Okoume wood
Okoume Wood is known as the "King of African Trees". Distributed in Central Africa and West Africa and the equatorial region. This species is mainly imported from Cameroon, Gabon, Equatorial Guinea, and Malaysia. Mainly used as materials for musical instruments and high-end furniture. After the Allied forces occupied North Africa during World War II, the wood was used extensively to make butts. It is said that on June 6, 1944, the Allied forces also used the wood extensively as a defensive material for ships when they landed in "Normandy".
Structural features
The bark is 0.5~0.8cm thick, hard, and easy to peel off. The outer skin is grayish-brown; it is easy to fall off in small pieces and leave shallow pits; it is dense with fine dots. The inner skin is dark reddish-brown; the fiber is well-developed, and it is easy to enter the party long. When the fresh bark is just peeled off, the surface and the bottom of the bark are all red and yellow. Cross section: The difference between heart and sapwood is slightly obvious. The heartwood is orange-red to light reddish brown. The sapwood is gray and narrow. The growth ring is not obvious. Macro structure: diffuse porous material. The tube holes are visible to the naked eye, slightly less, and of medium size; the main ones are single tube holes, with very few diameter rows of multiple tube holes (2~3). The axial parenchyma is almost invisible under the magnifying glass. It is obvious under the magnifying glass of wood ray, thin to medium and narrow.
Distributed
Large arbor, about 25~35m high and 1.0~2.5m in diameter; with large buttress roots, it is known as the "King of African Trees". Distributed in Central Africa and West Africa. This species is mainly imported from Cameroon, Gabon, and Equatorial Guinea. Mainly used as materials for musical instruments and high-end furniture.
Wood properties
Strong gloss. The okoume veneer wood texture is straight; the structure is fine and uniform; the weight is light; the hardness is soft; the strength is low; and the shrinkage is medium. It is easy to process, contains silica, and the knives are slightly blunt; the veneer surface has good slicing and rotary cutting performance; the surface is slightly fluffed; the adhesive performance is good; the nailing is easy. Slightly wear-resistant. It dries quickly and has no defects. The air-dry density is greater than 0.48g/cm.
Scope of application
It is suitable for peeling veneer, plywood, joinery products, furniture, wooden molds, packaging boxes, light components, musical instruments, etc. It is the most important material for veneer plywood.
Okoume veneer definition
The veneer is also called the panel and the dough. It is a wooden flake-like material produced by peeling and slicing methods. okoume wood veneer is the veneer processed with Okoume wood. Because Okoume has the characteristics of strong gloss, straight texture, fine structure and uniformity, light weight, soft hardness, low strength, shrinking, no scarring, etc. So it is widely used in the processing of veneer plywood. The thickness of okoume veneers wood on the market is generally between 0.1 mm and 0.6 mm. The thin wood veneer sheets, the better the wood.
Grade and judgment basis
According to different quality, Okoman veneer plywood sheets are generally divided into grades such as A, B, C and D. The judgement of the grade is mainly based on the color, wood, wormhole, color difference, scarring, small fresh knots, holes, etc. Bad, whether or not, how much.
Veneer
The veneer and its veneer manufacturing company started in the 1950s. After half a century of development, it has already possessed a considerable scale. Especially in the past two decades, with the rapid growth of my country's veneer furniture manufacturing and decoration industry, its development has advanced by leaps and bounds, and a large number of industry experts have emerged. In the past ten years, my country's veneer furniture board manufacturing and decoration industries have used a large number of ply veneer production processes.
Classification
1. Classification by thickness
Thickness greater than 0.5 mm is called thick thin wood; on the contrary, it is thin wood.
2. Classified by manufacturing method
It can be divided into sliced veneer; rotary veneer; sawed veneer; semicircular veneer. Usually, it is made more often by the slicing method.
3. Classified by form
It can be divided into natural veneer; dyed veneer; combined veneer (technical veneer); spliced veneer; rolled veneer (non-woven veneer).
4. Classification by source
Domestic veneer; imported veneer.
Quality items of veneer
1. Thickness and uniformity, length and width and error, moisture content
2. Early wood and late wood
In each year, the pith core part is formed at the beginning of the growing season. It is called early wood (spring wood) with light wood color, loose structure, and soft material; the bark part grows later, with deep wood color and texture. Dense, hard material, called late wood (autumn wood, summer wood)
3. Sapwood and heartwood
Some tree species have a lighter wood color near the bark. When the tree is felled, this part contains more water and is called sapwood. The part with darker wood color and less water around the pith is called the heartwood
4. Pattern, color difference, smoothness, mineral line
Sliced veneer manufacturing process
Usually, the method of processing natural veneer wood is sliced. The process flow is as follows:
Log→cutting→cutting→softening (steaming or boiling)→slicing→drying (or not drying)→cutting→inspecting and packing→in storage
The following only introduces three important links:
1. Sectional
After the log enters the veneer sheet factory, it must first be cut into pieces according to the required length, and then when cutting the wood square, the sawing plan must be selected according to the diameter of the log, the wood texture and the fixing method of the wood square on the veneer peeling machine, so that the cutting The width of the natural veneer sheets shall not be less than the relevant requirements.
The reasonable plan not only has a high yield rate, but also produces more diameter-cut veneer and less string-cut veneer, and the resulting product has a high decorative value. Logs of different diameter grades should use different sawing schemes. The thick solid line in the plan is the saw section line, and the arrow direction is the cutting direction of the planer:
In actual production, logs with diameters less than 400mm usually adopt sawing plan B, while logs with diameters of 400 to 800mm usually adopt sawing D and E. When using these sawing schemes to produce wood veneer, the board yield rate is high, the veneer quality is better, and the efficiency of the planer is higher.
2. Cooking
After the wood is cooked (hydrothermal treatment), the plasticity of the wood increases. The most effective way to improve the plasticity of wood is to adjust the two factors of temperature and moisture content at the same time, that is, to increase the temperature of the wood while increasing the moisture content of the wood. This is the reason why in actual production, saturated steam or hot water is usually used to cook wood cubes and one hydrothermal treatment.
First of all, when the wood is put into the cooking tank, it should be carried out according to the tree species and the specifications of the wood; the water temperature should be kept at room temperature and the temperature should be raised slowly to prevent the wood from cracking due to thermal stress. When the temperature rises above 40℃, the heating rate should be slowed down; excessive cooking will also reduce the quality of veneer; the cooking pool should be cleaned frequently of resin, bark, and sand, and the water should be changed frequently to reduce wood pollution; after cooking treatment. The wood square should be put into the wood storage tank in front of the planer in time, and the heat preservation is in the range of 40~50℃ (depending on the tree species and the thickness of the veneer). The following table lists the cooking benchmarks for several types of wood, for reference only.
3. Dry
After drying, the dilute moisture content should be 8%~12%. The wood drying equipment has a general drying belt dryer for continuous operation and a drying chamber for the working machine. The drying room is not an old-fashioned drying equipment, it is very economical, but a relatively wide range of drying dryers, especially thin wood with a thickness of less than 0.4mm, must use a belt dryer.
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