Prediction of surface roughness in slotting of CFRP

Period. Polytech. Mech. Eng.

Pereszlai

2019

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.

Section: Introductionmentioning

confidence: 80%

Analysis of Characteristics of Surface Roughness of Machined CFRP Composites

Period. Polytech. Mech. Eng.

Pereszlai

2019

“…The machinability of materials may be defined as a material property, as a factor in tool life, in terms of the cutting speed or other criteria [31]. Generally, the machinability of fibrous composites requires information on the (i) formation of chip, burr and delamination [32]; (ii) surface integrity [33]; (iii) tool life and tool wear rates [34]; (iv) specific cutting force, torque and shear stress [35]; (v) achievable micro and macro geometrical tolerances [36]; (vi) mechanical properties (e.g. hardness, resultant strength) [37]; and (vii) cutting temperature [38], at certain machining setups (machine tool, cutting tool, lubrication, temperature, etc.).…”

Section: Introductionmentioning

confidence: 99%

Drilling of recycled carbon fibre–reinforced polymer (rCFRP) composites: analysis of burrs and microstructure

Int J Adv Manuf Technol

Poór

Pereszlai

et al. 2022

Since governments encourage sustainability, industries are making great efforts to reuse or recycle carbon fibre–reinforced polymer (CFRP) composites. Despite the promising early results concerning the material properties of recycled CFRP, there is no published knowledge available about their machinability. In this study, drilling-induced micro and macro-sized geometrical defects were analysed and compared in virgin and recycled CFRP. A total of 180 drilling experiments were carried out using uncoated solid carbide cutting tools. Six different CFRP composites were tested at different feeds. The burr characteristics and microstructure were analysed by optical and scanning electron microscopy. The analysis of variance (ANOVA) results suggest that the formation of drilling-induced burrs in CFRP reinforced by recycled chopped and nonwoven mats is less pronounced than in virgin CFRP. Micro- and macro-sized geometrical defects in both recycled and virgin milled CFRP were negligible. This study found no relevant objection to using recycled CFRP from the point of view of drilling-induced burrs and microstructure damage.

“…Nevertheless, the cutting of CFRP composite materials is complicated and expensive: (i) due to the inhomogeneity and anisotropy of the material, the characteristic geometrical errors caused by the machining and the chip formation mechanisms are significantly dependent on the machining directions; (ii) carbon fibres have a strong abrasive wear effect, which should be considered for the cutting tool and for the machine tool also; and (iii) heat dissipation is also problematic due to the low thermal conductivity of polymers and the dangers of using coolant lubricants (polymer wicking) [2, 4-6, 14, 15]. Because of these cutting features and conditions, CFRP materials are referred to as difficult-to-cut materials, which can result in a variety of micro-and macro-geometric material defects like delamination, uncut fibres, matrix burning, fibre pull-outs, or micro-cracking [13,[16][17][18][19][20][21][22][23][24][25][26]. Although centuries of experience in the field of metalworking have been accumulated, this theoretical and practical knowledge cannot be directly applied to the cutting science of fibre-reinforced technical polymer composite materials that have been researched for only a few decades.…”

Section: Introductionmentioning

confidence: 99%

Influence of fibre orientation on cutting force in up and down milling of UD-CFRP composites

Int J Adv Manuf Technol

2020

Machining of carbon fibre reinforced polymer (CFRP) composites is extremely difficult, mainly due to their inhomogeneous and anisotropic properties. Predicting of cutting force during machining of CFRP is also difficult because the machinability properties of the composite are significantly orientation-dependent (fibre and machining directions). The main objective of the present study is to analyse the influence of fibre orientation on cutting force in milling of unidirectional CFRP. Up and down milling experiences were conducted based on a full factorial design. Experimental data were processed by fast Fourier transformation, regression analysis, and graphical adequate analysis. Multiple-order polynomial models were developed in order to minimise cutting force. Experimental results show that fibre orientation angle significantly influences the cutting force; furthermore, it does not have a significant effect on the passive force component, while the radial force component is more sensitive to the fibre orientation at up milling, than at down milling. An optimal condition is recommended for zig-zag milling of unidirectional CFRPs.