Analytical modeling of grinding process for improved productivity, part quality and material properties

Official URL: https://risc01.sabanciuniv.edu/record=b2579626_(Table of contents)

Grinding is one of the oldest machining processes which accounts for about 25% of the total expenditure of machining operations in industry. It is mostly used in finishing operation of the parts to achieve the required final geometry, tolerance integrity and surface quality. For some special cases, it is also possible to use grinding technology to perform roughing operations, e.g. for difficult-to-cut materials. Due to many influential parameters and complicated nature of grinding, process conditions are mostly selected based on experience which cannot determine the optimum values. The aim of this thesis is to develop analytical models in grinding considering true physical mechanisms involved in the process. First of all, a kinematic-geometrical model to identify the real active number of grits and undeformed chip thickness is proposed as it is the fundamental parameter influencing the mechanics of the process. A thermomechanical force model is developed based on the trajectory of the grits. According to the model, the grinding force composed of three portions namely ploughing, cutting and dead metal zone. It has been showed that only the cutting portion of the force resulted in material removal and the ploughing and dead metal zone account for most of the grinding force. A new temperature model is also proposed based on the fundamentals of moving heat source theory. The state of the art is based on the fact that the heat source is time-dependent in nature instead of a constant heat source applied in the previous models. The theoretical results and experimental validations confirm that by considering the time-dependent heat source the workpiece temperature is predicted more accurately. The models are validated by measuring workpiece surface roughness and grinding force and workpiece temperature. Furthermore, surface burn as one of the thermally-induced damages has been studied in this thesis analytically and experimentally. All models showed good agreements with the experimental data.