In particular, used in the lost foam process.

Polyurethane: Synthetic resin polymer used for pattern material, ranging from dense elastomer to expanded, spongy, lightweight.

Porosity: Unsoundness in cast metals due to blow holes, shrinkage cavities and voids.

Post-processing: The processing of a prototype to remove extra material, finish the surface, and apply proper protection.

Pouring: Filling the mold with molten metal.

Pouring Cup: The flared section of the top of the downsprue.

Process Capability: The amount of variation in the product of a controlled manufacturing process, the range defined by plus or minus three standard deviations.

Pyrometry: A method of measuring temperature with any type of temperature-indicating instruments.


Q Quickcast: A rapid tooling process

developed by 3D Ssytems Inc. The Quickcast process utilizes a stereolithography (SLA) model with a solid outer skin and a hollow, honeycombed interior. The model is dipped in a ceramic slurry, which is allowed to harden. When the ceramic shell is heated, the thin-walled SLA model disintegrates allowing a metal of the customer's choice to be poured into the empty mold. After solidification, the ceramic is broken away to reveal the metal casting which is then finish machined (adding threads and removing burrs) as necessary.

Quenching: Rapid cooling for hardening; normally achieved by immersion of the object to be hardened in water, oil, or solutions of salt or organic compounds in water.

R Ramming: Packing sand in a mold by

raising and dropping the sand, pattern, and flask on a table. Jolt squeezers, jarring machines, and jolt rammers are machines using this principle.

Rapid Prototyping (RP): The physical modeling of component or tooling geometry using layered manufacturing. RP technologies make it possible to quickly generate polymer, wax, metal, or paper-based prototype parts from three-dimensional solid model computer-aided design (CAD) representations. Parts are typically generated by building up one layer at a time, with the thickness of each layer determining the accuracy of the part and the time required to make it.

Rapid Tooling (RT): The use of RP or CNC machining technology to quickly fabricate tooling for near net shape processes. Depending on the process and production volume involved, the mold or die can be made directly or a master pattern may be produced that is then used to make the mold or die. In all cases, a CAD solid model of the

part is required and computer numerical control technology is used to produce the master pattern or mold.

Rapping: Knocking or jarring the pattern to loosen it from the sand in the mold before withdrawing the pattern.

Rapping Plate: A metal plate attached to a pattern to prevent injury to the pattern and assist in loosening it from the sand.

Rechucking: Reversing a pattern upon a face plate in order to permit turning the opposite face to the required shape.

Recrystallization: A process whereby the distorted grain structure of cold-worked metals is replaced by a new, strain-free grain structure during annealing above a specific minimum temperature.

Resinoid: Solid materials produced by the union (polymerization) of a large number of molecules of one or more relatively simple compounds. Resinoids are classed as thermosetting or thermoplastic.

Rigging: Gates, risers, loose pieces, etc., needed on the pattern to deliver the metal to the mold cavity and produce a sound casting.

Riser: Reservoir of molten metal from which casting feeds as it shrinks during solidification.

Riser, Blind: A riser that does not break through the top of the cope and is entirely surrounded by sand; opened to the atmosphere by means of a firecracker core.

Riser-Gating: Practice of running metal from the casting through the riser to help in directional solidification.

Riser Neck: The connecting passage between the riser and casting. Usually only the height and width or diameter of the riser neck are reported, although the shape can be equally important.

Riser, Open: Conventional form of riser usually located at the heaviest section of the casting and extending through the entire height of the cope.


Riser Pad (Riser Contact): An enlargement of the riser neck where it joins the casting. The purpose of the pad is to prevent the riser from breaking into the casting when it is struck or cut from the casting.

Rollover Board: A wood or metal plate on which the pattern is laid top face downward for ramming the drag half mold, the plate and half mold being turned over together before the joint is made.

RTV: Room Temperature Vulcanizing, a term describing ability of silicone rubber to set at ambient temperatures, as in flexible, synthetic rubber molds. There are two families, the RTV-11, 60 and 88 and a newer high-strength RTV-662.

Runner: The channel through which the molten metal is carried from the sprue to the gate.

