Additive Manufacturing (AM), which more commonly known as 3D printing, is an extremely popular, fast and flexible manufacturing method. Rectangular prismatic textures are created on a surface via 3D ...printing technique. It is observed that the surface texture obtained by AM reduces particle erosion by half under the same erosion direction, and the angle of blasting direction on the prepared surface texture has a major effect, where there is an evident change in wear rate when the surface texture is smaller than the particle size. Also, it is seen that small changes in the dimension of the texture has no remarkable effect on particle erosion.
•3D printed surface textures has many advantages over surface preparation techniques.•Surface textures can be created in detailed geometry and precision by 3D printers.•Textured surfaces produced by 3D printer significantly reduces the particle erosion.•An evident change was observed if the surface texture was smaller than the particle size.
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•Al 6082-T6 surfaces were treated with pulsed Nd:YAG laser.•Optimum laser process parameters were investigated.•Taguchi optimization method was used to obtain optimum laser ...parameters.•Results obtained by Taguchi are quite compatible with literature.•Taguchi method is reliable to obtain optimum laser parameters for Al 6082-T6.
In order to obtain optimum laser parameters for laser treating of Al 6082-T6, the effects of focus position, pulse energy, gas type and pulse duration used for laser surface treating were investigated. Optimum laser process parameters were intended to achieved to obtain minimum crack, porosity, roughness, defect depth, percent porosity in Heat Affected Zone (HAZ), maximum HAZ depth.
The most effective parameters for ablation are Gas Type with 57.54% for Crack Length, Gas Type with 76.20% for Porosity, Gas Type with 75.92% for Roughness, Gas Type with 59.91% for Defect Depth, Gas Type with 66.01% for (HAZ) Depth, Pulse Energy with 49.39 for Percent Porosity in (HAZ).
In the confirmation experiment with the proposed parameters by Taguchi method, minimum Crack Length was obtained as 208.56 (μm/mm2), minimum Surface Porosity was obtained as 0.024%, the best surface Roughness was obtained as 28.29 μm, minimum defect depth was obtained as 217 μm, maximum HAZ depth was obtained as 3129.6 μm, minimum Percent Porosity in (HAZ) was obtained as 6.75%. These results are better than the results obtained from 9 experiments with Taguchi method. Using the Taguchi method, accurate results were found with less experimentation.
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•Mathematical modelling of laser ablation of CF reinforced PEEK composite were performed.•Properties of the polymeric materials can be defined by measuring the geometries after the ...ablation.•Cavities in desired geometry can be obtained the parameters which are found by the proposed model.•The shapes of the cavities may help to define the contents of composite materials.•This method could be used for structural health monitoring of polymer composites in the future.
Since large amounts of energy are transferred precisely to the material in a very short time, laser and material parameters strongly affect the laser process quality. Mathematical modeling of heat distribution during cavity formation on carbon fiber reinforced PEEK composite material was performed. The temperature distribution equation has been obtained by the Fourier method.
At the first stage, 1 J energy laser beam was sent onto the material and the cavity on the composite material was obtained. The constants in the temperature distribution equation obtained by making measurements over the cavity were found. Then the cavities were created with 2, 3 and 4 J laser beams to prove its reliability of the model. The results obtained from the measurement on the cavities and calculated from the temperature distribution equation were compared.
Since the unidirectional carbon fibers were used, the obtained cavities have an elliptical shape. Verification experiments were carried out using two different heat conduction constants for in direction along fibers and perpendicular to carbon fibers. Experimental results and the mathematical model are in good agreement.
