Client: Various sawmills and plywood mills
Project duration: 6 to 8 weeks
Client: 1 to 2 people
Concept Systems: 1 engineers
Concept Systems’ time on site: 2 days
- Wasted wood due to less than optimal bucking of logs.
- Reduced loss during trimming of logs.
- SICK time-of-flight laser scanners
- ScanMeg photo cells (on Lite version)
- Diameter scanner (on Pro version)
- PC-based control system
A common challenge for any wood products mill is getting the most use and least waste from raw logs. Typically logs arriving at a mill are 35 to 55 feet long.
A sawmill may need to cut into logs that are anywhere from 4 to 20 feet long depending on the market demand or orders it needs to fill.
One big source of waste is trim — how much of the log is left over and is too short to produce a high-value product. Plus, the more fiber that reaches the mill means the operator can improve grade and reduce defects.
LengthScan uses time-of-flight laser scanners to measure the length of a log as it moves down the conveyer.
How it works
The laser can find the location of one end of the log as it moves. At the instant the other end of the log triggers another scanner — either a diameter scanner or a photo-eye, depending on the system — the system can calculate the length of the log plus or minus an inch.
A standard PC receives the data and then, using a table of preferences set up by mill managers, it calculates the most effective way to buck the log into lengths. A best solution is presented to the sawyer, who then cuts the log.
“It’s all about reducing the amount of trim and using more of the log to add more value to your product mix,” said Steve Karter, a Concept Systems’ Account Manager who has worked on a number of LengthScan installations.
Pro and Lite versions
Concept Systems developed a system that integrated various existing technologies — both hardware and software.
LengthScan comes in two basic versions: Pro and Lite. LengthScanPro includes a diameter scanner, so that the diameter can also be used to determine which set of trim rules to use for the solution. LengthScanLite measures only length. Some sawmills are helped by knowing the diameter of the log at the cut point, but for sawmills that run a narrow range of log diameters, factoring in the diameter is not a huge concern at the stage when the log is being bucked.
Short downtime for installation
Installation of a LengthScan system is straightforward. Once it is designed, mill owners typically construct housings to hold the scanners. Most of the installations have been outside, so the lasers need to be protected from the elements and from any possible impacts.
Once the housings are in place, the final installation and testing can happen in a weekend. So downtime due to the upgrade is minimal. After installation, start-up typically happens in parallel with full production.
Across the more than 15 LengthScan systems we have installed, therenwith full production and testing can happen in a weekend. So downtime due to the upgrade is minimalions have been outside, so the lasers need to be protected from the elements and from any possible impacts. the log within ed very few problems.