Machinability Analysis of Delamination and Thrust Force in Drilling of Pure and Added GFRP Composites

The aim of this work is to define the cutting conditions that allow the drilling of added glass fiber reinforced epoxy composite materials by taking into consideration the exit delamination factor, thrust force and the optimum combination of drilling parameters. The experiments were carried out under two cutting parameters such as cutting speed and feed rate for three levels each. Taguchi experimental design is used to reduce the excessive number of experiments. The experiment design was accomplished by application of the statistical analysis of variance (ANOVA). Correlations between cutting speed/feed rate and the various machining parameters were established to optimize cutting conditions. These correlations were found by quadratic regression using response surface methodology (RSM). Multiple regression analysis (MRA) was also employed to establish parametric relationships between the experimental parameters and the machinability outputs consisting of delamination and thrust force. The machinability refers to the relative ease or difficulty under certain cutting conditions. Therefore, it is very important to understand the factors affect the machinability and to evaluate their effects. Machinability of GFRP composites was enquired. It is aimed to evaluate the machinability of these materials. A machinability index has been developed in current study.

A Study on the Machinability of Steels and Alloys to Develop Recommendations for Setting Tool Performance Characteristics and Belt Grinding Modes

This article presents a methodology for designing belt grinding operations with grinding and lapping machines. It provides the results of a study on the machinability of various steels and alloys with belt grinding, which are then classified according to an indicator that we have developed. Namely, cast aluminum alloys, structural alloy steels, structural carbon steels, corrosion-resistant and heat-resistant stainless steels, and heat-resistant nickel alloys have been investigated. The machinability index is the ratio of the performance indicators of the grinding belt and the depth of cut to the indicators of grade 45 structural carbon steels (similar to steel AISI 1045) and similar steels and alloys. The performance indicators of the grinding belt are chosen from a set of calculated and estimated indicators. Experimentally determining the dependences of the performance indicators on the belt grinding modes and conditions, taking into account the established levels of machinability, allowed us to develop recommendations for designing belt grinding operations with grinding and lapping machines. The proposed methodology for designing belt grinding operations guarantees optimal performance and ensures that the necessary quality of the machinable surfaces is achieved. At the same time, it takes into account variable machining conditions, which change within specified limits.

The structural, electronic, elastic and thermodynamic properties of V2AX (A = B, Al, Ga, In and TI; X = C and N): A DFT calculation

The structural, electronic, elastic and thermodynamic properties of [Formula: see text] ([Formula: see text], Al, Ga, In and TI; [Formula: see text] and N) phase have been systematically investigated by the first principles. The optimized lattice parameters are in good agreement with the experimental values and better than the available theoretical data. We calculated the elastic constants [Formula: see text] and the total density of states, which verified mechanical stability and electronic structural stability, respectively. The other elastic parameters including bulk modulus, shear modulus, Young’s modulus, Cauchy pressure, shear anisotropy factor, linear compressibility coefficients, Pugh’s ratio, Poissons’s ratio, microhardness parameter and machinability index are calculated and discussed in this work. The results show that the compounds we studied are stable in mechanics and are anisotropic materials; the compressibility along [Formula: see text]-axis is lower than that along [Formula: see text]-direction except for [Formula: see text] ([Formula: see text] and N); the compounds of [Formula: see text] ([Formula: see text]) and [Formula: see text] ([Formula: see text]) are brittle in nature, and [Formula: see text] and V2TIN are ductile in nature; the shear modulus [Formula: see text] limits the mechanical stability of the materials under consideration; the ability to resist shape change and the stiffness of [Formula: see text] are stronger compared with [Formula: see text] when A takes B, Al, Ga, In, TI, respectively. Finally we have estimated the Vickers hardness which shows that the hardness of the [Formula: see text] ([Formula: see text], Al, Ga, In, TI) would decrease when C is replaced by N. At last, we investigated the thermodynamic properties of [Formula: see text] by calculating the phonon dispersion, Debye temperature and minimum thermal conductivity. The results show that all structures are dynamical stable and the compounds of [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] are candidates for thermal barrier coating (TBC) materials.

