Tool wear and hole quality investigation in dry helical milling of Ti-6Al-4V alloy

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A comparative study on conventional drilling and helical milling has been reported under the context of aircraft alloy hole making. The impacts of these two different machining processes on the microstructures and the fatigue performance of different aircraft alloys have been elaborated. Results show that both alloys undergo more severe surface/subsurface plastic deformation under conventional drilling comparing to helical milling process. Helical milling leads to a longer coupon fatigue life compared to conventional drilling for both alloys. The fatigue life of Al 2024-T3 is significantly longer than that of Ti-6Al-4V under all machining conditions. The use of coolant generally produces less damaged surface and leads to enhanced fatigue performance of the machined alloys. In addition, the machined surface roughness has been studied to further elaborate the effects of different machining processes.

Section: Introductionmentioning

confidence: 98%

Hole-making processes and their impacts on the microstructure and fatigue response of aircraft alloys

Sun

Lemoine

Doyle

et al. 2016

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“…Although a few studies have deployed coated tools in helical milling of alloy or composites [12,26,27], the role of different coatings in helical milling of Ti/CFRP stack is still lacking. Since helical milling is increasingly used in aircraft assembling, it is necessary to systematically evaluate the coated tool performance and understand their degradation mechanisms in helical milling of Ti/CFRP stacks.…”

Section: Introductionmentioning

confidence: 99%

A comparative study of hole-making performance by coated and uncoated WC/Co cutters in helical milling of Ti/CFRP stacks

Qin

Jin

et al. 2017

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General rights Copyright for the publications made accessible via the Queen's University Belfast Research Portal is retained by the author(s) and / or other copyright owners and it is a condition of accessing these publications that users recognise and abide by the legal requirements associated with these rights.Take down policy The Research Portal is Queen's institutional repository that provides access to Queen's research output. Every effort has been made to ensure that content in the Research Portal does not infringe any person's rights, or applicable UK laws. If you discover content in the Research Portal that you believe breaches copyright or violates any law, please contact openaccess@qub.ac.uk. AbstractCarbon fiber reinforced plastic (CFRP) and titanium alloy stacks are typical difficult-to-machine materials and often results in rapid tool wear, leading to a low drilling efficiency in aircraft assembling. Helical milling process has demonstrated its superior performance in making holes in these materials, but selecting a proper cutting tool is still a great challenge and little research has been carried out to investigate the effect of different coatings on tools performance. Therefore, in this paper, milling tools with and without coatings (diamond coating, TiAlN+AlCrN multilayer coating and TiAlN coating) were employed in helical milling of Ti/CFRP stacks. The cutting performance and the degradation mechanisms of these milling tools were investigated in details. It is found that, uncoated tools demonstrate the best cutting performance with lowest cutting force, highest hole quality and slightest tool wear. Degradation of nitride coated tools is due to the combined effects of increased roundness of cutting edge and the strong dependence of cutting performance on the tool sharpness. Diamond coated tools showed the greatest degradation, which has been attributed to the low materials ductility at tool cutting edge, weak adhesive strength between the coating and substrate, and the poor thermal resistance of the diamond coating.

“…There is significant theoretical study [1,4,5], and there is a background comprising literature that deals with corresponding sensing, processing methods [6], and reliability assessment [7]. This is due to the fact that successful monitoring [1] of the tool wear during machining may provide significant benefits in terms of cost and machining quality [8]. It is reported [9] that using wear sensors, a tool cost saving up to 40 % may be reached.…”

Section: Introductionmentioning

confidence: 99%

Tool wear predictability estimation in milling based on multi-sensorial data

Stavropoulos

Papacharalampopoulos

Vasiliadis

et al. 2015

136

The safe and reliable operations in industrial manufacturing processes play a crucial role in the economic productivity. Machining process disturbances such as collision, overload, breakdown, and tool wear tend to cause production system failures. The current study aims at investigating the limitations of tool wear prediction on the milling of CGI 450 plates, through the simultaneous detection of acceleration and spindle drive current sensor signals. Tool wear prediction has been accomplished, by utilizing the experimental results that derived from third degree regression models and pattern recognition systems. These results indicate that predictability is affected by the mean signal energy, acquired from the vibration acceleration signals.