CNC Dictionary

CNCCookbook Software and Information for Machinists

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CNC Dictionary

I've produced this dictionary to make it easy to understand the definitions of the various arcane terms used in CNC. Take a look at the list of tutorials at the bottom of this page as well.

2.5D to Brushless DC Motor

2.5 Axis or 2.5D CNC
3 Axis or 3D CNC
3DM (see also "Rhino")
4 Axis CNC
4th Axis
5 Axis CNC
A-Axis
ABEC
Absolute Coordinates
Absolute Move
Accuracy
Acetal
ACME Screw
Active Low/High Logic
AGC: See Automatic Grinding Center
Angular Contact Bearing
Annealing
Arbor
ASE
ATC: Automatic Tool Changer
Automatic Grinding Center
Axes
Back Driving
Back EMF or Back Electromotive Force
Backlash
Backlash Compensation
Backlash Eliminator
Ball Mill
Ballnut
Ballscrew
Ballscrew Mapping
Bar Feeder
Bar Puller (see Bar Feeder)
B-Axis
Bed Mill
Bellows
Belt Drive
Bipolar Stepper or Driver
Block
Block Delete
Box Ways
Bounding Box
Breakout Board
Bridge Rectifier
Bridgeport Taper (see "R8 Taper")
Brushless DC Motor

CAD to Cycle Stop

CAD (Computer Aided Design or Drafting)
CAM (Computer Aided Manufacturing)
Canned Cycle
Capacitor
Carbide
Carbide Inserts
Cartesian Coordinates
CAT Taper: See Taper
CAT5: See Taper
C-Axis
Center Cutting
Centerline Programming
Chain Drive
Chamfer
Charge Pump (See "Safety Charge Pump")
Chatter
Chip Auger or Chip Conveyor
Chip Breaker
Chip Load or Chipload
Chopper Supply: See PWM
Chuck
Circular Interpolation
Climb Milling
Clock Spring Cover
Closed Loop
Coarse In-Position
Cogging
Collet
Constant Surface Speed or CSS
Constant Velocity Mode
Contactor
Contouring
Contour Turning
Conventional Milling
Conversational CNC
Coolant
Coordinate Rotation
Coordinates: See Cartesian Coordinates
Coordinate Word
Counterbore
Counterweight
Crash
Cutter Offset
Cutter Radius Compensation
Cutting Force
Cycle Start
Cycle Stop

Datum to Following Error

Datum
DDA
Deflection
Delrin: See Acetal
Detent Torque
Digitizer
DIN 66025
DNC
DOC (Depth of Cut)
Dongle
Dovetail Ways
Down or Downhill Milling: See Conventional Milling
Drawbar
Drill Collar: TBD
Drill Drift: TBD
Drip Feed
Drive or Driver
DRO (Digital Read Out)
Dry Machining
Duplex Bearing
Dwell
DWG
DXF File
Edge Finder
Electrolytic Capacitor: See Capacitor
Encoder
End Mill or Endmill
E-Stop / Emergency Stop
Exact Stop Check
Exact Stop Mode
Face Mill or Facemill
Face Turning: TBD
F-Code
Feed
Feed Hold
Feed Override or Feedrate Override
Feed Speed: See Feedrate
Feedback or Feedback Loop
Feedrate or Feed Rate
Feeds and Speeds
Ferrite Beads
Fine In-Position
Finishing Pass
Fixture
Fixture Offset: TBD
Flood Coolant
Flutes
Flycutter or Fly Cutter
Following Error
F-Word: TBD

G12/G13 to Knee Mill

G12/G13 Circular Pocket Milling
Gang Tooling
Gantry Mill
Gas Spring
G-Code
GD&T: See Geometric Dimensioning & Tolerances
Gear Drive
Gecko
Geometric Dimensioning and Tolerances
Gibs
Gib Adjustment
G-Rex or GRex or G101
Hall Effect Sensor or Switch
Handwheels
Hardness
Harmonic Drive
Heat Treatment
Helical Beam Coupler
Helical Interpolation: TBD
Helix Angle
High Speed Machining or HSM
High Speed Steel or HSS
HMC: See "Horizontal Machining Center"
Holding Torque (see also "Torque")
Home Position: See Machine Zero
Home Switch
Horizontal Machining Center
Horizontal Turning Center: TBD
HSS: See High Speed Steel
HTC: See Horizontal Turning Center
Hybrid Stepper Motor
Idle Current Reduction
IGES or Initial Graphic Exchange Specification
IGS (see also "IGES"): The file extension for IGES files.
Inches Per Minute
Inches Per Tooth (see also Chip Load)
Incremental Coordinates & Positioning: See Relative Coordinates
Index Pulse
Indexable Tooling
Inserts
Insert Drill
Interpolation: See Linear Interpolation or Circular Interpolation
Inverter: See VFD
IPAC (see "Keyboard Emulator")
IPM: See Inches Per Minute
Jig
Jog, Jogging, and Jog Mode
Kerf: TBD
Keyboard Emulator
Knee Mill

Ladder Diagram to MPG

Ladder Diagram
Ladder Logic: See Ladder Diagram
Lapping
Laser Interferometry
Lead
Lead Accuracy
Lead In/Lead Out
Leadscrew
Leadscrew Mapping: See Ballscrew Mapping
Limit Switch
Linear Interpolation
Linear Motion
Linear Power Supply
Linear Scale
Linear Slide
Linear Ways
Live Tooling
Load Meter
Lookahead
Lost Steps
Lovejoy Coupler (see "Oldham Coupler")
Mach 3
Machine Coordinates
Machine Reference: See Machine Zero
Machine Zero
Machining Center
Macros: TBD
Manual Pulse Generator or MPG
M-Codes
MDI (Manual Data Input)
Metrology: TBD
Micron: TBD
Microstepping
Microswitch
Mist Cooling
ModBus : See ModIO
Mode
Model: See Solid Model
ModIO
Moglice
Motion Control
Motor Driver: See Driver
MPG: See Manual Pulse Generator

