Indian Journal of Science and Technology

Replicating the complex sculptured surfaces with fair degree of precision cannot be accomplished without the use of reverse engineering technologies. The modern Computer Aided Design (CAD) systems offer variety of tools to manipulate 3D data of the reverse engineered parts/surface features so that these can be manufactured using multi-axis machining systems. Objectives: In the present work an attempt has been made to use the 3D scanning, CAD and Computer Numeric Control (CNC) technologies together for the machining of pseudo-symmetrical sculptured models. The 3D scanned models have been first converted to a triangulated/ STereoLithography (STL) data model of suitable accuracy. Methods/Statistical Analysis: The developed STL models are further manipulated in the Pro-E CAD environment for making machinable STL model suitable for a custom developed CNC tool path planning software code. The CNC tool path code takes the modified STL model as input to generate the roughing and finishing tool path data required for actual machining. The validity of the developed CNC tool path data files is verified using a 3D graphical CNC simulator before machining. Findings: The design details of the complex sculptured parts can be captured from initial handmade / crafted models using 3D scanning technologies. The scanned data can be used to generate the 3D CAD model of the scanned part using the general purpose CAD modelling software. Finally the sculptured artistic models are machined on a 3-axis CNC milling lathe. The machined sculptured surface models closely matched the design intend of the scanned parts, which proves the validity of the procedure followed for the machining of complex pseudo-symmetric surface models. Application/Improvements: To machine the complex sculptured surfaces. Five axis CNC milling can be use to machine the Bezier and Non-Uniform Rational B-Spline (NURBS) surfaces instead of STL. 
Keywords: Computer Numeric Control (CNC), Pseudo-symmetric, Reverse Engineering, Sculptured Surface Models, STereoLithography (STL)