Effect of laser beam on the chip formation in machining of titanium alloys

Abstract

The effect of laser beam on chip formation when machining Ti6Al4V alloy has been investigated at different cutting speeds, laser power and tool-beam distance. The characteristics of the segmented chip produced by laser assisted machining (LAM) in terms of the tooth depth and tooth spacing are strongly dependent on the cutting speed, laser power and tool-beam distance. Two types of segmented chip were formed, one at low and the other at high cutting speeds respectively with the continuous chip occurring between these two types of segmented chips. The critical cutting speed at which the transition from the sharp, segmented chip to the continuous chip occurs increases with laser power and strongly depends on the tool-beam distance. The chip becomes sharper with increasing cutting speed. To obtain the continuous chip, plastic deformation near the free surface to match the deformation strain by the cutting tool is required, which can be achieved by laser pre-heating the material in front of the cutting tool.