Design of a High-precision 3D-Coordinate Measuring Machine

In Precision Engineering components are getting smaller and tolerances become tighter, so demands for accuracy are increasing. To improve the precision of Coordinate Measuring Machines (CMMs) we designed an alternative high precision 3D-CMM with measuring uncertainty beneath 0.1 µm in a measuring volume of 1 dm3. The machine design is based on the Abbe and Bryan principle, thus smaller measuring errors are feasible with less effort on software compensation. Application of a light and stiff construction, compensated air bearings and well-positioned linear motors result in high stiffness and favourable dynamic behaviour. A statically determined design, extensive use of aluminium and mechanical thermal length compensation make the machine less sensitive to temperature changes. To prevent mechanical disturbances an active vibration isolation system was designed. This paper focuses on machine design aspects showing analytical- and experimental results and design synthesis