Views: 11 Author: Site Editor Publish Time: 2020-05-05 Origin: Site
Generally speaking, the vast majority of trees, through the veneer peeling machine(rotary cutting machine )and other plywood production line processing, can produce plywood veneer. Not all trees can produce qualified plywood after processing.
Therefore, in the industry of plywood production, we need to constantly study various new production processes, expand the available tree species, and expand the source of raw materials for plywood production to meet the needs of plywood production.
In the process of producing plywood, in order to ensure the normal production of the factory, each factory will store a certain amount of logs. The methods of storing logs are mainly water storage, dry storage, wet storage and chemical storage.
The water storage method is widely used in conventional wood processing enterprises and plywood production enterprises, but rarely used in modern mahogany processing enterprises. Many mahogany processing and production enterprises have added the mahogany wood boiling process when handling materials. If the enterprise has a boiled production process, it can use the water preservation method to store the wood.
Water storage is generally in southern cities in China. The logs need to be immersed in water for a long time to maintain the moisture content of the logs, and the logs will not cause cracking and other problems. This storage method is to store the wood in areas such as rivers and rivers where the water flow speed is slow and gentle. It is more suitable for the storage of large quantities of logs transported by water. The management cost of this method is relatively low, because some of the mahogany logs are floating and cannot be completely immersed in water. As a result, the part exposed to the water surface must be cracked, discolored or decaying. Floating logs can also be turned frequently to keep the wood in a fully wet state. Water spraying can also be used to keep the wood in a fully wet state.
The dry storage method is a storage method that reduces the moisture content of the log sapwood to 25% or less in the shortest period of time to prevent the propagation of bacteria and insects, but it cannot completely prevent dry cracking. In the dry storage method, it is best to peel the wood and classify it as a well-ventilated, easy-to-dry layer or bundle. Generally, the flute height does not exceed 2m, in order to make more reasonable use of mechanical operations and flute. In order to reduce the cracking of the wood, measures such as rough peeling (toughness-retaining skin), shading and end coating (such as bituminous coal tar) can be taken.
The wet storage method is a preservation method that keeps the wood at a high water content to avoid the occurrence of fungi and cracks. The wet storage method is most suitable for newly harvested logs and wood transported to the site, but requires the retention of bark. When using the wet storage method to save the logs, the return work should be completed in the shortest time. In order to maintain the moisture content of the wood, the corrugated floor structure adopts dense corrugation, the corrugation length is more than 40m, and the corrugation interval is small, preferably about 1m. At the same time, it is best to create a light rain climate environment. In this way, the life activities of bacteria and insects are restricted, and the surface of the corrugated pile should be covered with a thin branch or treetop as much as possible, so that the log sapwood maintains a high moisture content.
In addition to the method of controlling the moisture content of the logs to save the logs, in order to reduce the damage and cracking of fungi, they can also be treated with chemical agents. Spray paraffin emulsion (10%) on the cross section of the log, or apply lime, coal tar or polyvinyl acetate emulsion and urea-formaldehyde resin (30:70) carboxymethyl cellulose and urea-formaldehyde resin and other synthetic coatings to prevent the evaporation of water at the log end To reduce end splitting. It also has a certain anti-corrosion effect on corrugated piles sprayed with preservatives. The preservatives commonly used are zinc oxide, copper sulfate, zinc sulfate, sodium fluoride, sodium pentachlorophenol, etc., but the control of spraying time, the penetration of the liquid The degree of logs still needs to be experimented and explored.