铣削参数对加工7075铝合金表面完整性的影响

Effect of Milling Parameters on Surface Integrity of 7075 Aluminum Alloy

采用单因素试验法,开展7075铝合金铣削加工试验,分析了转速与进给量对切屑形态、表面粗糙度、已加工表面形貌和残余应力的影响。结果表明:随着转速和进给量的增大,切屑卷曲程度提高,使切屑形成规律卷曲与折断;进给量f=0.05mm/r时,切屑呈现两种状态,不规律的切屑形态容易引起切削过程的不稳定,导致表面质量变差;转速越高表面粗糙度越小,随着进给量的增大,表面粗糙度呈现先减小、后增大,先减小的原因是进给量f=0.05mm/r时,切削过程不稳定,引起表面粗糙度值较f=0.1mm/r时大;高转速有利于形成更规律的加工表面纹路,黏结物更少,表面轮廓清晰更规律;进给量越大,刀纹宽度、深度越大,表面轮廓越粗糙;在“挤光效应”下,铝合金切削加工表面残余应力呈现压应力状态,转速越高,加工表面残余压应力越小;进给量越大,切削力越大,残余压应力越大。

A single factor method was used to conduct milling experiments on 7075 aluminum alloy,and the effects of rotational speed and feed rate on chip morphology,surface roughness,machined surface morphology,and residual stress were analyzed.The results show that as the rotational speed and feed rate increase,the degree of chip curling increases,resulting in regular curling and breaking of chips.When the feed rate f=0.05 mm/r,the chips exhibit two states,and irregular chips can easily cause instability in the cutting process,leading to poor surface quality.Higher rotational speed indicates smaller surface roughness.As the feed rate increases,the surface roughness first decreases and then increases,the reason for the initial decrease is that when the feed rate f=0.05 mm/r,the cutting process is unstable,resulting in a larger surface roughness value than when f=0.1 mm/r.High rotational speed is beneficial for forming more regular machined surface patterns,with fewer adhesives and clearer and more regular surface contours.A larger feed rate ensures a wider and deeper blade pattern and rougher surface contour.Under the squeezing effect,the residual stress on the surface of the aluminum alloy during cutting presents a compressive stress state,and as the rotational speed gets higher,the residual compressive stress on the machined surface becomes smaller.As the feed rate increases,the cutting force and the residual compressive stress are larger.