| Reducing friction loss by surface texture technology is recognized as a valuable energy saving new technology. The morphological or mechanical properties of biological structures lead to an interdisciplinary of mechanical disciplines and biological disciplines. Combined with the characteristics of mechanical processing, simulation of biological form and function structure are important research areas in the field of surface structure processing. In recent years, the rapid development of aerospace and defense industry et al lead to an increasingly high demand on the surface properties of mechanical components. Processing method based on specific surface morphology with different functions and different dimension and different scales and regularly arranged with certain functions, is an effective way to solve the increasing demand on the performance of the surface. Different biological surface topographies and surfaces may have the same functions. It can get different drag reduction, viscosity reduction, desorption, wear resistance, noise and other performance requirements by non-smooth surface morphology of different scales and different shape ratio, different height of the non smooth surface morphology.Choosing the carp squamous surface as the research object, based on MATLAB computer image processing technology by the image enhancement image segmentation, edge detection and other steps, the surface feature was obtained by image processing of carp. Selecting suitable operator and image processing algorithms, based on the characteristics of the original image retention, the image noise has been reduced to a certain extent, and then further extraction of image features has been accomplished using the method of Otsu. Edge detection method is used to locate the edge pixels and refine the feature edge, and edge pixels are extracted. The effect of curve fitting of the characteristic parameters with sine function is good.Establishing the feed direction of ultrasonic vibration assisted milling surface processing model, through the analysis of the cutting edge in the same rotating quadrant, with cutting edge in different rotating quadrant, different cutting edge in the same rotating quadrant and different cutting edge in different rotating quadrant at the four rail trail knife closed regional characteristics, the track closed area function with universal application has been established. The track function is the sine function the same as the squamous surface feature. The results show that the applicability of the function in accordance with the features of sine function, namely the surface texture of feed direction of ultrasonic vibration assisted milling the scaly surface texture stacked on top of each other.Assuming that the cutting edge completely sharp cutting edge, simplify the cutting model based on the actual machining conditions. Simplify the milling process as the tool minor cutting edge's shape reflection on the cutting plane and complex interference of different cutting edges. Through space coordinate conversion and Boolean operations, the cutting edge shapes reflect on the workpiece cutting surface. A simulation model of ultrasonic vibration assisted milling in feed direction for 3D surface features has been established. Establishing the feed direction of ultrasonic vibration assisted milling tool path model, choosing two close cutting tool pathes to judge the 3D shape size of bottom surface and obtain optimal combination of fish scale surface. Experimental research and analysis of the main processing parameters have been accomplished to study the influence of ultrasonic vibration on surface roughness. The results showed that, in the case of ultrasonic vibration, the spindle speed 5000r/min-7000r/min, with certain machining and vibration parameters, can form a good squamous surface morphology.Based on the Tlusty and MacNeil based milling mechanical model, considering the actual experiment processing conditions, the feed direction of ultrasonic vibration assisted milling mechanical model is established. The occurrence conditions of empty cut phenomenon are determined, and X/Y/Z direction cutting forces are computed whether empty cut phenomenon occur or not occur. Feed direction ultrasonic vibration assisted milling experiment with different spindle speed, feed rate, and ultrasonic vibration amplitude has been carried out to verify the accuracy and regularity of the mechanical model of the milling process. In the minimum time interval, milling processing is simplified as the stress processing of the axis, and the feed direction ultrasonic vibration assisted milling satisfies the rotation direction and the axial direction of the single degree of freedom forced vibration. Based on the model, the influence of the periodic hysteresis and the axial displacement of the contact point on the rotation of the main shaft after ultrasonic vibration are analysed. And the influence on the surface morphology of the side and the bottom surface of the machined workpiece is also analysed. The results showed that when the feed direction ultrasonic vibration was applied, the cutting forces in X/Y/Z direction changed obviously, and the cutting force performance was improved obviously especially when the feed rate was larger (12?m/tooth) and ultrasonic amplitude was larger (12?m). After ultrasonic vibration was exerted, the rotation of spindle and the axial displacement of the contact point will cause a certain impact on the surface topography of the machined workpiece.Aiming at the field of possible application of the feed direction ultrasonic vibration assisted milling and some possible situations, the problems needing attention in practical application are discussed. Study on the oxidation resistance and hydrophobicity of the ultrasonic vibration assisted milling surface exposed to air through the contact angle test. Dry friction and starved lubrication friction performance test of the surface were carried out to verify the feed direction of ultrasonic vibration assisted milling surface of excellent dry friction and oil friction resistance. The results show that the surface hydrophobicity of ultrasonic vibration assisted milling is better than that of the traditional machining surface. Large amplitude (12?m) of ultrasonic vibration assisted milling surface with high friction coefficient and fluctuation cycle to zero, small amplitude (6?m) when the fluctuation of the friction coefficient is much smaller than the ordinary machining surface, the performance of dry friction is much better. In the starved lubrication condition, the friction performance of milling surface after applying ultrasonic is better. But in the case of lack of grease, friction with time will gradually change to the condition of dry friction, a large fluctuation of the friction coefficient then occurred. So although grease lubrication friction performance of the ultrasonic vibration assisted milling surface is more excellent, but timely supplement of the grease is necessary. |
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