Raw-material Information:
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Plywood
Plywood is an engineered wood sheet material manufactured from thin layers or "Plies" of wood veneer that are glued together with adjacent layers having their wood grain rotated up to 90 degrees to one another. Each wood veneer will be produced from a good log, called a peeler, which is generally straighter and larger in diameter than one required for processing into dimensioned lumber by a sawmill. The log is laid horizontally and rotated about its long axis while a long blade is pressed into it, causing a thin layer of wood to peel off (much as a continuous sheet of paper from a roll). An adjustable nosebar, which may be solid or a roller, is pressed against the log during rotation, to create a "gap" for veneer to pass through between the knife and the nosebar. The nosebar assists in keeping the veneer being peeled to an accurate thickness. In this way the log is peeled into sheets of veneer, which are then cut to the desired oversize dimensions, to allow it to shrink when dried.
The sheets are then patched, graded, glued together and then baked in a press at a temperature of at least 140°C and at a pressure of up to 1.9 MPa. The panel can then be patched, have minor surface defects such as splits or small knot holes filled, re-sized, sanded or otherwise refinished, depending on the market for which it is intended. Plywood for indoor use generally uses the less expensive urea-formaldehyde glue, which has limited water resistance, while outdoor and marine-grade plywood are designed to withstand moisture, and use a water resistant phenol-formaldehyde glue to prevent delamination and to retain strength in high humidity. Anti fungal additives such as Xyligen may sometimes be added to the glueline to provide added resistance to fungal attack.
Marine plywood is graded as IS710 as per Indian Standards. It is much more expensive than standard plywood. Keeping the wet conditions in kitchen we suggest to use this type of plywood.
Medium Density Fibre Board (MDF)
MDF is an engineered wood product made by breaking down hardwood or softwood residuals into wood fibres, often in a defibrator, MDF is typically made up of 82% wood fibre, 9% urea-formaldehyde resin glue, 8% water and 1% paraffin wax. The trees are debarked after being cut and debarked logs are then chipped. The chips are washed and checked for defects.The chips are then compacted using a screw feeder, are heated/steamed for 30–120 seconds to soften the wood, then joined with liquefied wax and fed into a defibrator. The defibrator maintains a high pressure and temperature while grinding the wood chips into a pulp. The pulp enters a blowline, where it is joined with resin, often urea-formaldehyde. The wax improves moisture resistance and the resin dries quickly when it enters an expansion chamber and expands into a fine, fluffy and lightweight fibre that is stored until needed at the forming line.
Dry fibre gets sucked into the top of a pendistor, which evenly distributes fibre into a uniform mat below it, usually of 230–610 mm thickness. 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. After pressing, MDF is cooled in a star dryer or cooling carousel, trimmed and sanded. In certain applications, boards are also laminated for extra strength.The Environmental Impact of MDF has greatly improved over the years. Today, many MDF boards are made from a variety of materials. These include other woods, scrap, recycled paper, bamboo, carbon fibres and polymers, forest thinnings and sawmill off-cuts. As manufacturers are being pressured to come up with greener products, they have started testing and using non-toxic binders. New raw materials are being introduced. Straw and bamboo are becoming popular fibres because they are a fast-growing renewable resource.
MDF is generally denser than plywood. It is made up of separated fibres, but can be used as a building material similar in application to plywood. It is stronger and much denser than particle board. We suggest to use MDF in Bed Rooms, Living Rooms etc., and even in Kitchen also we can use.
Particle Board
Particle Board is cheaper, denser and more uniform than conventional wood and plywood and is substituted for them when appearance and strength are less important than cost. Particleboard or chipboard is manufactured by mixing wood particles or flakes together with a resin and forming the mixture into a sheet. Amino-formaldehyde or Urea Melamine resin is then mist-sprayed through fine nozzles onto the particles. The particles then pass through a mist of resin sufficient to coat all surfaces and are then layered, first into a continuous carpet. This carpet is then separated into discrete, rectangular blankets which will then be compacted in a cold press. The sheets formed are then cold-compressed to reduce their thickness and make them easier to transport. Later, they are compressed again under 290 and 440 psi pressure and temperatures between 140 and 220°C. This process sets and hardens the glue. The boards are then cooled, trimmed and sanded.
They can then be sold as raw board or surface improved through the addition of a wood veneer or laminate surface. A major disadvantage of particleboard is that it is very prone to expansion and discoloration due to moisture, particularly when it is not covered with paint or another sealer. Therefore, it is rarely used outdoors or in places where there are high levels of moisture, with the exception of some bathrooms, kitchens and laundries, where it is commonly used as an underlayment - in its moisture resistant variant - beneath a continuous sheet of vinyl flooring.
The advantages of using particleboard over veneer core plywood is it is more stable, (unless it gets wet), much cheaper to buy, and somewhat more convenient to use. These boards would be used commonly in ready made wood products and office furniture.
"There is nothing like staying at home for real comfort."
- Jane Austen