Title: Numerical slicing and optimum hatching of parametric B-Rep solids in layered manufacturing

Authors: Regalla Srinivasa Prakash, Arnab Jyothi Ghosh, Amit Kumar Singh, P.K. Pakala, P.V.M. Rao

Addresses: Mechanical Engineering Group, Birla Institute of Technology and Science, Pilani, Rajasthan, India. ' Mechanical Engineering Group, Birla Institute of Technology and Science, Pilani, Rajasthan, India. ' Mechanical Engineering Group, Birla Institute of Technology and Science, Pilani, Rajasthan, India. ' Sustainable Design Laboratory, Department of Manufacturing, University of Missouri, Rolla, Missouri, USA. ' Department of Mechanical Engineering, Indian Institute of Technology, Delhi, Hauz Khas, New Delhi &ndash 16, India

Abstract: In this paper, numerical slicing of parametric B-Rep solids has been proposed based on the concepts of virtual cloud points and Delaunay triangulation for the purpose of layered manufacturing. The layer geometry thus obtained readily lent itself to application of an optimum hatching algorithm that minimises the build time. The problem has been treated as intersection of parametric surfaces. The purpose is to estimate the slice geometry, both its domain and boundary, which will enable in building an automatic database of each slice for the purpose of finding the optimum hatching direction. The algorithm and Matlab™ code have been developed for a general parametric B-Rep solid. The proposed slicing methodology has been implemented and presented here for two different B-Rep solids, namely, a non-rational Bezier solid and a NURBS solid. It was observed that developments in this direction will ensure further automation and streamlining of the layered manufacturing process with an integration established from CAD solid model to the actual layering in the machine.

Keywords: layered manufacturing; numerical modelling; simulation; numerical slicing; optimum hatching direction; B-Rep solids; virtual cloud points; Delaunay triangulation; slice geometry; CAD solid modelling; rapid prototyping.

DOI: 10.1504/IJCAET.2008.021259

International Journal of Computer Aided Engineering and Technology, 2008 Vol.1 No.1, pp.105 - 124

Published online: 14 Nov 2008 *

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