N-Code to PWM

N-Code
Negative Rake
NEMA (23, 34, 42, Enclosure)
Noise
Normalizing
NURB
Offsets
Oldham Coupler
Open Collector: See Active High/Low Logic
Open Loop
Optical Encoder: See "Encoder"
Optical Limit Switch
Optional Stop
Opto Isolator
Origin
Oz - in
Pallet Changer
Parallel Port (with pinout information)
Parameters
Parametric Drawing
Parametric Programming
Part Chute
Part Program
P-Code
Peck Drilling
Pendant
Peripheral Milling
Picture Frame Machining: TBD
PID
Pitch or Leadscrew Pitch
Plasma Table
Plunge
Pocket
Positive Rake
Post or Post Processor
Posting
Powered Drawbar
Preload (Bearings and Leadscrews)
Program Zero: See Work Zero
Print
Prismatic Ways
Probe: See "Touch Probe"
Profiling: See "Contour Turning"
Program Zero
Proximity Switch
PTFE
Pull Stud: See Retention Knob
Pulse Rate
PWM (Pulse Width Modulation)

Quadrature to Rulon

QCTP: TBD
Quadrature
Quill
R8 Taper: See Taper
Rack and Pinion
Ramping (Motor and Machining Technique)
Rapids
Rapid Traverse: See Rapids
Rectifier
Recutting
Refractometer
Regulated Power Supply
Relative Coordinates
Relative Zero
Relay
Repeatability
Resolution
Resolver
Resonance
Retention Knob
Rhino 3D
Right-Hand Rule
Rigid Tapping
Rigidity
R-Level
Rockwell Scale: See Hardness
Roughing
Round Column Mill
Router Table
RPM
RS232
RS274
Rulon: See Acetal

Safe Start Block to Swiss Lathe

Safe Start Block
Safety Charge Pump
S-Code
Scallop: TBD
Scraping
Screw Machine
Screw Starts
Secondary Operations
Serial Port: TBD
Servo
Servo Amplifier
Servo Fault
Servo Gain
Servo Tuning
Set Point
Setup
SFM: See Surface Speed
Shielded Cable
Single Block Mode
Single Shot Oiling
Slitting Saw: TBD
Slot Drill / Mill: TBD
Slot Milling
Soft Jaws: TBD
Soft Limits
Solid Model
Solid State Relay
Solidworks
Spindle
Spindle Overide
Spindle Sensor or Spindle Index Sensor
Spindle Speeder
Spot Drilling
Square Column Mill
Squaring a Block
Squaring a Mill
STEP Files
Step / STEP & DIR
Step-over
Stepper
Stepper Resonance: See Resonance
Stick Slip
STL: TBD
Surface Speed
Swiss Lathe

Tangential Control to Workshift Offset

Tangential Control
Tape Emulator: TBD
Taper
Tapered Gibs
Tapping Head: TBD
T-Code
Tempered
THC: See Torch Height Control
Timing Belt
Tombstone
Toolchanger or Tool Changer
Tool Length Offset
Tool Nose Radius and Tool Nose Radius Compensation
Tool Offset: Another name for Tool Length Offset
Toolpath or Tool Path
Toolpath Simulation
Tool Post: See "Posting"
Tool Probe: See "Touch Probe"
Tool Table
Tool Pre-Setter
Toolsetter
Torch Height Control
Toroidal Transformer
Torque
Touch Off
Touch Probe
Touchsetter: See Tool Pre-Setter
TPI: See "Turns Per Inch"
Tramming a Mill or Vise
Transformer
Travels
Trepanning
Tribology
T-Slot
Turcite: See Acetal
Turning Center
Turns Per Inch or TPI
Turret
Twisted Pairs
Undercut
Unidirectional Positioning (G60): TBD
Unipolar Stepper or Driver
Up or Uphill Milling: See Climb Milling
USB
USB Key: See Also Dongle
Variable Helix Endmill: TBD
Vertical Machining Center
Vertical Turning Center
VFD (Variable Frequency Drive)
VMC: See "Vertical Machining Center"
VTC: See "Vertical Turning Center"
Wall Wort or Wall Wart
Way Covers
Wear Offsets
Whipping (for leadscrews)
Wiper (for leadscrews and ways)
Woodruff Cutter: TBD
Word
Work Envelope
Work Hardening
Work Offset
Workpiece
Workshift Offset
Work Zero
X-Axis: See Axes
Y-Axis: See Axes
Z-Axis: See Axes

TBD = Topic placeholder. A definition still needs to be written.

= Dipicts a newly added topic, for those who are reading the dictionary and want to know what's changed. I will likely be pretty random in how I update these, so you may miss a new topic if I happen to flip the new flag off a bit early. I'm thinking of doing something real simple, like flipping them off at the beginning of a month or some such.

CNC Tutorials

Tutorial	Comments
Breakout Board I/O	This page offers a round up of different breakout boards and other technologies that may be used to interface your PC to the different motor controllers, relays, and other devices on a CNC machine.
CNC Control Panels	This page provides a survey of commercial and hobbyist control panels and pendants so you can see what's out there before designing you own panel.
CNC Software	A description of how all the different software fits together including CAD, CAM, and machine controller software.
CNC Tips & Techniques	How to get started programming, tool length offsets, and other notes.
Stepper/Servo/Backlash Simulator	This Excel-based simulation graphically shows the difference in accuracy for these systems when following a circular toolpath.

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