Volume 14, Issue 2

Since the need for the joining of dissimilar materials is increasing, the wide range of requirements of the numerous industries would lead to the development of new welding techniques or at least to improvement of the existing technologies capable of joining the components from the miniature assemblies to extremely large earth-moving vehicles. Among the different materials, iron-based alloys and aluminum-based alloys are the most significant materials that are finding applications in the various industries to offer more viable and sustainable products. However, welding of these metals has been always a kind of dilemma for the engineers. There are a certain number of methods to join these dissimilar metals but no one could establish a reliable or a sort of credible welding method for the industrial applications while quality, cost, human resources and facilities are taken into the main considerations. This paper reviews the recent works on the joining of different aluminum alloys to different steels. The effect of the joining conditions on the formation of intermetallics and microstructural development, mechanical properties and applications of the joints are discussed.

Pulsed Current Plasma Arc Welding (PCPAW) is one of the most widely used welding processes in sheet metal manufacturing industry. In any fusion arc welding process, the weld bead geometry plays an important role in determining the mechanical properties of the weld and hence quality of the weld. Moreover, the geometry of weld bead involves several simultaneously multiple quality characteristics such as front width, back width, front height and back height, which must be closely monitored, controlled and optimized. The present study is focused on the multi-objective optimization of performance parameters of weld bead geometry of PCMPAW welded AISI 304L sheets. The enhanced elitist non-dominated sorting genetic algorithm (NSGA-II) is used to solve this multi-objective problem. A mathematical predictive model for each of the weld bead parameters was developed using Response Surface Method (RSM) based Central Composite Design (CCD) design matrix. Further, an enhanced NSGA-II algorithm is used to optimize the models developed by RSM. Experiments were carried out to validate the results obtained from RSM and enhanced NSGA-II.

This paper concerns with the design of a computer integrated manufacturing system to identify an optimal path in a vehicle routing problem (VRP) network regarding to triple criteria. In most VRPs just one criterion, either time or cost was considered in decision making. But in this paper all time, cost, and AGV capability are noticed in decision making, simultaneously. Recently automated guided vehicles (AGVs) are being applied in material handling process that travels on a network of guide paths. To satisfy a material requirement planning (MRP) by providing the bill of material (BOM), AGVs are suitable devices. In this paper an AGV is employed to carry the parts based on the BOM, therefore the AGV is confronted with various paths in the shop network in a job shop layout. For controlling the time, cost, and AGV capability, intelligent agents are proposed. To decide about selection of the optimal path which is confined in time, cost, and AGV capability, mathematical programming approach is applied. The effectiveness of the proposed algorithm is validated using two illustrative examples.

This paper presents a manufacturing method for parts with trochoidal profile on CNC milling machines. The method is based on a new real-time interpolation algorithm capable to drive the cutter along the offset of trochoid curves with precision equal to the resolution of the machine. The structure of the presented algorithm may be adapted accordingly so as to be used either for parts with an epitrochoidal or a hypotrochoidal profile. Both types of curves, known as trochoid curves, have important industrial applications such as gears with trochoidal tooth-profile, cams, trochoidal-shaped housings for rotary internal combustion engines and rotary piston pumps etc. The effectiveness and accuracy of the proposed method is verified by simulation tests of the generated tool path for the machining of two representative mechanical parts, an inner rotor of a hypogerotor pump and an epitrochoidal-shaped housing.

In the recent time rubber has emerged as a very useful and suitable material for wider varieties of engineering and other applications which includes but not limited to domestic, sports and many more. It possesses large elasticity compared to metals, has greater damping capability, high internal friction and can accumulate energy to a greater extent compared to steel or other metals. During the deformation of rubber material, particularly by compressive force, internal damping of the material leads to energy dissipation. This is the cause of hysteretic friction of rubber. Friction of rubber has practical importance. At the same time it has many disadvantages too Use of rubber as engineering material is not new. However, in the recent time its application is gaining renewed importance as well as interest due to several engineering researches and property enhancement too. It is, however, needless to be mentioned that prediction of exact behavior of any viscoelastic material like rubber is very difficult. In the present work compression tests have been carried out to determine the flow characteristics of EPDM rubber of different hardness. Flat mild steel platens have been used to apply axysymetric compressive load on the specimen under dry working condition. The flow behavior like load – elongation curves, true stress – true strain curves and specific energy requirements have been computed from the experimental data. Statical hysteresis and the loss factors have also been obtained. Experimental results reveal that the hardness of EPDM rubber has significant effect on the flow behavior. Thus, it can be stated that the flow behavior can be governed by controlling the carbon black (CB) concentration in EPDM rubber as the hardness depends on it. It is proposed to extend the experiments with the application of different kind of lubricants.

In the present work, efforts are made to develop the input-output relationships for squeeze casting process by utilizing the fuzzy logic based approaches. Casting density in Squeeze casting is expressed as function of process parameters, such as time delay before pressurizing the metal, pressure durations, squeeze pressure, pouring temperature and die temperature. It is to be noted that, Mamdani based model and Takagi and Sugeno's model have been developed to model density in squeeze casting process. Manually constructed Mamdani based fuzzy logic controller and Takagi and Sugeno's based fuzzy logic controller have been used in approach 1 and approach 2 respectively. Training of FLC is carried with the help of five hundred input-output data set generated artificially through regression equations, obtained earlier by the same authors. The performance of the developed models was tested for both the linear and non-linear membership function distributions with the help of ten test cases. Moreover, the test data was collected by conducting the experiments and not used in training of FLCs. It is interesting to note that both approaches are capable to make accurate predictions. However, the performance of approach 2 with G bell shape membership function distribution is found to outperform approach 1 and other type of membership function distributions. The findings are useful to foundry-men, since it provides information on casting density in squeeze casting process for the different combination of process parameters without conducting any experiments.