Cardboard sheet warp (distortion) after corrugation is a common defect that disrupts subsequent offset lamination, die-cutting, and box folding.
1. Why Do Corrugated Cardboard Sheets Warp?
The root cause of warping is moisture imbalance between the top liner and the bottom liner of the combined board:
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As moisture evaporates unevenly from the paperboard liners, the drier liner shrinks faster, pulling and curving the sheet towards itself.
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Warped blanks cause feeding jams on automatic litho-laminators (offset bồi mặt) and registration errors on flatbed die-cutters.
2. Advanced Handling and Storage Rules at Chau Thai Son
At our 30,000m² manufacturing plant in Que Vo Industrial Park, we execute specialized rules to keep cardboard blanks perfectly flat:
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Intermittent Stack Flipping: Cardboard sheets exiting the corrugator are stacked into piles of 1.0m to 1.5m high. Every 4 to 6 hours during temporary storage, operators use automatic stack flippers to invert parts of the pile. This balances temperature and moisture dissipation on both liners.
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Mechanical Top Weighting: Placing flat plywood sheets or steel plates on top of newly corrugated piles maintains physical downward pressure while the starch adhesive sets.
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Rigid Pallet Underlay: Sheet piles are always stacked flat on ISPM-15 certified acacia or pine wood pallets, avoiding uneven sagging caused by gravitational loads.
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Protective Stretch Wrapping: If sheets are not scheduled for immediate offset lamination, piles are stretch-wrapped with PE film to block local humidity shifts at the edges.
3. Free Structural 3D CAD Mockups and Design Testing
Chau Thai Son offers complimentary 3D structural package designing and physical mockup plots. We help B2B packaging buyers select correct fiber weights (GSM) to increase box rigidity and prevent warping during local warehousing.
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