Mustafa Bakkal

The effects of different chemical treatment methods on the mechanical and thermal properties of textile fiber reinforced polymer composites

In this study, the effects of improvement methods on the mechanical and thermal properties of textile fiber reinforced (T-FRP) composites were investigated. Five different chemical methods namely, silane treatment, alkaline treatment, alkali–silane treatment, maleic anhydride, and alkali–maleic anhydride coupling agents were applied to evaluate the suitable process parameters (concentration, soaking time, ratio by weight) for the enhanced properties of T-FRP composites. Tensile, three-point flexural and impact tests were performed on both untreated and treated composites for comparison purpose. Treated and untreated T-FRP composites were characterized using scanning electron microscopy, differential scanning calorimetry, and Fourier-transform infrared spectroscopy to evaluate thermomechanical properties of composites. Results show that a significant improvement up to 60–70% can be seen on the mechanical properties of T-FRP composites via improving the interfacial adhesion and compatibility between fiber and matrix.

Utilization of various non-woven waste forms as reinforcement in polymeric composites

In this study, various forms of non-woven waste were recycled for the manufacture of composites by the extrusion technique. The performance of the composites, as well as the effect of the reprocessing steps, was investigated with regards to the mechanical and thermal properties. A reinforcement material of polyester non-woven waste in differing forms (cut piece, fiber and particle) and a matrix of polypropylene (PP) and low-density polyethylene (LDPE) were used. Performance tests were evaluated based on the type of reinforcement material. Particle form reinforced composites were subjected to reprocessing and tested for their performance. Results indicate that particle type reinforcement maintained better mechanical performance, whereas reinforcements using cut pieces and fibers showed enhanced thermal insulation with lower densities. The effect of the reprocessing of the particle forms has been observed positively on the tensile characteristics, especially up to the second stage.

Experimental Investigations of Machinability in the Turning of Compacted Graphite Iron using Minimum Quantity Lubrication

Unique mechanical properties of the compacted graphite iron (CGI) attracted attention of manufacturers and suppliers mainly in automotive industry in last decades. However due to the low machinability of the CGI material, more efficient machining strategies need to be implemented. Improvement in the cost-effective and environmentally sensitive processing of compacted graphite iron (CGI) is one of the major concerns of the manufacturing world because of the allure of CGIs mechanical properties. This study assesses the efficiency of minimum quantity lubrication (MQL) in CGI turning when compared to the dry-cutting condition. The turning tests were conducted across a wide range of cutting parameters: three different cutting speeds (100, 200, 300 m/min) and three different feed rates (0.1, 0.2, 0.3 mm/rev), all at a constant depth of cut (1 mm). The MQL efficiency is evaluated through cutting force and surface roughness measurements, optical and SEM analyses of chip formation and tool-wear analysis. The results showed that MQL usage provided a reduction in the resultant cutting forces by 2–5%, a reduction in surface roughness by 25%. The SEM analysis also revealed much clearer and smoother cutting edges on tool surfaces used in the MQL tests.

The effect of cutting parameters and tool geometry on machinability of cotton-fiber reinforced polymer composites: Cutting forces, burr formation, and chip morphology

Due to the increasing importance of natural fiber reinforced polymer composites, a large number of papers published about fabrication of these materials, but yet the secondary manufacturing performance knowledge of such materials is rather limited. Understanding cutting performance of a novel natural fiber (cotton) reinforced polymer composite is the primary interest of this work. In the first part of the study, suitable cutting tool geometry was designated through milling tests and the results of cutting force, burr formation, and chip morphology. One flute left helix WC (Tungsten Carbide) tool was the most suitable tool geometry for cotton-fiber reinforced polymer milling. The optimum cutting parameters were selected with the designed quantitative scoring procedure for combined evaluation of cutting force and burr formation results. According to the evaluation system, the optimum cutting parameters were found as 25 m/min cutting speed and 200 mm/min feed rate. Three form of burr which are roll-over, poisson and entrance burr, and short ribbon shape chips with linty look were observed due to the embedded cotton fibers in LDPE matrix. At the end of the study, the benchmarking cutting force tests were conducted with pure low density polyethylene material and results compared with the cotton-fiber reinforced polymer.

