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Traditionally, a machine tool is regarded as a rigid-multi body system, and it is studied by integrated geometric error modeling. Considering a three axis-machine, this study introduced the ratio and effects of the geometric errors on the surface figure error. First, based on synchronous iteration location, a surface matching model was employed to assess the coordinate measurement result. Subsequently, considering all the geometric error functions having the same parameters, the effect ratio and the surface figure error of a single geometric error were obtained. Concurrently, based on the effect ratio and surface figure error results, the main geometric errors were obtained, such as EZX, EZY, EAX, and COY. Moreover, the proposed method and the main errors were experimentally verified. By compensating the main errors, the sphere accuracy was improved by 53.4% and the flat accuracy by 70.0%. Additionally, the method proposed in this paper could be utilized to detect the surface figure error. [ABSTRACT FROM AUTHOR]

Universal materials such as metal and marble are applied for aerostatic guideway. However, metal or marble guideway is usually manufactured by traditional turning and grinding. The corresponding geometric error, load and stiffness of the guideway are limited by the accuracy of traditional manufacture. Glass guideway can be measured by the optical method, thereby improving the performance. This paper presents a guideway designed and manufactured with the K9 glass. The guideway is manufactured by computer controlled optical surfacing and magnetorheological finishing. Moreover, the optical measurement is applied to measure the flatness and the geometric error of the guideway. Besides, the slider on the guideway is designed based on orifice compensated. The working surface error of the guideway is less than 0.1 μm, and the gas film is smaller than traditional aerostatic bearing. Therefore, the load and stiffness of the aerostatic sliders are higher than the traditional slider. Additionally, the effects of configuration and load onto the accuracy of guideway are introduced. The motional geometric error is measured after assembling, with the results that the pitch is better than 0.4 arcsecs and the yaw is better than 0.9 arcsecs. Furthermore, the straightness is compensated at 50 nm/200 mm. At last, the guideway is applied for an ultra-precision profilometer, and a flat is measured by the profilometer, giving 0.1 μm repeatable flatness. [ABSTRACT FROM AUTHOR]

A new non-aqueous and abrasive-free magnetorheological (MRF) polishing method is adopted for processing KDP crystal due to its low hardness, high brittleness, temperature sensitivity, and water solubility. Water content in magnetorheological fluids has an important effect on polishing surface quality. In addition to affecting the removal efficiency and fogging, the recrystallization of KDP can produce great influence on surface quality. This paper analyzes the formation of recrystallization process, chemical composition, influence factors and finds a method to restrain recrystallization. Results indicate the surface roughness of KDP crystal by MRF is 0.624 nm (Ra), 0.809 nm (RMS). We get neat, non-nick and ultra smooth surface after MRF polishing. Besides the improvement of surface roughness, the tool marks imported by single-point diamond turning (SPDT) are eliminated clearly. This has significant meaning on KDP crystal processing. Large size KDP crystal is widely used in high power laser system. The cutting tool marks will affect the laser induced damage threshold (LIDT) clearly. This means after MRF polishing the KDP crystal has better performance in high power laser system without recrystallization, obvious scratch, and tool marks. [ABSTRACT FROM AUTHOR]

When fabricating optical cantilever parts with single-point diamond turning (SPDT) technique, chatter phenomenon happens and degenerates the surface quality. This paper studies the chatter phenomenon and proposes a scheme to solve the problem. A kind of viscoelastic material is presented as the auxiliary supporter under the vibration location of optical cantilever parts to suppress chatter. Mirror surfaces can be generated and surface shape can be maintained after uninstalling the supporter because of the special features of viscoelastic material which acts like solid to enhance the rigidity of the cantilevers when cutting forces act on it and acts like liquid to avoid distortion of the surface shape during setting and unsetting the supporter. The effect of the viscoelastic material is discussed by virtue of finite element simulation on the basis of elasticity theory. Cutting experiments are carried out and the cutting forces as well as the surface quality with and without viscoelastic supporter are compared. The results show that chatter is suppressed effectively by using viscoelastic supporter, and surface roughness average (Ra) of around 5 nm is obtained on the whole surface with no obvious distortion on machined surface shape. [ABSTRACT FROM AUTHOR]