Fig. 9 shows a cross-section through a piece of plywood. The timber has been selected for its working properties and appearance. Different types of timber h...
Question 1 Report
Fig. 9 shows a cross-section through a piece of plywood. The timber has been selected for its working properties and appearance. Different types of timber have different characteristics that affect their suitability. The grain direction and moisture content affect how the timber can be worked.
It can hold a lot of weight.
The acrylic provides adequate lightweight nature while keeping the overall weight low. The dimensions of the product have been determined by the needs of the intended user.
(a) State what is meant by a manufactured board. [1]
(b) Explain why the grain direction of alternate layers (labelled A and B) runs at right angles to each other. [1]
Answer Details
(a) A manufactured board is a sheet material made by processing natural timber into thin veneers, fibres, or particles, which are then bonded together with adhesive under heat and pressure. [1] Unlike solid timber, manufactured boards are engineered products that combine natural wood in a processed form to achieve large, flat, dimensionally stable sheets.
(b) The grain direction of alternate layers (A and B) runs at right angles to each other to make the board equally strong in both directions. [1] In solid timber, the material is much stronger along the grain than across it. By alternating the grain direction of each veneer layer in plywood, the strength is balanced in both the length and width of the board. This cross-lamination also prevents the board from warping or splitting along one grain direction, because the tendency of one layer to shrink or expand is counteracted by the layer above and below it running perpendicular.
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