CNC Machining Positioning Error

Positioning error  

Locationerror mainly includes datum miscoincidence error and location pairmanufacturing inaccuracy error.   When the workpiece is processed onthe machine tool, it is necessary to select a number of geometric elements onthe workpiece as the positioning datum for processing. If the selectedpositioning datum and the design datum (the datum used to determine a surfacesize and position on the part drawing) do not coincide, it will produce thedatum mismatch error  

Thelocating surface of the workpiece and the locating element of the fixtureconstitute the locating pair together. The maximum position variation of theworkpiece caused by the inaccurate manufacturing of the locating pair and themating gap between the locating pair is called the inaccurate manufacturingerror of the locating pair.   The manufacturing inaccuracy error ofthe positioning pair can be produced only when the adjustment method is used,but not in the trial cutting method.