STATIC ERROR MODELING IN TURNING OPERATION AND ITS EFFECT ON FORM ERRORS
The static errors associated with a machine have a profound impact on the dimensional accuracy of a machined part. This research examines the effect of such errors on part geometry produced by a turning operation. The static errors considered in this research are the machine bed errors usually referred to as 21 geometric errors. These errors are present in the machine in the cold start condition and are induced over a period of time due to gradual wearing and misalignment. This research also includes modeling the spindle error as a significant source of part surface deviation from ideal geometry. In this work, a rigid body kinematics approach has been used to model the effect of machine tool errors. The model also takes into account the misalignment of the spindle axis and the machined surfaces are simulated under the combined influence of these two errors. To visualize the effect of machine errors on part deviation, the extent of the cylindricity form error is evaluated on a turned part. Finally, a design of experiments approach is used to analyze the individual impact of the error components on cylindricity error. Extensive numerical simulations are carried out to identify the most significant error sources. The outcome of this research can be used to simulate virtual surfaces and predict the cylindricity form error of a given workpiece to be turned on a particular CNC machine prior to the machining operation.
School:University of Cincinnati
School Location:USA - Ohio
Source Type:Master's Thesis
Keywords:21 errors cylindricty spindle error
Date of Publication:01/01/2008