Profile Measurement
High precision optical instruments utilize a projected beam and a specialized sensor to calculate the three dimensional surface geometry of paper, board, film or metal foil. A laser triangulation scanner determines the distance to the target by analyzing the angle at which the reflected light hits a position sensitive detector. This non contact method allows for real time monitoring of web thickness and surface roughness without damaging the sensitive coating or the moving substrate.
Data Acquisition
Rapid processing of the reflected signals enables the system to generate a detailed map of the surface topography at high production speeds. When a laser triangulation scanner is integrated into a quality control circuit, it identifies micro defects such as pinholes, bumps, coating streaks or surface contaminants. The accuracy of the measurement is often within microns, providing the high level of detail required for specialty papers used in electronics or medical packaging.
Digital filtering algorithms help to remove the effects of machine vibration from the height data.
Process Calibration
Calibrating the sensors against a known physical standard ensures that the readings remain consistent over long production runs. The laser triangulation scanner provides the feedback required for automatic adjustment of the head gap or the coating blade pressure. By maintaining a constant thickness profile, the system reduces material waste and ensures that every roll meets the specified tolerances.
The information gathered also helps in identifying the wear patterns of mechanical components, allowing for predictive maintenance before quality issues arise. This integration of optical data into the mill control system supports long term operational stability.
