ME 340: Traditional Machining Processes and Terminology

Comprehensive vocabulary flashcards covering the traditional machining concepts, tooling, cutting physics, and machinery introduced in ME 340 Module 1.

Machining

A material removal process in which a sharp cutting tool mechanically cuts away unwanted material from a workpiece through shear deformation to produce chips, exposing a new surface with high dimensional accuracy and good finish.

Workpiece (Stock)

The starting piece of raw material (such as bar stock, a casting, or a forging) that is held and cut by machine tools to produce a finished, precision-dimensioned part.

Second Operation ("Second Op")

A machining operation performed downstream of primary bulk manufacturing processes (such as casting, forging, or bar drawing) to create final dimensions, surface finishes, and intricate geometric features that initial processes cannot achieve.

Thermal Energy Distribution in Machining

The thermodynamic split of cutting energy during machining, where approximately $98\%$ of mechanical work is converted directly into heat at the tool-chip interface and the remaining approximately $2\%$ is retained as elastic strain energy within the chip.

Cutting Fluid

A coolant and lubricant (formulated as oils, oil-water emulsions, pastes, gels, or gases) applied to the cutting zone to stabilize workpiece temperature, extend tool life by minimizing tip welding, ensure operator and environmental safety, and prevent machine rust.

Thermal Expansion Inaccuracy

Dimensional distortion in a finished part caused when high cutting temperatures expand the workpiece during machining, resulting in undersized or inaccurate geometry once the material cools down.

Roughing Cut

An initial machining operation aimed at removing large quantities of material from the starting work part rapidly, characterized by high feeds, large depths of cut, and relatively low cutting speeds.

Finishing Cut

The final cut or cuts taken on a part to establish exact final dimensions, tight tolerances (such as $\pm 0.0002$), and smooth surface finish, operating at low feeds, shallow depths of cut, and high cutting speeds.

Drilling

A basic hole-making machining operation performed on a drill press where a rotating drill bit with cutting edges is fed axially into a stationary workpiece to produce a round hole.

Drill Press

A dedicated machine tool consisting of a powered rotating spindle and feed mechanism used for hole-making; manufactured either as a floor-standing upright drill press or as a smaller bench-mounted drill press.

Through Hole

A hole that penetrates through the entire thickness of the work part, exiting through the opposite side.

Blind Hole

A hole drilled to a specific, controlled depth that does not break through the opposite side of the workpiece.

Spot Drill

A short, rigid drill tool used to establish a small, precise dimple or pilot center point in a workpiece to prevent a twist drill from deflecting or wandering off-location.

Countersink

A hole-making operation and conical cutting tool used to enlarge the rim of an existing hole at an angle, allowing the head of a flat-head screw to sit flush with or below the part surface.

Counterbore

A hole-machining operation and stepped cutter that produces a flat-bottomed, cylindrical enlargement at the entrance of a hole to recess the head of a bolt or cap screw.

Reamer (Reaming)

A multi-fluted rotary cutting tool and operation used to slightly enlarge an existing hole to produce extremely accurate dimensions and a superior surface finish.

Tap (Plug Tap / Tapping)

A fluted, threaded cutting tool and operation used to cut internal screw threads into a previously drilled hole.

Milling

A versatile machining operation in which a work part is fed past a rotating cutting tool equipped with multiple cutting edges (teeth), with the axis of tool rotation oriented perpendicular to the feed direction.

Peripheral Milling

A form of milling (also known as plain or slab milling) in which the tool axis of rotation is parallel to the work surface being generated, with cutting edges located on the outer periphery of the cutter.

Face Milling

A form of milling where the tool axis of rotation is oriented perpendicular to the workpiece surface being machined, producing a broad, flat planar face using cutting edges located on both the face and periphery of the cutter.

End Mill

A multi-fluted milling tool featuring cutting teeth along both its cylindrical periphery and its end face, widely utilized for profile contours, pockets, slots, and general-purpose milling.

Face Mill

A large-diameter rotary cutting tool containing multiple indexable carbide inserts along its face and periphery, specialized for generating wide, flat planar surfaces efficiently.

