Abstract
wThe precision of machine tools is the foundation of machining to achieve high precision. Therefore, an investigation on the measurement technology for precision machines is extremely important for precision/ultraprecision machining. This chapter provides an overall introduction to the measurement of precision machines, including the precision along linear axes and rotary axes, e.g., the precision of length, precision of angle, straightness, squareness, parallelism, flatness, and runout. The basic principles, achievable accuracy, application, and characteristics of a wide variety of measurement methods and instruments with precision in the nanoscale or below are discussed. It is found that digitization, automation, and flexibility are the development trends of modern instruments used for the measurement of precision machine tools. Though a number of measurement methods have been developed during these years, the existed methods face challenges to comprehensively characterize the performance of machine tools, especially for ultraprecision machine tools with a precision better than 100 nm. In addition, online measurement still remains to be investigated to improve the performance of precision machining.