Laser process parameter optimization of dimple created on oriented carbon fiber reinforced epoxy composites

2021 ◽  
pp. 002199832110316
Author(s):  
Timur Canel ◽  
Ersin Kayahan ◽  
Sinan Fidan ◽  
Tamer Sinmazcelik
Keyword(s):  
Carbon Fiber ◽  
Aspect Ratio ◽  
Pulse Energy ◽  
Effective Rate ◽  
Effective Parameter ◽  
Focus Position ◽  
Laser Process ◽  
Laser Parameters ◽  
Spot Area ◽  
Thermal Defect

It was mainly aimed at the study to make the optimization of laser parameters to obtain dimples with the desired shape and size. Carbon Fiber EPOXY composite (CF-EPOXY) surfaces were ablated by Nd:YAG laser which has a 1064 nm wavelength. Some important laser process parameters such as focus position, pulse energy, duration and number were optimized to achieve maximum aspect ratio, circular shape and minimum thermal defect. In addition, it has been determined that which laser parameters are more effective to obtain the desired quality surface. These different shapes and geometry of dimples could be used to improve some properties such as wettability, friction, etc. The pulse energy with an effective rate of 55.97 % is the most effective parameter to achieve the larger aspect ratio. The focus position is the most effective parameter with the rates of 66.18 % and 47.94 % to obtain both perfect circularity and minimum thermal defects respectively. Confirmation experiments were performed and the highest aspect ratio was found as 1.14, the best circular dimple and the minimum thermal effects outside the spot area were found with the rates of 1.021. These are the optimum results of 9 experiment sets in this study for each output. The results were supported by confirmation experiments and regression analysis. It can be concluded that the Taguchi method is reliable and saves time and materials.

scholarly journals Femtosecond Laser Drilling of Cylindrical Holes for Carbon Fiber-Reinforced Polymer (CFRP) Composites

Molecules ◽  
2021 ◽  
Vol 26 (10) ◽  
pp. 2953
Author(s):  
Hao Jiang ◽  
Caiwen Ma ◽  
Ming Li ◽  
Zhiliang Cao
Keyword(s):  
Carbon Fiber ◽  
Femtosecond Laser ◽  
Picosecond Laser ◽  
Laser Drilling ◽  
Fiber Reinforced Polymer ◽  
Carbon Fiber Reinforced Polymer ◽  
Laser Parameters ◽  
Reinforced Polymer ◽  
Cfrp Composites ◽  
Cylindrical Holes

Ultrafast laser drilling has been proven to effectively reduce the heat-affected zone (HAZ) of carbon fiber-reinforced polymer (CFRP) composites. However, previous research mainly focused on the effects of picosecond laser parameters on CFRP drilling. Compared with a picosecond laser, a femtosecond laser can achieve higher quality CFRP drilling due to its smaller pulse width, but there are few studies on the effects of femtosecond laser parameters on CFRP drilling. Moreover, the cross-sectional taper of CFRP produced by laser drilling is very large. This paper introduces the use of the femtosecond laser to drill cylindrical holes in CFRP. The effect of laser power, rotational speed of the laser, and number of spiral passes on HAZ and ablation depth in circular laser drilling and spiral laser drilling mode was studied, respectively. It also analyzed the forming process of the drilling depth in the spiral drilling mode and studied the influence of laser energy and drilling feed depth on the holes’ diameters and the taper. The experimental results show that the cylindrical hole of CFRP with a depth-to-diameter ratio of about 3:1 (taper < 0.32∘, HAZ < 10 m) was obtained by using femtosecond laser and a spiral drilling apparatus.

Study on the mechanism of inhomogeneous microdamage in short-pulse laser processing of carbon fiber reinforced plastic

2021 ◽  
pp. 073168442098359
Author(s):  
Luyao Xu ◽  
Jiuru Lu ◽  
Kangmei Li ◽  
Jun Hu
Keyword(s):  
Carbon Fiber ◽  
Pulse Energy ◽  
Short Pulse ◽  
Heterogeneous Material ◽  
Carbon Fiber Reinforced Plastic ◽  
Fiber Reinforced ◽  
Processing Efficiency ◽  
Fiber Reinforced Plastic ◽  
Reinforced Plastic ◽  
Carbon Fiber Reinforced

In this article, a micro-heterogeneous material simulation model with carbon fiber and resin phase about laser ablation on carbon fiber reinforced plastic (CFRP) is established by Ansys. The ablation process of CFRP by nanosecond ultraviolet laser is simulated, and the mechanism of pulse energy and spot spacing on the heat-affected zone (HAZ) is studied, then the process parameters are optimized with the goal of HAZ size and processing efficiency, and finally the validity of the model is verified by experiments. It is found that the residual gradient and the width of the radial HAZ increase with the increase of the spot spacing, and the width of the axial HAZ decreases slightly with the increase of the spot spacing, which indicates the existence of the optimal spot spacing. Second, the ablation depth increases with the increase of the pulse energy, and the carbon fiber retains a relatively complete degree of exposure when the pulse energy is low, which has a certain guiding significance for the cleaning and bonding of CFRP.