This study fixates on determining the optimum laser input parameters that simultaneously meet the desired kerf width and depth during CO2 laser cutting of various polymethylmethacrylate (PMMA) ...sheets. It has three contributions. The first is to model the cutting process of PMMA by polynomial curve fitting as a function of laser power, laser speed, and standoff distance. R-squared (R
2
), adjusted R
2
and root-mean-square error (RMSE) criteria were taken into account to measure the performance of the proposed model. The effect of laser parameters on the process is investigated by analysis of variance (ANOVA) and sensitivity analysis. The second is to optimize the derived nonlinear regression models using genetic algorithm (GA), particle swarm optimization (PSO), whale optimization algorithm (WOA) and ant lion optimization (ALO) metaheuristic methods and compare the performances of the algorithms. The third is to compare the adequacy of the optimization process with the artificial neural network (ANN). The investigations exhibited that the best-fitting polynomials are obtained with the R
2
and adjusted R
2
values of over 99% and 97%, respectively. ANOVA and sensitivity test revealed that the sensitivity of the laser power, which is the most effective parameter, was 150 at low powers and decreased to 0 as the power value increased. When the nozzle distance is 4.1, the proposed metaheuristics gave effective and sufficiently accurate results. PSO stood out in terms of both best cost value (3.49 × 10
–8
) and relative error value (0.19%). The relative error of the ANN was found as 3% in terms of kerf depth.
In this study, the usability of nutshell, pistachio, and walnut shell wastes as reinforcement materials in industrial applications and their comparisons with each other was examined. For this ...purpose, composite samples with a polypropylene (PP) matrix were produced and their mechanical and tribological characterizations were performed. As a result of the tensile tests, both the tensile strength and elastic modulus values of all composite specimens are higher than those of pure PP. On the other hand, the value of elongation at break is lower. The sliding wear resistance increases with increasing reinforcement with walnut and pistachio shell reinforcement, whereas the positive effect becomes negative when the nutshell reinforcement is over 3 wt%. All three types of reinforcement positively affected the scratch resistance. Pistachio shell reinforcement gives the best result. It has been determined that the relative cutting volume value of the samples increases with the reinforcement rate and the wear behavior changes from ductile to brittle. In light of these results, it has been seen that nut, pistachio, and walnut shells could be used as reinforcement materials in industrial applications instead of being waste or fuel.
Abstract As it is known, Polytetrafluoroethylene (PTFE) is one of the most preferred polymeric materials for tribological applications. This study investigates the performance of PTFE and its ...composites under different tribological conditions. The effects of short glass fiber (GF), carbon particle (CP) and bronze particle (BP) reinforcement agents and their hybrid filling with molybdenum disulfide (MoS 2 ) on sliding, erosive and abrasive wear were examined. Sliding tests were carried out with a ball‐on‐disc test apparatus, erosive wear tests were carried out with solid particle erosion and abrasive wear tests were carried out with a scratch test. It has been found that reinforcement agents improve sliding and abrasive wear resistance but worsen the erosion resistance. The hardness and contact angle of the samples were associated with their wear performances. Topographic and morphological analyzes of worn surfaces were performed using optical profilometer and scanning electron microscopy (SEM), respectively, and wear mechanisms were discussed. Highlights Filling materials (glass fiber, carbon particle and bronze particle) increase the adhesion and abrasion resistance of PTFE, while decreasing its erosion resistance. The effect of hybrid addition of MoS 2 solid lubricant on wear performances depends on the type of filler. There is a correlation between surface properties (hardness and contact angle) and wear performances. Optical profilometer and scanning electron microscopy were used to examine wear mechanisms.
Polymer materials with high specific strength properties are widely used in engineering applications. Poly (methyl methacrylate) (PMMA) is a rigid and brittle thermoplastic with a high glass ...transition temperature. It is used in many engineering applications due to its low density, lightweight, high transparency, chemical resistance, and high toughness properties. Intense research efforts have been carried out in recent years regarding the scratching behavior of polymers. The scratch test is performed by moving a hard abrasive indenter across the surface of relatively soft material and is used to determine the mechanical resistance of the surfaces of materials. Scratches on the surfaces of amorphous polymeric materials such as PMMA cause optical and mechanical performance loss. For this reason, it is important to determine the scratching behavior of materials under different operating conditions. Within the scope of the study, the scratching behavior and multi-pass scratch behavior of PMMA were investigated. Experimental studies were carried out with Rockwell and Vickers abrasive indenters at different scratch force and velocity values. Scratch and wear marks were examined by means of an optical microscope, optical profilometer and Scanning Electron Microscope (SEM), and scratch hardness, volumes removed, surface topographies and surface morphologies are presented. It has been observed that these results vary remarkably depending on the type of abrasive indenter, scratch force and velocity.
