MODELING AND MULTI-RESPONSE PREDICTION OF MICRO EDM DRILLING ON INCONEL 718

Abstract Micro electric discharge machining is an important micro thermal erosion machining process which can produce high aspect ratio holes in electrically conductive difficult to machine materials irrespective of hardness. The objective of this study is to investigate the effect of various micro EDM drilling (RC pulse generators) parameters on machining inconel 718 using tungsten carbide as the tool electrode. Response Surface Methodology (RSM) and artificial Neural Network (ANN) with back propagation algorithm have been used for conducting experiments and modeling respectively. The experiments were conducted according to Box Behnken design matrix. Gap voltage (A), Capacitance (B), Feed rate (C), and Dielectric flow rate (D) were considered as the process parameters for experimentation. The performance measures were material removal rate (MRR), tool wear ratio (TWR), and overcut (OC). ANN models have been developed with varying number of neurons in the hidden layer from 5 to 15. It was found that one hidden layer with 9 neurons predicted the best results. Hence, a feed forward back propagation neural network of 4-9-3 was adapted to micro EDM drilling process. Based on regression analysis of experimental data, mathematical models were developed. The predicted values were compared with actual experimental results and the predicted values were almost equal to the expected with very less error

Standardization in a High Mix Low Volume Company : A Case Study

The market has been evolving from mass production towards mass customization, which has increased the complexity level for the companies. Unlike in mass production companies where the tasks are routine and standardized, the mass customization types of companies have a varied work demand which makes the work environment complex. These types of mass customization companies are known as High Mix Low Volume type of companies basically because of their characteristics of having a high mix in products and comparatively low volume production.  This thesis research was done with DEWTON INDUSTRIES, Kochi in India. Although product variety and complexity has been answered using technology development and modularization in the previous studies, there has been less focus given to reducing the complexity from the production process point of view. It is also evident that there is limited literature and research done regarding the standardization in High Mix Low Volume type companies both in the academia and in the industry. Hence, understanding the problems regarding standardization in a High Mix Low Volume company and how to handle them has been of a major importance at this point of time. The purpose of the research is to see how standardization can be increased in HMLV companies. The research approach used here was the case study to collect the necessary data to achieve the results. The data collection techniques used were interviews, observations and literature review, which gave the guidelines and suggested solutions to the identified problems related to standardization in High Mix Low Volume company in the production department.  The findings from the research suggest that standardization in HMLV production is very important for the companies in their current market demands. This is because standardization has a major effect on the quality of end products, production lead time, working standards of employees in the production department and design department. Various problems can occur, and only standardized procedures can solve these problems. It has been well exemplified in this thesis work, how these standardized procedures can increase the quality of the products, increase production speed, and also profit for the company. This research paper can be used as a guideline by other HMLV companies, while they plan to implement standardization in the production department. To the best of our knowledge this research was one of a kind in this particular field of study and also provides a base for in-depth research on each identified problem.

Development, structure and senescence of colleters in Gardenia lucida Roxb. (Rubiaceae)

Colleters are found on the adaxial basal part of the stipule and calyx of Gardenia lucida. They secrete a yellow transparent resinous substance commonly known as "Dikamali gum". They develop on both the stipule and calyx from a group of epidermal and hypodermal initials. A mature colleter consists of a central core of elongated parenchymatous cells surrounded by a palisade-like secretory epidermis. Druses type crystals of calcium oxalate are frequent in the colleters. At the time of senescence the central cells show lignification and the presence of tannin