Electrical Conductivity of Barium-Ferrite-Vulcanized Polychloroprene Filled with Short Carbon Fiber

1992 ◽  
Vol 65 (1) ◽  
pp. 7-23 ◽  
Author(s):  
P. B. Jana ◽  
S. K. De ◽  
S. Chaudhuri ◽  
A. K. Pal
Keyword(s):  
Carbon Fiber ◽  
Aspect Ratio ◽  
Carrier Concentration ◽  
Barium Ferrite ◽  
Volume Resistivity ◽  
Positive Temperature ◽  
Short Carbon Fiber ◽  
Fiber Aspect Ratio ◽  
Mixing Method ◽  
Short Carbon

Abstract Short-carbon-fiber-filled polychloroprene composites, prepared by mill-mixing and cement-mixing methods were vulcanized by barium ferrite. The effects of concentration and aspect ratio (L/D) of short carbon fiber on volume resistivity have been studied. Composites prepared by the cement mixing method having high fiber aspect ratio (L/D 100) show higher hardness and modulus accompanied by lower elongation and volume resistivity than the composites prepared by the mill mixing method, which give low fiber aspect ratio (L/D 25). Experimental values of volume resistivity agreed reasonably well with the calculated values from the theory based on probability of formation of conductive network. The temperature dependence of volume resistivity of the composite shows a positive temperature coefficient. The shape of the hysteresis loop, observed during the heating and cooling cycle in the variation of volume resistivity with temperature, depends on the concentration and aspect ratio of short carbon fiber. Hall-effect studies indicate that increase in fiber concentration and aspect ratio in the composites causes increase in carrier concentration and decrease in mobility of the carriers. With increase in temperature, both conductivity and carrier concentration decrease and mobility of the carriers increases.

scholarly journals Mechanically Improved and Multifunctional CFRP Enabled by Resins with High Concentrations Epoxy-Functionalized Fluorographene Fillers

2021 ◽  
Author(s):  
Junhua Wei
Keyword(s):  
Mechanical Properties ◽  
Thermal Conductivity ◽  
Elastic Modulus ◽  
Carbon Fiber ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Reinforcing Particles ◽  
Thermoset Resin ◽  
High Concentrations ◽  
Carbon Based

To meet the maximum potential of the mechanical properties of carbon fiber reinforced plastics (CFRP), stress transfer between the carbon fibers through the polymer matrix must be improved. A recent promising approach reportedly used reinforcing particles as fillers dispersed in the resin. Carbon based fillers are an excellent candidate for such reinforcing particles due to their intrinsically high mechanical properties, structure and chemical nature similar to carbon fiber and high aspect ratio. They have shown great potential in increasing the strength, elastic modulus and other mechanical properties of interest of CFRPs. However, a percolation threshold of ~1% of the carbon-based particle concentration in the base resin has generally been reported, beyond which the mechanical properties deteriorate due to particle agglomeration. As a result, the potential for further increase of the mechanical properties of CFRPs with carbon-based fillers is limited. We report a significant increase in the strength and elastic modulus of CFRPs, achieved with a novel reinforced thermoset resin that contains high loadings of epoxy-reacted fluorographene (ERFG) fillers. We found that the improvement in mechanical performance of CFRPs was correlated with increase in ERFG loading in the resin. Using a novel thermoset resin containing 10 wt% ERFG filler, CFRPs fabricated by wet layup technique with twill weaves showed a 19.6% and 17.7% increase in the elastic modulus and tensile strength respectively. In addition, because of graphene’s high thermal conductivity and high aspect ratio, the novel resin enhanced CFRPs possessed 59.3% higher through-plane thermal conductivity and an 81-fold reduction in the hydrogen permeability. The results of this study demonstrate that high loadings of functionalized particles dispersed in the resin is a viable path towards fabrication of improved, high-performance CFRP parts and systems.

