Ultrasonically assisted drilling of carbon fibre reinforced plastics and Ti6Al4V

Sandá, Alejandro; Arriola, I.; Navas, V. García; Bengoetxea, Ion; Gonzalo, Óscar

doi:10.1016/j.jmapro.2016.03.003

Cited by 82 publications

(25 citation statements)

References 23 publications

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“…As described in Section 2.2, the emissivity of the thermal imaging system has been adjusted for CFRP temperature measurement. As a result, the emissivity value was much greater than what was required for drill materials, hence the temperature measured for the drill can be significantly underestimated [52]. Meanwhile, combining results from the drills and the workpieces from Table 4(III), it can be concluded that the maximum temperature area in Fig.…”

Section: Maximum Temperatures At Drill Exitmentioning

confidence: 95%

Drill-exit temperature characteristics in drilling of UD and MD CFRP composites based on infrared thermography

Zhang

Wang

et al. 2018

International Journal of Machine Tools and Manufacture

124

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A B S T R A C TThis paper presents a comprehensive study on the complex drill-exit temperature characteristics in the drilling of unidirectional (UD) and multidirectional (MD) CFRPs using a state-of-art microscopy infrared imaging system. For the first time, temperature variation and distribution at drill exit have been revealed in full detail, associated with the CFRP material properties and drilling conditions. Results suggest that the actual drill/CFRP interactions have critical but similar effects on the drill-exit temperatures for UD and MD CFRPs. Specifically, three distinct cutting regions with varying temperature characteristics are evident when the main cutting edge is acting on the drill exit material. In all cases, the temperature distribution features elliptical shape, of which the eccentricity depends on the lay-up sequence and the drilling depth. In addition, the real-time temperature profiles and 2D/3D maximum temperature distribution maps are created with high visualization. With the aid of those findings, the relationships between drilling temperature maxima, their locations and drilling depths have been discovered and temperature effects on drill-exit damages have been elucidated for the first time. MD CFRP is proven more difficult to achieve high drilling qualities at certain fiber cutting angles than UD CFRP due to the associated temperature effects. Such important knowledge enables the identification of the heat affected zones and subsequently informs strategies for reducing the negative temperature effects.

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Section: Maximum Temperatures At Drill Exitmentioning

confidence: 95%

Drill-exit temperature characteristics in drilling of UD and MD CFRP composites based on infrared thermography

Zhang

Wang

et al. 2018

International Journal of Machine Tools and Manufacture

124

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“…In contrast to LF-VAD, the UAD of CFRP resulted in a significant reduction in the thrust force [22,23,[25][26][27]. This reduction was attributed to a lower coefficient of friction.…”

mentioning

confidence: 92%

“…Compared to the conventional drilling (CD), a significantly higher temperature was reported in [23], which was attributed to the tool impact mechanism. On the other hand, a lower cutting temperature compared to CD was reported in [27], which was attributed to the intermittent cutting mechanism.…”

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confidence: 93%

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Chip Morphology and Delamination Characterization for Vibration-Assisted Drilling of Carbon Fiber-Reinforced Polymer

Hussein

Sadek

Elbestawi

et al. 2019

JMMP

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Carbon fiber-reinforced polymers (CFRP) are widely used in the aerospace industry. A new generation of aircraft is being built using CFRP for up to 50% of their total weight, to achieve higher performance. Exit delamination and surface integrity are significant challenges reported during conventional drilling. Exit delamination influences the mechanical properties of machined parts and, consequently, reduces fatigue life. Vibration-assisted drilling (VAD) has much potential to overcome these challenges. This study is aimed at investigating exit delamination and geometrical accuracy during VAD at both low- and high-frequency ranges. The kinematics of VAD are used to investigate the relationship between the input parameters (cutting speed, feed, vibration frequency, and amplitude) and the uncut chip thickness. Exit delamination and geometrical accuracy are then evaluated in terms of mechanical and thermal load. The results show a 31% reduction in cutting temperature, as well as a significant enhancement in exit delamination, by using the VAD technology.

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“…The aluminum workpiece (5) was fixed on a special fixture which can slide along the axial direction of the lathe spindle. The special fixture (6) had a shaft and bearings (7) constrained by a loadcell (8) permitting measure drilling torque. The feeding motion of the drilling process was implemented by means of static gravity from a preset mass (12) via a roller (11).…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic-Assisted Cutting: A Beneficial Application for Temperature, Torque Reduction, and Cutting Ability Improvement in Deep Drilling of Al-6061

2018

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This paper presents an experimental study of the positive effects of vibration-assisted deep drilling of aluminum alloy Al-6061. The four most important evaluation criteria in drilling-machinability, workpiece temperature, torque, and material removal rate-were chosen to be investigated. Holes with a depth-to-diameter ratio of 13 were drilled by high speed steel (HSS) twist drill bits of 3 mm diameter, using both methods of conventional drilling (CD) and ultrasonic-assisted drilling (UAD). Three levels of axial force of 6 kgf, 9 kgf, and 12 kgf were kept constant for each pair of comparison experiments. It was found that workpiece temperature and torque not only changed from one drill to the other, but were also dependent on the hole depth being drilled. Comparisons were made in-pair between CD and UAD under the same axial force and at the same order of hole numbers. The result shows that the material removal rate with UAD was up to 3.5 times higher than that with CD and the average workpiece temperature and torque in UAD were reduced by 3.5 and 6 times, respectively. Moreover, tool life in UAD was observed to increase from 2.5 to 5 times, in terms of number of holes drilled, compared to that in CD. thrust force, morphology chip, built-up edge, exit burr, and hole oversize from UAD were reported as significantly improved compared with those from CD. In research by Chang and Bone [2], the authors predicted and compared thrust force induced in UAD and CD of Al-6061-T6. The conclusion shows that there is a vibration frequency that minimizes thrust force in different drills and cutting conditions. Burr height reduction of up to 85%, tool life increase (in terms of number of holes drilled), and an up to 20% reduction in the thrust force of UAD compared with those of CD have also been revealed in another study by these authors [3]. In other investigation, Li et al. [4] found that the thrust force of UAD is much smaller than that of CD, with a larger vibration amplitude resulting in the smaller thrust force of the cutting edge. A study by Babitsky et al. [5] verified several improvements in machining characteristics due to UAD in drilling, including faster penetration rates, reduction of tool wear, surface finish, roundness and straightness of holes, and the reduction or complete elimination of burrs when drilling ductile plates. Nevertheless, the effectiveness of UAD in deep hole drilling of aluminum alloys, where the depth-to-diameter ratios are larger than 5, have rarely been found in the literature.Investigations considering the reduction of torque and temperature as a primary factor which leads to major improvements in UAD compared with CD of other materials have also been limited in the literature. An experimental study from Azarhoushang and Akbari [6] drilling Inconel 738-LC considered on improvement in average surface roughness and circularity, hole oversize, and drill skidding, causing discontinuous and finer chips in UAD in contrast to in CD. Advantages of UAD such as reducing the thrust force and the cuttin...

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Ultrasonically assisted drilling of carbon fibre reinforced plastics and Ti6Al4V

Cited by 82 publications

References 23 publications

Drill-exit temperature characteristics in drilling of UD and MD CFRP composites based on infrared thermography

Drill-exit temperature characteristics in drilling of UD and MD CFRP composites based on infrared thermography

Chip Morphology and Delamination Characterization for Vibration-Assisted Drilling of Carbon Fiber-Reinforced Polymer

Ultrasonic-Assisted Cutting: A Beneficial Application for Temperature, Torque Reduction, and Cutting Ability Improvement in Deep Drilling of Al-6061

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