Historical records indicate that Chinese merchants used fingerprints as a signature on merchant contracts in the ninth century.  Law enforcement first adopted fingerprinting comparisons in the 1890s for criminal investigations.  The diverse patterns of “friction ridges” on a person’s fingers are said to make them unique to each individual.  Similar biometric techniques can also be successfully applied to wood surfaces to distinguish one piece from another, presenting an opportunity to track lumber for automated lumber processing applications.

Lineal scanning in lumber mills provides some critical technology advantages over transverse methods, with the most significant being the ability to apply more diverse sensor technologies to deal with the challenge of emulating the human brain.  Physics and cost are the two primary factors that limit the use of multiple scanning techniques.  However, the downside of lineal scanning is that boards must eventually transition to a transverse orientation for trimming and sorting.  That material handling requirement can lead to problems when boards get mixed up or removed (broken) before getting singulated and lugged for further processing.  Typical tracking methods utilize inkjet or paint spray systems to mark lumber during the scanning process and then look for those markings once the board gets onto the lug chain.  This introduces a high maintenance mechanical element into the automated process that adds cost and complexity, taking away from the bottom line.  

Alternatively, Lucidyne Technologies’ new “True-Q™” system takes advantage of the unique properties of lumber fiber by using a board’s biometric “fingerprint.”  The company recently received a patent for “boardprint” technology and has installed multiple systems in conjunction with its automated lumber grading system, GradeScan®.   Once boards reach the lug chain, a camera mounted on the lug chain captures a small section of the board face and this is compared with images that were taken earlier when the board went through the GradeScan scanner.  The technique is simplified through the fact that most boards are already in order, and the primary goal is merely to verify that the correct board is in the expected lug space.  When a few boards are upside down, missing, or mixed up, True-Q is able to detect the problem and self-correct by looking at neighboring boards.

Lucidyne expects to use the True-Q technology in the near future at the sawmill edger, gang, and trimmer for sorting out boards that were scrambled in a deep pile deck.  This will allow lineal scanning to be used on green lumber with minimal mill modifications.  This tracking method is used on all its GradeScan systems and is currently in production use in eight mills.

Lucidyne has completed nine GradeScan installations including the True-Q technology for Weyerhaeuser, with systems in British Columbia, Alberta, and North Carolina.  The Grande Prairie, Alberta, installation was started up about 8 months ago and currently operates at speeds up to 2600 ft/min. Next year it will operate at 3600 with bursts to 4000 feet/minute.  This plant processes SPF Dimension lumber and is configured to generate huge volumes of graded lumber and graded trim blocks.  

Carole Kordyban is Quality Control Manager at the Grande Prairie mill and took time out from her busy schedule to comment on the True-Q’s performance.

“We chose the GradeScan system for grading and needed to put something downstream to keep the right grade on the right board. That’s where the True-Q comes in. It’s smart enough to catch any mismatch and find the right board, even if 3 or 4 boards get mixed up. True-Q will notice and put crosslines on the screen to match the boards up. If there’s a major mixup and things get really of queue, True-Q alerts us long before everything ends up in the rejects bin.” There are different options for an alert situation.  True-Q can be set to send a warning to the operator or shut the system down. But that virtually never happens. 

“We’ve found we’re running in queue 99 percent of the time,” says Carole. 

She says it took some adjustments of the system at first to reach that level of reliability, “but the GradeScan people took care of it. We can trust True-Q to do its job now. Our expectations were met.” 

In addition to the peace of mind it provides, GradeScan with True-Q has also reduced manpower requirements on the line. 

“We used to have 9 graders per shift,” Carole notes. “Now there are only 3 and they’re grading for very specific defects that the system doesn’t control.”

Parts of this article were provided by Lucidyne.