Interest in tracking saw deviation has continued to grow in the forest products industry as limited resources, expensive stumpage, and keen competition have driven mills to look for ways to increase yield and bring more dollars to the bottom line. Tracking devices or detectors can sense when a saw is deviating from the set tolerances and warn the operator, who in turn can slow the feed speed to avoid miscutting lumber. It's a simple concept, but the benefits of such monitors can be quite substantial.
There are plenty of problems that can cause a saw to deviate and a number of variables have to be evaluated before pinpointing the cause of mis-cut lumber once the monitor indicates a problem. There could be a problem in the initial setup of the mill or the sharpness of the saw itself, but generally it's caused by wood characteristics and varying densities of the wood being cut. Saw deviation detectors provide real-time feedback of the exact position of the blade relative to the expected position. Any deflection of the blade, whether it's caused by excessive feed speed, knots, frozen lumber, dull or damaged blade, trash between the blade and guide block, or simple guide wear will instantly be detected by the monitor allowing the operator to correct the situation before the lumber is mis-cut or the saw is damaged.
Equally important, by monitoring the blade position and ruling out blade deviation as the source of mis-cut lumber, it becomes much easier to effectively zero in on other issues such as track misalignment or head blocks out of adjustment that might be causing production problems. All deviation detectors include a sensor that is placed next to the bandsaw guide. These sensors actually "feel" where the saw is running the cut. The advantage of real-time information is largely what makes the increased production possible. With real-time look at what the blade is doing, operators can actually see right away if they've cut irregular lumber, versus finding out when they measure the lumber later on.