Design,Manufacturing And Experimental Study On Large Aspect Ratio Pcd Micro-Milling Tool

The high-aspect-ratio microstructures,which are widely used in aerospace,space communication and bioengineering fields,have been concerned and researched at home and abroad in recent years.However,the processing difficulty of their small size,high aspect ratio and high surface quality has become a problem in the mechanical field.In this paper,the advantages and disadvantages of the existing micro-milling tool were summarized.A new type of large aspect ratio PCD micro-milling tool with 3/4 body was designed and manufactured considering the problem of poor surface quality and low stiffness in micro-milling deep narrow slot.And the influence of different parameters on the machining performance of PCD micro-milling tool through the milling test was studied.The main contents are as follows:(1)Based on the analysis of the design and manufacturing of the existing micro-milling tools,a new type of large aspect ratio PCD micro-milling tool with 3/4 body was proposed in view of the welding strength of the tool shank and head and tool head stiffness.The influence of structural parameters such as the side blade relief angle,the bottom blade relief angle,the bottom edge dip angle and the blunt radius of the cutting edge on the milling performance were analyzed by finite element simulation,and obtained the optimized micro-milling tool structural parameters.Then the static simulation and the modal analysis of the optimized micro-milling tool were carried out to verify that the strength and stiffness all meet the processing requirements.(2)Considering efficiency and accuracy,the composite processing combined nanosecond-picosecond laser and grinding was proposed to manufacture the large aspect ratio PCD micro-milling tool.Firstly,the roughing of PCD tool was carried out by the nanosecond pulse laser,leaving a margin of 10-20?m.Then the rough rake face was precisely sharpened on the diamond grinding wheel to obtain high surface quality.Finally,the picosecond pulse laser was used for the precision forming of the cutting edge.The influence of different picosecond laser parameters on tool surface quality and the blunt radius of the cutting edge was studied to obtain the PCD tool with a blade diameter of 0.5 mm,an aspect ratio of 3 and a blunt radius of 3.5 ?m.(3)The large aspect ratio PCD micro-milling tool and carbide milling-tool were compared in processing oxygen free copper.The effects of feed per tooth and axial depth on the milling force and the surface roughness were studied.The optimized parameters were implemented to process the deep narrow slot with the PCD micro-milling tool.What's more,the wear mechanism of the micro-milling tool was analyzed.