Cardboard Manufacturing Process
The raw material used for manufacturing of the card board are wood, bagasse saw dust etc. Generally the card board is manufactured from wood, however, bagasse form sugar industry can be used for the manufacturing of card board and it forms alternative raw material where the wooden chips are not available or costly.
Manufacturing of card board from the wood requires to cut the wood is cut into Small chips by a wood cutter. These chips are steamed in pressurized container. The thermally and hydrolytically softened wood chips are then defiberated in pressurized disc refiner and the pulp is blown into cyclone. In this process lignin is softened to loosen the fibers and is again used as binder in card board. Some part of lignin is dissolved and discharged with wastewater.
The stock is then diluted with to consistency of two percent and sheet is formed passing through a series of rollers of wet forming machine. The water is extracted from the card board and discharged as white water. The wet sheet is cut and then pressed to card board in hot press machine.
Manufacturing of card board from the wood requires depithing that is removing of bagasse cillo or pith which cannot be used for pulping in depither. The bagasse cillo or pith is used as fuel in boiler. The depithed bagasse is stored in bagasse chest and it is passed to defibrator unit, where live steam is applied to the bagasse to soften the lignin and form pulp. The pulp is then blown to cyclone. Then the pulp is diluted with water to two percent consistency and passed through number of rollers to squeeze the water and hot pressed to form a final product as card board.
