微切削加工Al7050-T7451过程切屑形貌及尺度效应研究

Experimental study on chip geometry and size effect in micro-cutting aluminum 7050-T7451

采用硬质合金刀具,通过一系列的单因素直角切削试验对铝合金7050-T7451微切削加工中的切屑形貌、切削力以及尺度效应等进行了研究。为了便于使用Kistler9257B型测力仪进行加工过程切削力的测量,对工件进行处理,使用数控铣削中心实现直角车削。试验方案在不同切削速度下变换切削深度,考虑刀具刃口半径的存在对微切削加工过程的影响。试验中收集不同切削参数下的切屑,得到切屑的宏观形貌;对切屑进行抛光腐蚀,在高倍光学显微镜下获取切屑的微观形貌,研究了切削参数对切屑厚度和卷曲程度等的影响规律。试验过程中实时测得不同切削条件下的切削力,讨论了微切削加工过程切向力和径向抗力受刀具刃口半径影响下的变化规律,并从单位切削力的角度出发研究了刀具刃口半径对微切削加工过程中尺度效应的影响规律。

The micro-scale machining characteristics of a non-ferrous structural alloy aluminum 7050-T7451 were investi-gated through a series of orthogonal cutting experiments.A carbide tool was used and the effect of cutting edge radius was considered.The workpiece was prepared as thin wafers so that orthogonal turning experiments could be conducted on the NC milling center.Different cutting speeds and various depths of cut were adopted in the single factor cutting experiments.Chips under different cutting parameters were collected for the investigation of chip geometry.The effect of cutting parame-ters and cutting edge radius on chip thickness and curls were investigated.The cutting forces were measured with the Kis-tler 9257B dynamometer.The characteristic of cutting forces and thrust forces were analyzed via considering the effect of cutting edge radius and the effects of cutting speed and depth of cut on cutting forces and size effect in orthogonal micro-scale cutting of Al 7075-T7451 were presented.