Modeling of Precision ReliabiLity for NC Machine Tool Based on Multi-body System Theory

Reliability is one of the most important performances of CNC machine tools. Precision exceeding tolerance is a special kind of faults different with general faults considered usually. This type of faults may cause large loss for users because of the loss of machining precision. To predict the precision and its reliability of machine tools in the design phase, the concept of precision reliability is introduced first in the paper. Second, the process of precision decline in the operating conditions is analyzed and a precision reliability model is proposed. To evaluate the parameters of the precision reliability model, the spatial error model based on multi-body system theory and multi-body system dynamics simulation are adopted. Forecasting precision life for a lathe has been done applying the model finally.