Improved examination and test procedure of tapping torque tests according to ASTM D5619 using coated forming taps and water-mixed metalworking fluids

Tapping torque test is a standardized (ASTM D5619-00) approach evaluating the lubricity of metalworking fluids. It was detected that running-in behaviors of taps and carryover effects caused by previously used fluids were not investigated. Further, it is detected that effects due to changed tap conditions or fluids are underestimated. The low number of measurements leads to deviations of torque means. In this contribution, the running-in phase of coated forming taps is evaluated by measuring tapping torque in AlMgSi1, C45E, and AlSi7Mg materials using water-mixed metalworking fluids. New tests and calculation methods considering tool wear are suggested. As outcome increased experimental significance at higher confidence levels, comparability between taps and test platforms, and better distinguishability of water-mixed metalworking fluids are obtained.