Laser Triangulation Topography Principles for Boxboard Surface Evaluation
Laser triangulation delivers uncompressed 3D areal topography data, isolating micro-roughness and void volumes that drive print quality across coated boxboard.
Abbott Firestone Curve
Surface Topology
A cumulative distribution function quantifies the distribution of peak heights across a substrate material profile to characterize its contact area as a function of the bearing depth. The abbott firestone curve provides a visual and mathematical representation of how the material surface supports load during mechanical engagement. It maps the ratio of the load-carrying material to the total cross-sectional area of the substrate at a specified depth from the peak.
Engineers utilize this data to predict how a surface interacts with inks or adhesives.
Measurement Protocol
Calculation of this material ratio requires the acquisition of a digitized topographic map derived from tactile profilometry or interferometry. Data processing involves sorting every measured peak height into a histogram that depicts the frequency of specific elevations across the sampled region. The resulting integral of this histogram produces the load-bearing curve that represents the material percentage at any given depth from the highest point.
A higher material ratio near the surface indicates a dense topography capable of supporting pressure without rapid degradation. Conversely, a distribution that shifts the bulk of its area toward the bottom of the profile indicates high porosity or deep valleys. Practitioners rely on these profiles to adjust coating weights when dealing with substrates that possess varying degrees of microscopic roughness.
Functional Application
Print converters and paper manufacturers observe these patterns to manage the ink transfer efficiency and the adhesion strength of synthetic films. High material ratios at the immediate surface optimize the wetting characteristics of low viscosity liquids. Rougher surfaces with deep valleys require higher volumes of coating to ensure full coverage and avoid skips in the printed layer.
Precise control of the surface peaks through calendering processes shifts the distribution to improve final print density and gloss uniformity across the substrate. A flatter curve distribution correlates with improved performance in high speed vacuum transport systems.