2 Numerical Control (NC) Defined Electronics Industries Association (EIA) standard defined as “a system in which actions are controlled by direct insertion of numerical data at some point.” ……machines controlled by electronic systems designed to accept numerical data and other instructions usually in a coded form.
3 NC System DefinitionsAbsolute Programming – all tool motion is derived from the origin of the part.G90Incremental Programming – Next tool movement is relative to the previous position.G91Machine/Tool Home Position – Internal machine reference typically used to initialize the system
4 NC System DefinitionsFloating Zero – Ability to set the machine zero to a location on a part relative to the parts datum(s)Work Offset Coordinate Shift – The ability to shift the machines home position to set a zero point for a particular part.G54 – 59
5 NC System DefinitionsCutter Compensation – The ability to adjust the cutter location with offset values in the controller. The adjustment may be necessary due to tolerance issues associated with cutter condition, material problems, or program utilization (ex. family of parts)G40, G41,G42
6 Common G-CodesG00 – Rapid positioning in mutual directions (X,Y,Z,A,B)G01 – Linier InterpolationNeeds a feed rate command to execute (F)G02 – Circular Interpolation Motion CWR value or I and J center point values of circleFull arc or quadrant inputG03 - Circular Interpolation Motion CCW
7 Common G-Codes G20 – Inch Input G21 – Metric Input Canned Cycles – A predefined string of variables which allows for a predetermined sequence of events. This programming method serves to simplify input as well a reducing program size.Examples G81 Drilling, G83 Peck Drilling,G80 Cancel Canned Cycle
8 Common M-Codes M00 – M01 Program Stop / Optional Program Stop M02/M30 – End of Program / EOP RewindM03 – Spindle On CWM04 – Spindle On CCWM05 – Spindle StopM06 – Tool ChangeM08 /09 Coolant On/Off
9 Other Common Addresses S – Spindle speed (CS or RPR)Lathe G96F – Feed rate inputN – Program Line Number ReferenceMotion LineO – Program LineTool Change Line / Safe Starting Point On Some Machine Tools