硬质合金涂层刀具铣削SiCp/Al复合材料刀具磨损研究

Study on tool wear of cemented carbide coated tool in milling of SiCp/Al composites

SiCp/Al复合材料因含有大量SiC硬质颗粒而使其切削加工性较差。针对该材料的高速高效加工问题,利用硬质合金涂层刀具对体积分数为20%的SiCp/Al复合材料进行面铣,通过单因素实验,研究了切削速度、进给量和轴向切削深度对刀具前刀面和后刀面的磨损过程的影响,以及刀具磨损萌生、扩展演化规律。结果表明:在硬质合金涂层刀具精加工SiCp/Al复合材料过程中,刀尖与工件表面的接触先是凸圆弧面接触,然后变成凹圆弧面接触,最后变成平面接触;刀具磨损随切削速度和轴向切深的增大而增大,而随进给量的增大而减小;硬质合金涂层刀具失效的原因主要是后刀面的耕犁磨损,后刀面最大磨损量VB_(max)超过了0.6 mm,而后刀面磨损的主要原因是磨粒磨损和涂层剥落。

SiCp/Al composites have poor machinability because of a large amount of SiC hard particles in them. In view of the high speed and high efficiency machining of this material,the face milling tests of SiCp/Al composites with volume fraction of 20% is carried out by means of carbide coated cutters. Through single factor experiments,the effects of cutting speed,feed rate and axial cutting depth on the wear process of the rake and flank faces were investigated,and the rules of tool wear initiation and propagation were studied. The experimental results show that in the process of finishing SiCp/Al composites with cemented carbide coated tools,the contact form between knifepoint and workpiece is convex arc contact at first,then turn into concave arc contact,and turn into plane contact at last. The tool wear increases with the increase of cutting speed and axial cutting depth,and decreases with the increase of feed rate. The main reason for the failure of cemented carbide coated cutting tools is the ploughing of the flank face,and the VBmaxexceeds 0. 6 mm. The main sources of wear are the abrasive wear and the peeling of the coating.