T4 Plywood: from log to sheet (4 marks) + cutting veneers (4 marks) · Industrial Technology Timber

T4 · Plywood: from log to sheet (4 marks) + cutting veneers (4 marks)

Fits: 2019 Q14 (4), 2021 Q14 (4), 2023 Q14 (4). Also 2017 MC2, 2023 MC8, 2015 MC9 · 187 words · 6 chunks

T4.1 · Log prepLogs are debarked, cross-cut into billets and softened by soaking or steaming so the veneer peels cleanly without splitting.T4.2 · Rotary peelFor plywood, the billet is spun on a rotary lathe against a long knife, which peels a continuous ribbon of veneer like unrolling paper. Decorative face veneers are instead sliced (flat/crown, quarter or rift slicing) or half-round cut to show figure.T4.3 · Clip + dryThe ribbon is clipped into sheets, dried in a veneer dryer to a low moisture content, then graded, and defects are patched.T4.4 · Lay-upGlue is spread and the veneers are laid up with the grain of each layer at 90° to the next, using an odd number of plies so the two face grains run the same way. Cross-graining gives strength in both directions and resists splitting and warping.T4.5 · Press + finishThe lay-up is hot-pressed so heat and pressure cure the adhesive (urea-formaldehyde for interior grades, phenol-formaldehyde for exterior and marine grades). The sheets are then trimmed to size, sanded to thickness, graded and stamped.T4.6 · Exam tipIf the question asks only about cutting veneers, describe peeling and slicing in detail; do not drift into the whole plywood process (NESA feedback, 2023).

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