Causes of Warping of Door Cabinet Made from Oak Fancy Veneer Overlaid Plywood

櫟木化粧單板貼合板製造框形門扇之翹曲原因

彭武財(W. T. Peng)

《林產工業》 15卷3期 (1996/09) Pp. 529-540

摘要

櫟木裝飾單板貼於合板兩面之框形門扇，其大小為11/16＂×21＂×29.5＂，而其中之一面刻有與門扇四緣平行之U型縱溝各一，且合板之四周以厚度1/8＂之櫟木框條膠合。然門扇於刻溝面發生嚴重之內曲，尤其該扇之一角更呈極度之趨曲，其高度甚至達一英吋之多。因此本研究即針對上述情形發生之原因進行探討，其結果如下：1. 此門扇之翹曲主要由於其一面之單板刻溝糟致使其兩面之內應力呈極度之不平衡狀態所致。2. 此門扇之四周以木框條膠合時亦有促使其兩面之內應力呈多少之不平衡狀態。3. 兩裝飾貼面板單板之品質，特性以至於該木理組織均相當均勻及平衡。4. 合板基板之上表層及下表層之單板厚度不甚相稱。此乃由於基板表面砂光時，未作妥善控制之故。此對其內應力亦有多少之不平衡影響。5. 因試驗之門扇已被使用了一年以上，在其使用期間內有可能或多或少受到外界環境（衝擊，溫濕或不當荷重）因子之影響所致。

關鍵字

內應力 ； 表面貼面 ； 表面刻溝 ； 應力不平衡 ； 翹曲問題

並列摘要

A piece of 11/16＂×21＂×29.5＂ 7-ply plywood cabinet door overlayed with red oak (Quercus borealis Michx. f. ) decorative veneers on its two faces, and lightly grooved the U-Shape straight decorative lines with a width of 1/4＂, depth of oak veneer thickness, parallel to (3＂ from) four slanted edges on one of is two faces. Its four edges were also framed with same oak strips (1/8＂ thick) firmly on them. The problem was whole door ＂courving-in＂ badly on the face with no grooving lines, where one of its four corners exceptionally warped-up to nearly a inch of its height. An investigation on the possible cause of its warpage was therefore, carried out. The key findings are: 1. The warpage of complaint door mostly caused by the grooving of lines on its one face where created stress imbalancing on two faces. 2. The framing of oak strips on its four edges also caused to have some degrees of stress imbalancing. 3. There had no faulty overlaying of two decorative veneers since their qualities and properties as well as the wood grain formations were examined to be satisfactorily uniformed and well balanced. 4. The thickness of top and bottom ply veneers on the base plywood was not quite uniform. The improper sanding of the said base plywood therfore, has to be blamed. 5. It must had encountered some exterior stimulations or impacts (got wet or improper subjected a load) since this door had been in use for more than a year.

並列關鍵字

interior stress ； face overlaying ； face grooving ； stress imbalance ； warping problem