Experimental Investigation of Drilling Small Hole on Duplex Stainless Steel (SS 2205) Using EDM

This work investigates drilling of small holes of 3 mm in diameter on duplex stainless steel. Its machinability index is very low (0.66) when compared to other steels; hence, electrical discharge machining is used. The input parameters are current, spark gap, and dielectric pressure. Each input parameter is considered for three levels. Therefore, the total number of experiments is 3 × 3 × 3 = 27. To reduce the number of runs, Taguchi L9 orthogonal array is used, which have the advantage of maximum and minimum trial runs in its design. The output response is metal removal rate (MRR). To find the best operating parameter, the regression model generated using ANOVA is given as input for MATLAB genetic algorithm (GA). The experimental results indicated that models are significant. The test result indicated that the contribution of the current on the MRR is 42.42%, dielectric pressure is 35.36%, and spark gap is 1.93%. From GA, it is observed that among these three factors, lower value of current and dielectric pressure produced the maximum MRR. The SS 2205 has wide variety of applications, such as high pressure components and control valves, which have large number of components attached to it. Hence, performing micro holes on such high hardness alloy is useful.

Characterization of Chip and Burr Formation at High Speed Machining of Nitronic 33 Steel Alloy

The energy consumption and machinability index of metallic alloys are very important in determining the economic and environmental value of manufacturing process. Various machinability problems with Nitronic 33 steel alloy have been reported in literature. These problems have been attributed to the work hardening of the material during machining operation and hence greatly influences and contributes to the green house gas emission. In this work, the chip and burr formation during the machining of Nitronic 33 steel alloy was investigated in other to optimize the cutting parameters and provide a knowledge base for machinists when machining austenitic stainless steels. The result shows that although continuous chips were formed throughout the machining tests, an evidence of continuous chip with built-up edges was also observed. This phenomenon tends to initiate the formation of discontinuous chips especially at high pressure coolant flow of 7 and 9.7 MPa. It is concluded that conventional cutting environment at 90 m/min cutting velocity is the optimum process parameter most suitable for machining Nitronic 33 steel alloy. The research outcome will address some of the problems encountered during high speed machining of Nitronic 33 steel alloy and the general understanding of the machinability of this alloy.

Machinability Index Evaluation: A Case Study of Carbide Inserts

The selection of carbide insert on the basis of performance measuring parameters is amulti-attribute decision making problem. This proposed work demonstrates a methodology to evaluate the machinability of the selected turning operation by using graph theory and matrix methods. The qualitative values of attributes are obtained by measuring the process attributes. The fuzzy score has been used to convert intangible factors to crisp scores and then graph theoretic approach has been applied to calculate the single numerical machinability index for ranking among the insert alternatives. Permanent function matrix has been solved by using computer software. This study, in particular, shows the potentiality of graph theory and matrix approach for the analysis, evaluation and selection of carbide insert for machining process. A hybrid decision making method of graph theory and matrix approach (GTMA) and analytical hierarchy process (AHP) is proposed to solve multi decision making problem. The result of study highlights the ranking of inserts based upon machinability index.

Machinability Evaluation of Ce-ZrO2/CePO4 Ceramics with Digraph Method

A new method is proposed for machinability evaluation of machinable ceramic materials. The relation of machinability attributes is modeled as a digraph, and machinability attribute matrix is defined. Machinability indexes are calculated with permanent function of the matrix, and machinabilities of machinable ceramics are ranked. Five composites consisting of CePO4 and zirconia were fabricated, measured and drilled with tungsten-cobalt carbide bits. Mechanical property parameters of Ce-ZrO2/CePO4 composites, including Vickers hardness, fracture toughness and Elastic modulus, are selected as machinability attributes. The experimental results of material removal rates are consistent with the ranking of machinability index values of Ce-ZrO2/CePO4 ceramics. The machinabilities of Ce-ZrO2/CePO4 ceramics improve with the increase of CePO4 proportions. Machinability of machinable ceramics can be evaluated with digraph method.