Reverse Engineering: Generation of Cad Model from Scanned Mesh File Captured using 3d Scanner Shaik Feroz 1 Research Scholar, Department of Mechanical Engineering, VFSTR, Vadlamudi, Guntur 52213, India. Dr. M. Ramakrishna Department of Mechanical Engineering, VFSTR, Vadlamudi, Guntur 52213, India. Dhaval Varma P. Department of Mechanical Engineering, VFSTR, Vadlamudi, Guntur 52213, India. Abstract:- Reverse Engineering is the method of capturing an existing object’s physical characteristics and reproducing a replica of it from the extracted data. This technique is widely recognized as a predominant technique in aerospace design & manufacturing. It is hard to reproduce a duplicate of any part or model the part when original designs are not available specifically in the case of legacy aircrafts. In this technique, various stages involved are data acquisition (scanned mesh file) using 3D scanning, feature extraction, segmentation to fit free form shapes and developing a 3D CAD model. This research paper signifies the role of reverse engineering in restoring the legacy features of aircraft components especially for an aging fleet. Keywords: Reverse Engineering, 3D scanning, mesh file, CAD, free form shape 1. INTRODUCTION The modern aerospace industry has an edge due to the substantial developments during the world wars. One of the major issues encountered by the aircraft manufactures is to restore the crucial design data of the older aircrafts that is lost over the years. To overcome this issue many aerospace companies are utilizing the reverse engineering technique to restore the data of legacy parts on digital platform. Further, this digital data is made compatible to the CAD requirements, which plays a vital role in subsequent manufacturing of aerospace components. The other reasons for using reverse engineering in aerospace industries are: 1. To retrieve the data for manufacturing. 2. To easily model, the complicated parts with intricate shapes. 3. Inspection and comparison for error analysis. 4. Development of new/customized parts based on existing parts with no designs. Reverse engineering is widely in use to produce various complicated aircraft parts and assemblies. It has also played a vital role in new product developments in different sectors including consumer electronics, automotive industry, medical devices, sporting equipment, toys and in making of jewellery. SME quotes reverse engineering as “starting with a finished product or process and working backward in logical fashion to discover the underlying new technology” [2]. The part, which was produced using reverse engineering technique, must be in compliance with the requirements, which are present in applicable program criteria. 2. WORKING PRINCIPLE OF SCANNER The object is recreated digitally with the help of 3D scanners in which millions of X, Y & Z coordinates (points) are captured all over the physical object by sensing the laser line reflection by 3D scanners. All scanners project lasers on the target and capture the points in relation to its position with respect to the part. When the scanner moves to new location on the part, it captures another set of points and its position. This process continues throughout the scanning process. To establish the relation between data captured at each instant and to align properly, scanner has to know its relative position at each instant with respect to part, International Journal of Engineering Research & Technology (IJERT) ISSN: 2278-0181 http://www.ijert.org IJERTV9IS050881 (This work is licensed under a Creative Commons Attribution 4.0 International License.) Published by : www.ijert.org Vol. 9 Issue 05, May-2020 1276