Log end can show core de­fects

New Zealand Logger - - Woodtech 2017 -

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

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