The papermaking workshop process runs from stock delivery and cleaning to wire forming, press dewatering, drying, surface treatment, and reeling, cutting, and packing. Supporting steps include additive dosing and equipment maintenance.
Stock delivery section
Stock pretreatment: Stock from the pulping workshop first enters cleaners and vibrating screens to remove sand, undispersed fiber bundles, and other impurities. A blending chest adjusts consistency to 0.3% to 0.5%. Retention and drainage aids, dry strength agents, and other papermaking additives are added according to paper grade.
Headbox distribution: The adjusted stock is jetted evenly through the headbox slice onto the forming wire. The slice is fine-tuned to control stock flow speed and cross-direction distribution. Cross-direction basis weight deviation is kept within ±3%.
Sheet forming section, wire section
Gravity and vacuum dewatering: Stock travels on the forming wire. Gravity removes most free water first. Vacuum suction boxes and the vacuum couch roll remove more water. Wet sheet dryness rises to 18% to 22%.
Wet sheet transfer: A vacuum pickup roll lifts the formed wet sheet from the forming wire and transfers it to the press felt. This prevents damage from low wet strength.
Wet pressing section, press section
Multi-roll pressing: The wet sheet passes through 3 to 5 press nip groups. Mechanical pressing raises dryness to 40% to 45%. High-speed machines may use shoe pressing to raise dryness above 50%.
Felt maintenance: Press felts absorb water removed from the sheet. An online washing system uses hot water and cleaning agents at intervals to keep dewatering efficiency and sheet cleanliness.
Internal sizing, optional: Some grades add a sizing unit in the press section. Rosin size and other agents mix into the wet sheet to improve water resistance. Hansheng Automation can machine custom suction box parts, couch roll shells, press roll components, and bearing housings from customer drawings, in single pieces or small batches.
Drying section
Dryer cylinder drying: The wet sheet enters a dryer section with 30 to 80 steam-heated dryer cylinders. Steam pressure is controlled at 0.3 to 0.5 MPa. Heat transfer through the cylinder surface raises sheet dryness to 90% to 94%.
Auxiliary drying: A hot air hood at the top of the dryer section adds drying to sheet edges and corners. This avoids uneven local dryness.
Sheet break protection: Paper guide rolls and dryer fabrics, used on some high-speed machines, carry the sheet continuously. An automatic stop protection device prevents equipment damage when a break occurs. High-temperature steam pipes and dryer cylinders create burn risks. Operators need heat-resistant protective gear and regular leak inspection.
Surface treatment section
Surface sizing, optional: Fine cultural paper and packaging paper may pass through a size press. Starch, polyvinyl alcohol, and other sizing agents are applied to both sides. This improves water resistance, printability, or packaging strength.
Calendering: Two to seven sets of steel calender rolls apply high pressure. This improves sheet smoothness and thickness uniformity and adjusts density and gloss.
Finished product finishing section
Reeling: A reel winds the continuous dried sheet into paper rolls with a diameter of 1.5 to 3 m. Reel width and tension are adjusted to customer order.
Cutting and slitting: Large rolls go through a cutter to make sheet paper, or a slitter to make narrow roll paper, to meet customer size requirements.
Packing and storage: Finished paper is wrapped in PE film, strapped with steel bands, labeled, and sent to the finished goods warehouse.
Beyond papermaking workshop equipment, our precision component customization is not limited to this topic. We machine yacht precision components, RC car precision components, tobacco packaging machinery parts, filling machinery parts, printing machinery parts, food machinery parts, and medical device components. Hansheng Automation works from customer drawings and delivers one-off or batch parts to the required material, tolerance, and surface finish. Our scope is precision components, not complete machines.
