Effect of different dielectrics on material removal rate, electrode wear rate and microstructures in EDM

Diesinker electric discharge machining is widely used non-conventional technique for making high precision and complex shaped parts. Dielectrics and electrical parameters were considered as the main factors for EDM performance. In this paper, the effects of pulse-on-time (μs) and current (ampere) were evaluated for performance measures using kerosene and water as dielectrics. A comparison was performed for both dielectrics in terms of material removal rate (mm3/min), electrode wear rate (mm3/min), and microstructures. Aluminum 6061 T6 alloy was used as material for this research due to its extensive use in aerospace and automotive industries. Experiments were designed using Taguchi L9 orthogonal array (OA). Time series graphs were plotted to compare material removal rate and electrode wear rate. Microstructures were taken by scanning electron microscope to analyze the surface produced in terms of cracks, globules and micro-holes. Higher material removal rate and lower electrode wear were achieved with kerosene dielectric. The novelty of this research work, apart from its practical application, is that Aluminum 6061 T6 alloy is used as work material to compare the performance of dielectrics (kerosene and distilled water). Paper presented at: Complex Systems Engineering and Development Proceedings of the 27th CIRP Design Conference Cranfield University, UK 10th – 12th May 2017

Evaluation of Lumbar Disc Herniation on Magnetic Resonance Imaging (MRI)

OBJECTIVE: To evaluate the lumbar disc herniation on magnetic resonance imaging (MRI) BACK GROUND: Lumbar disk herniation (LDH) is a common cause of low back pain in the world. The evidence has shown that the incidence of lumbar disc herniation (LDH) increases with age, weight lift and also depend on gender. In this cross-sectional descriptive study of LDH has been conducted to investigate the role of age in the incidence of LDH in elderly. The aim of the study is to investigate the relationship between the process of aging and the occurrence of LDH in old adults. Clinical studies have indicated that morphological characteristics of lumbar discs and signal intensity of patient’s MRI image have close relationship with clinical outcome Keywords: Intervertebral Disc, Herniated Disc, Protrusion, Degenerative Disc DOI: 10.7176/JHMN/90-07 Publication date:June 30th 202

Revealing the microstructure and mechanical attributes of pre-heated conditions for Gas Tungsten Arc Welded AISI 1045 steel joints

Gas tungsten arc welding (GTAW) is considered a well-established process in the manufacturing industry. Despite, certain challenges associated with high hardness of heat affected zone and cold cracking susceptibility of joints, are the main barriers for this process to be implemented successfully within high integrity structure. By using a combined procedure of experiments and modelling (response surface methodology (RSM) and multi-objective optimization: multi-objective genetic algorithm (MOGA)) allows obtaining good enhancement over uniform heating, cooling and the heat-affected zone which enable major progress in obtaining high quality welded parts. Therefore, this research study combines the experiments and modelling in a systematic manner considering for the first type the pre-heated treatment and without- pre-heating conditions of GTAW manufacturing. It leads to optimizing the process parameters of GTAW when manufacturing AISI 1045 medium carbon steel. The effects of critical parameters i.e. welding current: WC, welding speed: WS, and gas flow rate: GFR on the mechanical properties (ultimate tensile strength (UTS) and hardness) were investigated and evaluated against the microstructure of weld fracture. The multi-objective genetic algorithm corroborated with experimental observation enables to obtain a maximum UTS of approx. 625 MPa and hardness of 80.19 HRB for preheat condition. The results highlight an improvement in UTS of 0.2% to 6.7% and a decrease in hardness of 0.1% to 21.5% by implementing the preheating conditio

Silver nanoparticles protect tillering in drought-stressed wheat by improving leaf water relations and physiological functioning

The tillering phase of wheat (Triticum aestivum) crops is extremely susceptible to drought. We explored the potential of silver nanoparticles (AgNPs) in protecting wheat genotypes from drought injury during this sensitive stage. After treating with AgNPs (60 ppm), the plants were submitted to different water levels; i.e. 100% field capacity (FC), 75% FC (mild drought), 50% FC (moderate drought) and 25% FC (severe drought) from 15 to 41 days after sowing (tillering phase). Leaf physiological data were collected at stress termination, while yield attributes were recorded at crop maturity. We found that increasing drought intensity significantly impaired leaf physiology and grain yield of both studied genotypes. Compared with control, moderately and severely drought-stressed plants produced 25% and 45% lesser grain yield per spike, respectively (averaged across genotypes and years of study). Likewise, moderate and severe drought reduced photosynthesis by 49% and 76%, respectively, compared with control. In contrast, AgNPs significantly restored leaf physiological functioning and grain yield formation at maturity. For example, under moderate and severe drought, AgNPs-treated plants produced 22% and 17% more grains per plant, respectively, than their respective water-treated plants. Our study suggests that exogenous AgNPs can protect wheat crops from drought during early development stages

