ToolingU Materials

Branched Arrangement

A molecule chain with multiple branches or extensions of mer units. Branched arrangements of molecules can appear in both thermoplastics and thermosets.

Metal

A naturally occurring material with high electric and thermal conductivity, luster, density, and strength. Examples of metal include copper, iron, nickel, and lead.

Metals

A naturally occurring material with high electric and thermal conductivity, luster, density, and strength. Examples of metal include copper, iron, nickel, and lead.

Electron

A negatively charged particle that orbits the nucleus of an atom. Electrons are involved in chemical bonding and electrical conductivity.

Electrons

A negatively charged particle that orbits the nucleus of an atom. Electrons are involved in chemical bonding and electrical conductivity.

Neutron

A neutrally charged particle within the nucleus of an atom.

Titanium

A nonferrous metal that is lightweight, corrosion resistant, and has a high strength-to-weight ratio. Titanium is often used in the aerospace industry.

Aluminum

A nonferrous metal that is silvery white in color and lightweight. Aluminum resists corrosion and is a good conductor of electrical and thermal energy.

Copper

A nonferrous metal that is very ductile, thermally and electrically conductive, and corrosion resistant. Copper is often used to make electrical wiring.

Lead

A nonferrous metal that is very soft, ductile, and heavy. Lead is a poor electrical conductor and is often used as a soldering alloy and sound dampener.

Tin

A nonferrous metal that is very soft. Tin is often used as a plating metal and soldering alloy.

Castings

A part formed by pouring or injecting heated material into a mold. Castings take shape as the material cools and solidifies.

Shellac

A resinous substance that can be used as a coating. Shellac is a natural polymer that is chemically similar to synthetic polymers.

Phenolics

A rigid and relatively inexpensive thermoset with tightly cross-linked molecule chains. Phenolics are often used as an adhesive for plywood.

Plastic Deformation

Permanent deformation of a material due to stress. Plastic deformation occurs after excessive elastic deformation.

Ocular Scale

A scale built into a microscope that makes it possible to view magnified images and measure very small features. Brinell hardness testing indentations can be measured using an ocular scale.

Carbon Black

A soot-like additive that is used as a colorant and/or a protector against ultraviolet radiation in polymers. Carbon black is a type of light stabilizer.

Tool Steels

A specialized type of alloy steel that has excellent strength, toughness, and wear resistance. Tool steels are used in cutting tools, punches, and other industrial tooling.

Ductile Cast Iron

A type of cast iron with a similar composition to gray cast iron, but with improved ductility. Ductile cast iron contains tiny spheres of graphite.

Malleable Cast Iron

A type of cast iron with a similar composition to white cast iron, but with improved malleability. Malleable cast iron is heat treated.

Gray Cast Iron

A type of cast iron with high levels of carbon and excellent compressive strength. Gray cast iron is the most common cast iron.

White Cast Iron

A type of cast iron with lower levels of carbon and improved tensile strength. White cast iron contains little to no graphite.

Hypereutectoid Steel

Steel that contains more than 0.8% carbon. Hypereutectoid steel consists of pearlite and cementite at room temperature.

Secondary Bonds

A type of chemical bond formed between atoms that involves an attraction between molecules without the transfer or sharing of electrons. Secondary bonds hold thermoplastic molecules together.

Chloroprene

An elastomer that effectively resists oil, weather, heat, and flame. Chloroprene was one of the first successful synthetic rubbers.

Natural Rubber

An elastomer that is extracted as a sap from tropical trees. Natural rubber must be hardened and treated with sulfur in order to be used commercially.

Butyl Rubber

An elastomer that is odorless and impermeable to air. Butyl rubber can form an airtight seal.

Silicon

An element that is added to alloys to improve hot-forming properties. Silicon is often added to steel to improve hardenability.

Cold Working

Any metal shaping process that takes place when the metal is below its recrystallization temperature. Cold working adds certain properties to the metal, such as increased strength and improved surface finish.

Body-Centered Cubic

BCC. The crystal structure that contains an atom in the center and one atom in each corner of a cube. Body-centered cubic metals are often hard.

Body-Centered Tetragonal

BCT. A body-centered cubic crystal structure that has been distorted by the presence of extra atoms of carbon. Martensite has a BCT crystal structure.

BCC

Body-centered cubic. The crystal structure that contains an atom in the center and one atom in each corner of a cube. BCC metals are often hard.ff

BCT

Body-centered tetragonal. A crystal structure that has been distorted by the presence of extra atoms of carbon. Martensite has a BCT crystal structure.

Fracture

Complete separation or breaking apart due to force or impact. A fracture occurs more easily in a material that is brittle or has a low tensile strength.

Heat Treatment

Controlled heating and cooling processes used to change the structure of a material and alter its physical and mechanical properties. Annealing, quenching, and tempering are heat treatments.

Crucibles

A ceramic container in which substances can be melted at high temperatures. Crucibles used in metallurgy are made of ceramics.

Physical Properties

A characteristic that describes a material's volumetric, thermal, electrical, and magnetic qualities. Physical properties are a collection of characteristics that describe how a material responds to forces other than mechanical forces.

Mechanical Properties

A characteristic that describes how a material reacts when subjected to a force that attempts to stretch, compress, bend, dent, scratch, or break it.

Phase Diagram

A chart that depicts the effects of temperature and pressure changes on a substance. Steel phase diagrams illustrate how carbon content and temperature impact the microstructure of steel.

Aluminum Oxide

A chemical compound of aluminum and oxygen that is used as a conventional abrasive. It is extremely durable.

Solvent

A chemical that attempts to dissolve another material. Solvents are rated by their solubility.

Solvents

A chemical that attempts to dissolve another material. Solvents are rated by their solubility.

