An investigation of temperature effects on curled chip formation in metal machining

Almost all existing cutting models deal with continuous chip formation despite increasing need for producing curled chips for effective breaking and disposal in unattended machining systems. The present study investigates the temperature effects on curled chip formation via the understanding of temperature distributions within a curled chip during its formation cycle. Three methods have been developed to analyze the present problem. The analytical method solves the temperature distributions within the curled chip through a 2-D transient heat conduction equation in cylindrical coordinates and a simple 1-D heat equation in curvilinear coordinates. An unique infrared imaging system was applied to measure the temperature distributions within curled chips during the orthogonal machining process. To understand the transient process of the temperature distributions within one curled chip formation cycle, the finite element method was used to solve the temperature distributions within the actual curled chip and the cutting tool. Three methods have been correlated to each other through comparisons with the experimental results. The good agreement achieved shows that the developed analytical solutions and finite element method can be used to establish interrelationships among chip formation, chip curl development, chip fracture and temperature distributions within curled chips, which will enhance our understanding of temperature effects on curled chip formation in orthogonal machining.