Şener Karabulut

Dynamic Chip Breaker Design for Inconel 718 Using Positive Angle Tool Holder

This study has focused on the chip-breaker design and experimental cutting of Inconel 718 with the designed chip breaker. The process of chip breakage for Inconel 718 with respect to cutting speed, depth of cut, and feed rate then chips and machined surfaces were analyzed from the experimental results. For this purpose, the nickel-based super alloy, Inconel 718, was machined with two layers PVD coated (TiAlN–TiN) carbide insert at feed rates of 0.10, 0.15, 0.20, 0.30 mm/rev, 0.5, 1, 1.5, 2 mm with depth of cuts, and 30, 45, 60, 75 m/min cutting speeds using developed dynamic chip breaker with positive tool holders in dry cutting conditions. Chip pictures and surface roughness (Ra) were recorded. Chip breakability during machining of the Inconel 718 depends on DC motor speed and chip breaker position on the cutting tool. The experimental results show that the designed chip breaker can break long chips at any cutting condition and acceptable surface finish can be achieved. In addition to this, according to cutting conditions, the usages of dynamic chip breaker on the surface of cutting insert are measured between 1% and 44% cooling effects.

Wear Model in Milling Compacted Graphite Iron with Different Lead Angle Using Ceramic Cutting Tools

The objective of this study is to reveal the influence of the lead angle variation on tool wear in the process of face milling of compacted graphite iron with ceramic cutting tools. To achieve this goal, 36 milling experiments were carried out with different lead angles, cutting speeds and feed rates at the 2.5 mm constant depth of cut. The tool flank wear was strongly affected by the lead angle variations. SEM analyses of the cutting inserts were performed and experimental results have been modelled with artificial neural networks (ANN) and regression analysis. A comparison of ANN model with regression model is also carried out. The R2 values for testing data were calculated as 0.992 for ANN and 0.998 for regression respectively. This study is considered to be helpful in predicting the wear mechanism of the ceramic cutting tool in the machining of compacted graphite iron. A quicker method for the estimation of tool life is proposed, which requires less consumption of workpiece material and tools.

Study on Spindle Vibration and Surface Finish in Turning of Al 7075

In this study, the relationship between the spindle vibration and surface roughness was investigated and the effect of the cutting parameters on surface roughness and spindle vibration during the machining of Aluminum alloy 7075 (Al 7075) were determined. Experimental studies have been carried out on a CNC turning machine using coated cemented carbide cutting tools under dry cutting environment. L64 full factorial design of experiments was used to investigate the optimal machining parameters for spindle vibration and surface roughness. The influences of machining parameters on vibration and surface roughness were evaluated by using analysis of variance (ANOVA) and main effect plots. The results revealed that the feed rate was the most effective cutting parameters on spindle vibration and surface roughness. The machine tool vibration amplitude and surface roughness values were significantly increased with increasing cutting feed. The depth of cut and cutting speed have the least effect on the spindle vibration and indicated an insignificant effect on surface roughness. Mathematical equations were developed to predict the vibration and surface roughness values using the regression analysis.

R260 Çeliklerinin İşlenmesinde Kesme Parametrelerinin Yüzey Pürüzlülüğü, Güç Tüketimi ve Makine Gürültüsü Üzerine Etkileri

Hadfield celikleri yuksek asinma direncine, tokluga, yuksek akma ve cekme mukavemetine sahip malzemelerdir. Ray celikleri olarak da bilinen Hadfield celikleri asinma, darbe ve yorulma dayanimindan dolayi cogunlukla demiryolu ulasiminda kullanilmaktadir. Bu calismada, Hadfield celiklerinin isleme davranisi ve isleme parametrelerinin yuzey puruzlulugu, makine gurultusu ve guc tuketimi uzerindeki etkisi kuru isleme kosullarinda yatay freze tezgâhi kullanilarak arastirilmistir. Deneysel calismalar, agir isleme kosullarinda sabit kesme hizi, dort farkli ilerleme hizi ve alti farkli talas derinliginde ve gercek bir uretim ortaminda yapildi. Frezeleme degiskenlerinin yuzey puruzlulugu, makine gurultusu ve guc tuketimi uzerindeki etkisi varyans analizi (ANOVA) kullanilarak degerlendirildi. Deneysel sonuclar, kesme derinliginin yuzey puruzlulugu uzerindeki en onemli kesme parametresi oldugunu gostermistir. Kesme derinliginin artmasiyla yuzey puruzlulugu degeri belirgin sekilde iyilesmistir. Guc tuketimi ve makine gurultusu, deneylerde kullanilan artan ilerleme hizi ve kesme derinligi degerlerinin artmasindan etkilenmistir.