Brale

A conical diamond indenter used in hardness tests. Brale indenters are used in Rockwell hardness tests.

Ceramics

A hard, brittle material that can withstand high temperatures and resist corrosion. Ceramics include traditional materials such as brick and clay as well as advanced ceramics used in abrasives and cutting tools.

Electromagnets

A magnet formed from electric current. An electromagnet is typically formed by wrapping a current-carrying coil around an iron core.

Electromagnet

A magnet formed from electric current. An electromagnet is typically formed by wrapping wire around an iron core and electrically charging it.

Iron

A malleable, silver-gray metal that is highly magnetic. Iron is alloyed with carbon to make steel.

Allotropic

The ability of a material to exist in more than one crystal structure. Temperature determines whether iron has a body-centered cubic (BCC) or face-centered cubit (FCC) structure.

Stiffness

The ability of a material to resist bending or stretching. Stiffness is sometimes called rigidity.

Corrosion Resistance

The ability of a material to resist deterioration and chemical breakdown due to surface exposure in a particular environment. Chromium increases the corrosion resistance of ferrous metals.

Shear Strength

The ability of a material to resist forces that attempt to cause the internal structure to slide against itself and separate. Shear strength is the amount of shear force a material can withstand before fracturing.

Hardenability

The ability of a metal to be hardened by heat treatments or other processes. Steels have varying degrees of hardenability, depending on their alloying elements.

Compressive Strength

The ability of a metal to resist forces that attempt to squeeze or crush it. Cast irons have good compressive strength.

Durability

The ability of materials to withstand extended exposure to environmental wear and mechanical forces. Ceramics tend to have good durability.

Viscoelasticity

The ability to be both elastic and viscous when undergoing deformation. Viscoelasticity allows some plastics to be recycled and reshaped.

Damping

The ability to resist deformation through vibration. Damping capabilities in plastics are higher than the damping capabilities of metals.

Specific Heat

The amount of heat that is required to raise the temperature of a specific amount of material by one degree. Every material has its own unique specific heat.

Density

The amount of mass within a specific volume of a substance. Objects with greater density increase in mass and weight.

Mass

The amount of matter in an object. Mass gives an object weight when it is acted upon by gravity.

Coefficient Of Thermal Expansion

The degree to which a material increases in size as temperatures increase. Plastic has a low coefficient of thermal expansion.

Inspection

The examination of a part to determine if it conforms to specifications. Inspection traditionally follows the completion of a part or the components that compose a part.

Minor Load

The first and lightest load applied to a material during a hardness test. The force of the minor load varies, depending on the hardness test.

Load

The force applied to an object by another object. Prolonged or heavy loads can cause deformation.

Yield Strength

The maximum amount of stress a material can withstand before being permanently deformed. Yield strength is sometimes called a material's elastic limit.

Elastic Limit

The maximum stress a material can withstand before being plastically deformed. Elastic limit is also called yield strength.

Ductility

The measure of a material's ability to be drawn, stretched, or formed without fracturing. Ductility usually decreases when more carbon is added to a ferrous metal.

Solubility

The measure of a material's ability to dissolve in a solvent. The solubility of plastic depends on its molecular structure.

Impact Strength

The measure of material's ability to absorb energy from a sudden, sharp blow without fracturing. Impact strength is also known as impact toughness.

Impact Toughness

The measure of material's ability to absorb energy from a sudden, sharp blow without fracturing. Impact toughness is also known as impact strength.

Atoms

The smallest unit of an element. An atom consists of electrons orbiting around a center nucleus of protons and neutrons.

Atom

The smallest unit of an element. It consists of protons and neutrons in a center nucleus and orbiting electrons.

High-Carbon Steel

A carbon steel that contains more than 0.6% carbon. High-carbon steels are extremely strong and hard.

Superficial Rockwell Hardness Test

A Rockwell test designed for thin test materials. The Superficial Rockwell test is identical to the Rockwell test, except that minor load is 3 kilograms and the major load is either 15, 30, or 45 kilograms.

Vickers Microhardness Test

A Vickers hardness test used to test small or thin materials. The Vickers microhardness test uses light loads between 1 gram and 2 kilograms.

Soot

A black powder that forms when wood or coal is burnt. Soot and carbon black are similar, but soot is an unwanted byproduct whereas carbon black is produced in a controlled environment.

Medium-Carbon Steel

A carbon steel that contains between 0.3% and 0.6% carbon. Medium-carbon steels are strong, hard, and not as easily welded as low-carbon steels.

Low-Carbon Steel

A carbon steel that contains less than 0.3% carbon. Low-carbon steels are generally tough, ductile, and easily welded.

Hydrogen

A colorless, odorless gas that is the most abundant element on the planet. Hydrogen molecules bond to carbon molecules to form polyethylene.

Bainite

A combination of ferrite and cementite that is harder than pearlite. Bainite contains needlelike grain structures, and it requires an initial rapid cooling followed by gradual cooling.

Pearlite

A combination of ferrite and cementite. Steel with exactly 0.8% carbon consists of uniform pearlite at room temperature.

Carbon

A common, non-metallic element. Carbon molecules bond with hydrogen molecules to form polyethylene.

Shaping Die

A component of an extrusion machine that cuts or shapes material. A shaping die is used in extrusion while a mold cavity is used in injection molding.

Reciprocating Screw

A component of an injection molding machine that melts the resin and builds up pressure. Reciprocating screws inject melted resin into a mold cavity.

Carbide

A compound developed by the combination of carbon with other elements such as chromium, tungsten, or titanium. Carbide is often used to make metal cutting tools due to its hardness and wear resistance.

