CNC Lathe Process The reliability of a CNC machine tool means that the machine tool runs stably for a long time without failure when it performs its function under specified conditions. That is, the average time between failures is long, and even if a fault occurs, it can be recovered in a short time and put back into use. Choose machine tools that are well-structured, well-made, and mass-produced. In general, the more users, the higher the reliability of the CNC system.