CNC machining

Computer numerical control machining: cutting parts from solid metal or plastic with computer-guided rotating tools.

• A program specifies tool paths, speeds and feed rates, and motors move the tool or workpiece along 3 to 5 axes.
• Tolerances of about ±0.01 mm are routine and much tighter is possible, making it the backbone of aerospace and precision engineering.
• It is subtractive: complex aerospace parts can turn most of a costly titanium block into chips, one reason to consider 3D printing instead.
• Programming, fixturing and inspection need skilled machinists, who are in short supply; automating setup is a focus of new startups.