R. Kesavan

Vendor Evaluation Using Multi Criteria Decision Making Technique

A supply chain is a network of departments, which is involved in the manufacture of a product from the procurement of raw materials to the distribution of the final products to the customer. The term supply chain is already invoked effervescence among the managerial community. The purchasing function has gained importance in the supply chain management due to factors such as globalization, increased value addition in supply and accelerated technology change. A key and perhaps the most important process of the purchasing function is the efficient selection of suppliers, because it brings significant savings for the organization. In general, the supplier selection criteria most commonly used by the industries are quality, delivery and price. Also, depending on the corporate environment of the industries, the importance of the performance measure can vary. In this work a versatile technique namely multi criteria decision making (MCDM) technique which involves the analytical network process (ANP) and technique for order performance by similarity to idea solution (TOPSIS) method has been used to select the best vendor. Analytical Network Process and TOPSIS method are powerful decision making processes which help people to set priorities on parameters that are to be considered by reducing complex decision to a series of one-to-one comparisons, thereby synthesizing the result When any vendor for a particular item make changes for the parameters like price, quality etc to improve his performance or has improved abilities in managing supply chain by providing better delivery to his customer, the whole hierarchy process for arriving the ranking of vendors is to be performed again for finding out the best vendor. Now it is felt that a standard automated procedure which could perform the above processing task is essential. So, standard software was developed in a suitable platform such as VB, .NET and MS access that could meet the current requirement. This package can be executed several numbers of times with changing input parameters values thus serving the purpose.

Suitability Assessment of Lean Kitting Assembly through Fuzzy Based Simulation Model

The success of an industry depends on its product‟s quality, cost and delivery time. So, now a days all manufacturers are trying to implement new manufacturing methods for their production process. In this paper, an attempt has been made to find the suitability of new assembly method known as Lean Kitting assembly for a leading two wheeler manufacturer in India. Lean Kitting means supplying assembly station with kit of components. Even though lot of Multi Criteria Decision Making (MCDM) models like AHP, ANP and PVA are available, a Fuzzy Based Simulation (FBS) model is necessary to assure the suitability by considering important factors and simulate the factors with data given by the experts in those fields. This paper mainly focused on the modeling of a „Fuzzy Based Simulation‟ for finding the suitability of the Lean Kitting system by considering the following important factors: Work In Process inventory, Floor space required, operator walking distance.

Effect of Fiber Orientation and Stacking Sequence on Mechanical and Thermal Characteristics of Banana-Kenaf Hybrid Epoxy Composite

The usage of hybrid natural composites has surged in almost all fields of engineering due to their advantage of possessing high strength to weight ratio and biodegradability. This paper deals with the fabrication and investigation of mechanical and thermal properties of banana-kenaf glass fiber reinforced epoxy composite which is relatively a newer hybrid composite. In this study, the composite is fabricated by a hand layup process with different fiber orientations and also with different volume fractions. The composites are prepared with five different proportions of banana-kenaf fibers. Various mechanical and thermal tests are conducted and the result shows that the hybrid composite in which fibers are arranged at 450 inclination has better properties than the others. Also, failure morphology analysis is done using a Scanning Electron Microscope (SEM) through which the internal structures of the tested specimen are analysed.

Reverse engineering system for generator engine parts

In this modern world, there are always pressure on the designer and the manufacturer to respond to the consumer needs. Rapid product development (RPD) assists manufacturers and designers in meeting the demands by reducing product development time. Engineering involves designing, manufacturing, constructing, and maintaining of products, systems, service and structures. There are two types in a design process: 1) forward engineering; 2) reverse engineering. In this paper, an attempt has been made to derive all the parameters, which are necessary for designing the components of a generator using reverse engineering. Even though lots of methods are available for redesigning, the reverse engineering is selected by performing analytical hierarchy process (AHP). The data acquisition is done using laser scanner device. The data sculpt software draw profile lines using scanned data. Then the exact model is created using Pro E software. The manufacturing drawing is prepared using the collected data.

Identification of Optimized Welding Conditions for Pulsed Current Gas Metal Arc Welding of AISI 904 Super Austenitic Stainless Steel

The present investigation is aimed to study the effect of pulsed current gas metal arc welding on the tensile strength of AISI 904L super austenitic stainless steel joint 1.2 mm diameter solid wire of same composition. The joints were fabricated using pulsed current gas metal arc welding and by varying five factors such as peak current, pulse on time, pulse on frequency, background current and welding speed at five different levels. Design matrix based on central composite rotatable design was selected to conduct the experiment and an attempt is made to maximize the tensile strength by optimizing the factors using graphical and numerical optimization techniques. Results were correlated with weld metal microstructures.

