Coating Board Paper Making Line
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Drying Systems in Coating Board Production: Infrared, Air Fl...
Drying: The Largest Energy Consumer in Coating Board Lines Drying accounts for 55-65% of total thermal energy in coating board production, and the drying section configuration directly determines coat weight uniformity, binder migration and surface gloss. Selecting the right combination of infrared, air float and cylinder drying for each coating station is one of the highest-impact decisions in a board machine rebuild or new line specification. Technology Roles in the Drying Sequence Immediately after blade or curtain application, the wet coating at 52-68% solids cannot tolerate contact. Gas or electric infrared modules provide the first 30-40% of evaporation at high intensity without touching the sheet. Air float dryers then carry the web on cushion nozzles while completing non-contact drying at 150-350 degrees C air temperature and 30-60 m/s nozzle velocity. Only after the coating reaches critical solids does the web transfer to steam-heated cylinders at 3-8 bar for final moisture profiling to 5-8%. Performance and Consumption Data Typical figures for a 400 TPD duplex board line with two coating stations: specific steam consumption of 1.6-2.0 t of steam per ton of paper for the full drying section, with 0.3-0.5 t/t attributable to pre-dryers after each coater. Industry comparisons show that...
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Blade Coating Station Optimization for Coating Board: Coat W...
Coat Weight Uniformity Determines Print Quality and Coating Cost Coating board quality is won or lost at the coating station. Coat weight variation above 5% CV shows up as mottle in offset printing, uneven gloss, and register problems — while excessive average coat weight wastes coating colour worth 3-6 times the cost of base sheet furnish per tonne. Blade coating station optimization targets both problems simultaneously through application system design, colour preparation control, and blade geometry management. Application System and Colour Preparation Stable coat weight starts upstream of the blade. Coating colour must arrive at the applicator at consistent solids, viscosity, and temperature: Colour solids: 60-68% for blade coating, screened through 100-150 mesh pressure screens ahead of the supply tank Low-shear viscosity: 800-1,500 mPa·s (Brookfield 100 rpm) held within a 10% band by closed-loop thickener dosing Temperature: 40-50°C to stabilize rheology and reduce foam tendency Recirculation: Continuous return loop with 70-85% recirculation rate prevents pigment settling and ageing Leizhan coating colour preparation systems integrate high-shear dispersing, automatic pigment slurry dosing, and two-stage screening, with supply capacities matched to coater widths up to 5,600 mm and speeds to 1,000 m/min. Blade Geometry and Loading Control Blade coating operates in two regimes....
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Coating Preparation and Application Systems for Multi-Layer ...
Coating Kitchen Design Fundamentals The coating kitchen is the central processing hub for multi-layer board production, preparing pigment slurries at 62 to 68 percent solids content for coating weights of 8 to 25 g per square meter per layer. A well-engineered coating kitchen serves 2 to 4 coating stations simultaneously, with batch or continuous preparation systems capable of producing 15 to 40 tons of coating color per day depending on board machine capacity. Key Equipment and Technical Specifications Coating preparation begins with pigment dispersion using high-shear dispersers operating at 1,200 to 1,800 rpm. Calcium carbonate and clay slurries are dispersed to a Hegman gauge reading of 4 to 6 before blending with latex binders at 10 to 15 parts per hundred pigment, co-binders such as starch or CMC, and functional additives including optical brighteners and rheology modifiers. Coating application employs blade coaters or rod coaters depending on the required surface profile. Blade coaters deliver coating weights of 8 to 15 g per square meter with plus or minus 0.5 g per square meter cross-machine uniformity. The blade angle is adjustable between 15 and 45 degrees, with higher angles producing lower coat weights and smoother surfaces. Rod coaters, using metering rods...
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Double Disc Refiner for Coating Board Production: 15-20% Ene...
Double Disc Refiner for Coating Board Production: Precision Fiber TreatmentThe double disc refiner (DDR) plays a critical role in coating board production by developing fiber properties essential for multi-layer board formation. Unlike single disc refiners, the DDR uses two counter-rotating discs, providing double the refining intensity per pass while applying gentler fiber treatment. This is particularly important for coating board where fiber length preservation is crucial for bulk and stiffness.Technical SpecificationsDisc diameter options: 660 mm, 910 mm, and 1100 mmMotor power: 250-900 kW with direct drive or gear couplingRefining capacity: 50-300 TPD per unit at 3-5 percent consistencyDisc material: High-chromium alloy or stainless steel with specific plate patternsPlate life: 1,500-2,500 operating hours depending on furnish typeSpecific edge load (SEL): 0.5-1.2 J/m for coating board applicationsEnergy consumption: 60-120 kWh per ton depending on freeness reduction targetEnergy Savings Compared to Conventional RefinersDouble disc refiners deliver energy savings of 15-20 percent compared to conventional conical or single disc refiners. This is achieved through the counter-rotating disc design, which doubles the relative speed between refining surfaces without increasing motor RPM. For a 200 TPD coating board mill, this translates to annual electricity savings of approximately 8,000-12,000 USD.Impact on Coating Board PropertiesProper refining with a...
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Multi-Layer Forming Technology for Coating Board: Production...
Multi-Layer Forming Technology for Coating Board Production Coating board production combines multi-layer forming with precision coating application to achieve superior printability and packaging performance. Modern multi-ply formers produce boards with 3 to 7 layers, each optimized for specific functional requirements. Basis weight ranges from 200 to 600 gsm with production speeds up to 600 m/min. The precise control of layer composition and coating uniformity determines the commercial value of the finished board. Multi-Ply Former Configuration Each forming section delivers a specific ply with controlled basis weight and fiber composition. The top layer uses bleached kraft or high-brightness recycled fiber for print surface quality. Middle plies incorporate lower-cost recycled fiber for bulk and stiffness. The back layer balances sheet curl and provides economic fiber utilization. Headbox consistency is 0.5 to 1.2 percent with slice opening precision of 0.1 mm. Coating Preparation and Application Coating color preparation systems handle solids content of 60 to 68 percent with viscosity controlled between 800 and 1,500 cP. Film press and blade coating stations apply 8 to 15 gsm coating weight per side. Drying uses infrared and air flotation systems with specific steam consumption of 1.3 to 1.6 tons per ton of paper. Automated coat weight...
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Multi-Layer Coating Board Machine Technology: Achieving Supe...
Introduction to Multi-Layer Coating Board Production Modern packaging demands for premium graphics and structural integrity have driven the widespread adoption of multi-layer forming technology in coating board production. A typical 4-layer board machine produces base sheets with basis weights of 200-450 gsm, combining a top layer of bleached chemical pulp for print surface quality, an under-top layer of mechanical or deinked pulp, a middle layer of OCC or mixed waste for bulk and stiffness, and a back layer of selected recycled fiber for balanced curl characteristics. Headbox Technology for Multi-Layer Forming The heart of multi-layer board production lies in the headbox configuration. Modern multi-layer headboxes with dilution profile control deliver precise cross-machine basis weight profiles with 2-sigma variation below 1.5%. Key specifications: Number of layers: 3-5 independent channels with individual stock supply systems Slice opening: 6-12mm, hydraulically adjustable with 0.01mm precision Consistency per layer: 0.3-0.8% for top layer, 0.5-1.2% for middle layers Jet-to-wire ratio: 0.97-1.03, adjustable per layer for optimal formation Dilution control zones: 50-60mm spacing for precise CD profile management Forming Section Design Parameters The forming section configuration varies by board grade and production speed. For coating board at 300-500 m/min, a hybrid former with a fourdrinier base and...