Journal of Mechanical Engineering

Relationship between environmental manufacturing practices and their competitive outcomes

Syed Misbah Uddin — 2019-04-23

In today’s competitive market providing products only in low cost and high quality is not enough. Environmental concern in manufacturing is also an important issue now. To attract investors and customers organizations need to practice environmental manufacturing. This study is focused to present the relationships between some specific environmental manufacturing practices and their relative specific competitive outcomes in the important and vast industry of garment’s knitting sector in Bangladesh. Although there are several studies on the impact of environmental practices on the organizations outcomes but they are less construable due to many limitations. This study explores the environmental manufacturing practices under two categories pollution prevention and product stewardship and shows their relative competitive outcomes and establishes the relation between them. Based on the surveys and research it is found that some competitive outcomes are positively affected by some of the practices. These findings are believed to motivate the companies to turn towards the green manufacturing.

Effect of Fe, Ni and Cr on the corrosion behaviour of hypereutectic Al-Si automotive alloy in 3.5% NaCl solution at different temperature and velocity

M. S. Kaiser — 2019-04-23

The main focus of this study is to examine and evaluate the effect of Fe, Ni and Cr on the corrosion behaviour of hypereutectic Al-Si automotive alloy in 3.5% NaCl solution. Experimental information are attained using conventional gravimetric measurements under different solution temperature and velocity and complemented by resistivity, optical micrograph, scanning electron microscopy (SEM) and X-ray analyzer (EDX) investigations. All the alloys show the negative corrosion rate due to formation of a very thin film of aluminum oxide and hydroxid on the surface. Intermetallic particles in the alloys play a major role in passivity.

Temperature accelerates the corrosion and the higher velocity breakdown of the passive film. It also affects the resistivity of the alloys. The results from this study also indicate that the temperature and velocity increase the negative corrosion rate of the alloys due to higher rate of chemical reactions. SEM and EDX analysis indicate that the surfaces compose with a thin layer of aluminum oxide and hydroxide corrosion products.

Investigations for In-house prepared Biocompatible Feed Stock Filament of Fused Deposition Modelling: A Process Capability study

Nishant Ranjan — 2019-04-23

Fused deposition modelling (FDM) is one of the low cost additive manufacturing (AM) process. The feed stock filament of FDM is the only consumable in the process and by preparing (in-house) bio compatible feed stock filament the application domain can be increased. Some studies have reported the use of twin screw extrusion (TSE) process for preparation of bio compatible feed stock filament (comprising of polyvinyl chloride (PVC) and polypropylene (PP) and hydroxyapatite (HAp) particles) with improved mechanical, dimensional and thermal properties, for commercial FDM setup. But hitherto very less has been reported on process capability of in-house prepared biocompatible feed stock filament. In the present work statistical analysis (for tensile strength, hardness and dimensional accuracy) has been performed for investigations of process capability. The results have been also supported by control charts (X-chart and R-chart) based upon the best feedstock filament wire.

Effect of rolling on the fractional recrystallization behaviour of Al-Mg and Al-Mg-Zr alloys

M. S. Kaiser — 2019-04-23

One set of Al–Mg and Al-Mg-Zr alloys are directly cold rolled and other set of those alloys are hot rolled and then cold rolled using a laboratory rolling mill. The effect of rolling on the fractional recrystallization of the alloys has been investigated using the micro-hardness variation. Isothermally annealed samples are also studied using JMAK type analysis to see if there exists any correlation between experimental and JMAK type analysis. From the microstructure, it is observed that the Al-Mg alloy becomes almost fully recrystallized state after annealing at 600°K for 60 minutes. The results also show that recrystallization fraction obtained by the two methods, shows the higher variation in zirconium added Al-Mg alloy as compared to the Al-Mg alloy. The fractional recrystallization of the cold rolled Al-Mg-Zr alloy is significantly lower than that of cold rolled Al-Mg alloy and hot and colled rolled Al-Mg-Zr, owing to the presence of fine Al₃Zr precipitates. These metastable L1₂ Al₃Zr precipitates are thermally stable at high annealing temperatures.

Lean Implementation: The Progress and the future challenges of Apparel Industry to achieve the Manufacturing Competitiveness

Abul Bashar — 2019-04-23

Apparel industry plays an important role in the economic and social development of Bangladesh. This is now a multi-billion dollar manufacturing and export industry in Bangladesh. Its contribution to the foreign exchange earnings, poverty alleviation through creating employment opportunities and empowerment of women is remarkable. However, global competition and unstable market conditions prompted manufacturers to review their traditional manufacturing strategy. In today’s competitive business world, manufacturers are using Lean Manufacturing (LM) technique in order to improve performance and competitiveness. Lean Manufacturing (LM) is a holistic and sustainable approach of manufacturing system used for creating value for customers through eliminating waste in the manufacturing processes. This conceptual paper addresses the concept of lean manufacturing, its benefits and the challenges of implementing lean manufacturing.

Friction Stir Welding of Aerospace Alloys

Akshansh Mishra — 2019-04-23

Friction Stir Welding (FSW) is a solid state joining process which possesses a great potential to revolutionise the aerospace industries. Distinctive materials are selected as aerospace alloys to withstand higher temperature and loads. Sometimes these alloys are difficult to join by a conventional welding process but they are easily welded by FSW process. The FSW process in aerospace applications can be used for: aviation for fuel tanks, repair of faulty welds, cryogenic fuel tanks for space vehicles. Eclipse Aviation, for example, has reported dramatic production cost reductions with FSW when compared to other joining technologies. This paper will discuss about the mechanical and microstructure properties of various aerospace alloys which are joined by FSW process.