| Aircraft skin as the outer surface aircraft parts, has specific characteristics, such as high strength and good plasticity. The shape of skin surface is complex, and the stiffness is poor. Traditional mechanical processing cannot meet with the skin processing requirements. The traditional aircraft skin thinning technology is chemical milling. However, the chemical milling cannot meet the requirements of green machining. In recent years, numerical control milling gradually replace chemical milling processing technology. Mirror milling of aircraft is one of the aircraft skin processing technology.This paper introduces the principle of mirror milling technology, characteristics and advantages. The support ways of mirror milling are rolling support and slide support. Both two types of support will produce the problems such as deformation of workpiece and cutting chatter. Therefor, it proposes a new supporting way-liquid lubricant support and liquid static pressure support.In this paper, the features of fluid lubricant support are introduced, and making the theoretical analysis of fluid static pressure support. According to theoretical analysis and practical situation of the processing, the diameter and the length of capillary restrictor are chosen. According to the set of parameters, film thickness, adjustment quantity and liquid stiffness are calculated with different input pressure. According to machining characteristic of mirror milling the processing platform and the hydraulic system are designed.With the method of fluid lubricant support, measuring the liquid film thickness, film adjustment and film stiffness with different input liquid pressure. As the increase of input pressure, the thickness of liquid film is getting thicker and liquid film stiffness decreases. Through mirror milling process with different input pressure, it can be found that machining consistency and actual depth with the input pressure of 20kPa are better than that with other input pressure. And the machining consistency and actual depth with the input pressure of 20kPa are near with the condition of no liquid. The surface roughness of the workpiece is measured by experiment, the workpiece surface quality in the condtion of fluid lubrication is better than that without liquid input.With the method of fluid static support, measuring the liquid film thickness, film adjustment and film stiffness with different input liquid pressure. Through the experiment the change of the thickness of liquid film, film adjustment quantity and liquid film stiffness are basically same with the theoretical analysis. Comparing the static pressure support, lubricant support and no fluid support, got that the static pressure support way to get the surface consistency and deep processing is superior to other two support way, and the machined surface quality is also better. |
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