Silent Paper Grade Furnish Substitution Mechanics at Machine Gate
Furnish substitutions at the machine gate require wet end NIR tracking and ISO 1924 tensile verification to prevent runnability failures and yield losses
Ash Content Dry Basis
Filler Fraction
Laboratory testing measures the inorganic mineral content remaining after complete combustion of a paper sample at high temperature. Expressed as a percentage of total oven-dry mass, ash content dry basis identifies the total proportion of calcium carbonate, clay or titanium dioxide incorporated into the sheet structure. This value excludes absorbed moisture, establishing an absolute baseline for raw material accounting and quality control.
Converting plants rely on dry mass calculations to verify sheet opacity and stiffness targets.
Thermal Decomposition
Muffle furnace procedures heat paper specimens to five hundred twenty-five or nine hundred degrees Celsius depending on the specific mineral pigments present in the furnish. Calcium carbonate decomposes into calcium oxide and carbon dioxide at higher temperature ranges, requiring specific temperature protocols to avoid undercounting filler mass. Test technicians weigh crucibles before and after ignition to isolate the non-combustible residue.
Precise furnace calibration ensures consistent measurements across mill laboratories.
Sheet Property
Excessive filler loading reduces internal bonding strength while increasing opacity and print smoothness. When ash content dry basis exceeds specified contract limits, web breaks increase on high-speed offset presses due to diminished tensile strength. Paper buyers specify upper boundaries for mineral loading to balance optical performance against mechanical durability.