Cutting Processes 111

additive manufacturing

AM. The process of successively layering materials to make an object based on a three-dimensional computer model. Additive manufacturing allows for rapid prototyping, mass customization, and increased part complexity.

automation

The automatic control of equipment, a process, or a system. Automation is an efficient means of performing manufacturing processes.

axes

An imaginary line or circle that is used to define the position or movement of an object in space. Axes may indicate linear or rotational movement.

band saw

A saw that uses a flexible blade constructed from a continuous loop or band of metal. Band saws can be used to produce rough cuts and separate stock for additional processing.

bar stock

Raw material in the form of long bars or cylinders. Bar stock is commonly used to create cylindrical parts on a lathe.

bed

The main supporting structure or base of a machine. Beds provide a foundation for various machine tools.

beveled

Angled in comparison to the major surfaces of a part. Beveled surfaces are created during chamfering.

boring

The use of a single-point cutting tool to enlarge an existing hole. Boring can be done on either a lathe or a mill, and it helps create a hole that is concentric and that meets tight tolerances.

broaching machines

A machine that uses a multi-point cutting tool to shape either the interior or exterior surface of a workpiece. Broaching machines can complete a cut in a single cutting pass.

burrs

A sharp, unwanted bit of material remaining on an edge after machining. Burrs are injury hazards and often interfere with assembly.

cast iron

A metal that consists of iron, over 2.11% carbon, and 1 to 3% silicon and that offers heat resistance and compressive strength. Cast iron is often used as a machine base material because it dampens vibration.

centerline

An imaginary line that divides a shape into two equal halves or that runs through the center of a cylindrical object. Centerlines on lathe workpieces are generally the same as their axis of rotation.

chamfering

Machining a small angled feature along a part edge. Chamfering helps remove burrs and aids in part assembly.

chip evacuation

The proper clearance of chips during a metal-cutting process. Chip evacuation can become an issue during inner diameter operations.

chips

An unwanted piece of material that is removed from a workpiece. Chips are formed when a tool cuts or grinds a workpiece.

chuck

A device that holds a workpiece in place as it rotates on a lathe or other machine tool. Chucks commonly have three or four jaws that can be adjusted to fit various workpieces.

circular saw

A saw that cuts with a toothed disk. Circular saw blades rotate at high speed.

CNC

Computer Numerical Control. A combination of software and hardware that directs the operation of a machine. CNC machines are much more precise than their manual counterparts.

CNC lathes

A lathe that is controlled by a computer running programs driven by numerical data. CNC lathes are much more precise than their manual counterparts.

CNC mills

A milling machine that is controlled by a computer running programs driven by numerical data. CNC mills are much more precise than their manual counterparts.

column

The rigid, vertical support section of the mill. Columns suspend components and tools over the workpiece as well as support them.

composites

A material made from combining two or more materials from the separate groups of polymers, metals, and ceramics. In a composite, all the materials retain their respective properties.

computer numerical control

CNC. A combination of software and hardware that directs the operation of a machine. Computer numerical control machines are much more precise than their manual counterparts.

concentric

Two circular or cylindrical objects that share a common center or axis. Two objects that are concentric, such as a cylindrical workpiece and a hole inside that workpiece, are aligned and on-center with one another.

continuous chips

A long chip that folds in on itself rather than breaking and evacuating the workpiece. Continuous chips can pose difficulties in machining.

contour milling

Milling that requires non-linear tool movement along two or more axes at the same time to produce a curved surface feature. Contour milling creates complex shapes.

contouring

A machining operations that feeds a cutting tool along a non-liner path to create precise parts. Contouring provides finishing passes for non-linear or curved features.

cutoff

An operation performed on the lathe that uses a cutting tool to separate a finished part from the rest of the stock. A cutoff operation, sometimes called parting off, is often the last step on the lathe.

cutting edge

The leading face of a cutting tool that is in direct contact with the workpiece. Cutting edges perform the actual metal removal during a cutting operation.

cutting fluid

Any fluid used to cool, lubricate, and clear chips during metal cutting. Cutting fluid can be made of oil, water, synthetic fluids, or a combination of these.

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 ideally exhibit excellent hardness, toughness and wear resistance.

deflection

The unintended movement or repositioning of a cutting tool or component due to a mechanical force. Deflection, or walking, of a cutting tool can cause poor surface finish and inaccurate dimensions.

drill

A cutting tool with flutes and two cutting edges at its end. Drills are most frequently used to make round holes.

drill presses

A machine tool that is used for a range of holemaking operations such as drilling, reaming, and tapping. A drill press is limited to only the vertical motion of the spindle to feed the cutting tool into the workpiece.

drilling

Using a cutting tool to machine a new round hole into the surface of a workpiece. Drilling can be done on a mill, or lathe, or drill press.

end mill

A milling cutter that can be used for both peripheral and face milling. End mills engage the bottom and edges of the milling cutter.

