Mechanistic force model calibration for milling in multiple materials

Being able to measure and simulate cutting forces of milling is crucial to understanding the machining process at a higher level. The research objective of this thesis is to develop and validate a milling mechanistic cutting force model for a variety of materials that can be used to predict machining performance, which includes cutting force and the associated acceleration, velocity, and displacement of the tool and/or workpiece during milling. The cutting forces for development of the simulated model will be measured using a previously studied constrained motion dynamometer (CMD) compared to values from a commercially-available cutting force dynamometer. The CMD measures the displacement of the stage while milling and that displacement is deconvolved into a force using the frequency response function (FRF) of the system. Calculating the cutting force coefficients (CFCs) for a variety of material and tool combinations will be done utilizing a linear regression method with the mean cutting force from a range of feed per tooth values. The CFCs and system parameters are then input into a simulated milling mechanistic force model that can be utilized to predict the milling signals, including force and displacement, for cutting tests completed using the CMD.

Secondary tasks include making improvements to the data collection and calibration processes of the CMD. As well as determining if any changes in the CMDs dynamics, particularly a natural frequency shift, due to a change in workpiece mass can be modeled and compensated as a function of material removed from the workpiece. This will all be done for the purpose of validating and streamlining the process of constructing a simulated milling force mechanistic model utilizing the CMD that can be utilized to simulate cutting conditions beyond the ones used to calibrate the model.