Ferit Ficici

Purpose: This study aims to systematically investigate the effects of drilling parameters and SiC reinforcement content on the surface roughness of Al-2024 aluminum matrix composites fabricated by stir casting. The study further seeks to determine the optimum drilling conditions using the Taguchi optimization method, quantify the statistical significance of the machining parameters through analysis of variance (ANOVA) and develop a reliable regression model for predicting surface roughness. The ultimate objective is to provide practical machining guidelines for improving the surface integrity of particle-reinforced aluminum composites used in high-performance engineering applications. Design/methodology/approach: Unreinforced Al-2024 alloy and composites reinforced with 10 and 15 vol.% SiC particles were fabricated using the stir casting technique, followed by T6 heat treatment. The microstructures of the produced materials were characterized by optical microscopy and scanning electron microscopy (SEM), while Brinell hardness measurements were performed to evaluate the mechanical response. Drilling experiments were conducted on a CNC milling machine using TiN-coated HSS twist drills according to a Taguchi L27 orthogonal array. Surface roughness (Ra) was measured using a MarSurf VD140 contact profilometer. Statistical analyses, including Taguchi optimization, ANOVA, response surface analysis and multiple linear regression, were employed to evaluate the effects of material type, cutting velocity and feed rate on surface roughness. Findings: The results demonstrated that feed rate was the dominant machining parameter affecting surface roughness, contributing 82.85%, followed by cutting velocity (12.93%) and material type (1.93%). The optimum drilling condition for achieving the minimum surface roughness was obtained at a cutting velocity of 25 m/min and a feed rate of 0.05 mm/rev for unreinforced Al-2024. Optical microscopy and SEM analyses revealed that increasing the SiC reinforcement content promoted particle fracture, particle pull-out and surface damage during drilling. In contrast, Brinell hardness increased with increasing SiC content, reaching approximately 95 HB for the 15 vol.% SiC-reinforced composite after T6 heat treatment. Furthermore, the developed regression model exhibited excellent predictive capability with a coefficient of determination of R2 = 95.69%, confirming the reliability of the proposed statistical methodology. Originality/value: This study presents a comprehensive experimental and statistical investigation of the conventional drilling behavior of SiC particle-reinforced Al-2024 composites produced by stir casting. Unlike many previous studies that primarily focused on advanced machining techniques, the present work demonstrates that conventional drilling, when combined with systematic statistical optimization, can provide high-quality surface finish with reliable predictive capability. The excellent agreement among the microstructural observations, Taguchi optimization, ANOVA, response surface analysis and regression model provides a robust framework for machining optimization and offers practical guidance for the aerospace and automotive industries.

This study investigates the drilling performance of Polyamide 6 (PA6) composites reinforced with 30 wt% rock wool mineral fiber. The composite plates were fabricated via twin-screw extrusion and injection molding. Drilling experiments were performed on a 3-axis CNC machine using HSS, TiN-coated HSS, and Carbide bits to evaluate delamination, surface roughness (µm), and thrust force. Results indicated that higher cutting speeds generally reduced delamination by enhancing bit stability, whereas increased feed rates raised surface roughness due to higher cutting forces and vibrations. Specifically, at 20 m/min cutting speed and 0.1 mm/rev feed rate, the carbide drill bit achieved the lowest delamination factor (5.115) compared to HSS (5.23). Among the tested tools, carbide bits demonstrated the most effective performance regarding initial hole quality and delamination control. While advantageous for structural integrity, further quantitative research on wear progression is required to comprehensively evaluate long-term tool life.

In this study, rice husk-reinforced HDPE composites were produced to provide sustainable and economical solutions. For this purpose, HDPE composites with RH ratios of 5 %, 10 %, and 15 % by volume were produced using the injection moulding method. Density, hardness, tensile, bending strength, friction coefficient, and wear values of the produced bio-composite materials were measured. According to the results from the mechanical tests, the lowest density, hardness, tensile, and bending strength values were recorded in the 5 vol % RH + HDPE composite material, while the highest values were observed in the 15 vol % RH + HDPE composite material. Minimum tensile and bending strength values were 27.8 and 31.22 MPa, and maximum tensile and bending strength values were 28,5 and 31,35 MPa. As a result of friction and wear tests, the minimum coefficient of friction and weight loss were found in the 15 vol % RH + HDPE composite material, and the highest values were noted in the 5 vol % RH + HDPE composite material. The minimum coefficient of friction was measured as 00,957 µ and the corresponding weight loss was 00,008 g. The maximum coefficient of friction was 06,485 µ, with a weight loss of 00,022 g.

Purpose: This study explores the tribological properties and surface roughness of glass sphere-reinforced polypropylene (PP) composites. Drilling tests were conducted using various drill bits (HSS, TiN-coated HSS, carbide), feed rates, and cutting speeds, with experiments designed via the Taguchi L27 orthogonal array. Design/methodology/approach: The experimental design for drilling tests and surface roughness measurements was made using the Taguchi L27 (33) orthogonal array. Surface roughness measurements were carried out using a MarSurf VD 140 Profilometer Model (Mahr Metrology in Germany) device. Data obtained from drilling tests and surface roughness measurements were analyzed using analysis of variance (ANOVA) and signal-to-noise (S/N) ratio analysis. Findings: ANOVA and signal-to-noise (S/N) ratio analyses revealed that drill bit type significantly impacts surface roughness, accounting for 61.70% of the variation. Increasing feed rates raised surface roughness, while higher cutting speeds reduced it. Carbide drill bits yielded the lowest surface roughness values. Regression analysis indicated a high predictive accuracy for the model (R2 = 89.72). The optimal parameters for achieving minimal surface roughness were identified as a carbide drill bit, 0.05 mm/rev feed rate, and 25 m/min cutting speed. Originality/value: The results obtained reveal the potential of glass sphere reinforced PP composites in industrial applications. This study will contribute to the existing literature by enabling further research on the friction and wear behaviors of glass sphere reinforced PP composites, revealing the potential of these materials in tribological applications.