A Study on Effect of Different Process Parameters on the Quality of Overhang Surface Produced by Selective Laser Melting

2018 ◽  
Author(s):  
Sagar Sarkar ◽  
Ankit Porwal ◽  
Nuthalapati Yaswanth ◽  
Ashish Kumar Nath
Keyword(s):  
Aspect Ratio ◽  
Selective Laser Melting ◽  
Process Parameters ◽  
Support Structures ◽  
Metal Powders ◽  
Laser Melting ◽  
Scanning Strategy ◽  
Support Structure ◽  
Laser Process

Selective Laser Melting process enables production of geometrically complex parts directly from CAD model by melting metal powders layer by layer. For successful building of parts, some auxiliary structures namely support structures are also built to ensure proper heat conduction from actual parts to be built to the base plate. Support structures are needed if there are overhang surfaces in the design of the part. If the design of the part is very complex and features many overhang surfaces, then too many supports get generated. After building the part, these support structures need to be removed properly to get desired geometrical features and it may deteriorate the surface quality from where supports are removed. Sometimes removal of support structures becomes very difficult specially for parts having internal features. In this study, first effect of inclined angle, aspect ratio and different scanning strategies on the quality of overhang surfaces produced without any support structure under constant laser power and scan speed has been investigated. Scanning Electron Microscopy (SEM) images of overhang surfaces have been analyzed to investigate the presence of warping and uneven fused edges if any. It was found that with increase in inclined angles and aspect ratio, warping and presence of uneven fused edges increases. Rotational scanning strategy found to be better than linear alternate scanning strategy for reduced uneven fused edges formation and warping. Results show an overhang without any support structure can be built successfully with a single laser process parameters upto 25.343 degree which is less than theoretical critical angle of 26.565 degree. Further, it has been shown, using a novel strategy of building overhang with multiple laser process parameters, it is possible to build overhang even upto 24.132 degree.

High Aspect Ratio Machining of Carbon Fiber Reinforced Plastics by Electrical Discharge Machining Process

2020 ◽  
Author(s):  
Cibi Makudapathy ◽  
Murali Sundaram
Keyword(s):  
Carbon Fiber ◽  
Aspect Ratio ◽  
High Aspect Ratio ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Machining Process ◽  
Fiber Reinforced ◽  
Carbon Fiber Reinforced Plastics ◽  
Reinforced Plastics ◽  
Fiber Reinforced Plastics

Abstract Micromachining of Carbon Fiber Reinforced Plastics (CFRPs) is essential for numerous applications in several industries such as aerospace, automotive, defense, shipping, sporting goods, and biomedical industries. The major challenge in machining CFRP by electrical discharge machining (EDM) is due to the non-conductivity of epoxy material which is used as a binder for manufacturing these CRFPs. This study attempts a novel, yet simple approach to ensure the conductivity of the work piece through the entire machining process. Experiments were carried out in this work to assess the feasibility of machining high aspect ratio micro-holes in CFRP by micro EDM. The effect of process parameters such as voltage and feed-rate on the hole quality was studied. Using optimal process conditions, micro hole of 2500 µm deep with an aspect ratio of over 11 was achieved.

scholarly journals Effects of the Longitudinal Surface Roughness on Fiber Pull-Out Behavior in Carbon Fiber-Reinforced Epoxy Resin Composites

2013 ◽  
Vol 80 (2) ◽  
Author(s):  
Yin Yao ◽  
Shaohua Chen
Keyword(s):  
Surface Roughness ◽  
Theoretical Model ◽  
Carbon Fiber ◽  
Aspect Ratio ◽  
Epoxy Resin ◽  
Carbon Fibers ◽  
Fiber Reinforced ◽  
Fiber Stress ◽  
Pull Out ◽  
Carbon Fiber Reinforced

Surface modifications are known as efficient technologies for advanced carbon fibers to achieve significant improvement of interface adhesion in composites, one of which is to increase the surface roughness in the fiber's longitudinal direction in practice. As a result, many microridges and grooves are produced on carbon fiber's surfaces. How does the surface roughness influence the carbon fiber's pull-out behavior? Are there any restrictions on the relation between the aspect ratio and surface roughness of fibers in order to obtain an optimal interface? Considering the real morphology on carbon fiber's surface, i.e., longitudinal roughness, an improved shear-lag theoretical model is developed in this paper in order to investigate the interface characteristics and fiber pull-out for carbon fiber-reinforced thermosetting epoxy resin (brittle) composites. Closed-form solutions to the carbon fiber stress are obtained as well as the analytical load-displacement relation during pullout, and the apparent interfacial shear strength (IFSS). It is found that the interfacial adhesion and the apparent IFSS are effectively strengthened and improved due to the surface roughness of carbon fibers. Under a given tensile load, an increasing roughness will result in a decreasing fiber stress in the debonded zone and a decreasing debonded length. Furthermore, it is interesting to find that, for a determined surface roughness, an optimal aspect ratio, about 30∼45, of carbon fibers exists, at which the apparent IFSS could achieve the maximum. Comparison to the existing experiments shows that the theoretical model is feasible and reasonable to predict the experimental results, and the theoretical results should have an instructive significance for practical designs of carbon/epoxy composites.

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