Similar to solid sheets, the polycarbonate resin must be thoroughly dried. For multi-wall sheets, co-extrusion is standard: two different materials are fed into the extruder simultaneously—the main body of the sheet and a separate layer of UV-protected polycarbonate for the top surface.

The molten materials are forced through a complex die specifically designed to create the sheet's internal structure (e.g., twin-wall, triple-wall with vertical ribs). The die shapes the outer walls and the internal ribs in a single, continuous process.

As the hot, structured sheet exits the die, it passes through a vacuum calibrator and cooling system. This ensures the internal channels maintain their precise shape and the sheet achieves uniform thickness without warping.

The cooled, rigid sheet is cut to the required length. Protective masking film is applied, which often indicates which side has the UV coating to ensure correct installation.

Before installation, the open ends of the channels are typically sealed with specialized tape (e.g., breathable aluminum tape) to prevent dust and insects from entering while allowing condensation to drain.