Modeling and analysis on motion accuracy of hydrostatic guideways incorporating the manual lapping effect

As one of the crucial functional units in ultra-precision machines, the hydrostatic guideways have been commonly adopted due to their own superiority. Although the existed analysis approaches can enable researchers to understand the influence of various design parameters on motion accuracy of hydrostatic guideways, the corresponding imperfections remain to be captured easily. In this paper, targeted at avoiding those defectiveness as much as possible, the kinematic theory based quasi-static analysis model with less simplification is developed directly, wherein the profile pattern difference between main and vice guide rails induced by the manual lapping technology is taken into consideration, and the general structure of hydrostatic guideways extracted from Z axis of the ultra-precision grinding machine UPG80 is determined as the research object. Three CASE studies are proposed orderly to verify the correctness and effectiveness of the established analytical model, and the results demonstrate that the variation trends of the theoretically calculated vertical straightness errors are in good accordance with those of the experimentally measured. Furthermore, the fluctuation amplitude deviation between the predicted and the measured motion accuracy does occur in CASE 3, which should be attributed to the accumulated thermal effect revealed via an experimental platform of hydrostatic guideways with similar structure type to the research object. It also is figured out that, the variation of three components of guide rails' profile errors caused by the thermal accumulation leads to the fluctuation amplitude deviation reflected in CASE 3, and the level of influence can be known as Amplitude component (E) > Phase component (& phi;) Upside wavelength component (& lambda;(up)) > Downside wavelength component (& lambda;(down)). This study can serve as a valuable foundation for improving the motion accuracy of hydrostatic guideways and is also confirmed to be valuable to the peer designers.