Processes

Fabrication Technique

The process uses a patterned embossing roll, typically made of hardened steel and engraved with the desired pattern. The embossing roll contains raised areas corresponding to the desired pattern, while the recessed areas remain smooth. The plastic or paper web passes between the embossing roll and a back-up roll, where pressure is applied to the web, pressing it against the embossing roll and forcing it into the recessed areas of the pattern. The combination of pressure and heat, if applicable, softens the substrate, allowing it to conform to the shape of the embossing roll. For deeper patterns, a match pair of engraved rollers driven together with herringbone gears may be required to achieve the desired high quality grain definition.

The embossed web is then quickly cooled to set the grain of the embossed pattern. Cooling is usually achieved with chill rollers for faster line speeds, or convection cooling systems.

Plastic web embossing often involves thermoplastic materials such as polyethylene (PE), polypropylene (PP), or polyester (PET). Heat and pressure are applied to soften the plastic and allow it to flow into the embossing pattern. Infrared sources are typically used to preheat the web prior to entering the embosser rolls. Thermoplastic embossing is commonly used in packaging films, where it imparts decorative or functional textures such as leather grain, linen, or woodgrain patterns.

Paper web embossing utilizes cellulose-based materials such as paper or cardboard. The embossing process typically involves mechanical pressure without requiring heating.

Pyradia manufactures various types of embossers for the paper and plastic industries.