Runner Extension: In a mold, that part of a runner which extends beyond the farthest ingate as a blind end.

Runout: A casting defect caused by incomplete filling of the mold due to molten metal draining or leaking out of some part of the mold cavity during pouring; escape of molten metal from a furnace, mold, or melting crucible.

S Sand Mulling: A method of evenly

distributing the bond around the sand grain by a rubbing action.

Sand Reclamation: Processing of used foundry sand grains by thermal, attraction, or hydraulic methods so that it may be used in place of new sand without substantially changing current foundry sand practice.

Scale Measurement: Measurements taken from a scale drawing or a model to ascertain the true dimensions.

Segment: A section of a circle , the ends of which are radial lines.

Shakeout: 1) The operation of removing castings from the mold. 2) A mechanical unit for separating the molding materials from the solidified metal casting.

Shaw (Osborn-Shaw) Process: A precision casting technique in ceramic molds, which does not require wax or plastic investment.

Shear Modulus (G): In a torsion test, the ratio of the unit shear stress to the displacement caused by it per unit length in the elastic range. Units are Pa or psi.

Shear Strength: Maximum shear stress a material is capable of withstanding without failure.

Shell Molding: A process for forming a mold from resin-bonded sand mixtures brought in contact with preheated (300-500 oF) metal patterns, resulting in a firm shell with a cavity corresponding to the outline of the pattern.

Shift: A casting defect caused by mismatch of cope and drag, or of cores and mold.

Shrinkage: The decrease in volume when molten metal solidifies.

Shrinkage Hole: A cavity in a casting due to the insufficient feed metal.

Silica: Silicon dioxide, the prime ingredient of sand and acid refractories.

Slicing: Cutting 3D geometry into thin slice using a planar plane vertical to building direction is called slicing.

Silicon: An abundant element, chemically classed as a nonmetal, metallurgically a metal, used extensively in ferrous and nonferrous alloys; melting point 2593.4 oF (1423 oC).

Simultaneous Engineering: Refers to the process where user/designer and producer interact to reduce lead time and improve the manufacturing efficiency of a part design. This process is faster and more efficient than the traditional sequential process of design and manufacture.


Sintering: The bonding of adjacent surfaces of particles of a mass of powder or a compact by heating to a suitable temperature and cooling.

Skeleton Pattern: A framework representing both the exterior and interior of the casting.

Skewed Tolerances: Tolerances which are nonsymmetrically distributed about the design intent.

Skim Core (Skimmer): A flat core or tile placed in a mold to skim a flowing stream of metal. Commonly used in pouring basins.

Skin-Drying: Drying the surface of the mold by direct application of heat.

SLA: See Stereolithography Apparatus. Slurry: A term loosely applied to any

clay-like dispersion. It may be used to wash ladles or other refractory linings to impart a smoother surface.

Snap Flask: One that has hinges and latches so that it may be removed from the mold prior to the pouring.

Soldiers: Wooden pegs used to reinforce a body of sand.

Splash Core: A core of tile placed in a mold to prevent erosion of the mold at places where metal impinges with more than normal force. Splash cores are commonly used at the bottom of large rammed pouring basins, at the bottom of long downsprues, or at the ingates of large molds.

Spline: A thins strip of wood to reinforce butt joints. Also known as “feather” or “tongue”.

Split Pattern: A pattern that is parted for convenience of molding.

Sprue: The opening into which the metal is first poured.

Squeeze Board: A board used on the cope half of a green sand mold to permit squeezing of the mold.

Stereolithography Apparatus (SLA): Equipment used for computerized building of three-dimensional models and patterns.

Enables the data representation of a CAD solid model to be directly converted into a photo cured plastic model of a part or tool.

STL format: A data format widely used in rapid prototyping industry. STL is an abbreviation for Stereolithography and was first proposed by 3D Systems Inc. The .STL file is now a de-facto standard interface between CAD packages and rapid prototyping.

Stock Core: Core of standard diameter usually made on a core machine and kept on hand, cut to required length.

Stress, Residual: Those stresses set up in a metal as a result of nonuniform plastic deformation or the unequal cooling of a casting.

