panneau à dos grillagé

OBS: An exception to the pressing methods discussed previously occurs in the semi-dry hardboard plants. Mats are formed at moisture contents of about 25 to 30% (oven-dry basis). Screens similar to those used in the wet-process line are used to transport the mats. During hot pressing, these screens allow rapid venting of the moisture from the mat. The bottom surface of the pressed board has a screen impression, termed ""screen-back"", like that found on wet-process hardboards. Only relatively thin boards can be made with this type of pressing.