The accuracy improvement and high speed machining (HSM) of the machine tools are undoubtedly two of the main demands, which are the structural design with high stiffness characteristic and the high material removal rate (MRR) in the stable cutting condition without self-excited vibration (i.e. chatter) that occurs from the interaction between the cutting-tool and the workpiece during the machining process. The structural design optimization have simultaneously carried out with an effort to reduce the cost, which is the total weight of the structure, and increase the static, dynamic, thermal stiffness throughout the design or development stage of the machine tools. The static and dynamic stiffness are directly related to the chatter problem.
In this paper, the structural design optimization of the modular type micro milling machine tool (MmMT), which has the small size machine with the modularized units of machine tool parts for micromachining, focuses on the cost, the structural stiffness and the critical depth of cut with chatter free.
Chapter 1 presents the general domain of the this thesis, establishes the background and exposes the interest, motivation and objectives.
Chapter 2 presents the configurations of the modular type micro milling machine created from referred methodology in preliminary design stage. The initial design model of MmMT is designed based on the conceptual milling machine configurations. Then, MmMT has been modelled the finite element model and carried out the structural analysis for the structural design optimization.
Chapter 3 mentioned chatter vibration in milling operation. Analytical chatter vibration of the initial model is predicted by using stability lobe diagram (SLD).
Chapter 4 proposed CHAFDOP (chatter free structural dynamic design optimization) program for the multidisciplinary and multi-objective optimization method considering chatter vibration. The structural design optimization of MmMT applied to minimize weight and dynamic compliance and maximize critical depth of cut of the modular machine tool concurrently.
Finally, chapter 5 presents conclusions and outlook.
As the result, the weight and dynamic compliance of MmMT are decreased about 1.7% and 9.8% respectively and the critical depth of cut is improved 38.1% than the initial model, satisfying all constraints.
The proposed CHAFDOP is the efficient optimization to improve the performance and productivity of the machine tools due to deal with all of the weight, stiffness, and cutting performance. The CHAFDOP can contribute the comprehensive and effective structural design technique of the machine tools for the multidisciplinary design.