Band sawlines for maximum yield
22 March 2013
With band saws appearing in the market, woodworking industry experienced a quality breakthrough. Band saw technology allows to significantly decrease share of wastes, getting sawn timber with improved strength parameters, optimizing the cutting pattern.
In 1999 there were only four companies in Russia that supplied band saws to Russia, offering relatively high quality services and performing training of operators. Today number of companies that supply band saw technology has significantly increased, with Heinola Sawmill Machinery being among the leading suppliers of the technology in question.
Having quite a wide product range, HEINOLA has put significant efforts to R&D especially for saw lines.
Advantages of band sawing
Band sawing features a lot of advantages, including minimum of wastes, maximum yield of high quality sawn timber, low operation costs and high flexibility. Meantime band saw lines have high degree of automation and allow processing huge volumes of timber.
Minimum cutting width that is the basis for maximum yield performs the main advantage of band systems, with log diameter having no limits. HEINOLA technologies, including also saw lines are built from module-type machines, but to meet with customers’ demands.
For smaller capacities HEINOLA developed merry-go-round saw line, which includes 3D scanner, chipper canter, quad band saw and edger where logs and cants are returned once or more to sawing unit. For higher capacities there are one pass lines with 2 or more twin or quad band saw units. As a rule band sawlines are equipped with 1-3 edging lines to achieve the best possible yield for boards, but edgers can be replaced with profilers also. Band saw annual capacities start from 50.000 m3 ending up even 1.000.000 m3.
Disadvantages? Being removed!
Disability of band to keep stable position leads to a limited feeding speed, which is the main disadvantage of band saws. With feeding speed reaching a definite limit, the saw starts “wobbling” and sawn timber becomes snaked. So band saw’s most important issue is keeping the blade without vibration, which is achieved by servo control to blade tension and also by robust servo controlled blade guides. HEINOLA uses a patented system for saw vibration attenuation, which ensures high cutting speed and accuracy of sizes.
HEINOLA has developed adjustable upper controls to improve sawing performance of its bandmills. Height adjustment for the controls is done via either a hydraulic or electric servo function. The height adjustment is done automatically on the basis of log data and controlled by a setting automation system. Thanks to the precise height adjustments, sawing speed can be increased by up to 20% and produce better dimensional accuracy. The adjusting carrier on the sturdy round guides can be fitted with bandmills by other manufacturers.
Even better, even more precise
HEINOLA has built machines more robust and also put more servos to machines and feeding conveyors. This has made possible better curve sawing possibilities and better sawing accuracy when having either straight sawing or curve sawing with higher speeds.
When processing big logs like it is common in band saws it is important that machines are robust enough so that logs can be processed on desired way. Chipper canters are equipped with big motors with VFDs so that in each time chip size will be perfect, not depended on speed or season. With electric servos on setting the chipping heads we make sure that we have each time correct place for them and to keep them steady along to process.
Thus, band saw technology is an optimal solution when it is important to get maximum yield. HEINOLA specialists managed to solve the most urgent issues re. band sawing: increasing yield and ensuring cutting accuracy due to more stability and increased feed speed, which makes band saws so familiar to everyone – even more effective.