Patent ID: 6905393

Claim:
A method for establishing different parameters of a surface of a work piece during machining of the surface using a machine with a spindle supporting a tool, with the spindle rotatably supported in at least one bearing in a housing, and with displacement sensor means arranged for measuring displacement to which the spindle is subjected during machining operation, the method comprising: machining two first work pieces with different back off times to create two sets of sensor signals with different level at back off times; storing in an evaluation unit the sensor signals which represent displacement to which the spindle was subjected during the machining of the two first work pieces; measuring the two machined first work pieces to obtain measurement results which are loaded in the evaluation unit; comparing in the evaluation unit the stored sensor signals representing the displacement to which the spindle was subjected during the machining of the two first work pieces with the measurement results of the two machined first work pieces, and calculating transfer constants representing an influence of total deflection of machine stiffness on the sensor signals; recording a difference in feeding positions between the two first work pieces, whereby displacement sensor signals obtained at machining of subsequent work pieces are fed into the evaluation unit and are processed with the transfer constants to give a series of sensor signals representing a true total deflection of a loaded and running machine stiffness chain; and subsequently using the sensor signals representing the true total deflection to calculate different parameters of the subsequently machined work pieces.