Chipboard production | Shredding

After delivery, the processed material must be crushed to one size. A distinction is made between four types of shredding principles: Cutting, crushing, tearing and grinding.

Chipboard chips

Roundwood to wood chips

The roundwood is shredded to chip size by drum chipper, disc chipper or universal hogger.

Size of the wood wood chips:

  • Length: 30-100mm
  • Width: 20-25mm
  • Thickness: 4-6 mm

Wood chips to chips

In the next step the wood chips are processed into chips by knife ring flakers. The material is fed into the knife ring flaker from sanding from top. A magnet is used to eject metallic material to protect the cutters from mechanic damage. This also increases their service life. Stones are also separated from the wood chips by an air stream. The rotation presses the wood chips against the knife ring where they are cut into chips by the cutters and counter knife on the impeller.

Middle layer chips to surface layer chips

A dense surface is expected for miscellaneous types of board, e.g. furniture boards, which can only be produced using fine surface layer chips. For this reason, part of the chips are ground into a fine top layer in hammer mill.

Waste wood

The prerequisite for waste wood is that it is an uncontaminated material, i.e. it has not been impregnated.

In a waste wood treatment process, foreign matter such as glass, plastic, stones and metal are separated from the wood in stages. The material is pre-crushed in a crusher. After cleaning, the chip-sized material is processed into chips by the knife ring flaker. Chip-sized material can be processed further directly.

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OSB Beaches

The strands of OSB board consist of thin, flat wood chips with a high degree of slenderness. They usually have the following dimensions:

  • Length: 75-150mm
  • Width: 15-25mm
  • Thickness: 0.3-0.7mm

The board properties of OSB board are significantly influenced through the choice of type of wood, the average shape and the degree of variation of the strands. The thickness and width of the strands, their curvature and the surface quality are also control variables of the board properties.

Knife ring strander

Knife ring stranders are used for the production of strands. These cut the strands parallel out of debarked wood. Most manufacturers prefer a separated production of top layer and middle layer strands. These are then dried separated so that the drying process can be better adapted to the material.

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MDF /HDF

For the fibre materials, either wood chips from the sawmill by-products division or forest wood, which is shredded on the operation, is purchased. The forest wood is debarked before being shredded in drum and disc chipper. The wood chips are screened in order to sort out oversized wood for re-shredding. Fine material with a high proportion of sand and bark is also sorted out in the course of this process and fed into the boiler house for energetic use.

The wood chips have the following dimensions:

  • Length: 25mm
  • Width: 25mm
  • Thickness: 5mm

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Images

Hombak Trommelhacker
2020
Messerringzerspaner Halle
DIEFFENBACHER, 2019
Hombak Deckschichtmühle
2020
Siempelkamp Messerringzerspaner Funktionsprinzip
2016
Hombak Messeringzerspaner Späne
2020
Hombak Deckschichtmühle Späne
2020

Product brochures and leaflets (2)

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