INVESTIGATION OF TOOL WEAR IN GRINDING PROCESSES
Industrial Engineering, MSc., 2016
Prof. Dr. Erhan Budak (Thesis Advisor), Assoc. Prof. Dr. Bahattin Koç,
Assoc. Prof. Dr. Mustafa Bakkal
Date & Time: 29th, December 2016 – 10:30
Place: FENS L047
Keywords: Abrasive Processes, Grinding, Electroplated CBN Wheel, Wear Mechanisms, Tool Life, Inconel 718, Fracture, Attritious, Pullout, SAM (Superabrasive Machining), Surface Quality
Low cost, high quality and fast production are essentials of the competitive industry. Due to technological advances, grinding has come into the forefront for producing high quality parts in an economical way in recent decades. One of the most important critical issues in superabrasive machining processes is tool wear due to its impact on surface integrity, part quality and process cost.
The main aim of this thesis is to investigate the wear process of grinding wheels considering wear mechanisms, tool life and process outcomes. Wheel wear in grinding is a sophisticated phenomenon which can affect the entire grinding process profoundly. Different types of wear mechanisms such as attritious wear, grit fracture and pullout of the abrasive grits are studied. The effect of wear on the grinding forces and the quality of the part have been investigated. Grits were individually measured during the process and the wear mechanisms are discussed in detail. Some of the grits on the wheel surface are chosen randomly and all phases of worn grits are monitored during its lifetime under a microscope. Wear related surface roughness investigations are done for both the workpiece and the tool throughout the tool life.
The wear behavior of the grinding wheel is sensitive to the process parameters such as depth of cut, feed rate and cutting speed. An analysis on the effect of depth of cut on the wear and process results is done. Tool life criteria is provided for the selected wheel-workpiece pair. A new model is presented to predict the surface roughness of the electroplated CBN grinding wheel. The wear condition of the electroplated grinding wheel can be estimated by this model and the model can also be applied to the other type of single-layer wheels. The model can be used to predict the surface quality of the part, because surface roughness of the workpiece and grinding wheel are correlated to each other. The model is verified by experiments and good agreement is obtained.