CNC Programming Basics

• Each program has a program number, that should be different from other program numbers

• Each line of code in a CNC program is called a “Block”. It contains G and M codes in it.

• The block cannot have two M-codes in it

• The ending of a Block has a End-of-Block symbol and it is a semi-colon. (Example: G1X.5; )

• The last programmed feed rate is the one that will be used on G1 lines of code

• Any code inside ( ) does not get read by the CNC controller, thus they can be notes for the operator

The Order of a CNC Program

1. The Program Number

2. A Tool Change Call

3. Define a Tool Length Offset Number

4. Define a Work Coordinate System Number

5. Tool Path Code

6. Axis Zero Return

7. End of the Program