Predicting the tensile strength, impact toughness, and hardness of friction stir-welded AA6061-T6 using response surface methodology

In this research, an attempt has been made to develop mathematical models for predicting mechanical properties including ultimate tensile strength, impact toughness, and hardness of the friction stir-welded AA6061-T6 joints at 95 % confidence level. Response surface methodology with central composite design having four parameters and five levels has been used. The four parameters considered were tool pin profile, rotational speed, welding speed, and tool tilt angle. Three confirmation tests were performed to validate the empirical relations. In addition, the influence of the process parameters on ultimate tensile strength, impact toughness, and hardness were investigated. The results indicated that tool pin profile is the most significant parameter in terms of mechanical properties; tool with simple cylindrical pin profile produced weld with high ultimate tensile strength, impact toughness, and hardness. In addition to tool pin profile, rotational speed was more significant compared to welding speed for ultimate tensile strength and impact toughness, whereas welding speed showed dominancy over rotational speed in case of hardness. Optimum conditions of process parameters have been found at which tensile strength of 92 %, impact toughness of 87 %, and hardness of 95 % was achieved in comparison to the base metal. This research will contribute to expand the scientific foundation of friction stir welding of aluminum alloys with emphasis on AA6061-T6. The results will aid the practitioners to develop a clear understanding of the influence of process parameters on mechanical properties and will allow the selection of best combinations of parameters to achieve desired mechanical properties

Sustainability Assessment for Dry, Conventional and Cryogenic Machining in Face Milling of Ti-6Al-4V

Sustainability achievement in difficult-to-machine materials is major concern now-a-days. This paper presents sustainability assessment of machining titanium alloy Ti-6Al-4V. Face milling of Ti-6Al-4V hardened to 55 HRC with PVD (Physical Vapour Deposition) coated inserts was analyzed for dry, conventional and cryogenic cooling modes. Experiments were designed using CCD (Central Composite Design) for modeling and analysis of surface roughness. Feed, speed and depth of cut were used as input parameters. For a specific surface finish, the three cooling modes were compared for cutting power, machining time and material removal rate. The results indicate that cryogenic cooling was more sustainable as compared to dry and conventional cooling process. This sustainable model will help to select sustainable input parameters

Simulation Based Measuring the Benefits of Converting to Lean Product Design and Development: A Case Study of Manufacturing Sector of Pakistan

Designers are facing the principle problems of effective decision making at initial design stage of product development, which ultimately cost it in the form of profit loss, low quality and increased time to bring the product to market. It needs a lot of knowledge and experience. Tools are required to analyze and ensure that crucial decisions have strong foundation before implementation. Discrete event simulation provides such a tool and has got potential to provide assistant in decision making before final implementation. This research work aims to measure the benefits of transformation to lean product development (LPD) via simulation. Simulink-MATLAB tool was used for this purpose. The whole work is limited to design and cost estimation cells of a manufacturing company and consists of two phases. The first phase deals with the assessment of current working model of design and cost estimation cells. Areas for improvements were recognized at this phase. The proposed model for transformation to LPD was developed in second phase. Four lean enablers naming product values, knowledge-based engineering, set-based concurrent engineering and poke-yoke have been incorporated to further enhance the working of proposed model. This research work is quite a useful case for practitioners

Analysis of the Effect of Wire Electric Dischage Machining Process Parameters for the Formation of High Speed Steel Form Tool

The use of form tools are growing in industry owing to their inherent advantage of improving productivity. However, the accurate formation of form tool profile is really a tedious task. In this research work, wire electric discharge machining (WEDM) process has been used for the generation of form tool. Pulse on-time, pulse off-time, servo voltage, wire tension, flushing pressure have been considered as input parameters whereas tool geometry (clearance angle, included angle), surface roughness and material removal rate are the selected responses. Response surface methodology (RSM) (Box Bhenken experimental design) technique has been used for design of experiments. Analysis of Variance (ANOVA) has shown that pulse on-time and pulse off-time are the two influential control factors for material removal rate (MRR), surface roughness (Ra), clearance angle and included angle. Contour plot analysis has been performed to find out the optimal ranges of the most influential control factors for each response characteristic

Continuous Quality Improvement (CQI) framework: A case of industrial engineering department

This paper aims to present an educational framework for outcomes based continuous quality improvement. Well defined program outcomes, program educational objectives and assessment process have been developed to ensure graduates’ outcomes achievement. Direct and indirect tools have been used for assessment process. Course evaluation surveys, alumni surveys, and employer surveys have been deployed for indirect outcome assessment. Exams, quizzes, assignments and projects, on the other hand, have been used for direct outcome assessment. In developed framework, the educational processes committees and facilities committees have been integrated to continuously evaluate and monitor the educational processes. Furthermore, program outcomes and course learning outcomes are proposed to be evaluated and continuously monitored by programs goals committee and continuous course improvement committee respectively. Forms and procedures have been developed to assess student outcomes