Cemented Carbide

A compound developed by the combination of carbon with tungsten, titanium, tantalum, or other materials. Cemented carbide is used in hardness testing indenters and metal cutting tools due to its hardness and wear resistance.

Cementite

A compound of iron and carbon that is very hard and brittle. The presence of cementite hardens steel.

Tungsten Carbide

A compound of tungsten and carbon that appears as very hard particles bonded together with a cobalt binder. Tungsten carbide is used to make Brinell hardness testing indenters, which are indicated by a "W" in Brinell notation.

Coolants

A cutting fluid used to decrease the temperature of the tool and workpiece during machining. Metal cutting operations use coolants to counteract the high temperatures created during cutting.

Magnetic Fields

A detected force that exists around a magnet or electrical field. Magnetic forces work within a magnetic field.

Indicator

A device that displays a measurement. An indicator may be a dial with a needle or a digital readout.

Time-Temperature-Transformation Diagram

A diagram that illustrates phase changes that take place in metal due to time and temperature. Time-temperature-transformation diagrams are also called isothermal transformation diagrams.

Steel

A ferrous metal consisting of iron and carbon, usually with small amounts of manganese, phosphorus, sulfur, and silicon. Steel is the most common manufacturing metal.

Steels

A ferrous metal consisting of iron and carbon, usually with small amounts of manganese, phosphorus, sulfur, and silicon. Steels are popular, inexpensive commercial metals.

Coating

A finish used for protective and decorative purposes in manufacturing. Coatings can include different plastics because of their low thermal and electrical conductivity properties.

Shear Stress

A force that attempts to cause the internal structure of a material to slide against itself. Shear strength is a material's ability to resist shear stress.

Mechanical Force

A force that attempts to deform a material. A mechanical force may attempt to stretch, compress, bend, dent, scratch, or break a material.

Stress

A force that attempts to deform an object. Common forms of stress include compression, shear, and tensile.

Compressive Stress

A force that attempts to flatten or squeeze a material. Compression strength is the ability to resist compressive stress.

Tensile Stress

A force that attempts to pull apart or stretch a material. Tensile strength is a material's ability to resist tensile stress.

Petroleum

A fossil fuel that provides the raw base for many plastics through a chemical reaction called polymerization. Petroleum-based polyethylene is one of the most popular plastics.

Rhombus

A four-sided shape with opposite equal sides. A rhombus often resembles a diamond.

Stress-Strain Graph

A graph that depicts the relationship between stress and strain and marks the elastic and plastic regions for a given material. Stress-strain graphs are also called stress-strain curves.

Thermoplastic

A group of plastics that can be repeatedly heated, shaped, and cooled. Thermoplastic molecules are not cross-linked.

Thermoset

A group of plastics that is permanently hardened by heating. Thermosets, also known as thermosetting plastics, have covalent bonds and cross-linked molecule chains.

Thermosetting Plastics

A group of plastics that is permanently hardened by heating. Thermosetting plastics, also known as thermosets, have covalent bonds and cross-linked molecule chains.

Soldering Alloy

A metal alloy that melts at relatively low temperatures and is used to join metal parts. Tin is commonly used as a soldering alloy.

Ceramic

A hard, brittle material that can withstand high temperatures and resist corrosion. Ceramics include traditional materials such as brick and clay, as well as advanced ceramics used as abrasives, cutting tools, and electrical components.

Shore Hardness Test

A hardness test designed for elastic materials. The Shore tester is called a durometer.

Vickers Hardness Test

A hardness test that forces a pyramid-shaped diamond against a material for a standard dwell time to create an indentation. The Vickers hardness test is also known as the diamond pyramid hardness test.

Diamond Pyramid Hardness Test

A hardness test that forces a pyramid-shaped diamond against a material for a standard dwell time to create an indentation. The diamond pyramid hardness test is also known as the Vickers hardness test.

Rockwell Hardness Test

A hardness test that measures the degree of penetration into a material caused by a brale or ball indenter that is applied under a fixed load. Rockwell hardness testing applies two static loads to the material.

Brinell Hardness Test

A hardness test that measures the diameter of a circle formed by the penetration of a 10 mm steel ball under a fixed load pressure. Brinell hardness tests are often used for forged parts and castings.

Normalizing

A heat treatment in which the metal is heated to above the upper critical temperature, held for a period, and then cooled in still air. Normalizing produces a uniform rnicrostructure and relieves stress.

Macromolecules

A large molecule that consists of repeating molecular units. Polymers consist of long chains of multiple macromolecules.

Fiberglass

A lightweight and strong material composed of fine glass fibers. Fiberglass is used as a reinforcement in many composites.

Dyes

A liquid coloring agent that is mixed with resin. Dyes are an additive used to color a plastic throughout.

Alloy

A metal consisting of a mix of two or more elements, one of which must be a metal. Steel is an alloy of carbon and iron.

Cast

A manufacturing process that pours a liquid material into a hollow mold until the material cools into a solidified shape. Casting is often used to form metals that are difficult to machine.

Composite

A material made by combining materials from two or more of the following groups: metals, plastics, and ceramics. Composites are often used to make aircraft components and athletic equipment.

Composites

A material made by combining materials from two or more of the following groups: metals, plastics, and ceramics.Composites are often used to make aircraft components and athletic equipment.

Carbon Fiber

A material made from slender, thread-like strands of carbon, a strong nonmetallic element. It is a rigid material with good tensile strength, chemical resistance, and temperature tolerance.

Abrasives

A material made of hard, sharp particles used for cutting chips from a workpiece surface. They are often used in finishing operations that clean, polish, or otherwise prepare the surface of a part.

Polymer

A material made of very large molecules. Polymers are either natural or synthetic.

