Final Report Summary - INTERAQCT (International Network for the Training of Early stage Researchers on Advanced Quality control by Computed Tomography)
The INTERAQCT consortium has realized breakthroughs in CT metrology procedures and algorithms, the reliability of CT analysis, application-oriented CT-procedures for integrated quality control, including
• Procedures for fast and accurate CT model acquisition, with special emphasis on multi-material parts. A knowledge-based system is conceived that supports automatic determination of CT scanning parameters: manipulation parameters (magnification factor and workpiece orientation) are determined through simulation, whereas imaging parameters (e.g. X-ray tube voltage and current, etc.) are optimized by assessing similarity with a case database.
• New algorithms to reduce or eliminate X-ray imaging and reconstruction artefacts, such as beam hardening artefacts.
• Advanced segmentation algorithms to allow e.g. separating fibres from matrix material in CT scans of composite materials in a robust and reliable way.
• Achieving traceability for CT-based dimensional metrology, e.g an error model has been developed to relate geometrical misalignment parameters of the CT system to errors in dimensional measurements.
• A computationally efficient algorithm for the propagation of uncertainties throughout the entire CT metrology chain. These models and algorithms are complemented with reference objects for experimental quantification of the geometric misalignment parameters.
• An acceptance/verification test to evaluate the CT system behavior dedicated to multi-material measurements.
• Quantifying and improving the reliability of CT for material defect analysis, e.g. a reference object has been developed to evaluate the capability of a CT system for porosity detection and analysis. In addition, a method for Probability of Detection determination is developed.
• CT based quality improvement loops for key emerging manufacturing technologies:
o Additive manufacturing: CT based protocols has been used to investigate the influence of laser sintering process parameters on the porosity of the additive manufactured polyamide parts and on the surface quality of metal additive manufactured parts (e.g. scaffolds).
o Micro-manufacturing: process simulations and experimental CT measurements have been compared in order to enhance the understanding of shrinkage and warpage behavior in micro-injection molding processes. Moreover, dedicated procedures have been developed to characterize the influence of electron beam misalignment, thermal drift, focal spot, scale errors and vibrations on measurements at high magnifications.
o Composites: CT based protocols have been developed to extract quantitative information regarding fibre orientation and fibre length distribution, porosity, delamination, cracks and voids from the CT data of glass and carbon fibre reinforced composite workpieces. Image acquisition and processing parameters have been evaluated and optimized to increase the contrast between resin matrix and carbon roving as well as voids. A software framework has been developed, which integrates of automatic defect detection.
o Precision assemblies: CT based procedures for dimensional quality control of assemblies have been developed. A model, based on the theory of Lame has been developed and validated which allows for correction of CT measurements when a contact pressure is present between sub-parts of assemblies. An international round robin on CT metrology for has been organized to further assess the state-of-the-art.
The INTERAQCT consortium has successfully recruited 14 young talents as early stage researchers and 1 experienced researcher to address the challenges identified by the consortium with 11 European leading institutions in CT metrology value chain. The 14 ESRs have all registered at the host institution for a PhD study. Till the official completion of the INTERAQCT project, partially due to the difference on PhD regulations among the consisting institutions and the difference of the starting time of each fellow, no all the ESRs have completed their PhD study. Except one ESR failed to continue with the original institution for completing the PhD study, all the other ESRs are on a good track, with one successfully obtaining the doctorate in 2017 and another 8 in the final stage (hopefully obtaining a PhD in 2018). There are four late-started fellows stilling working towards the final phase of the PhD.
Various dissemination of the preliminary research outputs has been executed through seminars, workshops and international conferences to the larger EU community.
More information about the project is available at the project website http://www.interaqct.eu/
Contact: Prof. dr. ir. Wim Dewulf, KU Leuven – Mechanical Engineering Department, Andreas Vesaliusstraat 13, BE-3000 Leuven, E-mail: email@example.com