In the previous part of this article we reviewed various types of natural woods and explained about factors that affect the formation of wood texture. In this part we will overview the human made and synthetic wood types.
Wooden products or “synthetic” types of wood are processed under a series of regulations to deliver a final product better than the original material. Processed wood in the workshop environment is subjected to a variety of actions, such as heat and pressing, to create a product different from the natural raw material, depending on the purpose of the product. There are different criteria such as thickness, resistance to external factors, weight, beauty, strength so that the workshop can decide exactly what to do on the original wood.
These woods are usually made with disposable materials that do not work with carpentry workshops based on size and thickness. The wood raw material, by combining other intermediate materials, is pressurized to form the final board product. The following classification is based on the shape of the material used:
- If the resulting board is produced by putting together thin layers of wood and forms a set of layered compression plates, this product is called a layered board. Multilayer boards are another name for this product, which is named after the number of layers in the cutting board.
- When wood chips form the main board instead of wood layers, the product takes on the name chipboard. The texture of this board is not composed of layers mounted on top of each other, but of small and large pieces of wood that are visible to the naked eye.
- If the board is made of wood fibers, it gets the overall name of the fiberboard. Fiberboard itself is divided into different types. LDF, MDF and HDF are types of fiberboard.
- If we use only wood flour or powder instead of wood fibers or wood, we naturally need another supplement to form the board. The second material used is plastic, and for this reason, the name of the product made with wood flour under heat and press is plastic wood or polywood.
Since the plywood is made of multi-layered wood with adhesives, it can be trusted to a considerable extent and its range of application can be expanded. In fact, in this product, thin wooden layers have formed a thicker layer, and the overall thickness of the plywood means the total thickness of its forming layers. To maintain the strength of the board as much as possible, the layers are stacked perpendicular to each other based on their fibers to reduce the risk of breakage. The number of layers used in these boards varies depending on the application. This board can be made of different types of wood at different prices. The large size of these boards makes them work faster. Also, this wood is perfectly suitable for all kinds of drilling and sawing and other operations to be able to turn sand into any tool.
To become a wooden board, this product requires a material that acts like glue and sticks the pieces of wood together to form a single board. The material chosen for this purpose is resin or wax. The wood density of this board is high, but it is known among wood boards as the weakest and lightest board. Chipboard usually does not have a cover and is used in the same raw form for places that are not visible. Sometimes different covers or colors are used to make the board more beautiful. The coatings used for chipboard include natural wood veneer, synthetic veneer as well as glazed or varnished. Natural veneer that is natural and genuine wood; Artificial coatings are used in different colors and designs; The varnish is one or more coats of paint, which is responsible for the chemical protection of the chipboard. The board’s resistance to water and moisture is very low and can be a problem.
MDF, which stands for Medium Density Fibreboard, is a medium-density wood composite. That’s why it has the word medium in its name. Like chipboard, MDF is made from waste and wood fibers, but is much stronger than it is. A cross-section of the MDF shows a rough texture and shows what material the board is made of, but wood chips, unlike the chipboard, are not visible to the naked eye in the MDF. MDF can also be supplied with a variety of coatings. Fiberboard with a specific gravity or density higher than this HDF and with a specific gravity lower than this is called LDF.
The composite of HDF fiberboard, which stands for Hard Density Fibreboard, is named after its high wood density. The same MDF features are true for this board, but the only difference is that it has a higher density than it does. Higher temperatures and pressure are required to make HDF, but in some cases less adhesive is required. The result of this heat and high pressure makes the HDF highly resistant, which sometimes ends in a high price. The high density of this board increases its machining and tooling capabilities and creates better mechanical and physical properties for this board.
Unlike the Low Density Fibreboard, the LDF, unlike the HDF, has a low wood density. Like MDF and HDF, LDF is available in a variety of thicknesses and coatings.
Plastic wood or WPC wood, which stands for Wood Plastic Composites, is made from a combination of flour and plastic or thermoplastic. Recycled materials are used to make this type of board; Both the plastic used in it is recycled and the wood waste is used. Finally, this green product itself can be recycled.
Thermowood is the natural wood that is heated to change the cellular structure of the wood. Of course, heating has always been done to increase the strength of natural wood. This heating allows the thermowood to acquire positive properties and characteristics that either the natural wood did not have or acted poorly on. These properties, which are not present in natural raw wood, include resistance to decay, resistance to insects, resistance to moisture, high durability, and non-expansion and non-shrinkage. These features allow thermo wood to be used in exterior construction and parts of buildings such as roof gardens or swimming pools without any restrictions.