Definition
CAM (computer-aided manufacturing) is software used before production to generate toolpaths and NC code from a part's geometry and process plan. CNC (computer numerical control) is the control method a machine uses to execute a program, whether generated by CAM or, for very simple work, written manually. CAM produces the instructions; CNC is how a machine follows them.
Why CAM and CNC aren't strictly dependent on each other
A CNC machine doesn't require CAM specifically to run; simple parts can sometimes be programmed manually. CAM becomes valuable as geometry and toolpath complexity grow beyond what's practical to write by hand.
Where each fits in the workflow
Neither appears on the drawing directly; both are downstream production concerns triggered by the part's geometry and requirements.
Common mistakes
Using 'CAM' and 'CNC' interchangeably; CAM is the planning software, CNC is the machine's control method, and conflating them obscures where a specific problem (a bad toolpath vs. a machine issue) actually lies.
A CNC machine doesn't require CAM specifically to run; simple parts can sometimes be programmed manually. CAM becomes valuable as geometry and toolpath complexity grow beyond what's practical to write by hand.
See how Blake reviews a partFrequently asked questions
Can a CNC machine run without CAM?
Yes, for simple geometry a program can be written manually; CAM becomes valuable as complexity increases.
Is CAM software specific to CNC machines?
CAM specifically targets generating instructions for CNC (and similar automated) machines, as opposed to manual machine tools.
Which term describes the machine itself?
CNC describes the machine's control method; CAM describes the software used to prepare its program.