Timber grading standard

Timber grading standard

First, thin wood

Thin wood (commonly known as: veneer, veneer; English: veneer; hereinafter referred to as thin wood) and its veneer decoration industry started in the 1950s, and after half a century of development, it has reached a considerable scale. Especially in the past two decades, with the leap-forward growth of China's furniture manufacturing industry and decoration and decoration industry, its development has been advancing by leaps and bounds, and a large number of industry experts have emerged.

In the past ten years, China's furniture manufacturing industry and the decoration and decoration industry have used a large number of veneer veneer processes. Here are some of the explorations about thin wood, for your reference only:

First, the classification of thin wood:

1, by thickness

Thickness greater than 0.5mm is called thick wood; reverse is thin wood.

2. Classified by manufacturing method

Can be divided into sliced ​​thin wood; rotary cut thin wood; saw cut thin wood; semi-circular rotary cut eucalyptus. Usually, the cutting method is used to make more.

3. Classified by shape

Can be divided into natural thin wood; dyed thin wood; combined thin wood (technical veneer); spliced ​​thin wood; rolled thin wood (non-woven thin wood).

4, by source

Domestic thin wood; imported thin wood.

Second, the quality project of thin wood:

1, thickness and uniformity, length and width and error, moisture content

2, early and late wood

In each round, the core part is formed at the beginning of the annual growing season. The color of the material is shallow, the structure is loose, and the material is soft. It is called early wood (spring material); the part of the bark is later grown, the color is deep, and the tissue Hard, hard material, called late wood (autumn wood, summer material)

3, sapwood and heartwood

Some tree species are lighter near the bark, and when the trees are felled, this part has more water, called sapwood. In the part of the medulla that is darker and has less water, it is called heartwood.

4, pattern, color difference, smoothness, mineral line
Third, the cutting process of thin wood manufacturing
Usually, the processing of natural thin wood is carried out by means of planing. The process flow is as follows:

Log → cut → split square → soften (steaming or boiling) → planing → drying (or not drying) → cutting → inspection packaging → storage

Here are just three important aspects:

1, interception

After the logs are imported into the factory, they must first be cut into wooden sections according to the required length. When the wood is cut into sections, the sawing section must be selected according to the diameter of the logs, the texture of the wood and the fixing method of the wood on the planer. The width of the thin wood is not less than the relevant requirements.

The reasonable plan not only has a high yield, but also produces a large number of thin cut wood, less string cutting and thin wood, and the resulting product has high decorative value. Logs of different diameter grades should adopt different sawing schemes.

2, cooking

After the wood is cooked (ie hydrothermally treated), the plasticity of the wood increases. The most effective way to improve the plasticity of the wood is to adjust the temperature and moisture content simultaneously, that is, to increase the temperature of the wood while increasing the moisture content of the wood. This is the reason why the water treatment is usually carried out by steaming the wood with saturated steam or hot water in actual production.

First, when the wood is placed in the cooking pool, it should be carried out according to the tree species and the wood specifications. The water temperature should be kept at normal temperature and slowly warmed up to avoid cracking of the wood due to thermal stress. When it rises above 40 °C, it should slow down the heating rate; excessive cooking will also reduce the quality of thin wood; cooking pool should often remove resin, bark, sediment, and often change water to reduce wood pollution; after cooking The wood should be placed in the warm water tank in front of the cutting machine in time, and the temperature is in the range of 40~50 °C (depending on the tree species and the thickness of the wood).

3, dry

The moisture content after drying is generally required to be 8% to 12%, and the thin wood drying equipment has a drum dryer and a belt dryer which are continuously operated, and a drying chamber for intermittent operation. The drying chamber is an old-fashioned drying device that is uneconomical but has good drying quality. The most widely used is the drum dryer. The thin wood of the comparison book, especially the thin wood with a thickness of less than 0.4 mm, must use a belt dryer.

Second, new knowledge of dyed veneer

Recently, some customers have found that the requirements for veneer are not only in the processing process, but also in the color. There is also a requirement for color. Dyeing veneer is a new type of product. Although it is not very professional in this respect, the following is what I found on the Internet. Related knowledge, I hope everyone can learn to communicate together!

Dyed veneer: a new era of decorative materials, dyed with the original natural wood, without losing the natural wood characteristics (light chromatic aberration and natural texture), can also play a creative special color (ordinary oil 柒 effect will only cover the wood itself should There are obvious textures, chromatic aberrations, etc.), adding rich colors to modern design.

First of all, there is a veneer, from the selection of suitable veneer (some of the veneer can not be done due to the nature of the problem), and then to the factory processing bleach (usually takes about 6 hours, how many times to look at the wood) is to unify the color After the next treatment, after pre-prepared pigment (dye) soaked, the basic veneer has color, then fixed color, dried, hot pressed flat, cut, packaged.

Quality requirements: The color is not decolored, the whole batch of goods is no more than three kinds of color difference, flat, humidity is not more than 10%, no chemical residue, no odor.

Third, the American broad-leaved wood board grade

American hardwood board classification summary - grade introduction

The grades and metrics of edwards products are strictly in accordance with the NHLA (American Hardwood Board Association) rules.

â–¡ Level 1 (1com)

Grade 1 is suitable for the production of standard sizes of American cabinets, so it is often referred to as cabinet level in the United States. It is also for this reason that Grade 1 wood is widely used in the production of furniture parts. The minimum size of the first grade is 3 inches wide and 4 feet long, and the net aspect ratio is 66.67% (ths) to the minimum of the FAS level of 83.33% (not up to the FAS level). The minimum net footprint is 3 inches wide by 3 feet long and 4 inches wide by 2 feet long. The number of net faces depends on the size of the sheet. Both sides of the board must meet the minimum requirements of Grade 1.

â–¡ FAS level

The original meaning of the FAS grade is derived from the original [first-class and second-class] grades, which refers to wood that can provide a longer net finish. This grade of wood is best suited for high-end furniture, interior joinery and solid wood lines. The minimum dimension of the panel is greater than or equal to 6 inches in width and greater than or equal to 8 feet in length. The FAS grade includes a series of sheets with a net-faced yield (accounting for the entire outer surface area) of 83.33% (10/12 ths) to 100%. The minimum size of the net plan should be 3 inches wide, 7 feet long or 4 inches wide and 5 feet long. The number of net finishes in a sheet varies depending on the sheet size, and the maximum number of sheets allowed is 1 to 2. The minimum standard for sheet length and width will vary depending on the type of material and whether it has been treated by kiln drying. Both surfaces of the sheet are required to meet the minimum requirements of the FAS rating.

â–¡ Pu 2A (2com)

Grade 2 is often classified as economic grade, because the price and suitability of this grade of wood can make it a material for a wider variety of furniture components. This grade of wood is also a frequently used material for American hardwood flooring. The smallest board size in the 2nd grade is 3 inches wide and 4 feet long. The ratio of the net draw rate is 50% (6/12 ths) to 66.67% of the general grade 1 (not up to the grade 1). ). The minimum allowable net face size is 3 inches wide and 2 feet long, depending on the size of the board. If the worst face meets the minimum requirements of the 2A level, the level to which the better face belongs is irrelevant.

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