Computer-Numerical Control (CNC) Machining

This set covers vocabulary related to CNC machining, including turning and milling operations, programming terminology, and essential G/M codes based on the lecture by Jason Matthews.

Conventional Turning

A characteristic operation for rotational workpieces with cylindrical or disk-like shapes where a cutting tool removes material from a rotating workpiece.

Facing

An operation related to turning where the tool is fed radially into the rotating workpiece at one end to create a flat surface.

Taper Turning

An operation where the tool is fed at an angle relative to the axis of rotation of the workpiece to create a tapered cylinder.

Contour Turning

An operation where the tool follows a path that is not straight (non-parallel to the axis of rotation) to create a contoured form in the turned part.

Form Turning

Also called forming, this operation involves plunging a tool with a specific shape radially into the workpiece to impart that shape.

Chamfer

An angle cut on the corner of a cylinder, formed using the cutting edge of the tool.

Thread Cutting

An operation where a pointed tool is fed linearly parallel to the axis of rotation across the outside surface of a rotating workpiece to cut threads.

Prismatic Workpiece

A non-rotational workpiece that is block-like or plate-like, achieved by linear motions of the workpiece combined with rotating or linear tool motions.

Milling

A machining operation in which a workpiece is fed past a rotating cylindrical tool with cutting edges (teeth), where the axis of rotation is perpendicular to the direction of feed.

Peripheral Milling

Also called plain milling, this is an operation where the tool axis is parallel to the surface being machined, performed by cutting edges on the outside periphery of the cutter.

Face Milling

An operation where the axis of the cutter is perpendicular to the surface being milled, using cutting edges on both the end and outside periphery of the cutter.

Up Milling

Also called conventional milling; the direction of motion of the cutter teeth is opposite to the feed direction, effectively milling 'against the feed'.

Down Milling

Also called climb milling; the direction of the cutter motion is the same as the feed direction, effectively milling 'with the feed'.

Profile Milling

A form of end milling used to cut the outside periphery of a flat part.

Pocket Milling

A form of end milling specifically used to mill shallow pockets into flat parts.

Surface Contouring

An operation where a ball-nose cutter is fed back and forth across the work along a curvilinear path to create a three-dimensional surface form.

Programming Character

An alphanumeric character or punctuation mark used in CNC programming, such as $N$, $G$, or a semicolon ($;$).

Address

A letter that describes the meaning of the numerical value that follows it, such as $G$ in $G00$ or $X$ in $X12$.

Block

A complete line of information provided to the CNC machine, comprising a word or an arrangement of words.

Modal Command

A command that remains active until cancelled by another code, such as $G00$, $G01$, or Canned Cycles.

Non Modal Command

A command that is only active in the block in which it is issued, such as $M00$ and $M06$.

G00

A code for Rapid Traverse, used for rapid movement of the axis without cutting.

G01

A code for Linear Interpolation, representing straight line movement at a defined feed rate for cutting.

G02

A code for Circular Interpolation in a Clockwise ($CW$) direction.

G03

A code for Circular Interpolation in a Counterclockwise ($CCW$) direction.

G90

Setting for Absolute Positioning, where all coordinates are relative to the origin of the machine.

G91

Setting for Relative (Incremental) Positioning, where all coordinates are relative to the last position.

M03

A miscellaneous code to start the spindle in a forward clockwise ($CW$) direction.

M06

A miscellaneous code used to activate an automatic tool change.

M30

A code used to signify the end of the program and rewind it to the beginning.

Tool Nose Radius Compensation (TNRC)

Required for generating accurate profiles because the machine commands the Theoretical Tool Tip ($TTT$) rather than the actual curved edge of the tool.

$I$ and $K$ Addresses

Used in arc center programming; $I$ represents the relative distance from the arc start to the center along the $X$ axis, and $K$ represents the relative distance along the $Z$ axis.