Tool Path Planning and Optimization for Five-Axis Flat-End Milling Considering Machine Kinematics (Het plannen en optimaliseren van gereedschapsbanen voor het 5-assig frezen met behulp van vingerfrezen, rekening houdend met de kinematica van de machine)
Tool Path Planning and Optimization for Five-Axis Flat-End Milling Considering Machine Kinematics
Although ﬂat-end multi-axis milling has been proven to be more efficient than ball-end machining for more than twenty years, dedicated tool path generation and planning algorithms have been seriously suffering from insufficient intelligence because they originate from ball-end algorithms and do not consider issues attributed to the ﬂat-end shape of tools. This research work describes the development and implementation of new algorithms designed for tool path planning and generation aiming taking machine kinematics into account. The developed components are founded on prototype software that can handle STL geometry for robust computation of tool path tracks and interference-free tool postures. This STL kernel was also extended with support of facet machining status to enable machining simulation. In addition to the kernel, three different components were developed to facilitate optimization of tool inclination, material removal simulation, and tool path planning. First, two tool path optimization methods were elaborated to perform minimization of machine tool rotations in reasonable computation time. Second, a novel material removal simulation based on accurate estimation of swept sections has been introduced. Third, tool path planning algorithms integrating the developed material removal simulation allow efficient tool path generation with reduced machining strip overlaps and dynamic step-over between adjacent tool path tracks. This integration has also given an opportunity to introduce two strategies. First strategy implements the cutting plane approach to slice STL surfaces and generate zig-zag-like tool paths with intelligent selection of tool path tracks directions. Second strategy generates contour-like tool paths, going inwards from a workpiece outside, resulting in machined surfaces with predictable scallop height. This research highlighted and resolved several ﬂaws in existing algorithms. First, estimations of machining strip widths derived from a single posture are almost surely incorrect in a case of ﬁve-axis machining. Therefore, a new approach taking several postures into account has been developed and implemented. Second, regardless of the dramatic inﬂuence of machine tool kinematics and CNC behavior onto the actual shape of a machined surface, machine tool characteristics are not considered by the existing material removal simulation algorithms. Thus, in this research, tool motion has been interpolated in machine coordinates. The developed methods can be smoothly integrated with themselves and other CAM software. Eventually, these methods are believed to assist CAM programmers in generating efficient tool paths in an automated manner.