SURFACE QUALITY OF THE EDM PROCESSED MATERIALS
The article presents the importance of the EDM technology in the industry of machine building. It is mostly used in the machining of stamps and special processes in which the conventional technologies are inefficiently. It's known that only condition of machining with this method is that the material should be electro conductive. The main parameters that are followed during the process are the precision and the roughness of the surface. The collective tried to emphasise the importance variation of the roughness concerning some machining parameters. Some of the measurements were conducted at ETH Zurich using an electronic microscope.
Case studies on productivity improvement and supplier selection
Two case studies have been reported (i) improvement of productivity in Electrical Discharge Machining (EDM) and (ii) Multi-Criteria Decision Making (MCDM) approach for supplier selection.Case study (i) highlights EDM of stainless steel in which best process environment (optimal) has been determined to satisfy productivity and quality requirements simultaneously. Material Removal Rate (MRR) during the process has been considered as productivity estimate with the aim to maximize it. Where as surface roughness i.e. (Ra value) of the machined surface has been chosen as surface quality estimate with the requirement to minimize it. These two contradicting requirements have been simultaneously satisfied by selecting an optimal process environment (optimal parameter setting). Desirability Function (DF) approach coupled with Taguchi method has been used to solve the problem.In case study (ii), usefulness of grey based MCDM approach method has been highlighted to solve multi-criteria decision making problem of supplier selection. The method has been found efficient to aggregate multiple attribute values into an equivalent single quality index (overall grey relation grade) which facilitates ranking/benchmarking as well as selection of the appropriate alternative supplier
Transient temperatures in a semi-infinite cylinder heated by a disk heat source
Abstract This paper is part of a series of papers by the author providing the exact transient temperature distribution in bodies heated by disk heat sources. The body in this paper is a semi-infinite cylinder with a uniform disk source centered at the end and uniformly heated. Results are given by infinite series, tables, figures and approximate relations. Care has been taken to provide methods for efficient evaluation of the infinite series because direct evaluation can require thousands of terms. Alternative exact methods are provided that require as few as three terms. The solution is intrinsically important but it is also a basic building block for spatially and time varying heat fluxes for finite as well as semi-infinite cylinders. This is discussed briefly herein and references for more extensive treatment are provided. The solution is also a basic one for the new numerical procedure called the surface element method.