Effect of Milling Parameters on Surface Integrity of 7075 Aluminum Alloy
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.
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