Fly Cutter

A rotary vertical milling tool containing a single-point cutting tool bit mounted in a holder, designed to take wide, shallow cuts for fine surface finishing.

Ball End Mill

A milling cutter featuring a hemispherical ball nose, designed specifically for machining complex curved profiles, dies, molds, and 3D contours.

Roughing End Mill

A heavy-duty milling cutter designed with scalloped or wavy flutes along its teeth that break cut chips into smaller pieces, enabling rapid removal of large volumes of material under high loads.

Flute

The helical or straight groove and cutting edge running along the body of an end mill or drill bit that provides the cutting geometry and channels cut chips away from the cutting zone.

Conventional Milling (Up Milling)

A peripheral milling mode where the cutter teeth move against the direction of workpiece feed; chip thickness begins at zero and increases to maximum, resulting in higher friction, more heat, shorter tool life, upward lifting forces on the part, and mechanical backlash compensation.

Climb Milling (Down Milling)

A peripheral milling mode where the cutter teeth move in the same direction as workpiece feed; chip thickness begins at maximum and tapers to zero, resulting in less rubbing, lower heat generation, longer tool life, downward workpiece clamping forces, and superior surface finish.

Slot Cut

A peripheral milling operation in which an open slot, channel, or slit is machined across a work part in a single pass of the cutting tool.

Kerf

The width of the channel or slot of material removed during a single pass of a cutting tool (such as an end mill or a saw blade).

Form Milling

A peripheral milling process utilizing a specially contoured cutter whose teeth match the exact profile of the desired feature—such as gear tooth spaces, T-slots, dovetails, or V-grooves—reproducing that shape in the work part.

Turning

A fundamental machining operation where a cylindrical work part is rotated about a spindle axis while a single-point cutting tool is fed linearly parallel to the axis to reduce the external diameter.

Cutting Speed ($v$)

The primary relative surface velocity between the cutting tool and the workpiece at the cutting point, typically measured in surface distance per unit time.

Feed ($f$)

The rate at which the cutting tool advances along or into the workpiece per revolution (or per unit time) during a machining operation.

Depth of Cut ($d$)

The penetration distance of the cutting tool beneath the original surface of the work part measured radially or perpendicularly to the machined surface.

Lathe

A machine tool designed to hold and rotate a work part about its axis against various cutting tools to perform operations including turning, facing, grooving, parting, boring, and threading.

Headstock

The main stationary casting at the drive end of a lathe that houses the motor, speed-changing gears, and the main spindle that grips and rotates the workpiece.

Tailstock

The movable lathe unit located opposite the headstock along the machine bed, used to support the free end of long cylindrical workpieces or to mount non-rotating tools such as drills, reamers, and taps.

Carriage

The sliding assembly mounted on the lathe bedways that supports the cross-slide, compound rest, and tool post, transmitting feed motion to guide the cutting tool across and along the workpiece.

Boring

An internal turning operation performed on a lathe or dedicated boring machine using a single-point boring bar to enlarge, straighten, and refine the inside diameter of an existing hole.

Broaching

A high-production machining operation in which a multi-tooth cutting tool is moved linearly along its axis past or through a work part, cutting complex internal or external geometries in a single stroke.

Broach Tool Anatomy

A linear, multi-tooth tool composed of an alignment pull end, front pilot, a series of progressively rising roughing teeth with chip breakers, semi-finishing teeth, full-sized finishing teeth, and a rear pilot with follower end.

Sawing

A non-precision cutoff machining process used to slice long pieces of bar or tube stock into shorter, manageable workpieces suitable for subsequent precision machining operations.

Band Saw

A cutoff machine tool utilizing a continuous, flexible looped toothed metal band; commonly configured as a horizontal band saw (for cutoff of stock bars) or a vertical band saw (for contouring and manual cutoff).

Gear Hobbing

A specialized generating machining process in which a rotating helical multi-tooth cutter (hob) and a gear blank rotate continuously in a mechanically synchronized ratio as the cutter feeds across the gear blank face to generate involute gear teeth.