THE EFFECTS OF CONTROL FACTORS ON OPERATING TEMPERATURES OF A MECHANICAL HEAT PUMP IN WASTE HEAT RECOVERY: EVALUATION USING THE TAGUCHI METHOD

In the present study, the operating temperatures of the mechanical heat pump (MHP) in waste heat recovery were investigated to elucidate the effect of control parameters such as compressor speed, wastewater temperature and mass flow rate. The experimental trials were performed using the Taguchi L27 full factorial orthogonal array, and the results were optimized for compressor suction gas temperature, compressor discharge gas temperature, temperature difference of water entering and leaving the evaporator, temperature difference of water entering and leaving the condenser, evaporation temperature and condensation temperature. Analysis of variance was conducted to determine the effect of the control factors on the operating temperatures of MHP. The analysis results show that the wastewater temperature was the most significant factor on compressor suction gas temperature and discharge gas temperature. The compressor speed has shown a meaningful effect on the temperature difference of water entering and leaving from condenser. The nominal levels of control factors and the optimal temperatures were specified for the studied experimental parameters. Prediction models were developed for the operating temperatures through the Taguchi method (TM) and the operating temperatures were predicted with a mean squared error less than 12%.

Influence of Lead Angle Variation on the Coated Carbide Inserts Wear when Milling CGI and Modeling by Artificial Neural Networks and Regression Analysis Method

The aim of this research is to investigate the influence of lead angle, cutting speed and the maximum chip thickness on tool wear in face milling process of compacted graphite iron. Tool failure modes and wear mechanisms for all cutting tools were examined in respect of various cutting parameters and were evaluated on the base of the flank wear. SEM analyses of the cutting inserts were performed and experimental results have been modelled with artificial neural networks (ANN) and regression analysis. A comparison of ANN model with regression model is also carried out. Predictive ANN model is found to be capable of better predictions for flank wear within the range used in network training. The R2 values for testing data were calculated as 0.992 for ANN and 0.998 for regression analysis, respectively. This study is considered to be helpful in predicting the wear mechanism of the coated carbide insert in the machining of compacted graphite iron.

Dynamic Chip Breaker Design for Nickel-Base, Inconel 718, Alloy with Coated Carbide Tools Using Negative Angle Tool Holder

This study has focused on the chip-breaker design and experimental cutting of Inconel 718with the designed chip breaker. The process of chip breakage for Inconel 718 with respect to cutting speed, depth of cut and feed rate then chips and machined surfaces were analyzed from the experimental results. For this purpose, the nickel-base super alloy, Inconel 718was machined with a two layers PVD coated (TiAlN-TiN) carbide insert at feed rates of 0.10, 0.15, 0.20, 0.30 mm/rev, 0.5, 1, 1.5, 2 mm with depth of cuts, and 30, 45, 60, 75m/min cutting speeds using developed dynamic chip breaker with Negative tool holders in dry cutting conditions. Chip pictures and surface roughness (Ra) were recorded. Chip breakability during machining of the Inconel 718 depends on DC motor speed and chip breaker position on the cutting tool. The experimental results show that the designed chip breaker can break long chips at any cutting condition and acceptable surface finish can be achieved. In addition to this, according to cutting conditions, the usage of dynamic chip breaker on the surface of cutting insert is measured between 1% and 40% cooling effects using negative tool holder.