Finite Element Simulation Of Deformation And Fixture Layout Optimization In Milling Of Complex Thin-walled Parts

Cubing is made by milling aluminum alloy based on a ratio of1:1tothe three-dimensional geometric model and is playing a critical role in earlyR&D and late quality control of new vehicle models. It has to match thevehicle and the parts at the same time, creating a very high precisionrequired. Many parts of cubing are complex ones with thin-walled structures.Because of poor rigidity, these parts are prone to deformation during milling,leading to processing errors. In order to raise system stiffness and controlmachining deformation, engineers, in actual processing, used to placeintensive auxiliary supports by experience. However, this method takes a lotof time and effort.For the problems of large deformation and long-time clamping, asystematic research on milling process of cubing’s complex thin-walledworkpiece is carried out, which will provide theoretical basis to millingforce calculation, machining deformation prediction and optimization offixture layout.Firstly, milling forces, corresponding to common milling parameters,are measured through machining experiment. An orthogonal experimentscheme is adopted to study ball-end tool milling force. Orthogonalregression analysis is used to establish empirical formula for milling forcecalculation. At the same time, an approach is introduced to predict millingforce by finite element physical simulation during milling process.Secondly, take simple thin-walled workpiece as an example, machining deformation during milling is studied and a method is proposed to analyzeand calculate machining deformation with finite element simulation. Finiteelement analysis (FEA) model is constructed to investigate the deformation,with several influencing key factors, such as cutting loads, element types andremoved materials, considered. The model is solved in MSC.Marc softwareand verified by the machining deformation experimental measurements, witheddy current displacement sensors used. On this basis, FEA and experimentsare employed to analyze the relationship between machining deformationand milling parameters, which will provide guidance to parameterschoosing.Finally, machining deformation of cubing’s complex thin-walledworkpiece is analyzed with finite element method. Based on machiningdeformation control, take the typical case cubing’s hood as an example andoptimization of fixture layout is studied in two aspects: clamping locationsand auxiliary support locations. In request of controlling deformation withinallowable range, fixture numbers are reduced and processing cycles areshortened, while making deformation distribution more uniform.