Wood Matters

If resinous wood is used in exterior products (such as barge boards shown in picture 1 below) the resin can bleed out of the surface (see picture 2 below) within a summer and can continue bleeding for many years. When the board is re-machined the resinous wood in individual shooks is exposed (see picture 3). Normally manual graders would reliably remove this reject material during manufacture. However in this case numerous sections slipped through. Since one short shook can ruin a 5m long section of otherwise clearwood a low percentage of resinous material can have a significant effect.

Picture 1: Barge Boards with Resin Bleed

Picture 2: Close up of resin bleeding -note 2 shooks with finger joint

Picture 3: Close up of machined surface – resinous shook on left

Solid Wood Innovation (SWI) has worked on an automated detection system to reject resinous shooks before they are used in the final product. Picture 4 below illustrates the technology. Red sections are those predicted as being prone to bleed in final product. These pieces can then be diverted out of the production line automatically to give consistent and reliable grading. This improves product performance and reduces waste meaning more value is recovered from the wood to market supply chain.

Picture 4: Automated computer identification of resinous material

Progress made during the development of this technology is also being translated to scanning of the opening face of a cant (the sawmill's first cut of a log) to determine the appearance grade quality of the log. This information can be used to optimise the sawing of that log – but more on that topic another time.

Note: The supplier willingly replaced the affected barge boards.