Machining Of Different Materials Research Articles

Effect of gas cutting fluids on machinability of different materials

Using a gas as cutting fluid is a new solution for enhancing machinability. Traditional methods such as wet cutting have some drawbacks such as high cost, pollution, and unsatisfactory product quality. The present research is concerned with studying the effect of applying different gases (N2, O2, and CO2) on cutting forces and product quality under different cutting conditions for different workpiece materials. Two groups of experiments were planned. The first was performed using different gas flowrates to study the effect of flowrate on cutting forces and surface roughness. The second group was performed using different cutting conditions and workpiece materials. Empirical equations and a correlation for the behaviour of each of the output responses were investigated as a function of the independent variables when applying each gas. Results showed that better product surface finish and lower cutting forces could be achieved by using gas cutting fluids compared with dry cutting. Also, machinability improved when the gas flowrate increased.

Laser Micro Processing using short Laser Pulses

AbstractPulsed laser radiation is a powerful tool for micro machining of different materials. The laser beam can be focused to spot diameters in the micron range. Depending on the material properties (e.g. heat conductivity), the thermal influence can be limited by using different pulse duration between nanoseconds (10–9 s) and femtoseconds (10–15 s).

Structural Refinement in High Temperature Annealing of Magnetron Sputtered Titanium Vanadium Nitride Coatings

Development of advanced ternary nitride coatings such as titanium aluminium nitride and titanium vanadium nitride has attracted significant industrial interest in recent years. Titanium vanadium nitride is considered one of the advanced ternary nitride coatings of great commercial potential. It is believed with the additional element, the oxidation resistance of the coatings can be greatly improved at elevated temperatures. Furthermore, the type of elements selected can produce unique coating properties that can be beneficial to machining of different materials. This paper is to report a study on the structural stability of nanostructured titanium vanadium nitride coatings in high temperature annealing. Nanostructured titanium vanadium nitride coatings were produced by reactive magnetron co-sputtering on AISI H13 tool steel substrates at 240oC. Heat treatment was applied to the coatings at temperatures up to 1000oC. It was found that an unexpected grain refinement of the coatings occurred in the heat treatment process. Grain size of the coatings was found to decrease from ~200-300 nm to ~150 nm after the heat treatments. A strong TiN/TiVN (200) component was found to exist at temperatures up to 700oC but was depleted at higher annealing temperatures. With a finer and densified grain structure, the hardness of the coatings substantially increased from ~800 HV to ~1700 HV.

A PROPOSED RESIDUAL-STRESS MODEL FOR OBLIQUE TURNING

A proposed mathematical model is presented for predicting the residual stresses cause by turning. Effects of change in tool free length, cutting speed, feed rate, and the tensil strength of workpiece material on the maximum residual stress are investigated. Th residual stress distribution in the surface region due to turning under unlubricate condition is determined using a deflection-etching technique. To reduce the number c experiments required and build the mathematical model for these variables, Respons Surface Methodology (RSM) is used. In addition, variance analysis and an experiment check are conducted to determine the prominent parameters and the adequacy of th model.The results show that the tensile stress of the workpiece material, cutting speed, an feed rate have significant effects on the maximum residual stresses. The propose model, that offering good correlation between the experirnental and predicted results, i useful in selecting suitable cutting parameters for the machining of different materials.

An investigation on machinability of different materials by hydrodynamic polishing process

This paper studies the machinability of different materials by the hydrodynamic polishing process (abbreviated as the HDP process). The effect of the surface energy and hardness of a material on the machining rate is examined. A mathematical model, based on Rabinowicz's energy equation and the machining principle of the HDP process, is developed. This model suggests that the machining rate of a material is inversely proportional to its surface energy. The material hardness has no effect on the machining rate. The experimental study shows that the machining rate of a material (CuAl alloy) with low surface energy is higher than that of another material (silicon wafer) with high surface energy. The qualitative trend of machining rate for different materials is consistent with the prediction of the developed model. In addition, the effect of hardness for ductile materials has a negligible effect on the machining rate.

Anode Erosion in Wire-EDM – A Theoretical Model

Summary Theoretical predictions concerning the machinability of different materials by EDM are difficult because numerous aspects govern this problem. The influence of the thermophysical material properties which play a dominant role can be studied best by a theoretical model. Thus, a new model which is tailored after a typical wire-EDM discharge has been developed and experimentally verified. The model describes the impact of a discharge on the anode as a heat source on a semi-infinite solid whose size and intensity are time-dependent. The numerical analysis of this mathematical problem has been performed by using the Finite element method.