Dry Mill Grading for Shop Products


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The desire to automate the grading process to improve recovery for its Shop products, and the scarcity of qualified graders led Neiman Enterprises to invest in USNR’s Transverse High Grader (THG) for its operation at Devils Tower Forest Products, Hulett, Wyoming. With USNR’s experience grading for Shop and Moulding in the green mill, the company was confident the THG could do the same for its dry mill Shop products.

Devils Tower, founded in 1958, is one of 4 wood processing operations now owned by Neiman Enterprises. Its sister mills include Rushmore Forest Products in Hill City, SD (added in 1998); Spearfish Forest Products and Spearfish Pellet in Spearfish, SD (2008); and Montrose Forest Products in Montrose, CO (2012). Neiman Enterprises is a fourth-generation family business that began with its first mill in 1936. Today the company is a leading inland producer of Black Hills pine boards and pattern stock.

Grade Projectors are mounted on a frame above the outfeed of the THG. The system projects information onto the surface of the boards, and tracks that projection with the board as it passes by a check grader.

Devils Tower Forest Products operates a sawmill and planer mill, producing high quality 5/4 and 6/4 products, 1×4, 1×6, 1×8, 1×10, and 1×12 lumber, and shavings that are mostly marketed domestically. Annual production is in the range of 40 mmbf, and the operation employs 85 people.

For Shop products, the clear cuttings are projected as solid rectangles. Projected symbols are customizable so customers can create symbols their facility is used to using.

Tom Shaffer is general manager for Neiman Enterprises. He explained the reasoning behind the move to an automated grading system at Devils Tower. “We couldn’t get people interested in wanting to learn how to grade. With all the heavy Shop material, it was taking a toll on our aging graders. We felt we would get better grading accuracy and trim decisions with an automated system, and we could redeploy our team.” The mill was running 3 graders on the line and continually needed to train more graders for back up, so automating the grading process made good sense.

Shop products are a significant part of the mill’s output, with about 40% designated Shop products and the balance is 1″ Board products. Grading for Shop was a major requirement for any system the mill chose. Tom said that he had confidence in the THG technology, especially with USNR’s experience using the same technology on Shop and Moulding products in the sawmill. “You’re doing that in the green end – ripping and splitting for grade. We were comfortable USNR would make it work for us in our planer mill.” He also noted that the company employs USNR equipment throughout its 4 mills and is familiar with the level of service and support they could expect.

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Offset pairs of belts transport boards through the scan frame, and with staggered pairs of sensors mounted below the flow the system scans all four surfaces of each board. This new “occlusionless” transport and scanning configuration leaves no data gaps, ensuring that no defects get missed.
Unique Application, New Developments

The system at Devils Tower is required to grade differently than typical because of the product mix, which demanded additional development work to meet all the criteria. With USNR’s Deep Learning technology employed, the system readily recognizes defects including knots, rot, pitch, pitch streaks, pitch pockets, bark pockets, bird’s eye, pith, and blue stain.

Another significant aspect of this application is the use of a second set of belts to transport the boards through the scan frame, for occlusionless scanning. Combined with off-set sensors mounted below the flow, all 4 surfaces of the board are completely scanned with no obstructions. Shop grading is focused on finding sections of clear wood, so it was critical to obtain complete data from all surfaces. This new belt and scanning configuration allows the entire bottom surfaces to be exposed for scanning and data collection.

Just downstream from the scanner, the Grade Projector displays all grade decisions onto the boards for Shop as well as Board products.

6/4 3-Shop solution showing 2 No. 1 Sash cuttings, and a Jamb (top and bottom scans of the same board).
The number in brackets shows the scale size of the lumber.
6/4 Moulding solution showing, and a 1’ Scale off due to excessive wane (wane is shaded on the surfaces).
The number in brackets shows the scale size of the lumber.
Recovery is up!

Now that the system has been running for several months, mill management is satisfied with its performance. Ron Bears, Dry End Supervisor, said, “It’s doing a great job on the Shop. The raw material for the 1″ Board products changes week to week, so as the appearance of our boards changes we see things we didn’t see before. That requires some adjustment. The Shop products have a more consistent look, so we don’t have to single out varying characteristics on those products.”

Ron described how they’ve redeployed the graders. “We’ve moved our head grader into quality control. As a certified grader he operates and maintains the grading system and adjusts grade parameters as needed. He also does pack checks to ensure the system is performing to meet grade criteria to agency requirements. Then we have two newer grading staff who handle pre-grading ahead of the machine to spot a couple of machine defects like roller check.”

When asked about results, Tom said, “I don’t know our exact numbers but I do know our grade recoveries are up, and on some widths it is significant.” Ron added that he thought grade recovery was up in the range of more than 10%, depending on the product.

In addition to improvement in recovery, Ron said that it has allowed the mill to run faster. “We were wearing down the graders at production speeds. Now we are able to run faster. We are processing more lumber through the system in less time, and with greater recovery.”

Ron was involved with the project on a daily basis and remarked that it went smoothly. “The installation and start-up took about 3 weeks. The biggest challenge was training for Mike Bears (Ron’s brother) who is the head grader. He had to learn to operate and maintain the grading machine and its bank of computers and learn to set it up to grade both Shop and Board products.”

Training for Mike Bears and other mill personnel took place at USNR’s Salmon Arm, BC training facility with a hands-on 3-day course. Then onsite training was done once the system was installed, for in-depth knowledge on system setup, adjusting parameters for the variety of products, day to day operation and maintenance, troubleshooting, etc.

Shifting Mindset

Going from a manual to an automated grading process requires a shift in mindset from performing a familiar, though arduous task with well-known criteria, to letting a machine perform the same function at a high rate of speed. It requires trust that the system is recognizing every minute detail about each board’s characteristics, and then classifying it accurately. Results are offsetting any prior misgivings.

With this new investment paying off in more ways than one, Tom says, “We’re not bottlenecked, we’re balanced almost perfectly.” And with 4 mills under the Neiman umbrella, there are always new challenges to tackle somewhere else.