Medium Density Fibreboard (MDF)
What is MDF ?
Wood-based panel manufactured from lignocellulosic fibres by the “dry process”, i.e. having a fibre moisture content less than 20% at the forming stage and being essentially produced under heat and pressure with the addition of an adhesive.
How is it made?
The raw material (forest thinnings, sawmill byproducts, etc.) is chipped.
Reduction to fibres:
The chips are softened by pre-heating in low-pressure steam and then fed by Archimedean screw between segmented grinding discs, one of which rotates at great speed.
Adhesive, usually urea formaldehyde, and wax emulsion are applied to the fibre within the inlet pipe to the drying tube.
Drying / storage:
Drying of the fibre/adhesive mix is performed in a long drying tube (blowline). The dry fibre is stored in silos to await further processing.
A mattress is dry-formed on caul plates. This is gradually compressed by steel belts. For thick boards, more than one mat may be piled on another.
The dry mattress is pre-pressed to consolidate it and then cut and formed to press sizes, finally to be cured with heat and pressure in a multi-daylight or a continuous press.
Trimming and sanding:
After cooling, each panel is trimmed and sanded to precise dimensions.
What is it used for?
Standard boards for a wide range of interior uses are available in Europe with thicknesses in the range of 1,8 to 60 mm.
Unlike most other wood based sheet materials, the uniform and close packed fibre distribution throughout the thickness of MDF allows detailed machining operations to be carried out on the faces and edgeswithout breakout or the exposure of voids within the core of the board.
Standard MDF is being used successfully for the manufacture of table tops, door panels and drawer fronts with moulded edges or profiled surfaces. The smooth and stable surfaces of MDF provide an excellent substrate for painting or the application of decorative foils or wood veneers. The inherent stability, good machinability and high strength of MDF creates opportunities for it to be used as an alternative to solid wood for applications such as drawer sides, cabinet rails, mirror surrounds and mouldings.
Although primarily developed for use in furniture, standard MDF is being used increasingly for shop fitments, exhibition displays, wall panelling, architectural mouldings and many other applications where its good machining and finishing characteristics are used to advantage.
Moisture resistant , flame retardant , high density and exterior grades of MDF are available for use in more demanding situations.
Moisture resistant boards are being used for bathroom fitments, doors, window boards and other interior building applications where resistance to damp conditions or intermittent wetting are important requirements.
Flame retardant boards are being used increasingly for fitted furniture, doors and panelling in public buildings and other areas which have to conform to national fire regulations.
High density boards have improved machining and finishing characteristics as well as higher strength. They are used for the manufacture of specialised components, high quality kitchen and bedroom doors with complicated machined profiles, for instance, and for some structural applications as a replacement for solid wood.
Exterior boards with appropriate high durability surface coatings can be used for low load bearing, constructional applications for door and window components, road signs and shop fronts, for instance, and for garden furniture.
MDF – MEDIUM DENSITY FIBREBOARD
MDF is short for Medium Density Fibreboard. MDF is a very versatile panel & easy to work with. There are literally hundreds of uses for MDF in the cabinet-making, shop fitting, furniture & building industries including storage systems & display shelving, plus residential applications.
Decorative surface finishes on MDF panels also make it suitable for partitions & panelling – domestic & commercial. MDF is suited for the tradesperson & the home handy person.
There are various MDF types:
MDF – Bendable MR
MDF – Decorative
MDF – Melamine MR
MDF – Moisture Resistant
MDF – MR Colour Panel
MDF – Std (Slotted )
MDF – Veneered
MDF – Melamine
MDF – Profile
MDF stands for medium density fibreboard because it is a manufactured fibreboard similar to particle board. The difference between the two is the size of the particles, particle board is made from larger wood chips and medium density fibreboard is made from a very fine wood dust.
Medium density fibreboard is made basically the same way as particle board which is by gluing the fibres together with a resin and then compressing the board under heat, later the board is cut into appropriate lengths after it has dried.
The resin used in this fibreboard is toxic and because the fibres are so fine they are easy to breathe in so the timber should be cut in a well ventilated area or somewhere with a dust collection system.
Fibreboard is a useful woodwork product mainly used in cabinet making due to its affordability, lack of natural defects and range of sizes. Medium density fibreboard is usually covered with a plastic laminate and sealant to increase the aesthetics and prevent the fibres from becoming loose and airborne.
- It is cost effective
- It’s available in many sizes
- Has no natural defects
- Can be easily machined
- Contains toxic resins which means the saw dust created is dangerous
- Not suitable for most joints
- Should be fully sealed to prevent toxins from escaping
- Can split
- Needs to be cut in ventilated areas or in a room with a dust collection system
Sources: -MDF is a type of hardboard, which is made from wood fibres glued under heat and pressure.
Advantages: -There are a number of reasons why MDF may be used instead of plywood or chipboard. It is dense, flat, stiff, has no knots and is easily machined. Because it is made up of fine particles it does not have an easily recognisable surface grain. MDF can be painted to produce a smooth quality surface. Because MDF has no grain it can be cut, drilled, machined and filed without damaging the surface. MDF may be dowelled together and traditional woodwork joints may even be cut. MDF may be glued together with PVA wood glue. Oil, water-based paints and varnishes may be used on MDF. Veneers and laminates may also be used to finish MDF
Disadvantages: -MDF can be dangerous to use if the correct safety precautions are not taken. MDF contains a substance called urea formaldehyde, which may be released from the material through cutting and sanding. Urea formaldehyde may cause irritation to the eyes and lungs. Proper ventilation is required when using it and facemasks are needed when sanding or cutting MDF with machinery. The dust produced when machining MDF is very dangerous. Masks and goggles should always be worn at all times. Due to the fact that MDF contains a great deal of glue the cutting edges of your tools will blunt very quickly. MDF can be fixed together with screws and nails but the material may split if care is not taken. If you are screwing, the screws should not be any further than 25mm in from the edge. When using screws always use pilot holes. Urea formaldehyde is always being slowly released from the surface of MDF. When painting it is good idea to coat the whole of the product in order to seal in the urea formaldehyde. Wax and oil finishes may be used as finishes but they are less effective at sealing in the urea formaldehyde
Uses: -It may be used to make display cabinets, wall-panels and storage units.