text: what is the meaning of 'part programming' in relation to cnc (computer numerical control) machines?   the reason for strict program formatting is consistency. once you have a format that works, use it. if you use the same format (or structure) for all programs you write, you will be able to repeat past successes. if all programmers in your company use the same format for a given cnc machine, each programmer will be easily able to work on another's program.