Modeling of grinding process mechanics

Official URL: http://risc01.sabanciuniv.edu/record=b1589794 (Table of Contents)

Grinding process is one of the most common methods to manufacture parts that require precision ground surfaces, either to a critical size or for the surface finish. In abrasive machining, abrasive tool consists of randomly oriented, positioned and shaped abrasive grits which act as cutting edges and remove material from the workpiece individually to produce the final workpiece surface. Hence it is almost impossible to achieve optimum process parameters and a repeatable process by experience or practical knowledge. In order to overcome these issues and predict the outcomes of the operation beforehand, modeling of the process is crucial. The main aim of this thesis is to develop semi-analytical or analytical models in order to represent the true mechanics and thermal behavior of metals during abrasive machining processes, especially grinding operations. Abrasive wheel surface topography identification, surface roughness, thermomechanical and semi-analytical force models and two dimensional moving heat source temperature model are proposed. These models are used to simulate the grinding process accurately. The proposed models are more sophisticated than previous ones as they require less calibration experiments and cover wider range of possible cutting conditions. Once the wheel topography and abrasive grit properties are identified, uncut chip thickness per grain and final workpiece surface profile can be predicted. A novel thermo-mechanical model at primary shear zone with sticking and sliding contact zones on the rake face of the abrasive grit was established to predict cutting forces by assuming each of the abrasive grit similar to a micro milling tool tooth. Knowing the force and total process energy, by using two dimensional moving heat source theory, process temperatures are predicted. Moreover, an initial approach and experimental results are proposed in order to investigate and model dynamics and stability dynamics of the grinding process. All proposed models are verified by experiments and overall good agreement is observed.