This molding method involves extruding polymer resins (PP, PE) through T-Die using an extruder and cooling them by roller to create a sheet.

■ Process

Sheet Extrusion Equipment

Sheet extrusion equipment consists of an extruder, die, roll, and winder.

Extruder

Raw material resin and additives (Color M/B, scrap) are mixed in a mixer and the mixed raw material is supplied to the extruder. The resin heated and melted in the extruder is sent to the die/head whilebeing mixed.

Die/Head

Planar sheets are extruded from the linear die/head vents. Sheets that are melted and extruded in the die/head are adjusted to the desired thickness, cooled and solidified as they pass through the 3 cooling rolls.

Trimming

Sheets that pass through the cooling roll are trimmed on both sides and sized by the blades as they are being transferred to the winding roll. In this stage, the sheet that is trimmed and rejected as a product is called a scrap, which is pulverized and recycled in the early process.

Roll

Standardized sheets are wound (around the roll), sent to the secondary processing company, and remolded to the desired shape.

■ Key points for selecting resin

Two important requirements for resin used for sheet molding are MI and molecular weight distribution of resin. In other cases where transparency is required for the molded sheet, random PP is used.

There are two methods of sheet molding: horizontal and vertical. When using the molded sheet that passed through the vacuum and pressure molding processes as an end product, the horizontal sheet molding method is more commonly used. And when the vacuum and pressure molding processes are not used, then the vertical sheet molding method is used.