Case Study - Mechanistic Feed Scheduling for Multi-Axis Machining of Titanium

Tool path planning for multi-axis machining of titanium helicopter parts presents significant challenges with accordingly significant costs. These arise from variations in chip loads due to part geometry, tool and work-piece deflections, dynamic instability, and material deformation behavior. What is lacking in most of the existing tool path planning software is the ability to determine the appropriate speeds and feeds based upon machining mechanics considerations. Sikorsky Aircraft and The Georgia Institute of Technology have teamed together to develop a solution to this problem using mechanistic process modeling. This semi-analytical approach involves accurate modeling of process geometry and kinematics combined with experimentally determined coefficients for the tool and work piece properties. This approach, which has experienced some success in 2 and 2-1/2 axis machining applications, will be extended and applied to 3,4, and 5 axis-machining of Sikorsky components. This industrial case study will present how Sikorsky came to select mechanistic feed scheduling modeling as a tool for improving machining processes and the results of the ongoing research activities to develop a practical tool path planning strategy based upon the physics of the machining process.