PP corrugated sheet (also called PP hollow sheet) is widely used in packaging, advertising, and construction. In this guide, you will learn how to make PP corrugated sheet step by step. Each stage of the process is explained in detail, from material preparation to the final cutting stage.
- Step 1: Prepare the Raw Materials
Firstly, workers select polypropylene (PP) granules as the base material. In addition, they may add color masterbatch, UV stabilizers, and flame retardants. These additives improve durability, brightness, and resistance.
- Step 2: Extrude the Material at High Temperature
Next, the granules enter the extrusion machine. The machine heats the PP resin to around 200–250°C. As a result, the material melts and becomes ready for forming.
- Step 3: Form the Sheet with Molds (Core Process)
After extrusion, the melted PP passes through a special hollow sheet mold. The mold shapes the material into a twin-wall structure. Therefore, the sheet becomes lightweight yet strong.
- Step 4: Cool and Stabilize the Sheet
Then, the sheet moves through cooling rollers or water tanks. This step helps the sheet maintain its thickness and flat surface.
- Step 5: Pull the Sheet with the First Traction Machine
At this stage, a traction machine pulls the sheet forward at a stable speed. This ensures consistent flute size and avoids deformation.
- Step 6: Apply Secondary Heating and Shaping
In addition, the sheet goes through secondary heating equipment. The heating improves bonding strength, smooths the surface, and adjusts thickness.
- Step 7: Second Traction and Cutting
Finally, a second traction system keeps the sheet moving steadily. Cutting machines then trim the sheet into standard sizes such as 1220 × 2440mm. Manufacturers may also apply surface treatments like corona, lamination, or embossing.