Striping Plate: A plate, formed to the contour of the pattern, which holds the sand in place while the pattern is drawn through the plate.

Styrene: See Polystyrene. Styrofoam: A proprietary name for

expanded polystyrene. Synthetic Molding Sand: Any sand

compounded from selected individual materials which, when mixed together, produce a mixture of the proper physical and mechanical properties from which to make foundry molds.

T Template: A thin piece of material with

the edge contour in reverse to the shape to be checked.

Tensile Strength: The maximum stress in uniaxial tension testing which a material will withstand prior to fracture. The ultimate tensile strength is calculated from the maximum load applied during the test divided by the original cross-sectional area.

Tessellation: Representation of a smooth curvilinear CAD solid model surface with triangular shaped facets. Most RP processes


require tessellated surfaces which is a part of the .STL data format.

Thermal Conductivity: The property of matter by which heat energy is transmitted through particles in contact. For engineering purposes, the amount of heat conducted through refractories is usually given in Btu per hour for one square foot of area, for a temperature difference of one degree fahrenheit, and for a thickness of one inch, Btu/hr - ft2 - 0F/in.

Thermal Shock: Stress developed by rapid and uneven heating of a material.

Thermal Spalling: Breaking up of refractory caused by stresses that arise during repeated heating and cooling cycles.

Thermal Stability: Resistance of a material to drastic changes in temperature.

Thermocouple: A device for measuring temperatures by the use of two dissimilar metals in contact; the junction of these metals gives rise to a measurable electrical potential which varies with the temperature of the junction. Thermocouples are used to operate temperature indicators or heat controls.

3D KeltoolTM: A rapid tooling process developed by 3D Systems Inc. that integrates the use of SLA master patterns, RTV intermediate molds, 3D KeltoolTM fused powder metal inserts and standard MUD (Master Unit Die) frames to produce cores and cavity inserts.

Tight Flask: A type of flask which remains on mold during pouring. Lugs are normally provided for clamping cope and drag together for pouring.

Tongue: See Spline. Tooling Alternative Selection: the

comprehensive mental exercise involved in selecting the most efficient way to produce sand casting tooling. It generally includes the choice of tool fabrication method, material selection, and choice of tooling approach.

Tooling Points: The fixed positions on the casting surfaces used for reference during layout and machining.

U Ultrasonic Testing: A nondestructive

method of testing metal for flaws based on the fact that ultrasonic waves are reflected and refracted at the boundaries of a solid medium.

Urea Formaldehyde Resin: A thermosetting product of condensation from urea or thio-urea and formaldehyde, soluble in water, and used as a sand binder in core and mold compounds.

Urethane Elastomer: A resilient rubberlike pattern compound which has excellent abrasion resistance. It is a castable plastic requiring a hardener to complete poly-merization.

Urethane Foam: See Polyurethane. V Vacuum Casting: A casting process in

which metal is melted and poured under very low atmospheric pressure; a form of permanent mold casting where the mold is inserted into liquid metal, vacuum is applied, and metal drawn up into the cavity.

Veins: A discontinuity on the surface of a casting appearing as a raised, narrow, linear ridge that forms upon cracking of the sand mold or core due to expansion of the sand during filling of die mold with molten metal.

Vent: Small opening in mold to facilitate escape of air and gases.

Vibrator: A mechanical device used to loosen pattern from mold.

Viscosity: The resistance of fluid substance to flowing, quantitatively characteristic for an individual substance at a given temperature, and under other definite external conditions.

W


Washburn Core: A thin core which constricts the riser at the point of attachment to the casting. The thin core heats quickly and promotes feeding of the casting. Riser removal cost is minimized.

X X-Ray: Form of radiant energy with wave

length shorter than that of visible light, and with the ability to penetrate materials that absorb or reflect ordinary light. X-rays are usually produced by bombarding a metallic target with electrons in a high vacuum. In nuclear reactions, it is customary to refer to photons originating in the nucleus as gamma rays, and to those originating in the extranuclear part of the atom as x-rays.

Y

Yield: Comparison of casting weight to total weight of metal poured into mold, expressed as a percentage.

