WOOD PRODUCTS: Veneer, Plywood, Chip Board & Fibre Board etc.

 

WOOD PRODUCTS

The common industrial timber products are:

1. VENEERS -

• Timber veneer is a decorative building material comprising thin slices of timber glued onto wooden board, particle board or fibreboard. 

• It has been favoured by builders and designers since ancient times as the finest and most efficient use of the valuable timbers. 

• Veneer is produced as a thin layer of timber that is uniform in thickness. 

• The veneer is normally between 0.5 and 0.85mm thick. 

• Timber veneer is from a natural and renewable resource competing with non-renewable commodities like steel, aluminum and plastics. 

• The surface coverage of veneer is approximately forty times more than 25mm timber, which makes it the most economical way of utilizing precious wood. 

• One cubic metre of log produces around 1,000 square metres of real timber in veneer form. 

• No other form of wood working material results in such an efficient use with minimal wastage. 

 2. Plywood -

• Plywoods are boards which are prepared from thin layers of wood or veneers. 

• Veneers are thin sheets of slices of wood of superior quality. 

• The thickness of veneers varies from 0.4 to 6 mm.

• To make plywood, round logs of 1.5–2.5 m lengths are first cut. They are then steamed, and veneers are cut from these logs with a wide sharp knife. 

• About three or more veneers in multiples of odd numbers are glued one over the other. Care is taken to place the direction of the grains in one sheet at right angles to the other.

• The arranged veneers with adhesives in between are pressed under a pressure of 0.7–1.40 N/mm2 under hot or cold conditions.

• Three plywood is made using only three plies. The thickness varies from 6 to 25 mm. 

• Multiply plywood is made using more than three plies but keeping the number of veneers used as odd in number.

3. Particle Board or Chip Board -

• It is a waste wood product made by binding wood chips, sawdust or saw-mill shavings with a synthetic resin or some other binder. 

• These boards are made of particles of wood embedded in synthetic resins, which are then pressed under heat. 

• They are made by extrusion pressing or by pressing between parallel plates. 

• In the extrusion pressing process, the particles are oriented in the direction perpendicular to the plane of the board, whereas in the other case the particles are oriented parallel to the plane of the board.

• Particle board is heavier than solid wood. 

• Further, it provides broad and stable panels of reasonable strength. 

• They can be sawn just like regular wood. Particle boards are preferred for furniture works and for construction works.

4. Hard Board -

• Hard Board is made as per the Indian Standard (IS: 1658–1966). 

• It is made out of wood pulp that is compressed to make sheets usually of 3-mm thickness. 

• Its top surface is smooth and hard and the rear side is rough with patterns or cross lines.

5. Fibre Board -

• The technique adopted for the manufacture of fibre board is the combination of the process used is making particle board and hard board. 

• In this case, wood chips are steamed to separate the fibres from each other. 

• These fibres are blended with resin and wax. 

• These are turned into sheets by pressing under controlled heat and pressure. 

• The boards are available in thicknesses of 25–32 mm and as sheets of 2.44 m × 1.22 m size. 

• They are suitable for flush doors, cabinets, etc.

6. Block Board -

• Block board is also known as batten-board or solid-core board. 

• Batten board consists of a core solid block of thin wood sawn from natural wood. 

• The central block is then glued between two or more outer veneers on either side.

• Thicknesses are from about 19 mm upwards. 

• They are suitable for door panels, partitions, table-tops, etc.