Helical Milling of Carbon Fiber Reinforced Plastics Using Ultrasonic Vibration and Liquid Nitrogen

Due to its excellent specific mechanical properties, carbon fibre-reinforced polymer (CFRP) composite is a widely used structural material in the aerospace industry. However, this material is difficult to cut, mainly due to its inhomogeneity and anisotropic features and because of the strong wear effects of its carbon fibres. In the scope of aerospace industrial uses of this material, thousands of holes have to be machined for purposes of assembly. Nevertheless, conventional drilling technologyeven if special drilling tools are usedis only moderately able to manufacture good quality holes. Wobble milling is a novel advanced hole-making technology, which has been developed to minimize machining-induced geometrical defects like delamination or uncut fibres. The main objective of the present paper is to compare wobble milling, helical milling and conventional drilling technologies concerning unidirectional CFRPs. In addition, the kinematics of wobble milling technology is discussed in detail. In the scope of this paper, numerous machining experiments were conducted in unidirectional CFRPs: herein the impact of the type of cutting tool and of process parameters on the quality of machined holes are analysed and discussed (diameter of holes, circularity error and characteristics of uncut fibres). During these investigations, experimental data were evaluated with the help of digital image processing (DIP) and with the help of analysis of variance (ANOVA) techniques. Experimental results show that the amount of uncut fibres can significantly be minimized through the application of wobble milling technology.

Section: Conventional Drilling and Helical Milling Of Cfrpsmentioning

confidence: 99%

“…Even if previously many researchers investigated the impacts of technological and process parameters on conventional drilling induced damages in CFRPs, the number of scientific studies as far as the helical [7,32,35,[43][44][45][46][47], tilted helical [48,49] and wobble milling [50][51][52] of CFRPs are concerned is limited.…”

Section: Introductionmentioning

confidence: 99%

Comparative analysis of wobble milling, helical milling and conventional drilling of CFRPs

Pereszlai

Geier

2020

“…15 [74]. Ishida et al [75] [74] demonstrated helical milling of carbon fiber reinforced plastics using ultrasonic vibration with cryogenic tool cooling. High-precision holes were obtained at the inlet of the machined holes and the delamination size at the outlet was reduced as shown in Fig.…”

Section: Helical Millingmentioning

confidence: 99%

“…Figure 17a shows the surface Fig. 16 Digital microscope image of delamination at the inlet and outlet of the conventional and ultrasonic assisted helical milling [75] Fig . 17 Effect of VAM in surface tool produced a without VAM, b with VAM [66] generation by conventional milling, with peaks and valleys left by the cutter.…”

Section: End Millingmentioning

confidence: 99%

State-of-the-art review on vibration-assisted milling: principle, system design, and application

Chen

Huo

Shi

et al. 2018

Vibration-assisted machining (VAM) is an external energy assisted machining method to improve the material removal process by superimposing high frequency and small amplitude vibration onto tool or workpiece motion. VAM has been applied to several machining processes, including turning, drilling, grinding, and more recently milling, for the processing of hard-to-machine materials. This paper gives a critical review of vibration-assisted milling (VAMilling) research. The basic kinematic equations of 1D and 2D VAMilling are formulated and three typical tool-workpiece separation types are proposed. State-of-the-art on the principle and structural design of VAM systems are reviewed. The benefits and applications of VAMilling are discussed with emphasis on machining of hard-to-machine materials. Finally, the paper concludes with future possibilities for VAMilling.

“…In hole making processes for Ti/CFRP stacks, the low thermal conductivity, low deformation coefficient and high chemical reactivity of titanium alloys often result in severe tool wear [13,14], while the high hardness of carbon fibers in CFRP also poses a great challenge to the tool durability [15][16][17][18]. In spite of numerous advantages of the helical milling process, rapid tool wear still occurs in milling of Ti/CFRP stacks [19], leading to reduced processing quality.…”

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

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.