Planing wood with twist
2015 (English)Doctoral thesis, comprehensive summary (Other academic)
About half the total volume of sawlogs end up as sawn timber. The rest is lostdue to drying shrinkage or is turned into byproducts like wood chips, sawdustand shavings. As the raw material is a large expense for a sawmill, it is important to fully utilize the logs. The inherent properties of timber are such that warp, such as bow, cup, spring and twist, is inevitable, and extensive knowledge of whether and to what extent warp will appear is therefore important for managing the production. It is also important to develop strategies to handle warped timber, for example in the planing process.This thesis focuses on how twisted timber is affected by the planing process with regard to twist reduction, cross-sectional shape, planer misses and cutting depth. This was studied in three practical tests on sawn timber with differentapproaches. In one test, sawn pine timber with a large variation of twist withinthe group was planed with standard settings, and five evenly spaced crosssections along the length of the sawn timber were subjected to more detailed studies. In the second test, the main yield from spruce logs was planed. One sample board from each log was planed with the normal pressure settings of the planing mill, while the second sample was planed with a pressure either higher or lower than the normal settings. In this study, seven cross-sections were studied in more detail, three close to the top end, three close to the butt end, and one in the middle of the sawn timber. In the third test, sawn pine timber with a more moderate twist was planed with standard settings in another similar planer.
Place, publisher, year, edition, pages
Luleå tekniska universitet, 2015.
Doctoral thesis / Luleå University of Technology 1 jan 1997 → …, ISSN 1402-1544
Other Mechanical Engineering
Research subject Wood Technology
IdentifiersURN: urn:nbn:se:ltu:diva-17495Local ID: 3a27099a-9279-4abc-9f0a-bed57094eec2ISBN: 978-91-7583-326-2 (print)ISBN: 978-91-7583-327-9 (electronic)OAI: oai:DiVA.org:ltu-17495DiVA: diva2:990500
Godkänd; 2015; 20150408 (annaxe); Nedanstående person kommer att disputera för avläggande av teknologie doktorsexamen. Namn: Ann Axelsson Ämne: Träteknik/Wood Technology Avhandling: Planing Wood with Twist Opponent: Professor Kazimierz Antoni Orlowski, Section of Machine Tools and Machining, Gdansk University of Technology, Gdansk, Poland. Ordförande: Professor Mats Ekevad, Avd för träteknik, Institutionen för teknikvetenskap och matematik Luleå tekniska universitet, Skellefteå. Tid: Tisdag 2 juni 2015 kl 10.00 Plats: Hörsal A Skellefteå, Luleå tekniska universitet2016-09-292016-09-29Bibliographically approved