Grinding Nonferrous Materials 321

abrasive

A material consisting of hard particles used to wear away or remove workpiece material. Abrasives are bonded in the shape of a wheel for grinding operations.

adhesives

A nonmetallic substance used to join two or more materials. Adhesives have a wide range of properties.

aerospace

The industry that covers machines or vehicles of flight. Aerospace manufacturers generally require highly specialized parts made with very high precision.

aging

Heating a workpiece to a certain temperature to cause a change in its grain structure. Aged metals have increased hardness.

alloying elements

A substance that is intentionally added to a metal in order to change its properties. Alloying elements are usually added to a base metal in very small amounts.

alloys

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

aluminum

A nonferrous, silvery, lightweight, soft, very ductile metal. Aluminum is very difficult to grind.

aluminum oxide

A compound made from bauxite and other additives that is commonly used as an abrasive material. Aluminum oxide is also referred to as alumina.

arc of cut

The area of contact between the grinding wheel and the workpiece. Arc of cut is also called the cutting zone.

automotive

The industry that manufactures cars and other motor vehicles. The automotive industry utilizes steel amongst many more specialized materials.

binder

A material acting as the medium that holds together other materials. Carbide and cermets both utilize binder materials.

black silicon carbide

A less pure form of silicon carbide. Black silicon carbide is hard but less friable than pure green silicon carbide.

brass

A nonferrous alloy of copper and zinc. Brass may also contain additional alloying elements.

brittle

The tendency to break when drawn, stretched, or formed. Brittleness typically accompanies hardness.

bronzes

Any copper-based alloy that does not use zinc or nickel as the primary alloying element. Bronzes are commonly alloys of copper and tin.

carbide

A common cutting tool material made by sintering a mixture of metals with a cobalt binder. Carbide creates a toxic dust when machined or ground.

carbon dioxide

A colorless, odorless, inert gas used for extinguishing fires. Carbon dioxide works by reducing the amount of oxygen or fuel vapor in fire.

cemented carbide

A common cutting tool material made by sintering a mixture of metals with a cobalt binder. Cemented carbide is also known simply as carbide.

ceramic

A very hard, brittle material that contains metallic and nonmetallic elements. Ceramics are often used as cutting tools and electrical insulators.

ceramic aluminum oxide

An exceptionally hard, strong, sharp abrasive made from a process in which alumina gel is dried and crushed. Ceramic aluminum oxide has the ability to fracture easily at a high rate.

ceramics

A hard, brittle material that can withstand high temperatures. Ceramics are used to make cutting tools and abrasive materials.

cermet

A very hard, brittle composite material containing ceramic and metal. Cermets are often used in cutting tools.

chemical reactivity

A material's tendency to change due to exposure to other substances. Chemical reactivity may cause an energy release or degradation of the material.

chemically react

To undergo a change due to contact with another substance. During a chemical reaction, the physical structure of a substance will alter in some way.

chip

Pieces of metal that are removed from a workpiece when a tool cuts or grinds the metal. During grinding, small chips are formed by the grinding wheel’s abrasive grains moving through the surface of the workpiece material.

cobalt

A tough, lustrous, silver-white metallic element that is highly magnetic. Cobalt is often used as a binder material in carbide tools.

cobalt-based superalloys

A superalloy with cobalt as the base metal. Cobalt-based superalloys have very high corrosion resistance.

combustible

Any substance that is capable of igniting and burning. Combustible materials can pose a safety hazard.

composite

A material composed of two or more unlike materials that are bonded together without losing their individual properties or characteristics. The materials in composites are generally layered or suspended in one another.

compressed gases

Any gas held under pressure in a gas cylinder. Compressed gases may be used to cool dry machining and grinding operations.

compressive strength

The ability of a material to resist forces that attempt to squeeze or crush it. Compressive strength is the amount of compressive stress a material can withstand before fracturing.

conventional abrasive

The category of abrasive materials that includes the most commonly used, inexpensive abrasives. Conventional abrasives include aluminum oxide, silicon carbide, zirconia, and tungsten carbide, among others.

coolant

A substance, usually liquid, used to reduce or maintain the temperature of a part and add lubrication to any cutting or machining process. Grinding fluid is a type of coolant.