Resistor

A material or device that has little electrical conductivity and high resistance to electrical charges. Most resistors are plastics and ceramics. Resistors are sometimes called insulators.

Insulators

A material or element that has little electrical conductivity and high resistance to electrical charges. Most insulators are plastics and ceramics.

Conductor

A material that allows free movement of electrons and therefore enables the easy flow of electricity. Most conductors are metals.

Solute

A material that dissolves in a chemical. When testing the chemical reactions of plastics, the plastic material is the solute.

Insulation

A material that does not conduct electricity and is used to cover electrical conductors. Types of insulation include ceramics and plastics.

Insulator

A material with low electrical conductivity and a high resistance to electrical charges. Plastic has low electrical conductivity and is used as an insulator.

Toughness

A material's ability to absorb energy without breaking or fracturing. Toughness is a key property that determines a material's ability to withstand a sudden stress.

Electrical Conductivity

A material's ability to act as a medium for conveying electricity. Electrical conductivity depends on the material's structure.

Creep Resistance

A material's ability to resist distortion when under a load over an extended period of time. Creep resistance in a plastic decreases as polymer molecules uncoil.

Strength

A material's ability to resist forces that attempt to break or deform it. Strength is an important mechanical property.

Tensile Strength

A material's ability to resist forces that attempt to pull it apart or stretch it. Materials with high tensile strength tend to deform, bend, or stretch before breaking.

Hardness

A material's ability to resist indentation or scratching. An increase in hardness generally leads to a decrease in toughness, or ability to withstand fracture.

Corrosion Resistant

A material's ability to resist the gradual degradation caused by the atmosphere, moisture, or other substances. Corrosion resistant parts function properly for a longer period of time.

Chemical Resistance

A material's ability to resist the gradual degradation caused by the atmosphere, moisture, or other substances. Several structural adhesives have strong chemical resistance.

Oxidation

A material's chemical reaction with oxygen. Oxidation can damage a plastic, but manufacturers can use additives to prevent damage.

Brittle

A material's unwillingness to be drawn, stretched, or formed. Brittle materials tend to fracture when subjected to these forces.

Elasticity

A measure of a material's ability to reshape itself after being stretched or deformed. A rubber band is an example of an object with elasticity.

Permeability

A measure of how easily moisture or gases pass through a material. Low permeability means that is difficult for liquids or gases to pass through a material.

Volume

A measurement of the amount of space contained within a three-dimensional shape. Volume is a physical property.

Ferrous Metals

A metal in which iron is the main ingredient. The main groups of ferrous metals are cast iron and steel.

Forgings

A metal part that is formed by compressing the metal at elevated temperatures. Forgings have aligned grains.

Nonferrous Metals

A metal that does not contain iron as the main ingredient. Aluminum, copper, and zinc are nonferrous metals.

Pure Metals

A metal that does not intentionally contain any other material. Pure metals are usually used as alloying elements in commercial applications.

Chromium

A metallic alloying element that increases hardenability and corrosion resistance. Chromium is often used in ferrous alloys such as stainless steel.

Molybdenum

A metallic alloying element that increases hardenability, strength, and wear resistance. Molydenum is often added to steel to improve hardenability.

Vanadium

A metallic alloying element that increases strength and creep resistance. Vanadium is often added to ferrous alloys to facilitate the development of carbides.

Manganese

A metallic alloying element that increases strength, hardness, and hardenability. Manganese is often added to steel to improve hardenability.

Nickel

A metallic alloying element that increases strength, impact resistance, and corrosion resistance. Nickel is often added to steel to improve hardenability.

Knoop Hardness Test

A microhardness test that uses a small pyramid-shaped diamond indenter and relatively light loads between 10 grams and 1 kilogram. The Knoop indenter has a long diagonal that is perpendicular to and 7 times the length of the short diagonal.

Ultrasonic Microhardness Test

A microhardness test that vibrates a Vickers diamond against a workpiece under a specific load. In ultrasonic microhardness testing, the change in frequency determines the material's hardness value.

Ultrasonic Microhardness Test

A microhardness test that vibrates a Vickers diamond against a workpiece under a specific load. In ultrasonic microhardness tests, the change in frequency determines the material's hardness value.

Latex

A milky resin produced in plants that is the main source of natural rubber. Latex rubber is treated with heat and chemicals in order to be used commercially.

Brine

A mixture of water and salt. Brine cools metal faster than other quenching mediums.

Free-Machining Steels

A particular grade of steel that has small amounts of additional alloying elements to improve machinability. 11xx and 12xx grades are free machining steels.

Elastic Recovery

A period of slight rebound in a material after a load has been removed. During a hardness test, some materials experience elastic recovery and begin to return to their original shape after the major load is released.

Plastic Penetration

A permanent penetration of a material. If a material is penetrated beyond its elasticity, the material experiences plastic penetration.

Thermal Conductivity

A physical property that indicates how well heat energy transfers through a material. Materials with low thermal conductivity make good heat insulators.

Resulfurized And Rephosphorized Steels

A plain carbon steel that contains added sulfur and phosphorus for improved machinability.

Resulfurized Steels

A plain carbon steel that contains added sulfur for improved machinability.

Medium-Carbon Steels

A plain carbon steel that contains between 0.3% and 0.6% carbon. Medium-carbon steels are strong, hard, and not as easily welded as low-carbon steels.

Low-Carbon Steels

A plain carbon steel that contains less than 0.3% carbon. Low-carbon steels are generally tough, ductile, and easily welded.

High-Carbon Steels

A plain carbon steel that contains more than 0.6% carbon. High-carbon steels are extremely strong and hard.

Extrusion

A plastic molding process in which melted resin is pushed out of the machine into a shaping die. Extrusion is a continuous process that creates parts with a uniform cross section.

