Vision System Helps Speed Production, Maximize Efficiency at Pleasant River Lumber
A family-owned Maine business with four generations of experience in the forest products industry, Pleasant River Lumber produces more than 100 million board feet of spruce dimensional lumber and eastern white pine annually from its three mills in Dover-Foxcroft, Hancock, and Enfield, ME. Pleasant River Lumber’s reputation has evolved from its commitment to producing the highest quality product on the market. To that end, the company prints an image of the American flag and the grader’s name on all the lumber it produces.
The market for lumber is in a constant state of flux based on factors like the time of year and current customer demand, and mills such as Pleasant River Lumber need to be highly efficient to stay competitive. This efficiency needs to begin almost immediately after a tree is cut.
In Pleasant River Lumber’s original approach to lumber processing, tree-length logs—up to 64-feet long, the most economical for a mill to purchase—were delivered to the mill yard, where five manual slashers, or large circular saws, cut the logs into 16-foot lengths, usually leaving a short piece as waste.
“Since the entire process was done manually on multiple logs at the same time, there was no optimization of the material or of the time and effort required to process it,” says Christopher Brochu, one of the six partners who operate Pleasant River Lumber. “A human being made a decision as to where to cut each log, and it was impossible to determine accurately how to cut the log to get the greatest value from the material.” In addition, operating the slashers themselves was expensive in terms of fuel and labor costs, and the company lost money on the waste material, which often had to be trucked away from the site.
Getting an Optimum Look
When Pleasant River Lumber purchased its Dover-Foxcroft, mill in 2004, the partners committed to a $12 million investment to modernize the facility, including the part that processed tree-length logs for milling. Recognizing the benefit of leveraging technology for improved productivity and efficiency, the partners turned to Maine-based Progress Engineering, which specializes in designing and implementing innovative process automation solutions and has an impressive resume in the forest products industry. Progress Engineering designed a unique, hybrid system using best-in-class solutions from a number of vendors, which would allow Pleasant River Lumber to increase efficiency by getting the greatest amount of fiber possible out of each tree-length log.
As Dana Hodgkin, the president of Progress Engineering, explains, the new process begins in the mill yard where each individual log is evaluated using a Teledyne DALSAvision system that captures images of the log. “The complete Teledyne DALSA vision system is made up of six ceiling-mounted Genie 1600 color cameras, which work in tandem to take images of each log,” Hodgkin says. “These images are ‘stitched together’ by Teledyne DALSA’s GEVA Vision Appliance and Sherlock software, which calculates the length and diameter of each log, with accuracy to within an inch. That data is then seamlessly communicated via Ethernet with a PLCoptimization system developed by Progress Engineering.”
Progress Engineering’s original design used a camera from a different manufacturer, and Hodgkin notes that there were problems with this design from the start. “The first camera we considered didn’t have the versatility of the Teledyne DALSA solution. That particular product didn’t offer a way to capture a clear view of an entire log, which was critical to getting the accurate measurements that ensured the rest of the system operated as required. There were also challenges with the other camera’s ability to operate in a rugged mill environment,” he says. “When our first design failed, we researched alternatives and found an ideal solution in the Teledyne DALSA vision system.”
Since the competitive solution had challenges operating effectively in an environment where conditions—particularly lighting—changed frequently, ensuring that the Teledyne DALSA vision system could work under these conditions was a key factor in choosing the solution. One wall of the facility is open to the elements, which means that lighting, temperature, and even wind can vary from hour to hour. The Teledyne DALSA vision system offers automatic ambient light detection and can change the exposure time quickly to provide the right level of contrast between the log and the background for each image.
“We installed LED lighting overhead for greater consistency, and the Teledyne DALSA vision system adapts perfectly to the changing conditions of this environment,” Hodgkin says. “We have also benefited greatly during and since implementation from the expertise of the Teledyne DALSA team; I don’t believe they’ve ever supported their solutions in an implementation like this one, and they have absolutely met the challenge.”
Once the PLC system receives the data about the length and diameter of each log, it integrates with a new “bucking system”—equipment including log singulators and saws— that form the majority of the new production system. Manufactured by Endurance Equipment, this part of the system analyzes the data from the Teledyne DALSA vision system, determines the optimum location for each cut, and then cuts each tree-length log in a process that is fully automated.
“Investing in this new system was critical for Pleasant River Lumber to become more efficient, and to be highly efficient, we need to get the most usable material possible from each log,” Christopher Brochu says. “Raw material accounts for 70% of our total cost, so the more lumber each log generates, the more competitive we can be. With Teledyne DALSA’s vision system, we can now start the production process with precise measurements of each log.”
The Benefit of the Right View
Since the new system was implemented, the change has been so significant that Pleasant River Lumber’s partners see few similarities between the new production process and the previous approach. In particular, they note that the Teledyne DALSA vision system has helped them meet several of their key objectives, beginning with determining the accurate length and diameter of each tree. “The Teledyne DALSA cameras give us the critical starting measurement, which enables the rest of the system to calculate exactly how a log should be cut,” says Pleasant River partner Jason Brochu. “Getting an accurate length and width measurement is vital because the saws on the new system are accurate to a quarter of an inch, but this is irrelevant if our initial measurements aren’t right.”
Another of the company’s key objectives was to speed processing time, and the Teledyne DALSA vision system has helped them achieve this objective as well. “Our production capacity is so much greater today. The Teledyne DALSA vision system is able to calculate the measurements of each tree-length log in about seven seconds, or evaluate about nine logs per minute. This is nearly 10 times faster—and far more accurate—than our previous process,” Jason Brochu adds. “While this is a highly automated process, an operator is still involved for the brief second required to assure that the decision the system makes is accurate. There is an override capability if needed, if a log has a significant defect, for example, but since implementation, we’ve found that the system is accurate more than 95% t of the time.”
It wasn’t a stated objective of the project, but Pleasant River Lumber is committed to ensuring the health and sustainability of Maine’s forests, and the new system supports this mission by virtually eliminating waste. “All lumber processing is now done at a central location, so we can capture everything from the small pieces that can’t be used in production lumber to the sawdust and bark,” Christopher Brochu notes. “Then we can sell it all at a profit to get value for every byproduct of the system. We now have a zero-waste operation, which aligns with our environmental goals, and gives us a new revenue stream.”
Seeing a Competitive Advantage
Lumber is a “commodity” so the product itself has little to differentiate it from competitive solutions. Pleasant River Lumber’s new automated system gives the company competitive differentiation in the marketplace, however, in that the dimensions of the lumber produced can be changed quickly to meet market conditions. For example, if certain lengths and dimensions are in greater demand—and so are selling at a better price—Pleasant River Lumber can cut its logs accordingly, meeting the demand sooner. “Our new production system has made us more efficient, more productive, and more nimble,” says Jason Brochu. “Because we can work quickly and accurately, we have the flexibility needed to change the lengths as often as we need to to adjust to the current market. With our old system, changing the length of the logs we cut was virtually impossible.”