Calculating Counter Die Relief Depth across Laminated Substrate Thickness Variances
Counter die relief depth calculation requires adjusting nominal board caliper for dynamic fiber compression, film stiffness, and moisture regain clearance.
Cepi Repulpability Testing
Fibre Disintegration
Evaluation protocol determines the hydrodynamic breakdown efficiency of specialized paper grades within standard pulping mills. Cepi repulpability testing measures the mechanical disintegration threshold of wet-strength functional boards and polymer-coated packaging substrates. Laboratory hydrapulpers subject standardized circular specimens to intense shear forces inside heated aqueous sodium hydroxide solutions for specific operational durations.
Water penetration rates dictate the initial wetting phase before mechanical forces tear the hydrogen bonds holding the cellulosic matrix together. Residual flake counts on coarse fraction screens separate acceptable dispersible materials from problematic non-disintegrating elements. Converting plants rely on these quantitative disintegration metrics to prevent mill pulping line blockages during post-consumer paper recycling runs.
Board Dispersion
Laboratory operators collect dried paper fragments after standard pulping intervals to calculate percentage mass retention on slotted separation screens. Circular punch samples undergo processing inside temperature-controlled disintegration apparatus equipped with calibrated high-speed agitator blades rotating at fixed revolutions per minute. Visual inspection assesses whether extruded barrier coatings fragment completely or remain as large plastic sheets that blind industrial screening equipment.
Dispersion failure occurs when wet-strength resins or wax impregnations resist water-induced swelling and mechanical fatigue, leaving coherent fragments behind. Recyclers establish strict acceptance thresholds where material retention above a specific sieve aperture percentage disqualifies the packaging stock from standard repulping streams.
Slurry Quality
Filtrate clarity and chemical oxygen demand values quantify dissolved contaminants released from functional additives during the hydrapulping procedure. Excess binder dissolution or heavy polymer detachment fouls process water loops and reduces paper machine run speeds at the secondary mill. Suspended solid distributions dictate whether recovered pulp streams require additional refining stages before entering the paper machine headbox.
Slurry viscosity measurements reveal adhesive bleed or wax melting phenomena that interfere with downstream flotation deinking and washing stages. Repulpability test data ultimately predicts secondary fibre yield losses and chemical purification expenses for integrated paper mills processing coated board waste.
Lead Time Each Added Pass Buys between Approval and Pallet
Each added pass adds 24 to 48 hours of lead time through mandatory inter-pass drying, thermal stabilization, tooling lead times, and offline queue staging.