Method for determining the deformation of workpiece on grinding machine

A method for determining a deformation of a workpiece on a grinding machine having a grinding wheel, comprising the steps of:

• automatically measuring a diameter D(t) of the workpiece;
• automatically measuring a position of the grinding wheel;
• automatically and periodically computing, from the measured diameter of the workpiece, a reduction in the diameter of the workpiece;
• automatically comparing the computer diameter reduction to a predetermined diameter reduction value;
• upon exceeding of said predetermined diameter reduction value by the computed diameter reduction, setting an initial deformation value T(s) to be a difference between an initial deformation for an immediately prior workpiece and a final deformation for the prior workpiece, the initial deformation value for the first workpiece being set equal to zero;
• and
• upon exceeding of said predetermined diameter reduction value by the computed diameter reduction, automatically and periodically calculating (i) a shift .DELTA.A in position of said grinding wheel, (ii) a change in radius (D(s)-D(e))/2 of said workpiece, where D(s) is the diameter at start time s and D(e) is the diameter at finish time e, (iii) a change in deformation of said workpiece as a difference between grinding wheel position change .DELTA.A and workpiece radius change (D(s)-D(e))/2 and (iv) an instantaneous or real time deformation value T(t) of said workpiece by adding said initial deformation value T(s) and said change in deformation of said workpiece, .DELTA.A-(D(s)-D(e))/2:
• T(t)=T(s)+.DELTA.A-(D(s)-D(e))/2.