INVESTIGATION OF VARIATION IN TOOL-CHIP CONTACT LENGTH IN ORTHOGONAL CUTTING PROCESS

The tool-chip contact length has an important effect in view of tool life and tool wear in machining process. An increase in tool-chip contact length may results in a decrease of tool life. Besides the tool-chip contact length is an important element in formation of crater wear. The increasing of tool-chip contact length results in increase of friction forces acting on tool rake face and affects the temperature distributions along the cutting tool. First, in this study, all analytical models proposed to calculate the tool-chip contact length were compared with each other. Second, the tool-chip contact length was calculated using three different models for different workpiece materials and cutting parameters. The experiments were performed in a series of test in order to understand the relationship between tool-chip contact length and cutting velocity, material type and undeformed chip thickness. The turning tests were carried out under orthogonal cutting conditions and ceramic cutting tool was used. According to results, the increasing of feed rate and type of workpiece material have an important effect on the tool-chip contact length.