Medium-density fibreboard (MDF) is an engineered wood product made by breaking down hardwood or softwood residuals into wood fibres, often in a defibrator, combining it with wax and a resin binder, and forming it into panels by applying high temperature and pressure., MDF is generally denser than plywood. It is made up of separated fibres but can be used as a building material similar in application to plywood. It is stronger and denser than particle board.
The trees are debarked after being cut. The bark can be sold for use in landscaping or used as biomass fuel in on-site furnaces. The debarked logs are sent to the MDF plant, where they go through the chipping process. A typical disk chipper contains four to 16 blades. Any resulting chips that are too large may be rechipped; undersized chips may be used as fuel. The chips are then washed and checked for defects. Chips may be stored in bulk, as a reserve for manufacturing.
Compared to other fibre boards, such as Masonite, MDF is characterised by the next part of the process, and how the fibres are processed as individual, but intact, fibres and vessels, manufactured through a dry process.
Dry fibre gets sucked into the top of a “pendistor”, which evenly distributes fibre into a uniform mat below it, usually of 230–610 mm thickness. The mat is precompressed and either sent straight to a continuous hot press or cut into large sheets for a multiple-opening hot press.