How is the use of a CNC machine relevant to the story of 3D printers? Simply, because if you can afford a 3D metal printer, you can afford a CNC machine.
U in this sense, CNC machining is still a cost-effective way to produce a wide spectrum of metal prototypes. Of course, this technology comes with limitations. Engineers and designers who design parts and work with 3D printers must follow the rules for additive manufacturing, and on the other hand for CNC work machines must follow the rules for technology that works on the principle removal of material.
The rules for this technology come with two restrictions: Tool Shape and Tool Access. Wall thickness, depth of opening, internal diameter of corners, diameter of opening, all must be taken into account to reduce fabrication time and cost. Additionally, internal geometries are limited to shapes at specific angles such as T-Slot or dovetail shapes. Also small openings and cavities are limited to 2.5mm in diameter.
If your metal part design can stay within these limitations, CNC machining is faster and cheaper than metal 3D printing. In this way, the parts retain isotropic mechanical properties and can be made with greater precision, up to ±0.025mm, in contrast to DMLS 3D printing technology, which reaches a precision of ±0.100mm. On the other hand, in order to even start the race in the freedom of design that 3D metal printing brings, you need to have at least a 5-axis CNC device. Prices for such devices start at €100,000.
You can see how CNC technology compares with 3D printing technologies in the text at the LINK .