CNC machine tools offer precision machining to all works. No matter what kind of CNC machine tools being used, it can pretty much guarantee that it will offer precision machining that is absolutely unbelievable.
The machine tools itself is responsible for a lot of the precision; however, the operators and the programmers play a big role as well as the facility itself. Proper temperature control and good conditions allow for accuracy as much as 20 millionths in some instances.
Tolerances of CNC machines completely depend upon the type of CNC machine that is being used to complete the project. Each machine offers different tolerances. Of course a machine that operates off of several different axes will allow for closer, more specific tolerances. The four and five axes machines can produce specifically design parts that need precise measurements in order to work. Very tight tolerances are possible.
Exacting tolerances from 0.001mm to 0.1mm is possible. (Otherwise, one to one hundred microns) Because these machines are computer numerical controlled (CNC) the possibility that production can be this precise is easy. No more do operators have to make sure that the placement of the material is precise and so on in order to achieve these standards. The computer technology can grind, cut, sand, etc to the dimensions specified by the program. They will be extremely close if not all the way there.
One of the great benefits of CNC machining is the ability of high tolerances on a repetitive basis. Because the machines are computer operated, repetitive work is easy to perform. The machine keeps running to the programs specifications until the work is complete. Another job that comes months down the road that has the same specifications can be performed easy. It just takes the downloading of the original program and the exact same specifications and tolerances will be repeated with this batch of work as well. Repetitive, high tolerance machining is one of the added benefits of CNC machining.
Tolerances are directly related to the quality of the CNC machines. This is why you will find that different companies who offer CNC machining services can offer different tolerances. Some may offer 0.025mm tolerances and others will offer a variety of different tolerances. The higher the quality of the CNC machine and the programs that operate it, the better tolerance that you will be able to get.
Programmers, machinists, operators and the machines, have to work in direct relationship to one another. If all aspects are all the same page, the better the performance. If you have quality programmers and machinists, you will be able to get better performance out of your machines. It takes individuals who are skilled and knowledgeable in the area of CNC machining to perform to the best of the machines ability.