Analysis of thrust force and characteristics of uncut fibres at non-conventional oriented drilling of unidirectional carbon fibre-reinforced plastic (UD-CFRP) composite laminates

Geier, Norbert; Szalay, Tibor; Takács, Márton

doi:10.1007/s00170-018-2895-8

Cited by 67 publications

(32 citation statements)

References 36 publications

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“…Due to the extremely high experimental costs, the number of experiments had to be minimized, the central composite inscribed DoE method was therefore used to design conventional drilling and helical milling experiments. Factors and their levels were chosen based on previous researches [11,[41][42][43][44][45][46] and suggestions of tool producers. The experimental design table can be seen in Table 2.…”

Section: Methodsmentioning

confidence: 99%

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Analysis of Characteristics of Surface Roughness of Machined CFRP Composites

Geier

Pereszlai

2019

Period. Polytech. Mech. Eng.

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Measuring and characterizing of surface roughness of machined surfaces of carbon fiber reinforced polymer (CFRP) composites are difficult due to the occurrence of special surface damages (delamination, uncut fibers, fiber pull-outs or micro-cracks, etc.). The main objective of the present study is to analyze the characteristics of surface roughness of machined unidirectional CFRP in detail. Numerous conventional drilling, helical milling, and edge trimming experiments were carried out with different cutting tools in order to analyze the influence of them on the average surface roughness (Ra), on the roughness depth (Rz) and on the Rz /Ra parameter. The surface roughness was measured by a Mitutoyo SJ-400 contact profilometer and an Alicona Infinite Focus confocal microscope. The usability of the contact profilometer was experimentally tested and compared its results with the results of the confocal microscope. Experimental results show that the contact profilometer is suitable for measuring surface roughness of CFRP, furthermore, values of Rz /Ra of drilled and edge trimmed surfaces of unidirectional CFRP are changing in a wide interval: from 5 to 14 μm/μm due to the special surface damages. Based on this research, the machinability analysis of CFRP is suggested to be extended to the analysis of the Rz /Ra parameter.

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Section: Methodsmentioning

confidence: 99%

“…1. The influence of fiber cutting angle has been widely investigated by many researchers [6,[10][11][12][13][14][15][16][17][18][19][20][21][22][23][24][25][26] in order to describe chip removal mechanisms in unidirectional CFRP.…”

Section: Introductionmentioning

confidence: 99%

Analysis of Characteristics of Surface Roughness of Machined CFRP Composites

Geier

Pereszlai

2019

Period. Polytech. Mech. Eng.

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“…In computer science, digital image processing (DIP) consists in the use of computer algorithms for performing image processing on digital images [90]. Many researchers [23,25,26,28,29,47] characterized the quality of machined holes in CFRPs by using parameters calculated using different DIP methods. Yet, some of these parameters were not specific (diameter-independent) values.…”

Section: Digital Image Processingmentioning

confidence: 99%

“…In case improper machining technology is applied when machining CFRPs, many micro-and macro-geometrical damages can be generated easily: such damages include delamination [6,7,[14][15][16][17][18][19][20][21][22][23][24], uncut fibres and pull-outs [13,[25][26][27][28][29][30][31] as well as microcracks on the machined surfaces [30,[32][33][34]. In order to minimize the above-listed damages, there are many process and technological parameters that have to be optimized including (i) the geometry and coating of the cutting tool [18,33]; (ii) the cutting speed, feed rate and the depth of cut [7,18,35]; (iii) the tool path [7,13,32]; (iv) the cooling [36][37][38][39]; and (v) the type of support plate [40][41][42].…”

Section: Introductionmentioning

confidence: 99%

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

Pereszlai

Geier

2020

Int J Adv Manuf Technol

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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.

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“…The delamination phenomenon is closely influenced by the drilling process parameters [15][16][17][18][19][20]. In [21,22], an excessively high thrust force is reported as the main process parameter responsible for catastrophic tool failure and extended delamination damage.…”

Section: Introductionmentioning

confidence: 99%

Smart Multi-Sensor Monitoring in Drilling of CFRP/CFRP Composite Material Stacks for Aerospace Assembly Applications

et al. 2020

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Composite material parts are typically laid out in near-net-shape, i.e., very close to the finished product configuration. However, further machining processes are often required to meet dimensional and tolerance requirements. Drilling, edge trimming and slotting are the main cutting processes employed for carbon fiber-reinforced plastic (CFRP) composite materials. In particular, drilling stands out as the most widespread machining process of CFRP composite parts, chiefly in the aerospace industrial sector, due to the extensive use of mechanical joints, such as rivets, rather than welded or bonded joints. However, CFRP drilling is markedly challenging: due to CFRP abrasiveness, inhomogeneity and anisotropic properties, tool wear rates are inherently high leading to superior cutting forces and detrimental effects on workpiece surface quality and material integrity. Damage such as delamination, cracks or matrix thermal degradation is often observed as the result of uncontrolled tool wear or improper machining conditions. Sensor monitoring of drilling operations is, therefore, highly desirable for process conditions’ optimization and tool life maximization. The development of this kind of automated control technologies for process and tool state evaluation can notably contribute to the reduction of scraps and tool costs as well as to the improvement of process productivity in the drilling of CFRP composite material parts. In this paper, multi-sensor process monitoring based on thrust force and torque signal detection and analysis was applied during drilling of CFRP/CFRP laminate stacks for the assembly of aircraft fuselage panels with the scope to evaluate the tool wear state. Different signal-processing methods were utilised to extract diverse types of features from the detected sensor signals. A machine-learning approach based on an artificial neural network (ANN) was implemented to make smart decisions on the timely execution of tool change, which is highly functional for CFRP drilling process automation.

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Analysis of thrust force and characteristics of uncut fibres at non-conventional oriented drilling of unidirectional carbon fibre-reinforced plastic (UD-CFRP) composite laminates

Cited by 67 publications

References 36 publications

Analysis of Characteristics of Surface Roughness of Machined CFRP Composites

Analysis of Characteristics of Surface Roughness of Machined CFRP Composites

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

Smart Multi-Sensor Monitoring in Drilling of CFRP/CFRP Composite Material Stacks for Aerospace Assembly Applications

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