copper

A reddish metal that is very ductile, corrosion resistant, and thermally and electrically conductive. Copper is often alloyed to increase strength and hardness.

corrosion resistance

The ability of a material to resist destruction or deterioration when exposed to chemicals or elements. Stainless steels are known for corrosion resistance.

creep feed grinding

A grinding method in which the depth of cut is increased while the feed rate is decreased. Creep feed grinding is used to remove large amounts of material and produce a good surface finish with one operation.

cubic boron nitride

CBN. A cutting tool material with hardness that is second only to diamond. Cubic boron nitride tools are very effective and long-lasting, but they are also very expensive.

cupronickel

An alloy of copper and nickel. Cupronickel is similar in composition to nickel silver and copper-nickel.

cutting tool

A tool with one or more cutting edges designed to engage a workpiece and remove material in the form of chips. Cutting tools preferably exhibit excellent hardness, toughness, and wear resistance.

cutting zone

The area of contact between the grinding wheel and the workpiece. The cutting zone is also called the arc of cut.

cylindrical grinding

A common grinding process in which a cylindrical workpiece is held on one or both ends during grinding. Cylindrical grinding rotates both the workpiece and grinding wheel in order to finish a part.

deform

To change, alter, or distort the shape of a material. Deformation is a higher risk with soft, ductile, and elastic materials.

dress

To remove swarf, dull grains, and bonding material from a grinding wheel by fracturing away the wheel surface. Dressing can produce a dull or sharp wheel surface according to the desired surface finish.

ductile-mode grinding

A method of grinding ceramic materials that uses low depths of cut to encourage chips to flow rather than fracture. Ductile-mode grinding is also known as ductile-type grinding.

ductile-type grinding

A method of grinding ceramic materials that uses low depths of cut to encourage chips to flow rather than fracture. Ductile-type grinding is also known as ductile-mode grinding.

ductility

A material’s ability to be drawn, stretched, or formed without breaking. Ductility is present in the absence of brittleness.

dust collection system

A system that is installed to remove dust from the manufacturing environment. Dust collection systems generally utilize vacuum power.

elasticity

The ability of a material to return to its original shape after deformation. Elastic workpiece materials deform rather than fracture cleanly.

electrical conductivity

The ability of a material to convey electricity. Metals such as aluminum and copper have high levels of electrical conductivity.

electroplated diamond

A superabrasive with diamond particles on the wheel's periphery. Electroplated diamond wheels are extremely hard with an open structure allowing for large chip formation and good clearance of swarf.

elements

The most basic form of a substance, which cannot be further subdivided into more basic substances. Oxygen, hydrogen, and carbon are examples of elements.

feeds

The rate of movement of a workpiece, table, wheelhead, or other grinding component. Feeds often involve linear movement from one point to another and are measured in inches per minute.

ferrous

A metal containing iron, generally as a primary ingredient. Steel is a ferrous metal.

fiberglass

A material composed of glass fibers suspended in a plastic matrix. Fiberglass is used widely for its strength, light weight, and low cost.

fiber-reinforced composites

A composite made from threadlike strands of a material suspended within another material. Fiber-reinforced composites are often used in aerospace parts.

fire suppression system

An automatic system used for preventing or extinguishing fires. Fire suppression systems include sprinkler and chemical systems.

flammability

The ability or tendency to ignite and burn when exposed to an open flame. Flammability can pose a safety hazard.

fracture rate

The rate at which a material separates into two or more pieces. Fracture rate tends to be higher when working with brittle material.

fracturing

The breaking apart of abrasive grains in a grinding wheel. Fracturing occurs in proper chip formation and is part of the grinding wheel's self-sharpening process.

friability

The ability of abrasive grains to fracture and self-sharpen under stress. Abrasive grains with low friability may be too dull to grind effectively.

friction

A force that resists motion between two components that are in contact with each other. Friction creates heat.

glasses

A transparent material made from silica and other ingredients. Glass fibers are used in composites.

grains

A small, hard particle or crystal of abrasive material. Abrasive grains are bonded together to create grinding wheels and other abrasive tools.

graphite

A soft, black formation of carbon found alone and in other materials. Graphite is soft and has lubricating properties.

