A new ScanMeg scanner, installed by Automation Electronics, fits both the checklist and the wish list of the Rosvall Sawmill in New Zealand. 

You can’t always get what you want, says the song, but you can get what you need. How great, then, when you get both. 

That’s the case with the new ScanMeg Full Profile Carriage Scanner installation at the Rosvall Sawmill in Whangarei, New Zealand. Installed by Automation Electronics (A&E), based in Mt. Maunganui, New Zealand, the scanner is the newest upgrade and the sensor portion of A&E’s millwide LogView™ system.

The Rosvall mill had a scanner on its wish list for some time. Mark Hanson, the mill’s managing director, an innovative individual with a good understanding of technology and how it can be applied in the mill, had looked at some scanner options but, so far, the combination of price, exchange rate, and potential results didn’t add up to being cost-effective. 

A&E had been improving and modernizing the Rosvall mill for some years and were also looking for a solution. Then, at a trade show, Brian Smith from A&E met Benoit Carpentier from ScanMeg, a Quebec-based scanning technology developer. With a “We can do this for you” from Carpentier, the project was on its way. 

The Rosvall sawmill is a carriage-edger-resaw configurated softwood sawmill, with a bin sorter and a wood out stacker on the outfeed. The mill cuts radiata pine and typically handles logs that are up to about 800 mm (31.5 in.) diameter by about 6.1 m (20 ft.) maximum length. The log carriage where the new scanning system is installed is a three knee carriage with a slabber in front of the band saw. However, it presented a particular installation challenge. 

Brian Smith explains: “One of the difficulties is that the chipper head on the slabber is very closely coupled to the loading point where the log loads onto the carriage. This means you’ve got very little time to come up with a solution as you set the log into position. We’ve got to have a solution in about half a second and a set done in the same amount of time.” 

“With the ScanMeg scanner, because we have laser profiles every 5 inches, we’re able to get a good snapshot of the log and then we can update that profile as we move the log towards the slabber, which is only 115 mm away (about 2 feet) from the front end of the log.” 

Dave Lindsay, chief engineer at Rosvall, says that what the mill is trying to achieve with the new ScanMeg technology is a minimum opening face on each log. “On the first opening cut when we slab the first part of the log, we need to have a minimum,” he explains. “If it’s too small it’s not very sellable wood, but if it’s too big we have waste material.”

The mill also wanted flexibility, says Lindsay, and the new scanner provides it. “If we’re cutting one of our export logs, a pruned butt where all the outside is free of defects, we can go down to about a 100 mm (4 inch) opening face. But if the log has more knots and the opening face has to be bigger, we can adjust the system to do that. We’ve got a lot of variability and a lot of fixability in what we can achieve. We can specify the width and the minimum length as well.”

In addition, it’s all done completely electronically. Before, says Lindsay, “We used to have one single laser line running down the length of the log but if you’ve got a little sweep or a taper in the log it was a bit hard to get it right. We see huge increases in recovery rates now and a more uniform product  - less odd sizes coming off the headrig. We see huge positives in this.”

“The system takes the decision making off the operators,” explains Smith. “It’s also fairly simple for operators to use because everything is at their fingertips visually. The operators need to understand the technology, how it applies and how it works, but they’ve been very fast on the uptake and kind of fallen in love with the system. This is great news because getting the buy-in from the operators is sometimes the most difficult thing with new technology.”