" " wisno wood furniture finishing: Hardboard

Wednesday, August 24, 2011

Hardboard


Hardboard is a manufactured wood material. It is made in tiny, thread like wood fibers. The name “ hardboard” is identifies a wide range of panel products that are literally “ hard” and which are made in the shape and form of board or panel and using wood as the essential ingredient.
Hardboard is member of the family of forest product; it is closely to the other members of the wood products family. Nearly 100 % wood fibers which have been rearranged during the manufacturing process of form the hard panels with their own set of separate and distinct characteristics. All wood products consist basically wood fibers. In the lumber and plywood, the wood fibers remain in the same position within the wood just the did in the growing tree.
Wood fibers are made of two main ingredients: cellulose and lignin. Cellulose is the wood fibers that give strength, while the lignin is the natural binder. Lignin is like cements to fill and hold the fibers together and makes wood solid. The wood in each species has its own characteristic as it grows. When the wood broken down into fiber form, the fibers in all special used for hardboard have similar qualities which make them ideal for use in the product.
For its weight the wood is one of the strongest materials known to man. The fibers in wood are fairly uniform size shape and other properties. Hardboard consists entirely of these fibers. Sometimes  small amount of chemicals are added to give certain characteristic. Solid wood as it comes from the tree contain a number of defect which are eliminated at the hardboard. For example: there is no knot and grain in the hardboard.  Hardboard has two basic differences with the other composition boards such as particle board of flake board. First hardboard is produced from the wood which has been reduced to its individual basic wood fibers. Second hardboard is the only board which uses lignin the natural cohesive substances found il all wood.  The lignin in hardboard makes natural bond, while other product are synthetic binder. 

How Hardboard is made.

The first step in manufacturing hardboard is chipping the wood into tiny pieces, five eights of an inch wide and one inch long. The chipper consists of revolving disc fitted with many sharp knives. As the wood touches the knives it is “chipped” into that size. The chips are sent by conveyor into the de-fibering machines which tear them apart and reduce them into fiber bundles. Or the chips are defiberized be steam pressure and exploded. Next the refinery machines take the fibers bundle and reduce them to individual fibers.
The next step is the mat forming process, which can be accomplished in the two ways. First is the water suspension method, in which the fibers are mixed in a tank of water and fed onto screen to form mat.  The second is the air suspension method in which the wood fibers are blown into large metal cone and allowed to settle down (into mat) like snowflakes.
The formed mat, consisting of thick blanket of loose fibers in approximately the same size as the final panel emerges from the mat–forming stage and they ready to be compressed. The individual panel size mats are conveyed into a giant hot press. The press operation is the similar with the placing hot iron on a fluffed-up damp towel until it is compressed into a thin sheet of fabric. The press develops of hundreds of pounds per square inch. The result is a thin, grain less, dense, uniformly textured, and strong and bone- dry coated panel mat.  Because the hardboard at these stage is so dry (much drier than the air in the normal condition), a small amount of water are added to the boards by placing them in the humidification chamber. This treatment is done to minimize the possibility of the hardboard warping.
Born of research and engineering, hardboard throughout its development has depended upon technical controls and improvements. For many years the basic effort was concentrated on producing a superior material which was ideal for the fabrication. In more recent years the development has more to fulfill the end uses. The development to the end product was created because of the hard competition among the companies.
Hardboard has some characteristics that make it desirable to the home construction and woodworking industry. They are: high uniformity, easy workability, low cost, non corrosive, good compatibility, excellent compatibility resistant to weathering, abrasion, denting and cracking. But however the hardboard is more the engineering substance, it does not have the natural uniqueness of the wood anymore. Hardboard in the market has to compete with other synthetic material such as: plastic, polyurethane, melamine and other resin material.

0 comments:

Post a Comment