This Bachelor of Science thesis was carried out at Metso Panelboard AB, located inSundsvall, Sweden. The work lasted for 10 weeks and began at the end of February 2007.Metso Panelboard is one of the leading suppliers of complete lines, single machines,engineering knowledge and after-market services to the fibreboard industries.The task involved building a 3D-model of a dryer cyclone in the CAD-programPro/ENGINEER. A dryer cyclone is the part where the tree fibres are dried in the process ofmanufacturing fibreboards. Currently, it takes about two weeks to draw a dryer cyclone. Bycreating a 3D-model of it, which should have the functionality to be generated to differentsizes, the goal is to decrease the drawing time to about 20 hours and to increase the quality ofthe work.This report includes the fundamental theories behind the manufacturing of fibreboards withfocus on the dryer cyclone. It also describes how the work was carried out with detaileddesign descriptions of the cyclone’s different parts so engineers at Metso easily can take overwhere this work ended. / Uppsatsnivå: C