CNC machining, or Computer Numerical Control machining, is a form of programmable automated machining in which the process is controlled by numbers, letters, and symbols which is often called a machining program. Some of the reasons behind CNC machining is the fact that it is easier to write machining programs than to modify production equipment and once a CNC machining program has been created it can be run over and over again allowing for the creation or mass production of identical precision machined parts. Some of the advantages of CNC machining versus manual machining is the reduction of non-productive time, fixturing time, and manufacturing lead time. Some other advantages of CNC machining are greater manufacturing flexibility due to soft automation and improved quality control by means of automated electronic probes.