Numerically controlled machine tool

A numerically controlled machine tool, which has a main spindle and tool slide controlled numerically, for grinding a non-circular workpiece according to a profile data which defines a profile generating movement of a tool along the final shape of said non-circular workpiece, said numerically controlled machine tool comprising:

• ideal profile data memory means for storing ideal profile data, which is calculated from said ideal final shape of said workpiece;
• execution profile data memory means for storing execution profile data calculated from said ideal profile data and which is compensated for position error due to follow delay of said numerically controlled machine tool;
• control means for moving said main spindle and said tool slide according to said execution profile data so as to produce profile generation movement;
• measuring means for detecting an instantaneous positions of said main spindle and for producing measured profile data which indicate actual position change of said tool slide corresponding to angle position change of said main spindle;
• decision means for ascertaining whether or not the follow delay is within a predetermined tolerance by comparing said measured profile data and said ideal profile data, wherein said measuring means comprises position detecting means for detecting positions of said main spindle and said tool slide at a constant time interval, and converting means for converting positions detected by said position detecting means to said measured profile data which indicate actual position change of said tool slide corresponding to angle position change of said main spindle, and
• means for operating said position detecting means during spark-out machining.

A numerically controlled machine tool, which has a main spindle and tool slide controlled numerically, for grinding a non-circular workpiece according to a profile data which defines a profile generating movement of a tool along the final shape of said non-circular workpiece, said numerically controlled machine tool comprising:

• ideal profile data memory means for storing ideal profile data, which is calculated from said ideal final shape of said workpiece;
• execution profile data memory means for storing execution profile data calculated from said ideal profile data and which is compensated for position error due to follow delay of said numerically controlled machine tool;
• control means for moving said main spindle and said tool slide according to said execution profile data so as to produce profile generation movement;
• measuring means for detecting an instantaneous position of said main spindle and said tool slide during said profile generating movement and for producing measured profile data which indicate actual position change of said tool slide corresponding to angle position change of said main spindle;
• decision means for ascertaining whether or not the follow delay is within a predetermined tolerance by comparing said measured profile data and said ideal profile data wherein said measuring means comprises position detection means for detecting positions of said spindle and said tool slide at a constant time interval;
• and
• means for operating said position detecting means during spark-out machining.