1 The influence of shavings on the product The requirement for the oriented strand board material is that the tree species should be as single as possible, because the state and quality of the shavings are directly affected by the tree species. Tests have shown that the oriented strand board for packaging is mainly poplar, and also contains shavings of fir, hemlock, Douglas fir, and sweet gum. Although the content is small, the increase of these impurities seriously affects the strength of the bonding. Because the density during hot pressing is not large, the degree of gluing and connection state of wood shavings are different for different woods. Among them, poplar is the most easy to glue, and the transverse longitudinal strength of the fiber does not change much, which is easy to form anisotropic structure. And other softwoods. The longitudinal and transverse strengths are relatively large, and it is not suitable to form an anisotropic structure with good practical properties. The quality of shavings is directly related to the quality of oriented strand board products, especially the uniformity of oriented strand board and the surface quality of the product. Therefore, careful processing of the shavings must be carried out.
2 Relationship between shavings and product quality As with particleboard production, excessive moisture has an adverse effect on the sizing and hot pressing of shavings, so it is necessary to fully dry the OSB shavings. Under the same temperature conditions, the drying time of shavings is directly related to the initial moisture content, and the drying time of different tree species is also different. It is difficult to control the drying time of shavings. In order to improve the drying quality, the shavings can be naturally dried in the air to a moisture content of slightly less than 40%, and then dried in a drying apparatus. Loose poplar shavings will dry quickly.
In order to obtain a high-quality product, the moisture content of the shavings should be as low as possible, and the hot pressing time of the oriented strand board should be long, so that the moisture content of the oriented strand board product is very low.
3 The relationship between the amount of glue applied and the quality of the product has been found through experiments. The amount of glue used for the production of oriented strand board is related to the tree species. If the amount of glue applied is calculated as a percentage of the mass of the test material, then under the same amount of glue, after hot pressing, The needle-leaf oriented oriented particleboard sheet glue is obviously too much, while the poplar shavings are easy to absorb the glue, and the amount of glue is more suitable. The occurrence of the above phenomenon is related to the density of the wood. For example, the softwood has a higher density than the poplar. Under the same quality, the volume of the softwood is small, and the corresponding surface area of ​​the shavings is also small. Therefore, the mass percentage is determined by gluing. The calculated amount of softening of the softwood should be lower than that of the same quality poplar.
4 Influence of paving effect on product surface quality Paving is an important part of the manufacturing of oriented strand board. Oriented particleboard paving machine is a major difficulty in the research of international oriented particleboard. It still can't find the ideal paving machine, and it is very difficult to achieve uniform parallel placement of the current paving equipment, but if the shavings are better separated. When it is in a uniform structure, it can still be paved at the paving angle. Poplar shavings are easier to achieve the above paving principles.
Because the shavings are not parallel to each other during paving, but are inclined at an angle, this has a great influence on the appearance quality of the sheet. After shaving or grinding, the fiber texture is disorderly and cannot show the natural pattern of the wood.
The thickness of the pavement will also have an impact on the quality of the product. If the bad material is thick when paved, the density of the extruded oriented strand board is too large, and the internal stress is large. After being placed for a period of time, deformation is easy. Therefore, the correct paving is of great significance for the manufacture of oriented strand board structural materials with high rigidity, small creep, light weight and good surface quality.
5 Conclusion Poplar is an ideal raw material for oriented strand board, which is suitable for the production of oriented strand board products.
Compared with natural wood, the oriented strand board products made from poplar wood can only guarantee the physical and mechanical properties similar to the solid wood under the premise of increasing the density.
The processing of shavings is the key process for the industrial production of oriented strand board. From the principle analysis, it is not the ideal way to separate the shavings by using existing processing equipment. It is difficult to form uniform shavings by the experimental shavings.
Paving and hot pressing have a great influence on the physical and mechanical properties and surface quality of oriented strand board products. The thickness of paving, hot pressing pressure and time should be strictly controlled. Especially the variance control of paving angle is especially important.
The theoretical solution method of the main direction elastic modulus of oriented strand board is established by using composite mechanics, probability design theory and numerical integration method. It provides a basic theory for the prediction of the strength of oriented strand board, and provides a mechanical model for the computer simulation of the strength of oriented strand board. Calculation method.
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