Lasers detect knots in green mill

A CANADIAN COMPANY HAS DEVELOPED A new type of wood scanner that uses lasers to detect knots in the green mill so that sawing decisions can be made that will deliver more valuable products when the lumber enters the dry mill to be turned into the final product.

The laser scanner developed by Autolog in the Canadian province of Quebec follows years of research into the properties of knots and how to detect them.

Sylvain Magnan, President of Autolog, told the Wood TECH 2017 conference in Rotorua last month that the system developed by his company uses lasers to detect Tracheids in the wood. These are narrow cells that look like tubes or cavities in the wood, which are used to transport water and mineral salt through the tree.

The new technology, known as the Transverse Tracheid System, consists of projecting a laser dot on the surface of a rough-sawn board and then following the shape of the dots along the Tracheids and analysing the fibre orientation to show the presence of knots. This system produces very highquality images of the knots without the need to use a conventional vision scanning system.

Mr Magnan says the TTS has a very high detection rate, with very low ‘false’ knot detection, and he believes it will provide quick payback for saw mills.

The new TTS laser scanning system has been introduced at a very competitive price and is easy to install on a saw line using the Autolog modular scanner frame. NZL