REVERSE ENGINEERING OF FREE-FORM SURFACES

Reverse engineering is used in different areas of design and manufactu ring. In the automotive industry it is often necessary to change the s hape elf the prototype during the manufacturing process. The changes h ave to be then considered in the drawing and in the geometric model of some parts in CAD system, It is associated with the measurements of t he part surface and its approximation, The authors of this paper have concentrated on presenting methods of measurement and of the geometric modelling of free-form surfaces, An Integrated solution of these task s will be proposed, The identification of the object with coordinate m easurements is discussed, Measurement results are written in the forma t ready for rise by the program of the surface approximation, This pro gram was created by the authors of the paper. The NURBS method is used for surface description and the problem is solved by the least square s method. The results of calculations are written in the macrostatemen t format (for the definite CAD system) or in a way using the more univ ersal IGES standard. Two integrated CAD/CAM systems are used in the re search (Personal Machinist and Mastercam). In the CAD module, visualis ation of the geometrical model is effected. The CAM module is used for generating the cutter path for CNC milling machines. The machined par ts are measured for the purpose of determining of the manufacturing ac curacy. This is carried out on the CNC milling machine with a special probe. (C) 1998 Elsevier Science S.A. All rights reserved.