Identification of Position-Dependent Workpiece Dynamics in Milling Process

Thesis Type: Postgraduate

Institution Of The Thesis: Middle East Technical University, Faculty of Engineering, Department of Mechanical Engineering, Turkey

Approval Date: 2022

Thesis Language: English


Principal Supervisor (For Co-Supervisor Theses): Hakan Çalışkan

Co-Supervisor: Orkun Özşahin


Frequency Response Functions (FRFs) are utilized for analyzing vibrations created during milling process. FRFs obtained with external excitations are often not sufficient as machine-tool dynamics are position-dependent (to machine-tool axes, workpiece placement) and frequency domain to be identified requires specialized equipment. In this thesis, an identification method based on operational excitation addressing these problems is proposed. A single rectangular workpiece is processed and acceleration measurements are taken. FRF is calculated according to the proposed method of sampling engagements individually and force calculation based on mechanistic models. Results are compared with tap test results. Force coefficients to be used are identified by tap tests obtained from a different spot and mechanistic force model by processing a similar rectangular workpiece. Results are confirmed with FRF obtained in the same location.