Syed Husain Imran Jaffery

Statistical analysis of process parameters in micromachining of Ti-6Al-4V alloy

The demand for miniaturized components is on the rise, especially from the biomedical and aerospace industry. As a result, there is a strong research potential towards the micro-manufacturing of biomedical and aerospace components. Titanium-based alloys are known for their biocompatibility and high strength-to-weight ratio, making them most suitable for such applications. In this research, flank wear progression, surface roughness and side burrs, the basic performance parameters of a typical micromachining operation, are presented and analysed through analysis of variance in order to determine the key process parameters. It was found that micromachining can be classified into two categories: micromachining with undeformed chip thickness below the tool edge radius and micromachining keeping the undeformed chip thickness above the tool edge radius. The results showed that when machining with undeformed chip thickness above edge radius, the feedrate remains the most significant parameter affecting tool wear (41% contribution ratio), surface roughness (83%) and burr width (80%). This result places this type of machining closer to macro-machining where feed contribution was found to be 69%, 92% and 75% as against micromachining below edge radius, where contributions stood at 17%, 53% and 52% on tool wear, surface roughness and burr width, respectively. The results underscored the importance of considering the tool edge radius in micromachining.

Wear mechanism analysis in milling of Ti-6Al-4V alloy

This article presents an investigation into the wear of cutting tool during milling operation of Ti-6Al-4V using H13A carbide inserts. Wear tests were conducted using machining parameters (feed, speed, and depth of cut) falling in the permissible range recommended by the supplier of the inserts. A wear map was created to identify different regions that characterize the tool wear intensity. The wear map revealed a region of avoidance characterized by higher wear for cutting speed of around 55 m/min and feedrate of 0.15 mm/tooth. The Ti:Al ratio reached values between 4:1 and 6:1 for the cutting parameters that resulted in lower–tool wear rate. However, for higher wear rates, the ratio of Ti:Al did not exhibit any stability across the flank wear land. Scanning electron microscope and energy-dispersive x-ray analysis were performed on the worn inserts to identify the high–tool wear regions and material composition at different locations. Titanium aluminides (TiAl and TiAlN) were found just in the low–tool wear regions, and titanium nitride was found across the avoidance region in the wear map. Microscope and x-ray analysis of inserts in the safety zone clearly revealed a built-up edge on the cutting edge of the tools.

Turbine Blade Manufacturing Through Rapid Tooling (RT) Process and Its Quality Inspection

Rapid prototyping (RP) technologies have played vital role in product development and validation. Another aspect of RP is rapid tooling (RT). The development and manufacturing of conventional tools (die and molds) take considerable amount of time. RP technologies could be used to shorten the development time of these tools for shorten the time to production. This investigation focuses on the development of turbine blade through RT technique with quality inspection at three different stages, i.e., after manufacturing of master patterns, wax patterns, and casting in metal. Three different materials were considered for RT techniques, i.e., Room temperature vulcanization (RTV) silicon, polyurethane, and plaster of Paris. Master patterns were developed using stereolithography(SLA) and fused deposition modeling (FDM) process. Both master patterns were analyzed for surface roughness and dimensional accuracy. SLA pattern showed better results for surface finish and dimensional accuracy, and it was used for mold manufacturing. Wax patterns were produced from RTV silicon, polyurethane (PU), and plaster of Paris molds,and used for metal casting. Dimensional quality inspection was performed for both wax and metallic parts using noncontact three-dimensional (3D)digitizer. RTV silicon and SLA process were selected as the suitable mold material and process respectively for RT of turbine blade.

Study of the use of wear maps for assessing machining performance

Abstract The method of using wear maps in assessing tool wear over a range of cutting conditions was presented by Lim et al. in 1993 for turning steel using high-speed steel (HSS) tools. Since then this approach has rarely been studied or critically reviewed. The use of reliable wear maps can aid in assessing the wear rate and wear mechanism of cutting tools over a feed rate to cutting velocity plane. The focus of this paper is on improving the integrity of such wear maps. Unified cutting tests were undertaken to explore the effect of two different grades of carbide tooling on wear performance within a range of recommended cutting conditions. The methodology for developing such maps, as well as the underlying assumptions, was critically reviewed in light of two new wear maps created for different carbide grades. Additionally, by utilising energy dispersive X-ray (EDX) analysis and wear patterns, the paper presents new evidence in support of mechanisms responsible for the safety zone. Understanding the wear mechanisms in the low tool wear zone is important for developing extended life tooling.