Yield Strength: The stress at which a material exhibits a specified limiting permanent strain.

Young's Modulus (E): See Modulus of Elasticity.

Z Zircon: The mineral zircon silicate,

ZrSiO4, a very high melting point acid refractory material used as a molding material in steel foundries.

Zirconia: ZrO4, an acid refractory up to 4532 oF (2500 oC) having good thermal shock resistance and low electrical resistivity.

Zirconium: Silvery-white, metallic element, mp 3380 oF (1860 oC), a powerful oxidizer and aluminum stabilizer, when added to molten steel.


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Index

Numbers

25mm projectile, 133 2D drawing, 48, 74, 100, 102, 104 2D CAD file, 102 3D Modeling, 48 3DP, see three dimensional printing

A

Accuracy, 69, dimensional accuracy, 69 tessellation accuracy, 75

Actual size, 87 Allowance, 23-27, 84

pattern allowance, 23

B

Bridge tooling, 58-59 Build direction, 55 Building, 55 Building procedure, 53

C CAD, 15, 32, 33, 35 CAD model, 37, 38, 40 CAD modeling, 53 CAD software, 38, 102-103 Carrier housing 1, 125-126 Carrier housing 2, 135-136 Casting, 1

sand casting, 1 Caliper, 96 Ceramic powders, 46 Cleaning, 1, 4 CNC based tooling, 54-55 Cold gas dynamic spray, 68 Coordinate measuring machine (CMM), 97 Core, 3, 8, 20, 34, 101, 105

core making, 21, 70 core fabrication, 34, 101 core fabrication process, 34

Core box, 34-35 core box fabrication, 34-35

Core sand molding, 8

D

Data preparation, 48 Data status, 102, 113 Datum, 84

datum reference, 85 Datum points, 31, 48, Decision factors, 101

data status, 101 physical parts, 101 intermediate representation, 101 production volume, 103 prototype, 104 production, 104 part geometry, 104 pattern shop capability, 106 tool cost, 107 lead-time, 107 required accuracy, 107 tool durability, 107

Decision process, 113 data status, 113 geometry independent requirements, 114 geometry analysis, 114 alternative tooling proposals, 114 negotiate the final selection, 115

Decision space, 107 Decision structure, 107

decision constraints, 110 tradeoffs, 110 geometry considerations, 111

Decision variables, 99 fabrication method, 99-101 tool material, 101 tooling approach, 101

Decubing, 40, 50-51, 73-74 decubing error, 76-77

Dependent factors, 101 Die casting, 53, 56, 63 Dimensions, 82

161

basic dimension, 82 reference dimension, 82 specified dimension, 82 nominal dimension, 82

Dimensional accuracy, 4, 7, 9, 17, 64, 69 Dimensional error, 75-77, 89 Dimensional metrology, 88 Dimensional tolerance, 83, 87 Dimensional variability, 69 Direct AIM™ , 55, 58 Discretizing, 37 Draft, 27-28 Drawing interpretation, 48 Dry-sand molding, 7

E Errors, 69

conversion error, 74 decubing error, 76 orientation error, 76 post-finishing error, 77 process parameter error, 76 random error, 69, 89 system error, 69, 89 tessellation error, 74 time dependent error, 77

Error sources, 69-73 ExpressTool, 68

F

Fast freeform fabrication, 33, 37-48 3DP, 45 FDM, 41 LOM, 39 materials, 39-48 methods, 39-48 processes, 39-48 SGC, 44 SLA, 38 SLS, 42 SP, 46

FDM based RT, 66 Feature control, 84 Fishbone diagrams, 70-74 Fused deposition modeling (FDM), 41

G Gage, 95 Gage R&R, 95 Geometry considerations, 28, 111

fillets, 28 undercuts, 29 loose piece, 29 ribs, 29 lugs, 29 bosses, 29

Geometric dimensions and tolerances, 81 Geometric symbols, 85 Geometric tolerance, 83 Green sand molding, 4-7

