The interlayer gap and non-coaxiality in stack drilling

Gao, Yuhao; Wu, Dan; Nan, Chenggen; Ma, Xiaomeng; Dong, Yunfei; Chen, Ken

doi:10.1016/j.ijmachtools.2015.09.007

Cited by 22 publications

(11 citation statements)

References 22 publications

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“…This observation is in agreement with the work conducted by Li et al [10] and Yin et al [11], who focussed on aluminium-aluminium stacks. Gao et al [12] however point out that increasing the preload clamping force beyond a certain threshold does not lead to a further reduction in the interlayer gap. Melkote et al [6], who assessed the effect of various clamping methods on interlayer burr formation in drilling of aluminiumaluminium stacks, recorded an increase in interlayer burr height with an increase in the distance between drilling site and clamping location.…”

Section: Introductionmentioning

confidence: 99%

The effect of interlayer gap width on burr formation in drilling of aluminium-aluminium aerospace stacks

Pardo

Cseke

Heinemann

et al. 2019

Int J Adv Manuf Technol

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Interlayer burr formation during drilling of stacks is a widespread issue in the aerospace industry. The minimisation of the interlayer burr would contribute to significant time and cost savings, as it would allow for clamping, drilling and fastening to be carried out without any intermediate deburring that requires separating the layers. This paper reports about a notbefore observed phenomenon associated with the relationship between interlayer gap width and burr height when drilling aluminium-aluminium stacks with the presence of sealant at the interface. Initial experiments of the research were conducted to determine the interlayer gap widths in relation to a range of clamping forces, followed by drilling experiments to assess how the interlayer gap width affects the interlayer burr formation process and burr height. Although the presence of an interlayer gap results in larger burrs being formed, it allows upwards-travelling chips to enter the gap and erode away the newly formed burr. Larger interlayer gap widths were found to yield a more pronounced abrasion of the interlayer burrs, often leading to their complete removal; in some cases, this abrasion even resulted in a noticeable rounding of the borehole edges. This phenomenon was found to strongly affect the interlayer borehole quality and, thus, makes this research highly significant to the aerospace industry, where the quality of the borehole at the stack interface is of major interest.

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Section: Introductionmentioning

confidence: 99%

The effect of interlayer gap width on burr formation in drilling of aluminium-aluminium aerospace stacks

Pardo

Cseke

Heinemann

et al. 2019

Int J Adv Manuf Technol

View full text Add to dashboard Cite

show abstract

“…They conducted drilling experiments to understand the difference between the interlayer burr height and the interlayer gap. Gao et al [23] studied the interlayer gap formation and non-coaxiality occurrences in the drilling of stacked structures of broad skins and narrow stringers. They found that stack stiffness, drilling force and pressing force are the significant influencing factors.…”

Section: Introductionmentioning

confidence: 99%

“…However, on the premise that the interlayer gap is zero, we still need to find the optimal group of the bidirectional clamping forces. Because different groups of the bidirectional clamping forces will give rise to different deflections of the stacked plates, which will result in the non-coaxiality of the holes [23]. Therefore, the optimization objective of the bidirectional clamping forces is proposed, which is to reduce the degree and non-uniformity of the deflections of the stacked plates.…”

mentioning

confidence: 99%

Modeling and Optimization of Bidirectional Clamping Forces in Drilling of Stacked Aluminum Alloy Plates

et al. 2020

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Interlayer burrs formation during drilling of stacked plates is a common problem in the field of aircraft assembly. Burrs elimination requires extra deburring operations which is time-consuming and costly. An effective way to inhibit interlayer burrs is to reduce the interlayer gap by preloading clamping force. In this paper, based on the theory of plates and shells, a mathematical model of interlayer gap with bidirectional clamping forces was established. The relationship between the upper and lower clamping forces was investigated when the interlayer gap reaches zero. The optimization of the bidirectional clamping forces was performed to reduce the degree and non-uniformity of the deflections of the stacked plates. Then, the finite element simulation was conducted to verify the mathematical model. Finally, drilling experiments were carried out on 2024-T3 aluminum alloy stacked plates based on the dual-machine-based automatic drilling and riveting system. The experimental results show that the optimized bidirectional clamping forces can significantly reduce the burr heights. The work in this paper enables us to understand the effect of bidirectional clamping forces on the interlayer gap and paves the way for the practical application.

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“…In aircraft assembly, mechanical connections are the main type of connection between the components of the aircraft. The connection quality at the drilling hole has significant influence on the quality and lifespan of the aircraft [ 1 , 2 , 3 ]. With the traditional manual drilling method it has been difficult to meet the high-precision, high-efficiency and low-cost requirements of aircraft [ 4 ].…”

Section: Introductionmentioning

confidence: 99%

A Normal Sensor Calibration Method Based on an Extended Kalman Filter for Robotic Drilling

Chen

Yuan

Wang

et al. 2018

Sensors

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To enhance the perpendicularity accuracy in the robotic drilling system, a normal sensor calibration method is proposed to identify the errors of the zero point and laser beam direction of laser displacement sensors simultaneously. The procedure of normal adjustment of the robotic drilling system is introduced firstly. Next the measurement model of the zero point and laser beam direction on a datum plane is constructed based on the principle of the distance measurement for laser displacement sensors. An extended Kalman filter algorithm is used to identify the sensor errors. Then the surface normal measurement and attitude adjustments are presented to ensure that the axis of the drill bit coincides with the normal at drilling point. Finally, simulations are conducted to study the performance of the proposed calibration method and experiments are carried out on a robotic drilling system. The simulation and experimental results show that the perpendicularity of the hole is within 0.2°. They also demonstrate that the proposed calibration method has high accuracy of parameter identification and lays a basis for high-precision perpendicularity accuracy of drilling in the robotic drilling system.

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The interlayer gap and non-coaxiality in stack drilling

Cited by 22 publications

References 22 publications

The effect of interlayer gap width on burr formation in drilling of aluminium-aluminium aerospace stacks

The effect of interlayer gap width on burr formation in drilling of aluminium-aluminium aerospace stacks

Modeling and Optimization of Bidirectional Clamping Forces in Drilling of Stacked Aluminum Alloy Plates

A Normal Sensor Calibration Method Based on an Extended Kalman Filter for Robotic Drilling

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