Non Contact Thickness Gauging on Continuous Web Board Machines
Non-contact thickness gauging uses optical or nuclear sensors to deliver real-time caliper profiles, enabling basis weight down-gauging while meeting ISO 534 limits.
Furnish Density
Material Concentration
Physical property describing the mass of dry fiber material per unit volume within a specific pulp mixture. Papermakers monitor furnish density to ensure consistent sheet formation and grammage control on the machine. Measurement of the concentration influences the drainage rate on the forming wire and the final thickness of the paper.
Stock Preparation
Blending different pulp types alters the overall density of the suspension before it enters the headbox. A high furnish density often correlates with increased inter fiber bonding and higher tensile strength in the finished product. Refinement levels greatly impact this property by increasing the surface area of the fibers and allowing for a tighter packing arrangement.
Controlling the concentration of additives and fillers is necessary to maintain the desired physical characteristics of the stock. Inaccurate measurements at this stage lead to variations in the optical and mechanical properties of the board. Proper agitation in the chests ensures that the fibers remain evenly distributed throughout the volume.
Quality Variable
Drainage behavior in the forming section is sensitive to the concentration of solids. If the furnish density exceeds the design capacity of the drainage system, the sheet may retain too much water. This condition limits the maximum speed at which the paper machine can operate.