H

Hard tooling, see KelToolTM Hitch housing, 121

I Ice cleat, 138 Independent factors, 101 Injection molding, 57, 63 Inlet boost pump, 127 Investment casting, 57, 59-60, 66 ISO, 87 ISO 8062, 87 ISO/CD 8062-2, 87

J K

KelToolTM Process, 55, 56, 58 L

Laminated object manufacturing (LOM ), 39

Least material condition (LMC), 86-87 Load material, 49 LOM based RT, 59 LOMPapersTM, 40 Lost paper process, 59 Lower specification limit (LSL), 92

M Manifold, 128 Master core, 35-36 Master pattern fabrication, 30

manual, 31 CNC, 32 fast freeform fabrication, 33

Machine parameters, 49 Machine setup, 49 Maximum material condition (MMC), 86


Measurement system analysis, 95-98 Melting, 1, 3 Metal prototype, 59-61 Micrometer, 96-97 Model repair, 51 Mold dimensions, 80 Molding, 1, 3 Mold making process, 4

core sand molding, 8 dry sand molding, 7 green sand molding, 4 shell molding, 8

Muzzle brake, 136 N

Nickel-ceramic composite (NCC) tooling, 67

O

P

Paper, 23, 33, 39-41 Parting line, 1, 28

parting line complexity, 106 Parting plane, see parting line Pattern Allowance, 23

shrinkage allowance, 23 distortion allowance, 25 machining allowance, 26 Casting finish allowance, 26

Pattern, 15 pattern design, 20 pattern fabrication, 30 pattern type, 15

Patternmaking, 1, 2 Pattern design, 20 Pattern Materials, 20

wood, 20 metal, 20 plastic, 21 styrofoam, 22 fast freeform fabrication, 22

Pattern Type, 15 single pattern, 16 loose pattern, 16 gated pattern, 17 match-plate pattern, 17 cope and drag pattern, 19

special patterns and device, 19 Photo-reactive polymer, 44 Photopolymer, 39, 54 Plastic, 59 Plastic prototypes, 61 Polysteel, 67-68 Portage machine, 97 Post processing, 37, 48, 50, 100 Pouring, 1, 3 Precision, 88 Process capability, 92 ProMetal rapid tooling, 66-67 ProtoBuild, 47

Q

QuickCastTM, 58-59

R Random error, 69 Rapid prototyping (RP), see fast freeform fabrication Rapid tooling (RT), 53, 73 Repeatability, 88, 95 Reproducibility, 88 Rigid connecting link, 132 Roller bracket, 139 Room temperature vulcanizing (RTV), 56 Rubber plaster casting, 61 Rubber tooling, 56

S

Sand casting, 1-10 Sand casting process, 1, 70 Sanders prototype (SP), 46 Select materials, 49 Selective laser sintering (SLS), 42-44 Sensor box, 117 Set parameters, 49 Sheet vacuum forming, 62 Shell molding, 8 Shrinkage, 77 Silicone rubber molding, 57, 61 SLS based RT, 63 Soft tooling, 54 Solid ground curing (SGC), 44 Solidification shrinkage, 78 Spray metal tooling, 62 Stereolithography, 38 Stereolithography apparatus (SLA), 38 STL, 38 Stock size, see nominal dimension

163 Index

Surface finish, 51 System error, 69

T

Tessellation, 48-49 Tessellation error, 74 Three dimensional printing (3DP), 45 Thin wall, 51 Tolerances, 81 Tool, 11 Tool design, 11 Tool construction see Tool fabrication Tool fabrication, 13

manual, 13 CNC, 14 fast freeform fabrication, 14

Tooling alternatives, 99, 108 Tooling path review form, 119 Tooling path selection process, 115 Two part negative tooling, 60 Turbine blade machining fixture, 129

U

Ultrasonic machine, 98 Upper arm, 130 Upper specification limit (USL), 92

V Vacuum molding, 62 Volume contraction, 78

W Weight tolerance, 84

X Y

Yoke, 123 Z


Documents

Appendix Glossary of Terms - Springer978-1-4419-5731-3/1.pdf · gate or riser to facilitate clean breaking ... A separate part of the mold, made of sand and cured, which is used to