Papers by Author: Prakash R. Apte

Abstract: In drilling and boring process, the relief in clamping stress causes deformations that cause variations in the geometry of the drilled hole. In automobile industry, when such holes are used to hold gear systems or rods in place, this variation in geometry leads to poor fitting and subsequent failure. To avoid this, high level accuracy is required which is both expensive and time-consuming. Therefore, a high percentage of such drilled parts are rejected in industry. The present paper addresses this problem by characterizing the variations in hole geometry as a function of clamping force, hole diameter, hole eccentricity (distance of hole-center from center of drilled face) and angular position of hole with respect to clamp location. The analysis result quantifies the comparative effect of each aforementioned factor on hole geometry variation. Taguchi Method based Design of Experiments using L25 orthogonal array has been used for performing the parametric design to arrive at the best settings of the 4 parameters. The optimal settings minimize ovality and displacement of the hole-center, and thus increase hole-fitting and its reliability against manufacturing variability.

Abstract: Acceptable variations in the length of the valve stem, in a conventionally manufactured valve, give room to the possibility of the stem to buckle and get jammed in the guide. Salvaging such a situation is expensive and time consuming. The present paper addresses this problem by increasing the compliance of the valve stem by introducing holes in it. The desired elastic deformation along the length, however, causes transverse deformation, which needs to be minimized. The use of multiple holes helps achieve this. Taguchi Method based Design of Experiments using L25 orthogonal array has been used for performing the parametric design to arrive at the best settings of the 5 parameters. The optimal settings eliminate the buckling and thus make the operation of the valve stem robust against manufacturing variabilities.

Abstract: In this study, nanoclay and multi-wall carbon nanotubes have been used as a dual filler in an epoxy matrix. In the design of the experiment (DOE) the Taguchi Method was selected to study the effect of the factors involved in this study. The effect of the clay/MWNT ratio, types of solvent, clay cation, composition of LENR, cure time and cure temperature on tensile properties of the epoxy nanocomposites were investigated. The confirmation experiment obtained from Taguchi analysis, achieved 57% improvement in tensile strength. X-ray diffraction (XRD) and transmission electron microscopy (TEM) revealed the presence of intercalated and aggregated structures. Due to the lower crosslink density of the system, a decrease in decomposition temperature and glass transition temperature was observed in the optimum sample.