Numerical determination of task-specific measurement uncertainty using a virtual metrological X-ray computed tomography system

Abstract:
Industrial X-ray computed tomography applied for dimensional metrology is able to perform holistic measurements including inner features in one scan. The measurement consists of multiple complex process steps which are influenced by various parameters. Therefore, the measurement uncertainty for a given task depends on numerous influence factors which need to be taken into account in order to determine the task specific measurement uncertainty. The only standardised procedure for determining the task specific measurement uncertainty available at the moment is the use of calibrated workpieces according to VDI/VDE 2630 Part 2.1. This experimental procedure is cost intensive and time consuming. An alternative method is the numerical uncertainty determination according to GUM Supplement 1. This paper presents task specific numerical uncertainty determination for specific measurement tasks based on a virtual metrological CT developed using the program aRTist 2 by BAM Federal Institute for Materials Research and Testing in Germany. The results show that numerical uncertainty determination in good agreement with experimental values according to VDI/VDE 2630 Part 2.1 is possible for sufficiently simple measurement tasks.