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In this article, the adaptive neuro-based fuzzy inference system (ANFIS) model is developed to estimate the surface roughness (Ra) and tool vibrations (Acc) of AA6013 aluminum alloy during dry turning. Turning experiments were carried out with seven different cutting speeds, five different feed rates and seven different depth of cuts. These three different cutting parameters were tested with each other in different variations. ANFIS model is optimized using the genetic algorithm (GA), particle swarm optimization (PSO) and ant colony optimization. Performance of the developed model is compared with that of multi-linear regression model, which is one of the conventional prediction approaches. At the end of the study, it is revealed that the GA-ANFIS with an R-value of 0.946 is seen as the best model among the proposed approaches in the estimation of Acc. The PSO-ANFIS with an R-value of 0.916 is seen as the best model among the proposed approaches in the estimation of Ra. GA-ANFIS model for Acc prediction and PSO-ANFIS model for Ra prediction are the best approaches among the models discussed in the study. Moreover, the relationship between Acc and Ra values was examined and an empirical model was proposed.

Literally, hard machining describes machining of parts having hardness over 45 HRC. Besides its advantages like high metal removal rate, easiness of adapting to complex part geometries, possibility of dry cutting; this operation, which can substitute grinding in most cases, has some disadvantages. One of them is the significant increase of surface roughness due to tool wear even when the tool life limit is not exceeded. In this study, considering hard turning praxes, higher depths of cut (0.5 to 1.0 mm) were examined when dry turning AISI D2 cold work tool steel, through-hardened to 62 HRC. TiN coated mixed ceramic inserts (Al2O3 + TiCN) were employed in the operations. Relationship between surface roughness and cutting parameters (cutting speed, feed and depth of cut) was modeled and analyzed using a Box-Behnken response surface methodology (RSM) design. A linear model best described this relationship. Despite the higher depths of cuts, the surface roughness values achieved were comparable to those in grinding operations. Finally, the optimal values of cutting parameters for minimum surface roughness were predicted.

In this research, the tool-chip interface temperature (T-CTI), the tool temperature (T-T) and the average surface roughness (R-a) were measured experimentally during the turning of AISI 4140 alloy steel with TiAlN-TiN, PVD-coated, WNVG 080404-IC907 tungsten carbide inserts using an IR pyrometer technique, a K-type thermocouple and a portable surface-roughness measurement device, respectively. The workpiece material was heat treated by an induction-hardening process and hardened up to a value of 50 HRC. The Taguchi method L18 (21 x 37) was used for the determination of the optimum control factors. The depth of cut, the cutting speed and the feed rate were taken as control factors. The analysis of variance was applied in order to determine the effects of the control factors on the tool-chip interface temperature, the tool temperature and the surface roughness. The optimum combinations of the control factors for T-CTI, T-T and R-a were determined as a(2)v(1)f(3), a(1)v(3)f(2) and a(2)v(3)f(1), respectively. Second-order predictive models were developed with a linear-regression analysis, and the coefficients of correlation for T-CTI, T-T and R-a were calculated as R-2 = 92.8, R-2 = 68.1 and R-2 = 82.6, respectively.

The life of a tool is affected by many factors such as cutting speed, depth of cut, chip thickness, tool geometry, workpiece material, cutting fluid and the rigidity of the machine tool. This paper introduces the innovative turning strategy of variable feed turning. The workpiece material was AISI 1050, and two types of TiN-coated insert (CNMG-120408 (NC3020) and DNMG 150608-NM4 WPP20) were used as cutting tools in the machining tests. A thorough investigation was carried out on the effect on tool life of a gradual feed rate at a constant depth of cut and cutting speed with no cooling fluid. The feed rate was gradually increased twice every millimetre at the beginning of turning and kept constant for the rest of the cut. Turning experiments were conducted with both constant and variable feed rates. Brand new inserts were deployed in the experiments related with constant feed rate for each time period. Comparisons showed the significant influence of the variable feed rate. Apart from the reduction in initial wear, the new turning strategy produced very positive results regarding tool wear in the moderate wear zone, and a considerable increase of 32 % in tool life was achieved. Moreover, with the new strategy, total tool life was prolonged by up to 35 %. Balıkesir Üniversitesi Bilimsel Araştırma Projesi Birimi - 2012/101

The work presented in this paper examines the effects of cutting parameters (cutting speed, feed rate and depth of cut) onto the surface roughness through the mathematical model developed by using the data gathered from a series of turning experiments performed. An additional investigation was carried out in order to evaluate the influence of two well-known coating layers onto the surface roughness. For this purpose, the experiments were repeated for two CNMG 120408 (with an ISO designation) carbide inserts having completely the same geometry and substrate but different coating layers, in a manner that identical cutting conditions would be ensured. The workpiece material machined was cold-work tool steel AISI P20. Of the two types of inserts employed; Insert 1 possesses a coating consisting of a TiCN underlayer, an intermediate layer of Al 2 O 3 and a TiN outlayer, all deposited by CVD; whilst Insert 2 is PVD coated with a thin TiAlN layer (3 ± 1 μm). The total average error of the model was determined to be 4.2% and 5.2% for Insert 1 and Insert 2, respectively; which proves the reliability of the equations established.