grinding

The use of an abrasive to remove material from the surface of a workpiece and change its shape. Grinding operations commonly use abrasive grains bonded into a wheel shape.

grinding fluid

A liquid substance used in a grinding operation to control temperatures and add lubrication. Grinding fluid is a type of coolant.

grinding variables

The measureable rates of movement of cutting tools and workpieces. Grinding variables include speeds and feeds.

halon gas

A colorless and odorless or faintly sweet-smelling, liquefied gas used for extinguishing fires. Halon works by inhibiting the chemical reaction between fuel and oxygen.

hardness

A material’s ability to resist penetration, indentation, or scratching. Hard materials tend to be brittle and resistant to wear.

homogenous

Uniform in makeup or composition. A homogenous material does not have variations.

hydrogen

The most common chemical element. Hydrogen absorbed by titanium can diffuse into the metal and potentially cause it to become brittle.

hydrogen gas

A gas that is the lightest and most abundant element in the universe. Hydrogen gas is highly combustible.

inserts

A geometrically shaped component made of hardened material that is inserted into a toolholder to provide a cutting edge. The insert offers multiple cutting edges and can be adapted and repositioned to present a new cutting edge after the prior edge is excessively worn.

internal diameter

ID. The interior surface of a spherical or cylindrical object. Internal diameter is also known as inner diameter.

iron

A naturally abundant, commonly used metal. Iron is the main ingredient in steel.

laminar composites

A composite made from layers of different materials that are bonded together. Laminar composites have diverse applications, such as in the aerospace and automotive industries.

lathe

A machine tool that is used to produce a range of cylindrical workpieces. On a basic lathe, the part is rotated in a spindle while the cutting tool is guided along its exterior diameter or into the part to create a hole located on the part's centerline.

leach

To remove or draw out elements from a substance through the flowing or movement of liquid. Coolants can leach cobalt from carbide tools.

load

To build up swarf in a grinding wheel and clog the spaces between grains. Loading limits proper chip clearance, prevents the proper application of grinding fluid, and may damage the workpiece surface.

machining

The process of removing metal to form or finish a part. Common machining processes include milling and turning.

magnesium

A strong, extremely lightweight metal that is brittle and has poor wear resistance. Magnesium alloys often contain aluminum and zinc to increase hardness.

malleability

The ability of a material to be formed or shaped through impacts or pressure. Malleable materials do not break or fracture easily.

matrix

The material component of a composite that acts as a binder for the other material. The matrix is generally a tough or ductile material.

milling

A machining operation that uses a rotating multi-point cutter to remove metal from the surface of a workpiece. Milling includes a wide range of versatile metal cutting operations.

nickel

A silvery metal that is both tough and corrosion resistant. Nickel is often added to metals as an alloying element.

nickel silver

An alloy of copper and nickel. Nickel silver is similar in composition to copper-nickel and cupronickel.

nickel-based superalloys

A superalloy with nickel as the base metal. Nickel-based superalloys are the most common type of superalloy.

nonferrous

A material that does not contain iron or consists mostly of elements other than iron. Aluminum, copper, and zinc are nonferrous metals.

particulate composites

A composite made from particles of a material suspended within another material. Particulate composites are often used in the automotive and fabrication industries.

personal protective equipment

PPE. Safety equipment worn or used by personnel to prevent injury in the workplace. Examples of personal protective equipment used commonly in grinding include respirators and safety glasses.

plastic

A varied grouping of lightweight, synthetic materials with high elasticity and corrosion resistance. Plastics are easily shaped.

plastics

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

plate

To coat a material with a thin layer of a metal or other material. Plating may be performed for corrosion resistance or surface finish.

PPE

Personal protective equipment. Safety equipment worn or used by personnel to prevent injury in the workplace. PPE used commonly in grinding protects hands, arms, and eyes.

precipitation hardening

The process of producing hardness and strength in an alloy through a series of controlled heating and cooling processes. The precipitation hardening process includes solution heat treating, quenching, aging, and cooling.

properties

A measurable quality or attribute of a specific material. Properties include aspects such as hardness, toughness, and ductility.

rigid

The condition of a workpiece, machine, or machine setup characterized as stiff and immovable. Rigid components are fixed securely in place.

rubber

An elastic material made from the latex sap of the rubber tree. Rubber has high toughness.

semiductile grinding

A method of grinding ceramics that utilizes the transition phase between chips flowing and fracturing from the workpiece. Semiductile grinding is a relatively new and advanced grinding method.

