Method for producing boards of wood-based materials with structured and smooth surfaces using a continuously operating embossing press

Abstract

A process and plant for producing boards of wood-based materials having either a structured upper surface or a smooth upper surface. The plant has a continuously operating production press and a continuously operating embossing press. A discharge section and a transfer section are located between the continuously operating production press and embossing press. The continuously operating production press compresses and cures a mat of pressing stock to create a board that retains heat, while the continuously operating embossing press imparts the permanent embossed pattern on an upper surface of a board. The transfer section has a water spray device and a covered steam hood for cooling the board and producing steam. The cooled board is then accepted by the continuously operating embossing press which has an embossing pressure section having a steam-pressure build-up section, a steam-pressure plasticizing section, a high-pressure embossing section, and a drying and structure-fixing section for forming the embossed board. Disabling the sections of the continuously operating embossing press creates a board with a smooth upper surface. The transition of the board during the disabled period is numerically recorded in order to provide a flying changeover rate when switching between production of structured surface boards and smooth surface boards.