Fiberboard production begins with raw materials, which are primarily composed of individual wood fibers or fiber bundles. These materials are sourced from various forest residues such as branches, tips, and small-diameter wood, as well as processing byproducts like sawdust, shavings, and edge waste. In some cases, chemical processing residues and other plant stems can also be used for fiber production. Softwood generally has longer fibers—about 30 to 50% longer than those from hardwood. If hardwood is used, it must undergo treatment, either by mixing with softwood or through chemical processes like steam or hot water treatment.
Before the fiber separation process, the raw material is cut into pieces measuring 20–30 mm in length, 3–5 mm in thickness, and 15–25 mm in width using a chipper. The size of these chips plays a crucial role: if they are too large, they may not soften evenly during pre-treatment, leading to poor fiber separation. Conversely, if the chips are too short, more fibers will be cut, reducing interlacing and ultimately weakening the final product. After cutting, the chips are screened, re-crushed, and washed before being sent to the silo for fiber separation.
The production process includes three main methods: wet, dry, and semi-dry. In the wet method, water is used to transport the fibers, allowing them to intertwine and form strong bonds. The dry method uses air as the carrier, often without fine grinding, and the fibers are dried before pressing. The semi-dry method maintains a high moisture content while avoiding full drying, combining advantages of both wet and dry methods.
The basic process involves fiber separation, slurry treatment, slab forming, hot pressing, and post-treatment. Fiber separation can be achieved through mechanical or blasting methods. Mechanical pulping includes thermal, chemical, and pure mechanical approaches, each offering different benefits. Blasting involves high-pressure treatment to break down lignin and separate fibers efficiently.
Slurry treatment involves adding waterproofing agents, reinforcement chemicals, fire retardants, and preservatives depending on the desired properties of the final product. Drying is essential in dry production, where fibers are dried to a moisture content of 6–8% before forming. Slab forming can be done via wet or dry methods, with wet forming commonly used for soft boards and dry forming for medium-density and some hard boards.
Hot pressing is a critical step, with varying pressures and temperatures depending on the method. Wet pressing typically requires higher temperatures, while dry pressing relies on rapid adhesive curing. Post-processing steps include heat treatment, humidity conditioning, sanding, and surface finishing, ensuring the final product meets quality standards.
Overall, fiberboard manufacturing is a complex process that combines various techniques to produce durable and versatile materials suitable for a wide range of applications.
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