Theoretical and practical background for the characterization of CNC machining centers

The greater demand on the cutting capabilities of machine tools has prompted the need for the characterization of their cutting performance as a method of measuring and comparing the machines' cutting capabilities. This dissertation describes the development of methods for the computation and measurement of these capabilities. Previous attempts to generate a general methodology for the characterization of the machine tools have failed, in part, because the conditions at which the tests should be performed were not systematically selected. By using up-to-date knowledge of the machining process, conditions for the testing have been properly selected.; The basic knowledge required for the characterization of the cutting performance of a machine tool is the dynamic characteristic of the machine tool-tool-workpiece system which can be obtained by measuring transfer functions. Once the dynamic characteristics of the machine tool are known, it is possible to compute the chatter limitations and to estimate the errors of accuracy produced by the cutting force.; The methods developed for the computation of chatter limits include the use of very accurate time domain simulations of the milling process. Similar simulations are used to determine the cutting force induced errors in the finishing cuts.; Cutting test procedures are proposed as an alternative to find the chatter limits and errors of accuracy. These cutting tests must be carried out at specific conditions where the results are not affected by any of the spindle speed dependent phenomena. An important question with regards to the cutting tests, which have been resolved in this work, is the selection of tools and tool holders to be used.; The cutting tests for both chatter limits and errors of accuracy required the development of clever procedures which simplify the otherwise lengthy processes. These procedures and the philosophical reasons behind their development are discussed in detail. The results of the proposed cutting tests together with the results of the computational methods are presented and compared for a particular machine.