Using 3D Scanning for Accurate Estimation of Termination Points for Dimensional Quality Assurance in Pipe Spool Fabrication

Abstract

Increased prefabrication and modularization have resulted in fabrication shops producing more complex assemblies with tighter tolerances. Most measurements in fabrication shops are still done using manual tools that are not accurate enough for engineering tolerance specifications, which can lead to rework. Three dimensional (3D) scanning and measurement systems can provide increased accuracy and digital integration capabilities, however they do not sufficiently support fast and accurate dimensional quality assurance (DQA) of pipe spool fabrication. This is because no dimensional quality assurance methods to date have focused solely on termination points for pipe spool assemblies. In the present article, a new scan-vs-BIM method is developed to accurately estimate termination points for 3D scanned cylindrical assemblies. This method relies on statistically fitting circular features at termination points and thus eliminating conventional issues with target placement for laser trackers and measurement readings for tape measures. The method is tested in an industrial-scale experiment, where 30 pipe spool assemblies were fabricated, and more than 400 quality control steps completed. The accuracy of termination point detection was benchmarked against results from a laser tracker and compared against commercial scan-to-BIM software. Results show that the developed method has an average accuracy of 1.01 mm and is significantly better than the scan-to-BIM software with an average accuracy of 4.75 mm.