Proceedings of the
World Congress on Micro and Nano Manufacturing (WCMNM 2022 )
19–22 September 2022, Lueven, Belgium
doi:10.3850/978-981-18-5180-3_RP04-0036
Influence of Hydrogen-Free DLC Coated Micro Ball Endmills on Machining Response and Tool Wear in High-Speed Micromilling of Ti6Al4V
1Department of Mechanical Engineering, IIT Bombay, Powai, India
2Department of Mechanical Engineering, IIT Guwahati, India
3Surface Engineering Division, National Aerospace Laboratories, Bangalore, India
ABSTRACT
The micromilling process is extensively used in various industries owing to its capability to fabricate complex 3D miniaturized features and its applicability for a wide range of engineering materials. However, lower flexural stiffness of low diameter cutting tool is the major limitation which can lead to a high tool failure rate. This limitation can be addressed using high rotational speeds, but it can increase temperature and friction in the cutting zone. The friction and temperature rise can affect the cutting forces, tool life, and surface quality. One way to overcome these limitations is use of thin film coated tool, which will reduce the friction in the cutting zone and can withstand high temperatures. This study is focused on investigating the machining performance of hydrogen-free DLC coatings in high-speed micromilling of Ti6Al4V. A comparative study has been performed for tool wear and machining response in hydrogen-free DLC coated and uncoated tools. Cutting force coefficients has been estimated using mechanistic force model. Coating delamination and built-up edge are observed to be significant in DLC coated tools. The size effect and minimum chip thickness effect are more dominant at lower feeds in micromilling with DLC coated tools. The predicted and measured values of the cutting forces show good agreement.
Keywords: Micromilling, Hydrogen free DLC coating, Tool wear, Cutting force coefficients.
1Department of Mechanical Engineering, IIT Bombay, Powai, India
2Department of Mechanical Engineering, IIT Guwahati, India
3Surface Engineering Division, National Aerospace Laboratories, Bangalore, India
ABSTRACT
The micromilling process is extensively used in various industries owing to its capability to fabricate complex 3D miniaturized features and its applicability for a wide range of engineering materials. However, lower flexural stiffness of low diameter cutting tool is the major limitation which can lead to a high tool failure rate. This limitation can be addressed using high rotational speeds, but it can increase temperature and friction in the cutting zone. The friction and temperature rise can affect the cutting forces, tool life, and surface quality. One way to overcome these limitations is use of thin film coated tool, which will reduce the friction in the cutting zone and can withstand high temperatures. This study is focused on investigating the machining performance of hydrogen-free DLC coatings in high-speed micromilling of Ti6Al4V. A comparative study has been performed for tool wear and machining response in hydrogen-free DLC coated and uncoated tools. Cutting force coefficients has been estimated using mechanistic force model. Coating delamination and built-up edge are observed to be significant in DLC coated tools. The size effect and minimum chip thickness effect are more dominant at lower feeds in micromilling with DLC coated tools. The predicted and measured values of the cutting forces show good agreement.
Keywords: Micromilling, Hydrogen free DLC coating, Tool wear, Cutting force coefficients.