Molding

A plastic shaping process in which molten plastic is forced into a mold to form a shape and then released once it cools and solidifies. Molding involves higher pressure, whereas casting does not.

Rotational Molding

A plastic shaping process in which resin is heated, rather than melted, inside a rotating mold. Rotational molding is a no-pressure process that creates hollow parts.

Polyester

A plastic that can be manufactured as a foam or as a solid. Polyurethane can be used as a coating, in paints and varnishes, or in solid parts such as PPE equipment.

Polyurethanes

A plastic that can be manufactured as a foam or as a solid. Polyurethane can be used as a coating, in paints and varnishes, or in solid parts such as medical implants.

Plastic

A polymer material characterized by lightweight, high corrosion resistance, high strength-to-weight ratios, and low melting points. Most plastics are easily shaped and formed.

Plastics

A polymer material characterized by lightweight, high corrosion resistance, high strength-to-weight ratios, and low melting points. Most plastics are easily shaped and formed.

Semicrystalline Regions

A polymer molecule formation in thermoplastics in which the molecules follow an ordered and structured pattern as they cool. Semicrystalline thermoplastics have a higher melting point.

Amorphous Regions

A polymer molecule formation in thermoplastics that lacks a definite repeating structure. Amorphous thermoplastic materials form clear plastic parts.

Synthetic Polymer

A polymer that is chemically manufactured from separate materials. Some synthetic polymers can be used as quenching mediums.

Synthetic Polymers

A polymer that is chemically manufactured. Synthetic polymers include many different types of plastic.

Natural Polymers

A polymer that occurs in nature. Natural, or organic, polymers are not synthesized by humans.

Scleroscope Test

A portable hardness test that measures the rebound of a hammer dropped from a fixed height. In scleroscope tests, higher rebounds equal higher hardness values.

Leeb Hardness Test

A portable hardness test that measures the rebound of a hammer mechanism. The Leeb hardness test can be administered from any angle regardless of gravity.

Phases

A portion of material with a uniform crystal structure, consistent properties, and recognizable boundaries. At room temperature, steel consists of two or more phases.

Protons

A positively charged particle within an atom. Protons are located in the nucleus of an atom.

Proton

A positively charged particle within the nucleus of an atom.

Pigments

A powder coloring agent mixed with resin. Pigments are an additive used to color the surface of a plastic product.

Deoxidation

A process that removes or reduces the oxygen in molten steel. Deoxidation prevents the metal from oxidizing as it solidifies.

Chromium Oxide

A protective film that develops on the surface of stainless steel. Chromium oxide helps to prevent corrosion.

Solubility Rating

A rating system that gauges a material's likelihood of dissolving in a solvent. A low solubility rating is assigned to plastic that is not likely to dissolve in a solvent.

Feedstock Material

A raw material used in additive manufacturing. Feedstock material for many 3D printing applications includes polymers.

Resin

A raw polymer, usually in the form of beads or pellets, that is not yet molded into its final shape. Resin is melted to form plastic parts.

Foam Molding

A shaping process that involves pouring foamed plastic into a mold. Foam molding is a low-pressure molding process.

Mer Units

A single unit of atoms that chemically bonds to other similar units to form long, repeating polymer molecule chains. Mer units are also called monomers.

Monomers

A single unit of atoms that chemically bonds to other similar units to form long, repeating polymer molecule chains. Monomers are also called mer units.

Hammer

A small metal or diamond-tipped component used in rebound hardness testers. Hammers are found in scleroscope and Leeb equipment.

Graphite

A soft, black form of carbon. Excess carbon appears as flakes or spheres in cast irons and helps to dampen vibrations and improve machinability.

AISI-SAE Designations

A steel classification system developed by the American Iron and Steel Institute (AISI) and the Society of Automotive Engineers (SAE). AISI-SAE designations are usually four-digit numbers based on a steel's contents.

Martensite

A steel that consists of a distorted, body-centered tetragonal crystal structure. Martensite is very hard and brittle.

Alloy Steel

A steel that contains intentionally added materials that change the property of the metal. Common alloying elements include manganese, molybdenum, and nickel.

I-Beams

A structural support with a cross section resembling an 'I.' I-beams are usually made of steel.

Insoluble

A substance that cannot be dissolved. Insoluble plastics can be a result of increased cross-link density.

Foaming Agents

A substance that generates gases to produce foam. Foaming agents used in foam molding are added before the resin is molded.

Additives

A substance that is added to a material during manufacturing in order to improve its properties. Additives perform a range of functions, from changing the color of plastic to improving its strength.

Adhesive

A substance used to join two or more materials. Adhesives include phenolic resins due to the water-resistant properties of phenolics.

Elastic Deformation

A temporary change in the shape of an object or material due to the application of force or stress. When a material experiences elastic deformation, it returns to its original shape once the stress is removed.

Elastic Penetration

A temporary penetration of a material. When a material experiences elastic penetration, it will eventually return to its original shape.

Tensile Test

A test that evaluates a material's tensile strength by stretching a specimen until it breaks. Tensile testing is sometimes called tension testing.

Tension Test

A test that evaluates a material's tensile strength by stretching a specimen until it breaks. Tension testing is sometimes called tensile testing.

Polyethylene

A thermoplastic in the polyester family that is highly resistant to electricity and heat. Polyethylene is often used to manufacture tough plastic bags and beverage containers.

Polystyrene

A thermoplastic that is transparent and easily shaped. Polystyrene has elastic qualities.

Silicone

A thermoset that is both heat resistant and water repellant. Silicone can be a liquid, gel, rubber, or hard plastic.

Circuit Boards

A thin, insulating board that supports electronic components and chips. A circuit board base can be made from plastic.

