Sahatavaran jatkojalostuksen asettamat vaatimukset kuivauslaadulle ja eri tuotteille sopivat kuivausmenetelmät

In sawn timber refining it is important that raw-material has been dried in a way that there are no deformations in a product. This is important in product’s production process as well as in its target of usage. Deformations may cause for instance cracks in wooden plank floor, convexity in edge glued panels or non compatible wooden components in assembly line. In this research we have found out drying quality requirements for raw material in five case studies. With these drying quality requirements it is possible to avoid problems in sawn timber refining and in end use. The wood refining processes were production of wooden windows and doors, electrostatic painting and fingerjointing. The refined products were windows, doors, glulam beams, panels and floorboards. All products and processes had a requirement in common: average moisture content should be as close as possible to equilibrium end moisture content to prevent wood products from deformations and structrural tensions. On the other hand there are optimal wood moisture contents for painting, planing and glueing. In there moisture contents there is a need to compromise to achieve the best results. For instance they need to plane and paint raw material for furniture in a lower moisture content than it would be favourable for the process. Case hardening which results from fast drying causes those not desired deformations like for instance convexity when sanw timber has been split and planed for panels. With moderate drying and seasoning we can reach a desired case hardening level. We did a case hardening survey which tells that they find it difficult to set requirements for case hardening. However, there is a possibility to promote