A Dynamic Modeling Approach to the Optimal Design of Nonuniform Chip Loading in Face Milling

247 p.Thesis (Ph.D.)--University of Illinois at Urbana-Champaign, 1985.Recent industrial demands on improved quality and productivity have increased the need for analytically sound tools for design, planning, optimization and control of complex manufacturing systems. In this thesis, the improvement of the dynamic performance of the multi-tooth face milling process is studied. The chip loading pattern is considered as the design parameter, and the consequences of nonuniform chip loading obtained by uneven insert spacing design and varying spindle speed design are investigated. The dynamic system performance is evaluated through force characteristics and associated vibrations, either forced or the chatter condition.The dynamic force model describes the cutting process as a closed-loop dynamic system with structural dynamics and feedback mechanism. The system geometries considered include cut geometry, cutter geometry, workpiece geometry, and process geometry including dynamic runout and spindle tilting. The dynamic force model forms the basis for the design of optimal nonuniform chip load and serves as a tool in its own right for dynamic process performance study through real time process simulation.The use of a vibration contour map as an alternative to the standard stability chart is introduced and its value in assessing both steady-state forced vibration as well as the chatter condition is demonstrated. The advantages of the dynamic force model used as a real time process simulator over more classical frequency domain stability analysis are demonstrated.A minimum vibration design criterion is developed as a means to determine optimal nonuniform chip loading for improved process performance. The criterion is shown to be superior to either existing stability or spectral redistribution criteria, guaranteering stability while minimizing the level of forced vibration. The new criterion is implemented through both uneven insert spacing and a new and more versatile approach of varying spindle speed according to an optimal speed trajectory within one cutter revolution. The varying rotational speed concept is employed toward the development of an on-line dynamic runout compensation algorithm which enables the deleterious effects of runout to be accounted for and/or eliminated by the nonuniform optimal chip load design.U of I OnlyRestricted to the U of I community idenfinitely during batch ingest of legacy ETD