In this work a series of test were conducted in order to determine the machinability of tool steels. In these test the effects of tool material, type of coating on the insert (for coated tools) and the cutting parameters that affect the machinability were taken into considerations. The cutting force data used in the analyses were gathered by a tool breakage detection system that detects the variations of the cutting forces measured by a three-dimensional force dynamometer. The workpiece materials used in the experiments are cold work tool steel, AISI O2 (90 MnCrV8); hot work tool steel, AISI H10 (X32CrMo33) and mould steel, AISI improved 420 (X42Cr13). The cutting tools used are HSS tools, uncoated WC and coated TiAlN and TiC + TiCN + TiN inserts (ISO P25). The type of inserts is DNMG 150608. No cutting fluid was used during the turning operations. During the experiments cutting forces, flank wear and surface roughness values were measured throughout the tool life and the machining performance of tool steels were compared.

In this study, the effects of cutting speed, milling direction (down milling, up milling), coating layer (TiAlN and TiAlN-TiN) and the number of inserts of tool holder on the surface roughness and tool life in dry milling of Inconel 718 superalloy were investigated. In the first place, the effects of control factors on the tool life were studied at the cutting speeds of v = 50 m/min and v = 100 m/min. The alternation of flank wear depending on the cutting time was examined. The types of wear and wear mechanisms were determined by examining the optical images of worn tools. In the second part of the study, for the purpose of investigating the effects of control factors on the surface roughness, L16 Taguchi Technique was used and the optimal control factor levels, giving the lowest value of the average surface roughness parameter (Ra) were determined. The effect of cutting speed on the tool life was more than the effects of the milling type and number of inserts. Down milling resulted in longer tool life compared to up milling method. In up milling, longer tool life was obtained with 2 inserts at low cutting speeds and with 4 inserts at high cutting speeds. TiAlN- TiN coated tools exhibited twice as long tool life than the TiAlN coated tools. For both milling methods, the most effective wear types were flank wear and nose wear.

The surface roughness model was developed in terms of main cutting parameters such as cutting speed, feed rate and depth of cut, using response surface methodology. Machining tests were carried out in turning AISI 1050 hardened steels by cubic boron nitride (CBN) cutting tools under different conditions. The model predicting equations for surface roughness of R-a, R-z, and R-max were developed using an experimental data when machining steels. The results indicate that the feed rate was found out to be dominant factor on the surface roughness, but it decreased with decreasing cutting speed, feed rate, depth of cut for these tools. In addition, average surface finish of Ra value produced by CBN cutting tool was about 0.823 mu m when machining hardened steels. However, the Ra value decreased about 0.55 mu m in terms of trial conditions. Moreover, a good agreement between the predicted and experimental surface roughness was observed within reasonable limit. (C) 2007 Elsevier Ltd. All rights reserved.

The objective of the present work is to assess the effect of different coating materials on machinability in the turning of AISI 1050 steel. The cutting tools used in this research are PVD coated TiAlN, and CVD coated TiC + TiCN + TiN, TiC + AI(2)O(3) + TiN and TiN + TiCN + TiN inserts (ISO P25). The type of inserts is DNMG 150608. During the experiments cutting forces, and flank wear values were measured throughout the tool life. The machining performance of different coating materials was evaluated. In addition, cost analysis based on total machining cost per part was performed for the comparison of the economic viability between the different coating materials.

Experimental data are presented for the tangential and radial stresses in the disks of the 36,000 horsepower, 4000 rpm turbine for the M-1 engine oxidizer turbopump. The two-stage Curtis turbine is a special light-weight design utilizing thin conical disks with hollow sheet metal blades attached by electron-beam welding techniques. The turbine was fabricated from Inconel 718, a nickel-chromium alloy. The stresses were obtained by strain-gage measurements using a slip-ring assembly to transmit the electrical signals. Measurements were made at different rotative speeds and different thermal loads. In addition to presenting test data, the report describes test equipment, design of associated hardware, test procedures, instrumentation, and tests for the selection and calibration of strain gages. NASA ORDER C-10836 Approved for public release; distribution is unlimited.