In this study, the friction and sliding behaviors of Polyetheretherketon (Peek) and Ultra-high-molecular-weight polyethylene (Uhmwpe) polymers when sliding against different counterfaces unreinforced Polyethylenimine (Ur-Pei), 20 vol.% glass fiber reinforced Pei polymer (20 vol.% Gf + Pei), wear durable Pei polymer (Dw-Pei), and stainless steel (Aisi 304L Ss) were determined and compared. Additionally, the tribological behaviors of these two polymers used in the industry were tested using the Taguchi optimization method. Mathematical equations were created using the regression method for optimal friction coefficient and specific wear rate. Accordingly, the optimal friction coefficient was obtained when Uhmwpe polymer was slid against Ur-Pei counterface with a 10 N application load. In contrast, the optimal specific wear rate was determined under 20 N load test conditions for Uhmwpe polymer against Ur-Pei counterface.

In this research, the machinability characteristics of Al-2024 + SiC composite materials produced via the stir casting method were experimentally analyzed. The test samples included unreinforced composites and those with 5%, 10%, and 15% SiC particle reinforcement. Microstructural examinations were conducted using optical and Scanning Electron Microscopes (SEM). Hardness measurements were taken using the Brinell scale. Machinability tests involved drilling on a 3-axis CNC machine with both HSS and HSS + TiN drill bits, using three different feed rates and cutting speeds. The unreinforced sample exhibited the lowest hardness, while the sample with 15% SiC reinforcement showed the highest hardness. The HSS + TiN drill bit outperformed the HSS drill bit. Thrust force and torque values increased with higher feed rates and cutting speeds. ANOVA statistical analysis indicated that the drill type (variable A) influenced thrust force by 58.36%, the composite type (variable D) by 31.25%, and cutting speed (variable C) by 7.64%. For torque, the composite type (variable D) had a 55.94% influence, the drill type (variable A) 24.96%, and cutting speed (variable C) 13.26%. It was also found that the interaction between variables A and B did not affect cutting forces.

In this study, the abrasive wear behavior of composites reinforced with undoped polyetheretherketone (PEEK), 30% carbon fiber (CF) and 30% glass fiber (GFR) was investigated using Taguchi experimental optimization method. As a result of the investigation, the best abrasive wear rate occurred in 30% CF reinforced composite material at 4 N application load, 60 m sliding distance and 220 m grit size. In addition, by applying Analysis of Variance (ANOVA) analysis, it was determined that the most effective parameter on the abrasive wear rate was the grit size parameter with 62%. Finally, the mathematical equation obtaining the optimum abrasive wear rate was successfully established with a coefficient of 91%.

In this study, the effects of reinforcement ratio, drill bit material, and drilling process parameters on the cutting forces generated during the drilling of glass sphere‐reinforced polypropylene composites were investigated experimentally. Test specimens were produced by conventional injection‐moulding of glass sphere reinforced polypropylene composite materials at 5 %, 10 % and 20 % wt. ratios. High speed steel, titanium‐coated high‐speed steel, and carbide drill bits with 4 mm diameter were preferred for drilling. In addition, the drilling process was carried out on a 3‐axis computer numeric control milling machine. Three different feed rates of 0.05 mm/rev, 0.10 mm/rev, and 0.15 mm/rev and cutting speeds of 12 m⋅min⁻¹, 16 m⋅min⁻¹, and 20 m⋅min⁻¹ were determined for the drilling process. In addition, Taguchi experimental optimization method, analysis of variance and scanning electron microscopy were used to investigate the morphology of the drilled surface and the wear mechanisms occurring on the drill bit due to the drilling process. The test findings showed that the maximum torque value was 54.64 N⋅mm and the maximum thrust force was 100.43 N. The optimum test parameter for cutting forces was observed as C1D3FR1CS3. Drill parameter had an effect of 40.96 % on thrust force and 36.11 % on torque.

Reinforced PTFE materials can be designed to show high mechanical stability against harder materials under sliding wear conditions. Especially bearing metal-reinforced PTFE is of high practical interest. In this class of materials, bronze-filled PTFE was reported to obtain high wear resistance, a low coefficient of friction (COF), and excellent self-lubrication properties in sliding conditions. In the statistical approach of this work, PTFE composites reinforced with 25 vol%, 40 vol%, and 60 vol% bronze particles were evaluated against pure PTFE regarding wear behavior under varied wear test parameters, i.e., material, normal load, and sliding speed. Wear tests were planned to use a standard orthogonal array based on the Taguchi design method. An analysis of variance test was utilized to quantify the effects of test parameters on the wear behavior of the bronze/PTFE composites and pure PTFE. According to the variance analysis, the material type has the largest influence on the COF and the specific wear rate (SWR) under test conditions of this work. Both COF and SWR were found to be influenced by the material type (29.83% and 96.16%), the normal load (33.34% and 0.95%), and sliding speed (9.14% and 1.28%). The lowest SWR and COF values were achieved at the optimum wear test conditions where the wear test parameters were 1 m/s sliding speed (A4B2C2) at PTFE + 60 vol.% bronze reinforced composite 50 N application load and 0.32 m/s sliding speed (A4B3C1) at PTFE + 60 vol.% bronze reinforced composite 100 N application load, respectively.