How is mdf wood made

MDF is traditionally made of wood fibers that have been broken down into residuals, then mixed with wax and resins and heat pressed into dense, durable sheets. A sheet of MDF will be heavy, smooth and even, with a flat surface that can be painted or sealed. While it typically contains urea-formaldehyde as part of its manufacturing process, it can also be specified as NAF or no added formaldehyde for those concerned about off-gassing.

Decorative veneer core hardwood plywood is made up of many thin layers — or plies — of hardwood that has been pressed and glued together to form a panel.

These different layers are placed at right angles to one another, which helps make plywood very stable — the wood is balanced from expanding or contracting in the same direction at once, which helps it keep its shape. Veneer core hardwood plywood is lighter in weight than MDF and offers greater screw-holding power. The other big difference is that the top layer of veneer can be made of different wood species, each of which has its own color, grain and characteristics.

You can find plywood with a very smooth finish and now, new types of hardwood plywood offer enhanced, textured surfaces to amplify finishing effects. While MDF tends to have a similar appearance between products, plywood can take on many different looks and can have many different uses depending on the material you choose.

Next, the fiber is pushed through scalping rolls to produce a mat of uniform thickness. This mat goes through several pressing steps to produce a more usable size and then is trimmed to the desired width before the final pressing step. A continuous press equipped with a large drum compresses the mat at a uniform rate by monitoring the mat height. Presses are equipped with electronic controls to provide accurate density and strength.

The resulting board is cut to the appropriate length using saws before cooling. Presses have counterbalanced, simultaneous closing systems that use hydraulic cylinders to effect platen leveling, which when operating in conjunction with a four-point position control gives greater individual panel thickness control.

The hydraulics system can close the press at speeds and pressures that reduce board precure problems while shortening overall pressing cycles. Most MDF plants use computerized process control to monitor each manufacturing step and to maintain product quality. In combination with continuous weight belts, basis weight gauges, density profile monitors, and thickness gauges, product consistency is maintained. In addition, the American National Standards Institute has established product specifications for each application, as well as formaldehyde emission limits.

As environmental regulations and market conditions continue to change, these standards are revised. Panels can undergo a variety of finishing steps depending on the final product.

A wide variety of lacquer colors can be applied, as well as various wood-grain patterns. For example, laminating machines are used to apply vinyl, foil, and other materials to the surface. This standard classifies MDF by density and use interior or exterior and identifies four interior product grades. Specifications identified include physical and mechanical properties, dimensional tolerances, and formaldehyde emission limits.

Specifications are presented in both metric and inch-pound limits. Physical and mechanical properties of the finished product that are measured include density and specific gravity, hardness, modulus of rupture, abrasion resistance, impact strength, modulus of elasticity, and tensile strength. A Happy Accident and A Sustainable Solution In , William Mason, an inventor and friend of Thomas Edison, made it his mission to find a use for the huge amount of leftover wood chips and shavings that lumber mills discarded.

This results in sheets of thin, strong wood. There are a few things to remember when designing or working with MDF: Experiment with it! Wear your gear. Use the right tools. This product is heavy! Chips are fed into the centre and are fed outwards between the discs by centrifugal force. The decreasing size of the grooves gradually separates the fibres, aided by the softened lignin between them.

This is an expanding circular pipeline, initially 40 mm in diameter, increasing to mm. Wax is injected in the first stage, which coats the fibres and is distributed evenly by the turbulent movement of the fibres. A urea-formaldehyde resin is then injected as the main bonding agent.

The wax improves moisture resistance and the resin initially helps reduce clumping. The material dries quickly in the final heated expansion chamber of the blowline and expands into a fine, fluffy and lightweight fibre. This fibre may be used immediately, or stored. The mat is pre-compressed and either sent straight to a continuous hot press or cut into large sheets for a multi-opening hot press.

The hot press activates the bonding resin and sets the strength and density profile. The pressing cycle operates in stages, with the mat thickness being first compressed to around 1.