end milling

A milling operation that uses a narrow cutter to machine surfaces both parallel and perpendicular to the spindle axis. End milling may cut with both the bottom and sides of the cutting tool.

face mill

A flat mill cutter with multiple cutting teeth on the periphery of the tool. The bottom of the face mill is the primary cutting surface during face milling operations.

face milling

A milling operation involving a relatively wide cutter that removes material from the part to produce a flat surface. Face milling is typically done to establish the part's height on the mill.

facing

A lathe cutting operation that feeds a cutting tool across an end of a cylindrical workpiece to create a flat surface and shorten its length. Facing is an outer diameter operation.

fastener

A device that holds objects together or locates them in relation to one another. Common fasteners include screws and bolts.

finish

To alter the texture or appearance of a part in order to obtain the desired tolerance and surface appearance. Finish can affect the way parts fit together.

finishing

A metal cutting process that emphasizes tight tolerances and smooth surface finish. Finishing usually takes place as a later step in the machining process.

fixture

A customized workholding device that is designed to effectively support, locate, and hold a specific workpiece design. Fixtures are often required to secure workpieces with multiple, complex dimensions.

flutes

A groove on the periphery of a cutting tool that provides room for chips to flow away from the cut. Flutes are present on cutting tools such as mills, drills, and reamers.

holemaking

A machining operation in which a cutting tool creates, sizes, or finishes a hole. Holemaking encompasses a number of operations, including drilling, boring, reaming, and tapping.

hybrid machining centers

A type of CNC machine that is capable of both additive manufacturing and traditional subtractive machining. Hybrid machining centers typically resemble the basic structure of a traditional CNC mill.

ID

Inner Diameter. The interior surface of a hole or recessed feature. ID cutting operations include drilling, boring, and tapping.

indexes

To select a tool in the tool turret or toolchanger and move it to the cutting position. Operators must index the appropriate tool when completing a cutting operation.

Industrial Internet of Things

IIoT. A network of physical devices used in manufacturing containing embedded computing systems that allow them to send and receive data. The Industrial Internet of Things allows devices to exchange data and automate processes without any human intervention.

inner diameter

ID. The interior surface of a hole or recessed feature. Inner diameter cutting operations include drilling, boring, and tapping.

insert

A replaceable cutting tool with a geometric shape that has multiple cutting surfaces and is mechanically held in a toolholder. Inserts can be indexed to present a new cutting edge.

lathe

A machine tool that is used to produce a range of cylindrical workpieces. Lathes rotate a workpiece in a spindle while the cutting tool moves along its exterior diameter or into the part to create a hole.

live tooling

Rotating cutting tools held in the turret of a lathe. Live tooling allows the lathe to perform holemaking operations away from the centerline of the part as well as other operations traditionally done on a mill.

machine tools

A power-driven machine that is used to manufacture parts by guiding a tool to shape workpieces. Machine tools include drill presses, lathes, and mills.

machining

Manufacturing a part by using a tool to remove material in the form of chips. Machining operations include milling, drilling, turning, and sawing.

machinist

A person responsible for ensuring a machine performs its job correctly, efficiently, and safely. Machinists, or operators, are responsible for interpreting manufacturing prints and implementing the design using various metal-cutting machines.

manual machines

A machine tool that a machine operator controls, rather than automated or computerized actions. Manual machines are less expensive than computer numerical control (CNC) machines but also less precise and efficient.

metals

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

mill

A machine tool that is used to produce a range of rectangular or prismatic workpieces. Mills move a rotating cutting tool along or into workpieces to remove material.

multi-axis CNC machines

A CNC machine tool that has four or more linear and rotational axes. Multi-axis machines can create more complex and precise parts than machines with fewer axes.

multi-point tooling

A cutting tool that has two or more cutting edges. Multi-point tooling operations use such tools as mills, drills, and reamers.

OD

Outer Diameter. The outer surface of a cylindrical workpiece or feature. OD cutting operations include turning, cutoff, threading, and grooving.

operator

A person responsible for ensuring a machine performs its job correctly, efficiently, and safely. Operators, or machinists, are responsible for interpreting manufacturing prints and implementing the design using various metal-cutting machines.

outer diameter

OD. The outer surface of a cylindrical workpiece or feature. Outer diameter cutting operations include turning, cutoff, threading, and grooving.

parting off

An operation performed on the lathe that uses a cutting tool to separate a finished part from the rest of the stock. A parting off operation, sometimes called cutoff, is often the last step on the lathe.

plastics

A material consisting of very large molecules, characterized by light weight, high corrosion resistance, a high strength-to-weight ratio, and a low melting point. Plastics are generally easy to shape or form.

pocket milling

The use of a milling cutter to create an interior recess in the surface of a workpiece. Pocket milling may create square, round, or rectangular pockets.

profile milling

The process of milling the overall shape or outline of a part. Profile milling often creates linear, angled, or contoured surfaces.

profiling

A machining operation that feeds a cutting tool along a non-linear path. Profiling creates complex or curved features.