Plywood

A thin, strong wooden board consisting of two or more layers glued and pressed together. Plywood often contains phenolic resins as an adhesive.

Stainless Steels

A type of alloy steel that contains a large percentage of chromium. Stainless steel exhibits excellent corrosion resistance.

Stainless Steel

A type of alloy steel that contains a large percentage of chromium. Stainless steels exhibit excellent corrosion resistance and high strength.

Indention Hardness Testing

A type of hardness test in which a hardened indenter is forced against a material under a fixed load. In indention hardness testing, the size of the indentation indicates the hardness of the material.

Rebound Hardness Testing

A type of hardness test that measures rebound of a mechanism dropped onto a test material. Leeb and scleroscope tests are examples of rebound hardness tests.

Elastomers

A type of plastic with slightly cross-linked molecules that can stretch and then return to its original shape once the stretching force is removed. Elastomers will eventually lose some elastic properties after repeated stretching.

Covalent Bonds

A type of primary bond formed between atoms that holds polymer molecules together. Covalent bonds hold thermoset molecules together.

Torsion Stress

A type of shear stress that attempts to twist a material against itself. Torsion strength is the ability to resist torsion stress.

Modulus Of Elasticity

A variable that describes the relationship of stress to strain within a material's elastic region. On a stress-strain graph, the modulus of elasticity depicts a material's tendency for temporary deformation.

Chemical Reaction Tank

A vessel designed to contain chemicals. Chemical reaction tanks require an inert material, such as polyethylene, in which to store chemicals.

Hygroscopic

Able to effectively absorb moisture from the air. Hygroscopic plastics are often used in plastic wrap.

Calibrated

Adjusting a measuring instrument against a standard to ensure its accuracy. Hardness testers must be calibrated using a calibration block with a known value.

Heat Treated

Altering a material by heating and cooling in a way that will produce desired properties. Metals are heat treated using the processes like annealing, quenching, and tempering.

Polishing

An abrasive finishing process used to improve the surface of a part. Polishing results in a smooth, shiny surface.

Coloring Agents

An additive that can be used to help a plastic absorb ultraviolet light or change the color of a plastic part. Coloring agents include dyes and pigments.

Flame Retardants

An additive that helps a material to resist igniting when exposed to a flame or elevated temperatures. Flame retardants are often added to polyurethane foam.

Stabilizers

An additive that helps prevent a plastic from breaking down when exposed to adverse environments. Stabilizers protect a plastic from ultraviolet radiation by absorbing ultraviolet rays.

Antioxidants

An additive that prevents oxidation from damaging a plastic. Antioxidants can extend the life of a manufactured plastic part.

Grains

An arrangement of atoms that creates a uniform, repeating structure. Grains are individual crystals in a metal.

Synthetic

An artificial or human-made material that does not occur in nature. Plastic and nylon are examples of synthetic materials.

Neutrons

An atomic particle with no charge. Neutrons are located in the nucleus of an atom.

Superalloys

An expensive metal alloy consisting of numerous alloying elements. Superalloys, or high-performance alloys, are designed to perform under intense conditions.

High-Performance Alloy

An expensive, complex metal alloy designed to perform under intense conditions, such as elevated temperatures. High-performance alloys are also known as superalloys.

Superalloy

An expensive, complex metal alloy designed to perform under intense conditions, such as elevated temperatures. Superalloys are also known as high performance alloys.

Static Loads

An external force that is applied and held in a fixed position for a specific amount of time. Static loads are an important component of standardized hardness tests.

Charpy Test

An impact test that measures the amount of energy a material can absorb. During a Charpy test, a notched sample is supported on both ends and broken by a falling pendulum.

Izod Test

An impact test that measures the amount of energy a material can absorb. During an Izod test, a notched sample is supported on one end and broken by a swinging pendulum.

Fillers

An inert particle added to plastic resin to take up space and lower costs. Fillers do not add significant amounts of strength to a material.

Dwell Time

An intentional time delay during a hardness test in which an indenter is held against a material under load. Dwell time is used to ensure accurate hardness ratings.

Cast Irons

An iron alloy usually containing more than 2% carbon, along with silicon and sulfur. Cast iron products are formed using molds and casting processes.

Alloying Elements

Chemical elements that are added to a metal to modify its properties. Alloying elements, like manganese, chromium, molybdenum, and nickel, are commonly added to steel.

Abrasion

Damage from repeated rubbing or scraping that is concentrated in the same place. Abrasion-resistant plastics include hard thermosets, such as phenolics.

Thermal Stress

Damage to a material due to excessive or abrupt changes in temperature. Coolants can decrease the thermal stress on cutting tools.

Thermal Degradation

Deterioration of a material due to overexposure to heat or sun. Thermal degradation is usually associated with plastics and can be caused by ultraviolet radiation.

Ultraviolet Degradation

Deterioration of a plastic material due to overexposure to the ultraviolet radiation in sunlight.

Pole

Either of two oppositely charged ends of a magnet field. Poles are either negative or positive.

Face-Centered Cubic

FCC. The crystal structure that contains one atom in the center of the six sides of a cube and one atom in each corner of the cube. Face-centered cubic metals are often ductile.

Fiberglass-Reinforced Plastic

FRP. A composite made from thermoset polyester resin and fiberglass particles. Fiberglass-reinforced plastic cannot be re-formed once it has hardened, due to the cross-linking that occurs during curing.

FCC

Face-centered cubic. The crystal structure that contains one atom in the center of the six sides of a cube and one atom in each corner of the cube. FCC metals are often ductile.

Forging

Forming a metal by compressing it at elevated temperatures. Forged parts are very strong due to their compressed grain structure.

