Research on experiments with water vapor as coolant and lubricant in drilling Ti6Al4V

Abstract

PurposeThe purpose of this paper is to develop water vapour as a new cooling and lubricating technique in drilling Ti6Al4V. Water vapor is an economical and eco‐friendly coolant and lubricant. However, it is necessary to study the drilling chip deformation, forces and drilling temperature when drilling Ti6Al4V using this new green drilling technology, which meets the development trend of green machining technology.Design/methodology/approachComparative experiments are carried out with HSS drill bits and YG6X (K10 type in ISO) cemented carbide drill bits in drilling Ti6Al4V under the conditions of oil water emulsion, water vapor as coolant and lubricant and dry drilling, respectively. The drilling forces, temperature and drill bit wear VBmax have been examined and analyzed. Further, a new type practical drilling quick‐stop device is developed for studying the chip deformation in drilling Ti6Al4V. The drilling forces distribution test in drilling Ti6Al4V is also developed.FindingsWhen water vapor is used as coolant and lubricant, the torque is reduced by 15‐25%, 5‐10% in comparison with dry drilling and oil water emulsion, respectively; the thrust is reduced by 5‐10%, 4‐5%; the temperature is reduced by 15‐20%, 5‐8% and the wear VBmax of drill bit is reduced by 60‐80%, 10‐15%, correspondingly. Also, the contact length in chip‐tool interface decreases and the drilling deformation is reduced. The coolant and lubricant conditions and feed rate have little impact on the drilling force distribution in drill bit cutting edges.Originality/valueA green machining technology, water vapor used as coolant and lubricant, is used in drilling Ti6Al4V; it can reduce drilling deformation, drilling forces, temperature and flank wear. A new drilling quick‐stop device is devised to obtain the drilling chip roots. Also, the drilling force distribution test was developed for obtaining the rate of drilling forces in cutting edges when drilling Ti6Al4V.