Abstract: In order to obtain the error terms causing great machine setting errors, the physics meaning of spiral bevel generator spatial errors are analyzed, and the geometrical model of machine spatial errors are built. Based on transformation matrices the geometric relations of machine settings and machine spatial errors are obtained. It’s found that the straightness error of axis x and perpendicularity error between axis x and axis y can bring great error to machine tool position settings, and the straightness errors of axis z and axis B, position error of axis A can bring great setting error to workpiece position settings. It provides theoretical foundation for optimization of machine settings and error compensation of spiral bevel gears.

Key words: Computerized numerical control, Machine settings, Machine spatial errors, Spiral bevel gear