Wastage Reduction through Lean Manufacturing in Head Lamp Casing Manufacturing Process

In Case Industry motorcycles models Head lamp casing is made up of Aluminium and it is manufactured by gravity pressure die casting (GDC) process. The rejections rate and cycle time are very high. These results in frequent line stoppage due to the shortage of Head lamp casing. Hence we have decided to proceed with some other process for the manufacturing of head lamp casing, since the existing GDC process has some limitations it cannot be improved further. To move with other process, we have studied sheet metal, in which our head lamp casing design is so complicated and process would be more tedious. Moreover aesthetics look of the head lamp casing will be affected. So we progressed with other die casting process. We have studied pressure die casting (PDC) process first, but in PDC, head lamp casing cannot be manufactured two halves, due to the size of our head lamp casing. Hence we proceeded with low pressure die casting (LPDC) process, in which sand cores are made and thru which Head lamp casing are manufactured. To move with LPDC process, the present supplier base is not feasible. Hence we decided to move with an alternate source for LPDC process. Three LPDC manufacturing suppliers were shortlisted. Among the three suppliers, based on the quality, cost and delivery time, one supplier is approved. Approved supplier is permitted for die making and manufacturing head lamp casing after the product and process audit. Once die manufacturing is completed, samples were taken and tried out at our end. The new LPDC head lamp casing is found ok and hence rejections at supplier end had minimised and rework at our end had eliminated. These results in eliminating the dispatch constraints and thus our motto of avoiding line stoppage due to the shortage of head lamp casing are eliminated.

Vibration Analysis of a Constant Speed and Constant Pitch Wind Turbine

In order to increase the reliability of the rotating machineries like rotor, gear box, high speed shaft, low speed shaft, generator, and yaw of wind turbine (WT), it is important to monitor the vibration level. The key aim of the paper is to study the vibration characteristics experienced in the 400 kW WT at different load and operating conditions. The experimental vibration analysis of WT components is done and vibration characteristic curves are generated with the help of data acquisition software. These vibration characteristic curves are studied and observations made from them for their severity and effects are analyzed. Some indispensable recommendations have been given for vibration control.

Computation of Availability and Performance of Wind Turbine with Markov Analysis in India

This paper deals with the availability analysis for the wind turbines (WT) located in hill and main pass having uncertainty in wind. Availability is a key performance index for WTs. In this paper, the concept of Markov analysis (MA) is used to model the failure characteristics of the WTs for calculating probability and reliability of reaching various system states of WT having the capacities of 225 kW, 250 kW, and 400 kW. Due to uncertainty in the wind, the probability of component failure is independent of the past history. Hence MA is considered as the best mathematical tool for modelling WT with complex system. The field data obtained from the Muppandal site in India such as Mean time between failure (MTBF), Mean time to repair (MTTR), failure rate and repair rate are used to compute the WT availability, using ITEM Toolkit version 8.0.2 as a measure of performance. No attempt is made to analyze the individual state of the WT system. In this paper, for seven critical components, a resultant of 128 states has been analyzed. This analysis yields some surprising results that some WTs are the most unreliable due to the rapid failure of its sub assemblies in view of the very high uncertainty in the wind and frequent grid failures.

Reliability Analysis of Sub Assemblies for Wind Turbine at High Uncertain Wind

The wind energy plays a vital role in the world renewable energy scenario. The modern wind turbine system has a complex and repairable components due to sophistication and centralized control. The failure characteristics of the onshore wind turbines depend on the terrain conditions. In the main mountain pass and hill area, there is a heavy uncertainty in the wind that is due to the frequent change in the direction of wind and the change in the velocity. It causes a rapid failure in the individual sub assemblies. There is a substantial need for improving the reliability in the stages of design, manufacturing, operation and maintenance. Normally the infant mortality failures are more in the onshore wind turbine and the failure rate is constant during normal operating period. It is a surprise that the failure rate has rapidly increased during normal operating period of the wind turbines placed exactly in the mountain pass and hilly area due to the high uncertainty in the wind. This paper deals with reliability analysis of major components of wind turbine system and its sub system such as rotor system, gear box, brake system, generator, hydraulic system and yaw system. This paper also investigates the reliability of wind turbines and its sub assemblies placed at Aramboly pass in India by using Weibull software as reliability tool for a grid connected 250 kW wind turbine. This analysis yields some surprising results about some sub assembly like yaw system, brake system and generator which are most unreliable.