V, Vassiliou
Department of Harvesting and Technology of Forest Products,
School of Forestry and Natural Environment, Aristotelian University,
54 006 Thessaloniki, Greece
Subject Effect of core ไม้บาง joints on the longitudinal bending
strength of thin 3-ply ไม้ในตระกูลเดียวกันมณฑา จำปา plywood used for fruit boxes
Introduction-Background Thin 3-ply ไม้ในตระกูลเดียวกันมณฑา จำปา plywood of
approximately 3.5 mm in thickness are usually produced by small-sized
units in Greece, and mainly used for fruit boxes and for some furniture
applications as well. The peeled ไม้บาง of lower quality are used as
inner piles of these panels in the form of full sheets (Fig. la) and in
the form of strips usually without mechanical jointing. The lack of
mechanical jointing in the formation of the inner ply results in either
overlapping (Fig. lb) or leaving gaps along the edges of adjacent strips
(Fig. lc).
The efficiency of various jointing methods has been extensively
investigated for parallel laminated veneers (Laufenberg, 1983).
Materials and methods Bending strength tests were carried out on
industrial 3-ply poplar unsanded plywood (hybrid 1-214). Panels were
fabricated with rotarT-peeled veneers, by using the urea-formaldehyde
glue as binder and were visually graded as A/B (A-grade face/B-grade
back). For each one of the three core veneer joints, 30 specimens
were prepared (3.5 mm thickness x 50 mm width x 200 mm length)
and tested. The longitudinal bending strength was determined,
according to DIN 52371 standards.