A new approach for the development of textile waste cotton reinforced composites (T-FRP): laminated hybridization vs. coupling agents

Abstract This paper presents two separate methods to improve the tensile strength (TS) of textile waste cotton reinforced polymer composites (T-FRP) as prospective functional materials with respect to environmental concerns. Two very different methods were designed in order to improve the TS of the composite. In the first method, maleated anhydride polyethylene was added as the coupling agent into the composite composition, whereas in the second method, a totally new glass fiber and glass fabric laminated hybrid composite structure was designed. In this first study, the coupling agent was mixed up to 5 wt% into the composite structure in order to improve the bonding interface between low density polyethylene (LDPE) matrix and cotton waste fibers. The effect of the coupling agent was evaluated and compared with the unmodified one. By contrast, chopped glass (CG) fibers and woven biaxial glass fabrics were introduced into the composite layers with the intention of designing a new hybrid composite structure as a second study. The TS of the materials was evaluated and the fracture surface was assessed with an optical microscope. Consequently, an improvement in TS of 50% and 230% was achieved by the addition of the coupling agent and the creation of a new hybrid composite, respectively.

Development of Natural Fiber Reinforced Laminated Hybrid Composites

In this study, mechanical properties of composite laminates reinforced with various forms of glass fibers have been investigated. Tensile testing, impact testing and optical microscopy and SEM analysis results were discussed. The results of glass fiber reinforced novel composite material have been compared with the results of a commercial car front bumper material tests performed in same conditions. Study concluds that glass fiber has positive hybridization effect and increased tensile strengths, elastic modules and impact strengths in laminar hybrid composites.

Machinability of Bulk Metallic Glass Materials on Milling and Drilling

In this study, machinability of Zr-based bulk metallic glass (Zr52.5Ti5Cu17.9Ni14.6Al10) (BMG) material was investigated by conducting a set of milling and drilling experiments. In milling, two different tool paths, spiral and slot milling, were used. To investigate the behavior of BMG in drilling by two different tools at different feed rates, two sets of drilling experiments are conducted. Crown shaped exit burr formation are observed in drilling of BMG. Best results on thrust force, exit burr formation and hole surface roughness is obtained while using micrograin WC tool on BMG drilling. No chip light emission was observed during all tests. This study concludes that BMG can be achieved machining with good surface roughness, (Ra=0.113 µm), using conventional cutting tools.

The effect of chemical treatment methods on the outdoor performance of waste textile fiber-reinforced polymer composites:

In this study, weathering effect on untreated textile fiber-reinforced polymer composites and the effect of different chemical treatments for better interfacial adhesion on the outdoor performance were investigated. Degradation of physical, mechanical, and chemical properties of textile fiber-reinforced polymer composites was evaluated through common chemical treatments such as maleated coupling, alkaline treatment, silane treatment, and alkali–silane treatment. Untreated and chemically treated textile fiber-reinforced polymer composites were subjected to water uptake and UV exposure up to 1000 h. Tensile and impact properties were mechanically examined, and the changes on the physical properties due to water uptake, swelling, and color change were investigated. In addition, Fourier transform infrared spectrum analysis was performed in order to evaluate the chemical changes after exposure.

Autonomous hole quality determination using image processing techniques

This paper introduces a technique which evaluate performance of hole quality after drilling process. Hole making is one of the most time consuming process in industry. For some applications the quality of holes are very crucial and be expected of tight tolerance from manufacturer. One of the most common device used by manufacturers to investigate the hole quality is coordinate measurement machines. However investment cost of coordinate measurement instrument machines are very high. Therefore a new image processing technique is proposed in this paper and coordinate measurement machine and image processing technique results were compared.

The Effect of Cutting Speed in Metallic Glass Grinding

In this paper, the effects of the cutting speed in metallic glass grinding were investigated in dry conditions. The results showed that grinding forces decrease as grinding energy increase with the increasing cutting speeds. The present investigations on ground surface and grinding chips morphologies ‐shows that material removal and surface formation of the BMG are mainly due to the ductile chip deformation and ploughing as well as brittle fracture of some particles from the edges of the tracks. The roughness values obtained with the Cubic Boron Nitride wheels are acceptable for the grinding operation.