Analysis of ignition risk in intermittent turning of UNS M11917 magnesium alloy at low cutting speeds based on the chip morphology

Abstract

This study is based on a series of turning tests of UNS M11917 magnesium alloy, using low cutting speeds to emulate the conditions of repair and maintenance operations. More specifically, intermittent turning process, using both dry machining and minimum quantity lubrication system, is analysed. Cutting operations are done to evaluate the chip morphology obtained in order to assess their suitability for the cutting process and chip ignition probability of occurrence. From the point of view of machining, favourable chips are identified in all the tests done, getting chips of short length. However, in terms of ignition risk, short chips are considered unfavourable. Main results show how uncoated tools (HX) provided worse results in terms of short chips, while coated tools (TP2500) provided chips of size higher than 1 mm in all the cutting operations performed. Besides, a detrimental effect of the use of the minimum quantity lubrication system in the ignition risk is also identified.