Effects of Milling Methods and Cooling Strategies on Tool Wear, Chip Morphology and Surface Roughness in High Speed End-Milling of Inconel-718
This paper presents the results of experimental investigation of the effects of milling methods (up-milling and down-milling) and cooling strategies [emulsion cooling, minimum quantity lubrication (MQL), cryogenic cooling using liquid nitrogen (LN2) and combined (MQL + LN2)] on flank wear, chip morphology and surface roughness in peripheral high speed end-milling of Inconel-718. The experimental results show that down-milling generated lower maximum flank wear than up-milling for all cooling strategies, thus improves machinability. MQL cooling with down-milling generated lowest maximum flank wear of 0.072 mm after eight passes and is recommended for machining Inconel-718, whereas LN2 cooling with up-milling generated highest flank wear of 1.984 mm after first pass only. Tool wear mechanism in up-milling is adhesion and failure modes are chipping and plastic deformation, causing rapid tool wear, while abrasion is the tool wear mechanism under down-milling causing progressive tool wear. Also, emulsion up-milling generated lowest surface roughness of 0.29 µm, whereas emulsion, MQL and combined (MQL + LN2) cooling strategies with down-milling generated equal and second lowest surface roughness of 0.34 µm. Results show that using MQL cooling under down-milling for machining Inconel-718 can lead to significant cost saving and sustainable machining.
A. C. Okafor and P. M. Jasra, "Effects of Milling Methods and Cooling Strategies on Tool Wear, Chip Morphology and Surface Roughness in High Speed End-Milling of Inconel-718," International Journal of Machining and Machinability of Materials, vol. 21, no. 2019-01-02, pp. 3-42, Inderscience Enterprises Ltd., Jan 2019.
The definitive version is available at https://doi.org/10.1504/ijmmm.2019.098065
Mechanical and Aerospace Engineering
Intelligent Systems Center
Keywords and Phrases
Chip morphology; Cooling strategies; Cryogenic cooling; Emulsion cooling; High speed end-milling; Inconel 718; Machinability; Machining; Milling methods; Minimum quantity lubrication; Surface roughness; Tool wear
International Standard Serial Number (ISSN)
Article - Journal
© 2019 Inderscience Enterprises Ltd., All rights reserved.
01 Jan 2019