Log end can show core defects
A SIMPLE AND LOW-COST WAY OF detecting the inside properties of lumber prior to cutting decisions being made could help saw mills in New Zealand get “more bangs” for their investment bucks.
In the future, mills could use a pair of low-tech vision scanners to check the ends of the log in order to identify the position of core wood prior to making the first cut, the WoodTech 2017 conference in Rotorua heard last month.
Scanning the ends of the log to predict the location of the core wood may be a viable alternative to current surface scanning methods, or could be the precursor to investing in higher and more accurate technology further down the track, according to Carl Thomas, International Sales Manager with saw mill machinery manufacturer USNR of Canada.
He joined Jonathan McLachlan, Sales Manager for New-Zealand-based Skookum Technology, on stage at the conference to deliver a presentation on the latest advances in vision scanning.
Vision scanning the cut surface of cants is already undertaken by a number of mills as a way to identify a variety of defects in the wood before the final cutting decisions are made. It’s used to search for knots, splits, crook, twist, bow, wane, blue stain, sap stain and a whole lot more.
Being able to identify the location of the core wood can help with making the final cut decisions on what boards to cut from a log in order to obtain higher value.
Mr Thomas told the conference that a case study carried out at a medium-size saw mill in the US showed that it was able to increase the value from its wood by 2.7% using surface vision scanning, equating to US$330,000 in additional earnings.
Using surface vision scanning to detect the location of core wood, another mill was able to make better cut decisions on 24% of the cants running on its line.
USNR researchers then looked at whether using vision scanners to check the ends of a log, rather than the surface, could provide the same information to determine the pith/ core zone size and location.
Early results are promising, says Mr Thomas. Whilst he acknowledges that end scanning would not be of much value to mills who already undertake surface scanning, for those who do not scan the surfaces, it could be very useful.
“We are still at the early development stages on this, but it is very exciting because it looks like it will deliver more bangs,” he says.
“If you already have a lesser log optimiser, all you would have to do is put a couple of end scanners and some computer software and for a fairly low capital investment you could probably get a pretty good return.” NZL