A sawmill simulation study of the volume yield changes when sawing with thinner kerfs

• Using thinner sawblades in sawmills has a potential for both increasing volume yield and decreasing energy usage in the sawing process; possible secondary effects of this are reduced outtake from forests or at least a better use of what is harvested, lower greenhouse gas emissions and higher productivity. How much the sawing kerf can be reduced depends on several factors, such as maintaining the stability of the sawblade, feeding accuracy and so on. This study deals with the possible volume yield increases when reducing the sawing kerf, based on different possible scenarios of which some are more realistic to achieve in the near future than others. The study is based on simulated sawing of 1464 Scots pine (Pinus sylvestris L.) and Norway spruce (Picea abies (L.) H. Karst.) logs. Tests were made for both circular sawblades as well as for band saws, deployed in a cant sawing process with a primary and a secondary saw. Both variable sawing patterns as well as fixed sawing patterns was investigated. In the first case, the choice of sawing pattern was optimized based on volume yield, while in the latter case, logs were presorted on top diameter into log classes that were each assigned a specific sawing pattern. The results show an increased yield of about 1.3 to 1.5 percent units per mm reduced sawblade thickness, and a maximum theoretical yield of 57-59 % for a 0 mm saw kerf. The latter is of course not possible to achieve in practice, but it hints at the maximum potential of reducing the sawblade thickness. In the near future, it is expected that a kerf reduction of around 1 mm is possible. This would thus result in a possible yield increase of 1.3-1.5 percent units, with further increases depending on improvements in sawblade design, sawblade stabilization, improved materials, and machines that are more accurate. Possible future studies include quantification of secondary effects from the yield increase; effects that can help mitigate deforestation and climate change, with a retained level of production volumes.

Ämnesord

TEKNIK OCH TEKNOLOGIER  -- Maskinteknik -- Annan maskinteknik (hsv//swe)

ENGINEERING AND TECHNOLOGY  -- Mechanical Engineering -- Other Mechanical Engineering (hsv//eng)

Nyckelord

Computer simulation

Picea abies

Pinus sylvestris

Sawing kerf

Sawing yield

Thinner sawblades

Träteknik

Wood Science and Engineering

Publikations- och innehållstyp

ref (ämneskategori)

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