CNC machining, or CNC milling or mechanical machining, uses the CNC technique (i.e., numerical computer control). This method of material processing by subtraction allows direct cutting into the mass by means of numerical milling machines.
For this reason, this method is used for individual production in “real material”, for example for functional tests. The method is inexpensive and fast when fewer than ten prototypes are produced, since no mold has to be produced. It is also powerful because you can produce parts of identical quality from the later series material.
However, CNC machining is not recommended for more than 10 parts. The quantity advantages from this number are much lower than those of the vacuum casting process. The vacuum casting also enables faster production. In addition, CNC is a subtraction technique of material and the non-usable pieces are additional costs. The latter are proportional to the number of parts produced.
The principle of CNC machining
CNC machining uses machines with numerical control – in this case three or five-axis milling machines. These machines are automated and computer controlled. The processing consists of a material removal. Depending on the file stored, the milling machines are also used for cutting into the mass in order to manufacture the part.
How CNC machining works
The 3D file loaded into the computer determines the milling process of the machine, which processes the mass: the part is shaped by three-dimensional milling. During the production of the prototypes, the milling machine makes a cutting movement (so-called cutting speed) and a feed movement (so-called feed speed).
The main steps of CNC machining
Create a digital design of the desired part using a suitable software: CAD / CAM (Computer Assisted Design / Computer Aided Manufacturing). This file determines the dimensions and geometry of the finished part.
- Connect the CNC machine to the computer: The transferred file allows automatic control of the milling machine.
- Insert the material block into the machine, it is held in position by hydraulic clamping.
- The milling machine processes the mass to produce the desired part.
- The part is removed and a new block is inserted if necessary.
- Surface treatment (polishing, varnishing …).