Observation of Non-Taylorian tool wear and machining parameter selection for miniature milling of Ti-6Al-4V on regular CNC machines

ABSTRACT

The nature of tool wear is analyzed for end milling the titanium alloy Ti-6Al-4 V using miniature solid carbide endmills. Established thermal and mechanical machining models are used to predict tool temperature and cutting forces. Model outputs are used as the basis for selecting machining parameters under constraints imposed by regular CNC machines lacking ultra-high-speed spindles. Chiploads of the order of a few microns put the application in the regime of micromachining. Tool wear of the principal peripheral has been examined, which distinguishes our tool wear study. Microscopic observations reveal tool wear to be non-Taylorian, i.e., abrasive flank wear is not the main mode of wear. Depth-of-cut notching, edge chipping, and corner crumbling are the dominant tool wear modes. Negative helix endmills are found to be advantageous in delaying corner crumbling. The machining parameter selection method developed has direct industrial relevance in miniature feature machining of Ti-6Al-4V on regular CNC machines in which high-speed spindles are not used.

KEYWORDS:

• Micromilling
• titanium machining
• non-Taylorian tool wear

Acknowledgments

The authors wish to acknowledge Prof. Wallace Gregory Sawyer for his generosity in providing access to microscopy facilities in his Tribology Laboratory at the University of Florida.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes

1. In this document, all commercial products are identified for the sake of completeness, and to enable other investigators to replicate the experiments. This does not constitute endorsement of any of these products.

Additional information

Notes on contributors

Abhijit Bhattacharyya

Abhijit Bhattacharyya is an Associate Professor of Mechanical Engineering at Mahindra University, École Centrale School of Engineering, Hyderabad, India. He earned a PhD from the University of Florida. His research interests include modeling of machining processes, micromachining of metallic alloys, and tribological analysis of cutting tool materials.

Scott W. T. Payne

Scott W. T. Payne is a Manufacturing Engineer at the Halliburton Jet Research Center, Alvarado, TX . He earned a Bachelors in mechanical engineering from the California Institute of Technology, and a Masters from the University of Florida. His professional interests include the application of improved technologies for enhancing the productivity of industrial manufacturing processes, with a special emphasis on machining processes.

John. K. Schueller

John K. Schueller is a Professor of Mechanical and Aerospace Engineering at the University of Florida. He earned a PhD from Purdue University. He has two competing professional research interests, one in precision agriculture for which he won the 2018 Kishida International Award for agricultural research, and the other in discrete part manufacturing for which he won the 2003 Robert L. Pinckney Award of the American Helicopter Society as a member of the Bell-Sikorsky High Speed Machining of Titanium team