Corrugated Box Manufacturers & Wholesale Suppliers

Corrugated board types, flutes, and structural performance

Corrugated board consists of two flat liner sheets bonded to a fluted (wave-profile) corrugated medium in between — the arch structure of the flutes provides compressive strength far exceeding the component weight of the board. Single-wall corrugated (a single fluted medium between two liners) is the standard for most shipping boxes. Double-wall corrugated (two fluted media and three liners) provides higher stacking strength and is specified for heavier goods, export packaging, and products requiring extra cushioning. The flute profile determines cushioning and stacking performance. B flute (approximately 3mm thick) is used for die-cut retail-ready packaging and point-of-sale displays — a thinner, denser profile with good surface printability. C flute (approximately 4mm thick) is the most widely used flute for general-purpose shipping boxes — balancing stacking strength and cushioning. E flute (approximately 1.5mm thick) is a micro-flute used for high-quality printed outer cartons and small shipping boxes where print resolution is important. F and N micro-flutes (below 1mm) are used for high-quality retail cartons and food service packaging. BC double-wall (B + C fluted layers) is used for heavy-duty export packaging, refrigerated goods shippers, and industrial packaging. Liner grades affect stiffness and printability: Kraft linerboard (natural brown — the strongest liner grade), test liner (made from recycled fibre — lower cost), and white-top liner (bleached or white-coated for superior print quality on the outer face).