Amber

Fossilized plant resin that forms over millions of years and involves a complex oxidation and polymerization process. Amber is used in varnishes, jewelry, and other ornamental items.

Hexagonal Close-Packed

HCP. The crystal structure that contains a collection of atoms that are closely packed into the shape of a hexagon. Hexagonal close-packed metals are often brittle.

High-Density Polyethylene

HDPE. A common thermoplastic known for its high strength-to-density ratio. High-density polyethylene has a higher chemical resistance than low-density polyethylene.

High-Strength Low-Alloy Steels

HSLA. A type of steel that contains low levels of carbon and alloying elements. High-strength low-alloy steel exhibits good strength and is relatively inexpensive.

Microindentation Testing

Hardness testing designed to test thin or brittle test materials. Microindentation tests, or microhardness tests, usually involve loads less than 1 kilogram.

Macrohardness Tests

Hardness testing of normal-sized materials with standard loads, indenters, and dwell times. Macrohardness tests usually involve loads greater than 1 kilogram.

Microhardness Testing

Hardness testing that is designed to test thin or brittle test materials. Microhardness tests, or microindentation tests, usually involve loads less than 1 kilogram.

Microhardness Tests

Hardness tests that are designed to test thin or brittle test materials. Microhardness tests, also known as microindentation testing, usually involve loads less than 1 kilogram (kg).

Viscoelastic

Having both elastic and viscous properties. Viscoelastic materials have the ability to return to their original shape after undergoing stress, but they will lose shape over time.

Transparent

Having the ability to allow light to pass through. Transparent plastics, such as polystyrene, are useful in eyeglass lenses or food packaging.

Elastic

Having the ability to return to an original shape after being stretched or deformed. Most plastics exhibit elastic qualities.

Case Hardened

Heated within a carbon-rich environment to increase carbon levels on the metal surface. Case hardening creates a hardened exterior shell.

HCP

Hexagonal close-packed. The crystal structure that contains a collection of atoms that are closely packed into the shape of a hexagon. HCP metals are often brittle.

HSLA

High-strength low-alloy steel. A type of steel that contains low levels of carbon and alloying elements. HSLA steel exhibits good strength and is relatively inexpensive.

Vulcanized

Increasing the number of cross-linked bonds in an elastomer by using additives, chemicals, heat, and pressure. Vulcanization adds strength and toughness to an elastomer.

Low-Density Polyethylene

LDPE. A translucent to opaque thermoplastic with loosely packed molecules. Low-density polyethylene is not as chemically resistant as high-density polyethylene.

MRI Scanner

Magnetic Resonance Imaging. A medical device that uses a magnetic field and radio waves to produce a detailed image of the soft tissues and bones in the body. MRI scanners typically include hard plastic casings.

Tempered Martensite

Martensite steel that has been heated and gradually cooled. Tempered martensite has better ductility and toughness than standard martensite.

Mar

Melted salt. Mar is a quenching medium that cools materials faster than air but slower than oil or water.

Polyvinyl Chloride

PVC. A thermoplastic that can be rigid or flexible. Polyvinyl chloride usage is controversial because of its potentially toxic environmental effects.

Polylactic Acid

PLA. A biodegradable thermoplastic in the polyester family. Polyactic acid is a natural polymer derived from corn starch and other renewable resources.

Forged

Shaped using force to compress and align the metal's internal structure. Forged metals are typically heated during operations.

Austenitic Stainless Steel

Stainless steel that exhibits high strength and ductility and a unique microstructure. Austenitic stainless steel is the most corrosion resistant.

Ferritic Stainless Steel

Stainless steel that has a low carbon content and a unique microstructure. Ferritic stainless steels are easy to weld but not hardenable by heat treatment.

Martensitic Stainless Steel

Stainless steel that is stronger than ferritic stainless steel, but less corrosion resistant. Martensitic stainless steels have a unique microstucture and are hardeneable by heat treatment.

Alloy Steels

Steel that contains added materials that change the property of the metal. Common alloying elements include chromium, manganese, molybdenum, and nickel.

Hypoeutectoid Steel

Steel that contains less than 0.8% carbon. Hypoeutectoid steel consists of ferrite and pearlite at room temperature.

Plain Carbon Steels

Steel that contains less than 3% of elements other than iron and carbon. Plain carbon steel is considered the most "pure" form of steel.

Plain Carbon Steel

Steel that contains less than 3% of elements other than iron and carbon. Plain carbon steel is considered the most pure form of steel.

Critical Temperatures

Temperatures at which a steel changes phases. The upper critical temperature and lower critical temperature are two significant temperatures.

Weldability

The ability of a material to be welded into a suitable structure. HSLA steels exhibit good weldability.

Presser Foot

The component on the bottom of a Shore hardness tester. The indenter is located in the middle of the presser foot.

Heat Treating

The controlled heating and cooling process used to change the structure of a material and alter its physical and mechanical properties. Annealing, quenching, and tempering are heat treatments.

Weight

The degree of heaviness of an object that results from gravity. Weight is a physical property.

Surface Finishes

The degree of roughness and variation on the surface of a manufactured part. Surface finish affects how a plastic component will function.

Corrosion

The gradual deterioration of a material due to atmosphere, moisture, chemicals, or other agents. Corrosion often appears as rust.

Tempering

The heat treatment of metals to temperatures below the recrystallization phase, followed by gradual cooling. Tempering can increase a material's hardness.

Soaking

The heating of a metal at a constant temperature for an extended duration of time. Soaking is part of annealing processes.

Self-Extinguishing

The inability to support flame after the source of the flame is withdrawn. Self-extinguishing plastics include polyvinyl chloride.

Eutectoid Temperature

The lowest temperature at which austenite transforms into ferrite and cementite. Steel with 0.8% carbon transforms at the eutectoid temperature.