ratio

The relationship between two quantities. Ratios can be expressed as a fraction or as two numbers separated by a colon.

raw material

An unprocessed material that has not yet been manufactured. All workpieces begin as raw material.

reamer

A fluted holemaking tool with straight cutting edges that is used to enlarge or smooth holes that have been previously drilled. Reamers look similar to a drill but lack a cutting point.

reaming

The use of a cutting tool with straight cutting edges to enlarge or smooth holes that have been previously drilled. Reaming can tighten the tolerance of a machined hole.

reciprocates

Moves back and forth repeatedly. To move back and forth repeatedly. Some saws reciprocate to complete cutting operations.

reciprocating saw

A saw that cuts with a stiff blade that reciprocates back and forth. Reciprocating saws are used to rough cut raw materials.

robots

A machine, often with articulated joints and gripping capabilities, that can be programmed to precisely perform a variety of complicated, repetitive tasks. Robots assist in cutting processes by completing a variety of tasks, including loading and unloading parts from the machine tool.

roughing

A cutting pass that emphasizes high material removal rates. Roughing cuts are often the first cuts made in a machining operation.

sawing

A basic metal cutting process that uses a blade with a series of teeth on its edge to cut a narrow opening in a workpiece. Sawing may be used to produce slots or grooves or to separate a workpiece into two pieces.

saws

A multi-point cutting device that is used to rough cut a workpiece to a certain length or shape. Saws come in many forms such as band saws, circular saws, and hacksaws.

sensors

A device, often within or attached to another device, that detects a physical stimulus and turns it into an electronic signal that can be measured and recorded. Sensors in smart devices make it possible for machines to communicate digitally.

single-point tooling

A cutting tool that has one cutting edge. Single-point tooling is often used in turning and boring operations.

slot milling

A milling operation that produces a narrow channel or groove in the workpiece. During slot milling, an end mill engages the workpiece on its bottom and sides.

smart manufacturing

A method of manufacturing that integrates digital technology throughout the supply chain. Smart manufacturing increases connectivity across all areas of product development.

spindle

A machine tool component that spins or rotates. On the mill, the spindle holds a cutting tool, while on the lathe, the spindle holds the workpiece.

spot drilling

The use of a shorter, sturdier drill to locate a hole for drilling. Spot drilling often uses a drill size slightly larger than the hole diameter to leave a chamfer after the hole is drilled.

surface finish

The degree of smoothness of a part’s surface after it has been manufactured. Surface finish is the result of the surface roughness, waviness, and flaws remaining on the part.

synchronized

Controlled to operate in exact unison. Synchronized movement of the turret and spindle allow lathes to complete threading operations.

table

The part of the machine that supports the workpiece and any workholding devices. Tables often move to change the position of the workpiece relative to the cutting tool.

tailstock

The component located at the end of a lathe opposite the headstock. Tailstocks support the end of longer workpieces.

tap

A cylindrical cutting tool used to produce internal threads in a pre-existing hole. A tap has thread forms on its outer surface that match the internal threads it is designed to produce.

tapering

Cutting a workpiece to form a shape with a gradually decreasing diameter, similar to the shape of a cone. Tapering can be performed on a lathe.

tapping

The process of cutting internal threads in a round hole with a specialized tool called a tap. Tapping can be performed on multiple machine tools, including mills and lathes.

tapping centers

A specialized CNC machine tool designed to complete holemaking and tapping operations. Tapping centers offer increased production speed and improved control over the holemaking process.

threading

The process of cutting a long, spiraling groove into a workpiece with a single-point tool. Threading processes are essential for the creation of fasteners.

tolerances

An unwanted but acceptable deviation from a given dimension. Tolerances indicate the allowable difference between a physical feature and its intended design.

toolchanger

A device on a machining center that arranges multiple cutting tools in order and then positions these cutting tools for replacement. Toolchangers allow many cutting tools to be used in a single operation.

toolpath

The course a tool follows as it creates a workpiece. Toolpaths are determined on CNC machines by programs that control the tool’s movement.

turning

A machining operation that rotates a cylindrical workpiece while a single-point tool is guided along the length of the part. Turning is performed on a lathe.

turret

The component of a lathe that holds a number of cutting tools. The turret rotates to place tools in the cutting position.

vise

A workholding device with two jaws that grip and hold a workpiece in place. Vises are often used to hold workpieces on a mill.

walking

The unintended movement or repositioning of a cutting tool or component due to a mechanical force. Walking, or deflection, of a cutting tool can cause poor surface finish and inaccurate dimensions.

ways

Two precisely measured, parallel tracks that support and guide the movement of a machine tool component. Lathe ways guide cutting tool movements, while mill ways guide the position of the mill table.

workholding

A device used to secure, support, and locate a workpiece during a manufacturing operation. Workholding helps to ensure that parts are created accurately and with good repeatability.

workpiece

A material that is being machined or undergoing another type of processing. Workpieces can be shaped by processes such as cutting, welding, and grinding.