Advanced Computed Tomography for dimensional and surface measurements in industry (AdvanCT)
Third Party Funds Group - Sub project
Acronym: AdvanCT
Start date : 01.06.2018
End date : 31.05.2021
Website: https://www.ptb.de/empir2018/advanct/home/
Overall project details
Overall project
Advanced Computed Tomography for dimensional and surface measurements in industry
Overall project speaker:
Project details
Scientific Abstract
Scientific Abstract
Computed tomography (CT) is an aspiring contact-free measurement method which allows to determine the complete geometry of objects (inner and outer geometry including surface texture) typically not fully accessible to other measurement methods.
To support dimensional metrology in future advanced manufacturing, the project will develop traceable CT measurement techniques for dimensions and surface texture. Open issues regarding traceability, measurement uncertainty, sufficient precision/accuracy, scanning time, multi-material, surface form and roughness, suitable reference standards, and simulation techniques will be clarified.
Therefore the AdvanCT project will face the following objects:
- To develop traceable and validated methods for absolute CT characterisation including the correction of geometry errors by 9 degrees of freedom (DoF). This will include the development of reference standards, traceable calibration methods and thermal models for instrument geometry correction, as well as the correction of errors originating in the X-ray tube and the detector in order to improve CT accuracy.
- To develop improved and traceable methods for dimensional CT measurements with focus on measurements of sculptured / freeform surfaces, roughness, and multi-material effects including supplementary material characterisation.
- To develop fast CT methods for inline applications based on improved evaluation of noisy, sparse, few, or limited angle X-ray projections, reconstruction methods. This will be done using reduced number of projections from well-known directions and include enhanced post-processing.
- To develop traceable methods for uncertainty estimation using virtual CT models and Monte-Carlo simulations. This will include calibrated reference standards, the determination of accurate model parameters and the development of correction methods for specific CT image forming artefacts.
- To facilitate the take up of the technology and measurement infrastructure developed in the project by the measurement supply chain (accredited laboratories, instrumentation manufacturers), standards developing organisations (e.g. ISO TC213, VDI-GMA 3.33 Technical Committee Computed Tomography in Dimensional Measurements) and end users (e.g. plastic manufacturers, automotive, telecommunication, medical and pharmaceutical industries and metrology service providers).
The institute of manufacturing metrology will focus on the following aspects:
- The investigation of temperature variation within a CT system and its impact on projection stability as well as measurement deviations. The resulting thermal data can improve the characterization of CT systems.
- The systematic determination of model parameters for measurement simulation („digital twin“). The simulation of the measurement process could allow e.g. numerical measurement uncertainty evaluation. A successful parameter determination is a prerequisite for a faithful virtual CT model. Therefore, it is a key element for the simulation based uncertainty evaluation