Medium density fiberboard (MDF) is an engineered wood product, a generic term that refers to materials made of various types of wood that are bonded together. MDF is made of wood chips combined with synthetic resin and compressed by heat and pressure. MDF can be cut into a variety of shapes and sizes and is commonly used for furniture, industrial packaging, toys and ceiling molding.
MDF was developed in the United States in the early 1960s based on the design of hardboard, a similar product invented by William Mason in 1925. Mason attempted to turn wood chips discarded by lumber mills into affordable insulation, but when he forgot to shut down his equipment one evening, his machinery continued working, turning the wood chips into a thin, durable sheet.
Wood chips from various types of lumber and sawdust are the most common raw materials that make up fiberboard, but some manufacturers add other materials, including waste paper and corn silk. Some companies even use expired telephone directories, old newspapers and recycled cardboard cups. There are two reasons for this: consumers are more concerned about waste, and recycled materials are cheaper to use than wood chips that are purchased from lumber mils.
The raw materials that make a piece of MDF must go through a certain process before they are suitable. A large magnet is used to remove any magnetic impurities, and the materials are separated by size. The materials are then compressed to remove water and then fed into a refiner, which shreds them into small pieces. Resin is then added to help the fibers bond. This mixture is put into a very large dryer that is heated by gas or oil. This dry combination is run through a drum compressor equipped with computerized controls to guarantee proper density and strength. The resulting pieces are then cut to the correct size with an industrial saw while they are still warm.
MDF is finished in a wide variety of lacquers, colors and wood-grain patterns. Laminating machines are also used to apply vinyl, leather or other materials to the surface of a piece of MDF. Special machines are used to cut fiberboard into very thin strips if necessary.
Health Concerns Over MDF
MDF is a widely used material found in millions of homes and offices worldwide, but there are serious health concerns about MDF. The low-cost resins used as binding agents during production often contain urea-formaldehyde, and MDF can potentially emit formaldehyde particles into the air. Formaldehyde is classified as a likely carcinogen by the Agency for Toxic Substances and Disease Registry. There are other resins that do not emit fomaldehyde, but they are not commonly used because of their high cost.