Virtual uncertainty determination and error analysis for CMM laser scanners

The modern manufacturing industry demands high quality assurance and traceability from the manufacturing metrology [1]. As a result, quality inspections are time-consuming and a bottleneck in the manufacturing process [2]. Furthermore, to assure the high quality, the measurement uncertainty has to be taken into account to prove conformance to the specified tolerances according to ISO14235-1 [3]. This paper presents how a digital twin of a measurement system can be used to determine the measurement uncertainty. The digital twin simulates its physical counterpart, considering the specified error contributors. Based on the Monte Carlo method, the measurement uncertainty can be estimated according to the Guide to the Expression of Uncertainty in Measurement (GUM) [4]. Multiple virtual measurements are generated to obtain the measurement uncertainty. The considered measurement system is a coordinate measuring machine (CMM) with a laser line scanner (LLS) as sensor. Figure 1 depicts the measurement system discussed in this paper. An LLS is an optical probe that offers a high measuring speed and a dense point cloud generation, compared to the conventional tactile probes [5]. An LLS projects a plane of laser light onto an object’s surface and tracks the intersection thereof with a sensor. Based on triangulation the points of intersection can be determined.