Abstract Solid lubricants are added to polymers to upgrade their tribological properties, especially in cases where adhesive and abrasive friction are valid. However, there are not enough studies on ...the effects of solid lubricants on particle erosion. This study investigated the effects on solid particle erosion behavior of three different well known solid lubricants (molybdenum disulfide, polytetrafluoroethylene, and graphite). These solid lubricants were added at three different ratios (5, 10, and 15 wt.%) to the two different type (rigid and toughened) epoxy resins. Garnet abrasive particles (180–400 μm) were blasted to the sample surface under 1.5 bar for 15 s to conduct solid particle erosion tests. The erosive wear mechanisms of neat and solid lubricant‐reinforced epoxy resins were investigated in relation to the epoxy type, solid lubricant type, and solid lubricant reinforcement ratio. Statistical analysis was performed according to response surface methodology to support the experimental results, and ANOVA tables were obtained. The wear and deformations that occurred on the surface after solid particle erosion were examined using a noncontact optical profilometer system and scanning electron microscopy, and a significant relationship was detected between the deformation on the surface and particle erosion. Analysis results showed that the factor causing the greatest erosion rate change was the epoxy resin type. Finally, it has been observed that all solid lubricants reduce the erosive wear resistance, and this resistance decreases as the weight ratio increases. Highlights Investigations were conducted into the erosion behavior of two types of epoxy resins: rigid and toughened. The toughened epoxy resin exhibited greater resistance to erosion. Although it has the same type of content, on average, rigid epoxy worn 2–4 times more than toughened epoxy. The effect of adding polytetrafluoroethylene tended to increase the erosion rate of both rigid and toughened epoxy resin less than that of other solid lubricants. Graphite particles increased the erosion rate of toughened epoxy by 1.5–3 times and that of rigid epoxy by 2–3 times, depending on the value of the reinforcement ratio. MoS 2 increased the erosion rate of toughened epoxy by 1.5–3 times and that of rigid epoxy by 2–3 times. Using a noncontact optical profilometer (for investigating surface topography), it was proven that there is a significant relationship between the erosion rate and roughness characteristics. Wear mechanisms were identified by SEM analysis.
In this study, various heat treatments (annealings) were applied to carbon fiber reinforced polyetheretherketone (CF/PEEK) samples at four different temperatures (185, 225, 265, and 305°C) along two ...different holding times (30 and 270 min). The effects of changing matrix morphology, degree of crystallinity, and fiber‐matrix interface properties on thermo‐mechanical properties were investigated by differential scanning calorimetry (DSC) and dynamic mechanical analysis analyzes. Also, annealed CF/PEEK samples were tested to determine solid particle erosion characteristics. It was observed that the matrix crystallinity, fiber/matrix interface properties, and tribological properties of the CF/PEEK composites changed significantly with the thermal history. There was an increase in the degree of crystallinity with the increase in annealing temperature. It was observed that the degree of crystallinity increased up to about 27% and the damping factor decreased up to about 45%. As a result of the solid particle erosion tests performed under normal impact conditions, it was determined that the formation of the transcrystalline layer formed by heat treatment adversely affected the solid particle erosion resistance of the CF/PEEK. Erosion resistance of the heat‐treated samples (having higher fiber/matrix interface) was approximately 50% lower compared to the quenched sample. While the erosion rate for quenched samples is 14.5 × 10−5 g/g, this rate rises to 26.1 × 10−5 g/g for annealed samples. In addition, surface topography was examined by means of an optical profilometry, and surface morphology was examined by means of scanning electron microscopy. These examinations confirmed the experimental results.
The effect of matrix and interface properties modified by annealing on solid particle erosion behavior of CF/PEEK was determined.
