Nowadays, MDF board has become very popular. The full form of MDF is Medium Density Fibreboard. Low cost has made it a strong alternative of wood. Here in this article, details of MDF is discussed which includes types, properties, manufacture procedure of MDF.
What is Medium Density Fibreboard (MDF)?
An engineered composite wood product made from residues of hardwood and softwood gluing together with wax and resin under extreme pressure and pressure is called Medium Density Fibreboard or MDF wood.
Types of MDF
Different kinds of MDF are found which may be labeled by color. Followings are the main type of MDF board:
- Ultra-light MDF plate (ULDF)
- Typically green MDF those are moisture resistant
- Typically red or blue MDF which is fire retardant
Properties of MDF
In the past, the raw material was wheat for MDF in complete equipped pilot plants. For the manufacture of higher quality MDF binders are used. Chemicals like Urea melamine formaldehyde, Urea melamine formaldehyde adhesive mixture is used as a binder. Different quality MDF production needed different quantities of resin and different qualities of wheat straw, produced MDF was called Straw Medium Density Fibreboard (SMDF).
The properties analyzed of MDF are:
- Internal bond strength
- Modulus of rupture
- Modulus of elasticity
- Water absorption
Manufacture Procedure of MDF
The manufacturing process of MDF has changed a lot over time. Now advanced technology has changed the quality and saved time and cost of production. So it is a profitable business now a day. It contains some process, such as:-
Selection and refinement of raw material or wood residues is the first step of wood preparation. From sawmills and plywood plants chips and shavings are collected. If softwood is used debarking is done (eg. Eucalyptus sp). Debarking lessens the organic wastes and grit and increases finer finishing. Softwood is chopped and re-chopped if needed. A chopper may be used for this.
Using magnet metal impurities are removed. The materials are made separate into large lobes and small pitches. A magnetic detector is used to separate the rest metals. The selected fibers are then sent for pressing. A side-screw feeder and a plug screw feeder are used for this. Water is removed which is an important task for this. A refiner tears the material into usable fibers. Foreign objects are removed by larger motors.
Curing and Pressing
To reduce formaldehyde tolerance resin is added before refinement and addition of a catalyst after refinement. The amount of resin is controlled by the required amount. A scalping roll is used to produce a mat of uniform thickness. Compressing is done in several steps. These are cut or trimmed before final processing. A large drum is used to compress it into a uniform mat. Before cooling, the resulting board is cut.
The prepared panels are sanded for a smooth finish. Belts are used and coating with abrasives is found. Different ceramic abrasives are used such as zirconium alumina, aluminum oxide. Also, silicon carbide is used for a finer surface. For the improvement of consistency double-sided grading is done. During manufacture to avoid static electricity anti-static technology is used. Static electricity causes excessive dust.
The first step of finishing is cutting. Depending on the demand for the quality of MDF finishing steps varies. Colour verities, wood grain verities are noticed. For different size cutting, different cuttings are used
- Narrow strips cutting: (1-24 inch/2.5-61 cm) Specialty machines are used.
- Small size cutting: (42-49 inch/ 107-125 cm) Die cutting is used.
- Large sheet cutting: (eg. 100 inches) Guillotine cutting is used.
The second step of finishing is laminating. The fibreboard is sent between two rolls. Between the two rolls, adhesives are applied. Thus fibreboard becomes adhesive coated. For final coating vinyl, foil, etc. are used. These are applied by laminating machine.