36 n LINEAR MOTION May 2026 www.drivesncontrols.com Achieving cuttingedge performance in sawmills Trees are among the largest and heaviest items that have to be handled in any industrial production operation. Sawmill systems also have to cope with debris and dust, requiring a careful balancing of load handling and speed control. Sawmill profitability depends on cutting the maximum number of usable planks from each tree trunk and getting them to market at a competitive cost. A single log can weigh more than 10 tonnes and without adequate guidance, there is a high risk of uneven or otherwise compromised cutting. The speed of the cut is also critical. Designers of sawmill motion systems need to ensure that the logs move at a speed that allows the saw to cut them efficiently. Having a saw sit idle, waiting for a log to arrive, can lead to costly production bottlenecks. In addition to moving heavy logs at high speeds through multiple stages – for example, cutting, polishing and coating – the motion designer is also responsible for protecting the process from the dust and debris that emerges from the cutting process. This can penetrate automation components or stall operations in other ways, threatening quality and throughput. While load handling, speed and debris resistance are the top criteria when selecting motion equipment for woodworking, the cost of installation and maintenance can also affect operating costs and plant profitability. Linear motion systems can help designers to address all of these considerations. Linear motion systems used in sawmills typically include floor-mounted linear guides that provide the track along which a loadcarrying nut carriage rides, with roller bearings travelling between the guide rail and carriage to reduce friction. Linear guidance rail options for woodworking applications include round and profile (square) rails. Both types have adequate load- and speed-handling capabilities, but the high rigidity of profile rails makes them more appropriate for precision cutting applications, while round rail stands out for its lower cost, easier installation and superior performance in contaminated environments. Bearings options include roller and ball bearings. Roller bearings are better equipped to handle heavy loads at high speeds because they have a bigger surface contact with the rail, higher rigidity, and are more resistant to shock and vibration. Roller bearings with concave rollers offer improved load-handling capabilities because they hug the shaft more efficiently than flat rollers. The simpler design and larger component sizes of roller bearings make them less susceptible to debris and dust. When linked with chains, rollers’ environmental resistance is even more pronounced. Unlike the smaller, more complex ball assemblies, there are no interstitial spaces that can trap debris and jam the system, and no hidden spaces that can collect dust and debris. Using circulating ball bearings in a woodworking application, on the other hand, may require the addition of scrapers, seals, blowers or other protective equipment. Table 1 compares component configuration options for woodworking applications, including round rails with concave rollers or ball bearings, and profile rails using flat rollers or ball bearings. Round rails with concave rollers best meet the needs of the woodworking industry. The ruggedness of the round rail, the ability of the Sawmills place heavy demands on their equipment, not least because of the large amounts of dust and debris that they produce. As Charles Isaac, global manager of linear bearings and guides at Thomson Industries, explains, choosing the most suitable components for guidance systems can enhance a mill’s quality, throughput and profitability. This linear bearing uses concave rollers and has up to 20 times the load capacity of conventional linear ball bearings. It can carry logs at speeds of up to 30m/s.
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