Abstract
Minimal quantity lubrication (MQL) machining has so far been recognized as a representative near-dry machining operation and it has demonstrated successful results in a number of practical applications, becoming common technology mainly for machining of steels. Recent concern for environmentally friendly manufacturing further encourages the attempts at applying the MQL operation to machining of difficult-to-cut materials. Since titanium alloys are typical difficult-to-cut materials, this paper investigates the cutting performance of MQL methods in turning of a titanium alloy from the view point of elongating the tool life. As a MQL lubricant, the investigation uses such oxygen-including compounds as a synthetic polyol ester, which presents the successful cutting performance for MQL machining of steels, oleyl alcohol and oleic acid. The MQL operations have provided considerably long tool life compared with that of dry machining and oleyl alcohol has demonstrated the excellent cutting performance particularly at the small depth of cut.
