They make the cutting tool go based on the trajectory you've preprogrammed correctly. The CNC machining tolerances are considerably higher when compared with manual machining processes. In addition, the machining preparation time is a lot lower. This brings such processes in the community of rapid prototyping at ddprototype.com/prototype-machining/ , previously occupied by different casting and forging works.

CNC machine types include simple mills with linear and rotary movement, lathes plus much more complex machines with multiple axes that will work multi-dimensionally to make highly accurate parts which can be used for form, fit and functional testing.The CNC process involves sending a posh programme which was processed by using a 3D machining programme to create the required cutter paths towards the CNC machine which then runs a computerized process to carry out the necessary ‘machining’ procedures. The CNC machine is usually programmed to do this again, so multiple parts could be replicated for the same specifications.The result is pinpoint accuracy, consistency and quality, even within the most complex of concept models or parts.

Although it can be less accessible than 3D printing for small studios (considering that the machines involved be more expensive and because they might need more space running) you can still find a number of services from where CNC parts may be ordered. CNC machining typically describes three related but separate processes:

CNC milling involves utilizing a computer-guided tool to clear out material from the larger block in order to provide parts. CNC milling can be useful for prototype parts through which all the design features are available from one side from the part. Essentially, CNC milling makes parts from sheets of cloth. CNC at ddprototype turning produces parts by removing material at a rotating, cylindrically rod. This technology is wonderful for creating prototypes parts with round cross-sections.