The effect of controlling the drying distortion of laminas on the production yield of cross-laminated timber (CLT) using Larix kaempferi wood

摘要

The objective of this study was to evaluate the effect of lamina distortion control on the production yield of cross-laminated timber (CLT) using domestic larch (Larix kaempferi) wood. The measured production yield of CLT was 27 %. The yields based on log volume of sawing, planing, cross-cutting, and finish planing of CLT were 49, 66, 96, and 86 %, respectively. The yield of sawing and planing can be improved by controlling distortion during drying. Using an experimental enforced-loading apparatus, the cup and twist of laminas were reduced by 50 and 90 %, respectively. To analyze the effect of a reduction in sawing dimensions on the final production yield of CLT, an analysis of a geometrically applied sawing pattern of logs was used to predict the sawing yield and the number of laminas after sawing. The geometrical analysis showed that a change in the sawing dimensions affected the production yield of CLT. If the width and thickness of the sawing dimensions can be reduced by 5 mm by decreasing the distortion of lamina during drying, the sawing yield was unchanged (49 %), but it was expected that the number of laminas after sawing would increase from 278 to 303. It was also predicted that the production yield of CLT would increase from 27 to 32 %.