Holz als Roh- und Werkstoff

, Volume 65, Issue 1, pp 43–48 | Cite as

Relationship between lumber yield and board marker accuracy in rip-first rough mills

  • Urs BuehlmannEmail author
  • R. Edward Thomas


Lumber used for the production of wood products such as furniture, kitchen cabinets and interior elements, contains unacceptable character marks such as holes, rot, knots, etc. Today, the majority of the wood processing industry uses humans to identify such unusable areas and to mark them with fluorescent crayons. Automated saws scan for these marks and computers optimize the available clear areas and activate automated chop saws to make the cuts. However, if these fluorescent marks delineating the character are not made accurately (i.e., too far away or inside the characteristic), yield suffers. An earlier study found that yield losses incurred due to inaccurate marking are above 15 percent absolute lumber yield. However, no data was available regarding the influence of improved marker accuracy on yield.

Large yield improvements can be achieved if marker accuracy is improved only marginally. In fact, if marker accuracy was improved by 25 percent, the yield of usable parts increased by 5.3 percent. Since an average-sized rough mill typically saves several hundred thousands of dollars for each one percent yield increase, the potential cost savings from improved human marking accuracy are significant.


Error Reduction Partial Type Normal Error Rate Primary Part Usable Yield 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Einfluss der Markierungsgenauigkeit von Holzfehlern durch Holzsortierer auf die Ausbeute von Hartholz


Störende Holzfehler werden beim Holzzuschnitt in der Möbelindustrie manuell mit maschinenlesbaren Kreiden markiert und danach von automatischen Kappsägen herausgeschnitten. Verluste in der Holzausbeute entstehen, wenn die Markierungen zu weit ausserhalb oder innerhalb des Fehlerbereichs erfolgen. In einer ersten Studie wurde festgestellt, dass diese Verluste die Holzausbeute um mehr als 15 Prozent reduzieren können. Nicht aufgezeigt wurde jedoch, um wie viel die Ausbeute bei genauerer Markierung der Holzfehler verbessert werden könnte.

Die vorliegende Studie zeigt, dass bereits durch geringe Verbesserungen in der Markierungsgenauigkeit grössere Ausbeutegewinne möglich sind. Wird die Markierungsgenauigkeit um 25 Prozent erhöht, kann mit einer Zunahme der Holzausbeute um mehr als 5 Prozent gerechnet werden. Da beim Holzzuschnitt eine Zunahme der Holzausbeute um ein Prozent mehrere Hunderttausend Dollar sparen kann, ist das Kosteneinsparungspotential einer genaueren Markierung enorm.


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Copyright information

© Springer-Verlag 2006

Authors and Affiliations

  1. 1.Enkeboll DesignsCarsonUSA
  2. 2.Northeastern Research StationUSDA Forest ServicePrincetonUSA

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