Experimental investigation on finish intermittent turning of UNS M11917 magnesium alloy under dry machining

An experimental investigation on finish intermittent turning of UNS M11917 magnesium alloy under dry machining is presented. The objective of the study is the analysis of the chip morphology, surface quality and temperature when varying cutting conditions. The intermittent cutting process is analysed using three different workpieces (one continuous and two discontinuous). The experimental plan is based on full factorial designs. Main results of the investigation include the identification of the feed rate as the most important parameter to explain the surface roughness, while no clear influence was found for the cutting speed and slot width. The maximum temperature measured on the tool during the tests was below 50 °C in all of the tests. These low temperature values are explained by the low machining times, depths of cut and cutting speeds used. Thus, for the range of the cutting parameters tested, finish operations can be performed using dry machining under safe conditions. In addition, it was identified that the increase of the depth of cut and feed rate led to higher maximum temperatures, while the increase of the slot width led to lower values. Finally, the morphology of the chips can be classified as segmented chips, including the arc, elemental and spiral chips. Thus, in terms of machining, these chips can be considered as favourable, but, in terms of ignition, these chips are more likely to ignite.