Simulational And Experimental Study On The High Speed Milling Process For Aerospace Aluminum Alloy With Multi-flutes Milling Cutter

On the basis of former researchers of the Material Processing Simulation Laboratory in Zhejiang University, especially the material model of aluminum alloy 7050-T7451 through the material-stretching experiment under high temperature environment and SHPB experiment, peripheral milling of aluminum alloy 7050-T7451 under high speed conditions was analyzed.At first, the simulation model constructing method was analyzed and compared, including equivalent thickness chip model and variant thickness chip model. Based on the area-equivalent chip model, the feed per tooth was transformed into equivalent cutting thickness. Then two dimensional finite simulation models with various VB values were constructed, the affection of tool flank wear to cutting forces, cutting temperature, effective stress and strain was analyzed.As to the variant thickness chip model, to overcome the shortcoming of traditional simplified curve model, a geometrical model based on trochoid curves was constructed here. And it was used in the full-immersed mill cutting with a two-flute end-milling cutter at first. Then this trochoid based model was used in the same slot milling with multi-flutes cutter (three-flutes and four-flutes as present). Two or more cutters may join the cutting process when carry a slot milling with multi-flutes cutter, so milling forces will be changed greatly both in force shape and peak values. Through theoretical analysis, FEM simulation and necessary verifying experiments, this difference in milling forces was analyzed in detail. Cutting temperature and effective stress and effective strain were also discussed.Although only three flutes and four flutes cutter were analyzed here, this method can be used in face milling in which six or more flutes can be used. The meaning of milling with multi-flutes lies in that the metal remove ratio will be improved under the same rotation speed. At the same time, the full immersed milling was adopted in some cutting researches just because it has included both up-milling and down-milling.In above situations, theoretical analysis, finite simulation and milling experiment were used and combined, in order to analyze the mechanical character of alloy aluminum 7050. Cutting forces in three components were measured by the KISTLER instrument. Results from experiment and from finite element simulation agree well, which means the simulation is successful.Based on the two dimensional finite simulation model, the three dimensional finite simulation model of milling with helical flutes was constructed, under the condition of maximum radial cut depth and large axis cut depth separately. At first, the slot milling with a four-flutes helical mill cutter was also analyzed through the three-dimensional finite-element simulation, cutting forces and cutting temperature were analyzed. Then, as an application, two-flutes and four-flutes milling under large axis cutting variant when machining a thin-web part milling was compared and analyzed, just try to analyze the possibility of using four-flutes helical mill cutter under the condition of large axis cutting depth.