COLD AIR DRY MACHINING Part 2: SEM AND METALLOGRAPHIC ANALYSIS OF THE CHIP
ABSRACT Dry machining and near-dry machining were developed as an alternative to flood and internal highpressure coolant supply to reduce metal working fluids consuption. In dry machining, compressed air introduces into the cutting zone, while near-dry machining supplies very small quantities of lubricant into the cutting zone. Both these techniques have been introduced with the aim to reduce the use traditional coolant and lubricant. One of the many dry machining techniques is the usage of cooled compressed air. SEM and metallographic analysis of the chip during dry machining are presented in this paper. Machining tests were performed by turning of three grade of workpiece materijal: alloyed steel, aluminium bronze, and pure aluminium. Three ways of dry machining are performed: machining without the use of coolant and lubricant, cold air dry machining and with a cooling of workpiece before machining. Analysis of produced chips shows some advantages of dry machining, mainly in the process of chips segmentation, even in cases of machininig very ductile material.