DEVELOPMENT AND VALIDATION OF A NON-CONTACT LASER INSPECTION SYSTEM FOR DIMENSIONAL CONTROL IN INDUSTRIAL APPLICATIONS: CALIBRATION, VOLUMETRIC COMPENSATION AND MEASUREMENT PERFORMANCE ANALYSIS.

This thesis presents the development and validation of the Be-Line system, a non-contact laser inspection bench developed at Benelli Armi to automate dimensional and qualitative control of shotgun barrel assemblies, replacing traditional subjective visual inspection. The system uses dual laser triangulation sensors to reconstruct a three-dimensional point cloud of the barrel, from which key performance indicators — sight-line positional deviation, planarity, and linearity — are automatically extracted. The measuring bench was validated by comparing its results against a Coordinate Measuring Machine (CMM) on pump-action barrel samples. An initial poor correlation (R² = 0.26) was traced to a mechanical fixturing defect; once corrected, the correlation improved significantly (R² = 0.86). A silicon-carbide calibration bar confirmed the intrinsic geometric stability of the optical system. Measurement uncertainty analysis on 217 samples yielded expanded uncertainties of ±0.068 mm for the semi-automatic configuration and ±0.11 mm for the pump-action configuration. Statistical analysis of production data was then used to convert operators' visual judgment into objective acceptability tolerances for sight-line alignment. The results confirm that the Be-Line system meets industrial metrological requirements, reduces inspection time by approximately 50% compared to CMM probing, and supports a shift toward data-driven, traceable quality control in firearm manufacturing.