SiAlON

The trade name for Silicon Aluminum Oxynitride, a chemical compound of silicon, aluminum, oxygen, and nitrogen. SiAlON is a specialized ceramic abrasive material.

silicon

A metallic nonmetal element found in many materials. Silicon is found in cast irons and ceramics.

silicon carbide

A mixture that is heated, crystallized, then crushed and used as an abrasive material. Silicon carbide grinding wheels are hard and sharp, and the grains break away easily.

sintering

Creating a solid metallic material by pressing powders into a desired shape, then heating them. Sintered materials are very uniform in composition.

soft

Less able to resist forces that would break, penetrate, or scratch a material’s surface. Soft materials are characterized by their lack of hardness.

solid lubricant

A nonliquid material that may be applied to a workpiece surface, suspended in grinding fluid, or added to a wheel to reduce friction. Graphite is a common solid lubricant.

speeds

The rate of rotational movement of the grinding wheel, rotary table, or regulating wheel. Speeds are measured in revolutions per minute or surface feet per minute.

steel

A metal containing primarily iron and carbon, alloyed with small amounts of elements such as manganese, phosphorous, sulfur, and silicon. Steels are the most common manufacturing metals.

strength

A material’s ability to resist breaking or deformation due to outside forces. Strength is a material property.

superabrasives

A group of highly effective abrasive materials possessing superior hardness and abrasion resistance. Superabrasives include cubic boron nitride (CBN) and diamond.

superalloys

A specialized metal alloy that is designed to exhibit properties such as high strength under extreme temperatures and conditions. Superalloys are very expensive and have very high hardness.

surface finish

The quality of a surface after an operation. Surface finishes may be rough, smooth, or wavy, among other conditions, depending on the operation.

swarf

The gritty combination of chips, abrasive grains, and worn bonding material that is produced during grinding. Swarf can clog a grinding wheel and cause it to function improperly.

thermal conductivity

The ability of a material to convey heat. Thermal conductivity is also known as heat conductivity.

thermal resistance

A material’s ability to resist degradation when under extreme heat. Thermal resistance is also known as heat resistance.

titanium

A metal that has a high strength-to-weight ratio and corrosion resistance. Titanium is often used in aerospace and biomechanical applications.

titanium

A metal that has a high strength-to-weight ratio and corrosion resistance. Titanium is often used in aerospace applications.

tolerances

The acceptable or allowable deviation from the target dimension of a given workpiece feature. Tolerances indicate the allowable difference between a physical feature and its intended design.

toughness

The ability of a material to absorb the energy of mechanical forces acting upon it. Toughness is generally higher in softer materials.

tungsten carbide

A compound of tungsten and carbon. Tungsten carbide is the original carbide cutting tool material.

tungsten carbide

Tungsten carbide is usually a very hard and brittle material with a high resistance to wear. Tungsten carbide is a commonly used cutting tool material.

ventilation

A means of circulating clean, fresh air. Ventilation ensures that air containing potentially harmful dust or gas is removed from a space and replaced with clean air.

vitrified

A clay or ceramic bond characterized by its strength, rigidity, and resistance to oils, water, and temperature changes. Vitrified bonds have qualities similar to glass.

voids

The gap or pore between abrasive grains and posts on a bonded abrasive grinding wheel. Voids serve as small pockets of space to carry and release swarf.

wear-resistant

A metal with the ability to resist wearing away due to abrasion and friction. Wear resistance is an important property of cutting tools.

work hardening

Increasing the hardness of a metal through deformation. Work hardening may be intentional or an accidental consequence.

zinc

A bluish-white metal that is corrosion resistant and has a relatively low melting point. Zinc is often used as an alloying or coating element for other materials.

zirconium oxide

A hard, tough ceramic abrasive with good fracture resistance. ZIrconium oxide is commonly referred to as zirconia.