Exploration Series 2/On the Self-cultivation of Huasheng's High-quality Long Shavings

     Raw material preparation is one of the key processes in the production of oriented structural boards. Compared with ordinary particleboards, oriented structural boards require many key technical innovations from shaving preparation to drying, gluing, and slab paving. Among them, raw material preparation is a key process, and shaving preparation is particularly critical. The quality of shavings is crucial to the production of oriented structural boards. It has an important impact on downstream production steps such as drying, screening, gluing and pressing, thereby affecting the final performance of the board. Long shavings play a vital role in oriented structural boards. They can greatly improve the strength and bending resistance of the board and are the guarantee of the high strength of oriented structural boards.

     Generally, the shavings of particleboards are 40mm to 70mm long, 5mm to 20mm wide, and about 0.7 to 0.9mm thick. The shavings of Huasheng's oriented structural boards are 120mm to 160mm long, 20 to 40 mm wide, and about 0.4 to 0.6mm thick. Such high-quality long shavings are not only made from the carefully selected high-quality imported logs as the base material, but are also directly related to the advanced chipping production equipment and the control of each raw material preparation process.

   01The peeling process ensures clean and tidy wood shavings

   The raw wood is first sent to the peeling machine for peeling. Because the bark is mixed with foreign matter such as sand, peeling ensures that the output wood shavings are clean and there are no impurities and bark spots in the final product. The peeled logs pass through the metal detector to remove the logs containing metal. The qualified logs enter the batch feeder of the long-wood chipper and are then sent to the cutting room of the long-wood chipper batch by batch to be cut into wood shavings.

  02Advanced flaking preparation to obtain better quality shavings

  Huasheng introduced the world's top Canadian Kayden long-timber shaving machine, which is currently the world's largest single-machine long-timber shaving machine. Using the world's advanced German Meyer shaving machine and 6 imported Meyer ring shaving machines, and using advanced shaving production equipment, large-diameter wood can be directly sliced into flakes. The average length of shavings is as high as 120~160mm, which is much longer than the shavings on the market. Using it as a core material can greatly improve the bending resistance of the board.

Compared with traditional shaving machines, the edges of the shavings produced by Huasheng are irregular and not at right angles. This high-quality shavings have a significantly more uniform tension transition, which improves the internal bonding strength, static bending strength and The screw grip strength has been significantly improved.

    03Sectional drying ensures consistent moisture content of wood shavings

   The wet shavings and high-temperature flue gas from the thermal energy system are dried through a 32-meter drying drum. The entire drying process is divided into three stages: pre-drying section, drying section, and balancing section. The principle is to directly dry the shavings through heat convection and heat conduction. Allow to dry. Because of their small size and light weight, small shavings pass through the dryer quickly; under the dual action of the shovel and air flow inside the dryer, medium-sized shavings are dried in a freely suspended state; large shavings rotate along the inner wall of the dryer. Drying, compared with small and medium-sized shavings, the time they stay in the dryer and the route they travel are relatively long. Various shavings with different moisture contents are dried in the same dryer to ensure that the moisture content of the final shavings is relatively uniform and controlled at around 3%.

   04Separate screening allows large and small shavings to be classified

   The shavings coming out of the dryer are generally divided into two paths. One path is the large shavings that come directly from the dryer discharge box, and the other path is the fine shavings that are mixed in the dry exhaust gas and then collected by the recovery cyclone. The two paths of shavings are screened separately, and the shavings after sorting enter the surface and core layer dry shavings bins respectively. Before entering the glue mixer, the dry shavings are first weighed by a belt scale, and the weighed dry shavings are sent to the drum glue mixer for glue application.