Optimization of process parameters for plasma arc welding of austenitic stainless steel (304 L) with low carbon steel (A-36):

This research aims to optimize the process parameters of plasma arc welding for welding of dissimilar metals: austenitic stainless steel SS-304 L and low carbon steel A-36. It investigates the effect of welding current and welding speed on the quality of the welded joints. The quality characteristics like bead geometry, microstructure, hardness, ferrite measurement and tensile test are considered for qualification of the welded samples. Welded specimens were prepared both with and without filler material. These specimens were mechanically tested and analyzed using metallographic techniques. Based on the results, suitable welding parameters were found to be 45 A and 2 mm/s for samples prepared with and without filler wire. An all-martensitic weld zone structure was obtained for direct fusion. However, a complex heterogeneous microstructure was obtained by using austenitic stainless steel filler wire E 309 L. Hardness of directly fused sample was observed to be significantly higher compared to filler wire sample.

Improvement in the Mechanical Properties of High Temperature Shape Memory Alloy (Ti50Ni25Pd25) by Copper Addition

High temperature shape memory alloys Ti50Ni25Pd25 and Ti50Ni20Pd25Cu5 were developed, characterized, and tensile tested in both martensite ( − 50°C) and austenite (

Development of energy consumption map for orthogonal machining of Al 6061-T6 alloy:

The major source of environment and economic impact of machine tools has been attributed to their energy consumption. This article, therefore, proposes a novel energy mapping approach to evaluate specific cutting energy consumption with respect to cutting parameters. Unlike the studies presented earlier, which are machine-tool-specific, this study focuses on the basic tool–workpiece interaction for energy consumption analysis. The presented energy map reveals different energy consumption regions at varying machining parameters (feed and speed) during orthogonal machining of Al 6061-T6 alloy. The chip formation analysis indicates a strong correlation with the different energy consumption regions identified on the energy map. It has been observed that feed is the major contributing factor towards shear plane angle during chip formation as compared to cutting speed. Therefore, increasing feed results in a higher shear angle and consequently lowering the specific cutting energy as indicated on the energy map. Selection of machining parameters corresponding to the lowest specific cutting energy consumption region, as identified on the energy map, can result in energy savings up to 27% per kg of material removed. The developed map can be used for selection of suitable energy-efficient cutting parameters.

Analysis of weld characteristics of micro-plasma arc welding and tungsten inert gas welding of thin stainless steel (304L) sheet

This research work focuses on comparison of the weld geometry, distortion, microstructure and mechanical properties of thin SS 304 L sheets (0.8 mm thickness) welded using micro-plasma arc welding and tungsten inert gas welding process. Initial experiments were performed to identify suitable processing parameters for micro-plasma arc welding and tungsten inert gas welding processes. Microstructures of welds were analysed using scanning electron microscopy, X-ray diffraction and energy dispersive spectroscopy. The results indicate that the joint produced by micro-plasma arc welding exhibited higher tensile strength, higher ductility, smaller dendrite size and a narrow heat affected zone. Samples welded by micro-plasma arc welding process had lower distortion as compared to that welded by tungsten inert gas process. Micro-plasma arc welding was shown to be the suitable process for welding of thin 304 L sheets owing to its higher welding speed and better weld properties as compared to the tungsten inert gas welding process.

Numerical and experimental investigation of Johnson–Cook material models for aluminum (Al 6061-T6) alloy using orthogonal machining approach

This research focuses on the study of the effects of processing conditions on the Johnson–Cook material model parameters for orthogonal machining of aluminum (Al 6061-T6) alloy. Two sets of parameters of Johnson–Cook material model describing material behavior of Al 6061-T6 were investigated by comparing cutting forces and chip morphology. A two-dimensional finite element model was developed and validated with the experimental results published literature. Cutting tests were conducted at low-, medium-, and high-speed cutting speeds. Chip formation and cutting forces were compared with the numerical model. A novel technique of cutting force measurement using power meter was also validated. It was found that the cutting forces decrease at higher cutting speeds as compared to the low and medium cutting speeds. The poor prediction of cutting forces by Johnson–Cook model at higher cutting speeds and feed rates showed the existence of a material behavior that does not exist at lower or medium cutting speeds. Two factors were considered responsible for the change in cutting forces at higher cutting speeds: change in coefficient of friction and thermal softening. The results obtained through numerical investigations after incorporated changes in coefficient of friction showed a good agreement with the experimental results.

Evaluation of eddy current signatures for predicting different heat treatment effects in chromium–vanadium (CrV) spring steel

The nondestructive test method (eddy current) was employed to study the effect of different heat treatment cycles (normalizing, annealing, quenching, and tempering) on chromium–vanadium (CrV) spring steel. The calibration of eddy current setup was carried out as per ASTM E566 and frequency optimization for the evaluation of heat treatment was carried out in absolute mode using shielded eddy current testing core probe. The eddy current signatures successfully distinguished the effect of different heat treatments cycles and variation in hardness for CrV samples. Scanning electron microscopy images confirmed the different microstructures as predicted by the eddy current testing.