AISI-SAE

The most common classification in the United States for plain carbon steels and alloy steels. American Iron and Steel Institute (AISI) is an association responsible for setting standards and creating numbering systems for various ferrous metals, and the Society of Automotive Engineers (SAE) writes specifications and other data used in a broad range of industries.

AISI-SAE Number

The most common classification in the United States for plain carbon steels and alloy steels. American Iron and Steel Institute (AISI) is an association responsible for setting standards and creating numbering systems for various ferrous metals, and the Society of Automotive Engineers (SAE) writes specifications and other data used in a broad range of industries.

Ferrite

The phase at which solid steel has a body-centered cubic crystal structure. Ferrite steel can hold only a minimal amount of carbon, and it is relatively soft.

Austenite

The phase at which solid steel recrystallizes and has a face-centered cubic crystal structure. Austenite steel holds a greater amount of dissolved carbon and exhibits increased formability.

Properties

The physical and mechanical characteristics of a material that distinguish it from other materials. The properties of plastic can be altered with additives.

Strain

The physical deformation that occurs in an object when it is under stress. Strain can exist while the object is under stress but can also exist once the force has been removed.

Magnetism

The power of attraction and repulsion that exists in materials. Magnetism most often occurs between metals.

Shaping

The process of forming plastic resin. Shaping processes include injection molding and extrusion.

Cure

The process of using thermal energy or ultraviolet radiation to harden a polymer material so that it can be manufactured. Curing a thermoset creates a chemical reaction that permanently cross-links the molecules.

Speeds

The rate at which a cutting edge of the tool moves past the workpiece surface at the point of contact. Speed measures the rate of a rotational movement.

Feeds

The rate that the cutting tool travels along the surface of the workpiece. Feeds often involve linear movement from one point to another.

Crystal Structures

The regular, repeating pattern of atoms in a material. Crystal structures in a metal develop as the metal drops below the recrystallization temperature and solidifies.

Major Load

The second and heaviest static load applied during a hardness test. The force of the major load varies, depending on the hardness test.

Precipitation

The separation of a substance that was previously dissolved in another substance. Carbon appears as a precipitation of cementite in steels with over 0.02 percent carbon.

Microstructures

The shape and alignment of the microscopic components of a material. Microstructure is key in determining hardness, toughness, and other properties.

Microstructure

The shape and alignment of the microscopic components of a metal. Microstructure is key in determining hardness, toughness, and other properties.

Hot Working

The shaping of metal at temperatures above its recrystallization phase. Hot working typically leaves a tough, scaly surface on the metal.

Modulus

The slope of a stress-strain curve. The shape of the modulus indicates the stiffness or elasticity of a material.

Quenching

The soaking of a metal at a high temperature above the recrystallization phase, followed by rapid cooling. Water, saltwater, air, and oil are common quenching mediums.

Inert

The state of being non-reactive. Inert fillers are often added to plastics to take up space and save cost without affecting material properties.

Annealing

The steady heating of a metal above the recrystallization phase, followed by gradual cooling. Annealing can reduce hardness, improve machinablitiy, and facilitate cold working.

Quenching Mediums

The substance used to cool a metal during quenching. Water, saltwater, air, synthetic polymers, and oil are common quenching mediums.

Upper Critical Temperature

The temperature above which steel consists entirely of austenite. The upper critical temperature varies based on the steel's carbon content.

Melting Point

The temperature at which a material changes from a solid to a liquid. Melting point can be very low, like in some polymers, or very high, like in ceramics.

Lower Critical Temperature

The temperature at which austenite begins to form in a steel. The lower critical temperature is 1330°F (721°C).

Recrystallization Temperature

The temperature at which new grains are formed in a metal. Every metal has a specific recrystallization temperature.

Thermal Expansion

The tendency of a material to increase in size as it increases in temperature. Every material has its own rate of thermal expansion when subjected to increases in temperature.

Durometer

The testing instrument used in a Shore hardness test. A durometer has a needle and a spring on one end that presses into the plastic to measure hardness levels.

Dielectric Strength

The voltage at which the insulating qualities of a material break down. Ceramics and plastics have a high dielectric strength.

3D Printing

Three-dimensional printing. A process for making a physical object from a digital model by laying down many layers of material. 3D printers often use plastic resin as the raw material.

Deform

To change or distort an object's shape. Deformed objects have permanently lost their original shape.

Molecule

Two or more atoms jointed together by chemical bonds. A molecule is the smallest unit into which a material can be divided without changing its properties.

Molecules

Two or more atoms jointed together by chemical bonds. A molecule is the smallest unit into which a material can be divided without changing its properties.

Unified Numbering System

UNS. A common classification system that is used for both ferrous and nonferrous metals. UNS identifications include a prefix followed by five digits.

Ultraviolet Rays

UV rays. Potentially harmful wavelengths from the sun that are invisible to the naked eye. Ultraviolet rays can damage a plastic at the molecular level.

Rigid

Unable to bend or resistant to bending. Rigid plastics can include polystyrene or polyvinyl chloride, depending on how they are manufactured.

Opaque

Unable to transmit or reflect light. Opaque materials are not transparent.

Impact Tests

Used to measure a material's ability to absorb the energy of a sudden impact without breaking. Impact tests measure the toughness levels of a plastic.

Grinding

Using an abrasive to remove material from the surface of a part. Grinding is usually performed using abrasive wheels.

Creep Rupture

When an object breaks or permanently deforms after supporting a load over time. Creep rupture can occur when the molecules in a plastic begin to uncoil.

Wood Flour

Wood that has been finely ground to have the consistency of powder. Wood flour is an inert filler in many plastics.