The moisture content of mahogany furniture has a great relationship with the intrinsic quality of furniture. As we all know, the wood itself contains a certain amount of water. Before making furniture, it must be dried. However, drying should have a "degree", which is to make the moisture content of the furniture material consistent with the average moisture content of the atmosphere in the area of ​​use. Generally speaking, the mahogany furniture that has been prepared has a moisture content of preferably 1% to 2% lower than the average moisture content of the local air, and cannot be too low. Too low, the wood will absorb the moisture in the air. The furniture is inflated and deformed. The moisture content of mahogany furniture materials is preferably not high or low, and the furniture will rise. When it is low, it will open up and crack. The mahogany wood and its products under normal conditions will have a certain amount of water. In China, the weight of the moisture in the wood and the percentage of the weight of the wood after drying are defined as the moisture content of the wood. The water content can be calculated based on the weight of the whole dry wood, and the calculated value is called the absolute moisture content, and is simply referred to as the water content. There is a formula for calculating the water content: moisture content = (wet weight - soil weight) / wet weight × 100% Today, more and more businesses and buyers are paying attention to the moisture content. The main method of reducing moisture content today is through the drying of machines. Different shapes have a certain effect on the drying of wood. Simply put, the baking of the material is more difficult than the baking of the sheet material, because the material is large, the internal humidity is difficult to control, and the problem of large-area cracking, deformation and warping will occur if the material is not well controlled. Redwood is a hard-to-dry hardwood, so its drying should be carried out in two stages, that is, pre-drying, drying to a moisture content of 20-30%, and then kiln drying. The mahogany sheet is pre-dried in various ways, and then dried in the kiln, which may reduce energy consumption, reduce the drop, and maintain the natural color of the wood. Using air drying as a pre-drying measure can increase the drying kiln productivity by about 40% and reduce waste by 60%. In order to promote the drying of the mahogany, the method of pre-planing is also very useful. Raw materials are planed on both sides of the planer before the kiln is dried, which can eliminate the tiny gaps left during sawing and has a good anti-cracking effect. This tiny gap is also one of the causes of dry cracking, including dry cracks and internal cracks, and about 98% of the internal cracking of wood is caused by deepening of the crack. Extended reading: mahogany furniture collection market boutique is always king Studies have shown that pre-planed light can reduce surface cracking by about 75% and shorten drying time by 7%. However, it should be noted that the thickness of the pre-planed sheet should be slightly increased to avoid insufficient thickness due to shaving loss. This may cause a loss of volume loss, but after the planing of the wood, it can only be finely planed before use; and the unplaned plate must be flat and planed before use, so the total loss is actually the same. . The method for measuring the moisture content of the wood includes a drying method, an electric measuring method, a dry distillation method, a titration method, and a humidity method. In the field of wood processing, a drying method is usually employed. The drying method is a method of measuring the moisture content of the wood moisture test piece until it is completely dry. Generally, a representative moisture content test piece having a thickness of 10 to 12 mm is cut at a distance of 250 to 300 mm from the end of the saw material. The water content test piece is scraped, and the first weight is weighed on a balance with an accuracy of 0.01 g and a range of not less than 200 g; then the test piece is placed in an incubator at a temperature of 103 ± 2 ° C for about 6 hours, and then taken out. Repeat and record; put it back in the oven and continue to dry. It is then weighed every 2 hours until the weight of the last 2 weighings is constant, which is the absolute dry weight. According to the formula, we can get the absolute moisture content. Absolute moisture content = (the first weight of the test piece - absolute dry weight) / absolute dry weight × 100% The moisture content of wood decreases from high to low. When the water drops below the fiber saturation point (the water content is generally between 23 and 33%, taking an average of 30%), the size of the wood is discharged along with the sorption of water in the wood cell wall. Shortening and correspondingly reduced volume, this phenomenon is called shrinkage of the wood (ie shrinkage of the process of drying). The shrinkage of wood is expressed by the shrinkage rate. The shrinkage rate of the wood produced by completely discharging all the absorbing water is called the full shrinkage rate. The shrinkage ratio of the wood is different in three directions, and the wood is oriented in the grain direction (ie, the longitudinal direction). The full shrinkage rate is only 0.1~0.37%, while the radial direction of the horizontal stripes is about 3~6%, and the chord direction is 6~12%. The lateral shrinkage of the wood is much larger than the longitudinal shrinkage; the chordwise dry shrinkage is greater than the radial shrinkage, and the chordwise full shrinkage is about twice the radial. The directionality of the shrinkage of the wood, especially the difference between the longitudinal and the transverse, can also be reflected in the furniture sheet. The shrinkage of wood is closely related to the equilibrium moisture content of each region. The balance of water content in each region varies seasonally and climatically, and is between 7 and 18% (for example, the annual average moisture content in Guangzhou is 15.1%. The Beijing area is 11.4%). When the furniture is made, the moisture content of the wood should theoretically be equal to or slightly lower than the equilibrium moisture content of the furniture use destination by 1 to 4 percentage points (considering hygroscopic hysteresis), and the furniture will not shrink during use in such an environment. . However, after the material has not been dried or dried, the furniture material is not uniform or the overall moisture content is still higher than the equilibrium moisture content of the destination. After a period of use, the water inside the wood evaporates, agreeing with the equilibrium moisture content of the area of ​​use. Due to the loss of water inside the wood, the volume is reduced, which causes the wood to shrink. Of course, the requirements for water content are different in different regions and different uses. For example, the average annual equilibrium moisture content in Guangzhou is 15.1%, compared with 11.4% in Beijing. When drying to 11% of wood is suitable for Beijing, it can be used for Guangzhou to absorb moisture and deform.
This category presents different kinds of Portable Mirror. We have been professionally designing and producing portable mirrors for 17 years.
Not only are all the materials used in the mirror the best, but our technology is very good, using the most advanced and up-to-date machines. We also accept OEM and ODM. And our portable mirror are so nice! We have many types of portable mirror. Such as led Travel Mirror, hand mirror, led Compact Mirror and so on.
Our style is very popular in foreign countries, especially in the European and American markets, and the feedback in the local market is very good.
Our after-sales service is also professional and patient. So that our customers can buy with confidence, no worries, and no worries about the situation that they do not understand.
With the progress of the times, our design team is also keeping up with the pace of fashion, continuing to design more new styles of portable mirrors for our customers.
Portable Mirror,Portable Led Makeup Mirror,Portable Travel Mirror,Portable Lighted Mirror Dongguan Powerme Tech. Co., Ltd. , https://www.powermetech.com Water content (mass moisture content)
Moisture content and drying
Water content measurement
Wood shrinking characteristics
The vertical and horizontal "white" of a long table desktop
National mahogany furniture moisture content summary
