Abstract: In view of design and processing difficulty for complex crankshaft,reverse technique was applied to a type of four-cylinder crankshaft’s self-replication and model reconstruction.Data acquisition of the crankshaft was carried out through industrial 3D measuring instrument with optical dynamic tracking(Creaform VXtrack C-Track 780).After that,initial point cloud data of it was dealt with splicing,denoise,filling hole and repair processing in Geomagic Studio environment,and its initialization assembly model with surfaces was constructed successfully,thus then NURBS surfaces of the crankshaft with more better precise and quality was set up based on that.CAD model of the crankshaft on CREO platform was reconstructed by parameter exchange,and its structure was translated into the form of parameterization and feature.Besides,quality analysis of the crankshaft was done by Geomagic Qualify module,and cloud chart of chromatographic error was calculated,thus an important basis was provided for crankshaft’s detection and innovative design,at the same time,a new method and idea were also provided for crankshaft’s design and manufacture.

Key words: crankshaft, reverse engineering, scanning, NURBS surfaces, quality analysis, Geomagic software