Design and development of a new invented doctor blade: Design och utveckling av nyuppfunnet kräppningsblad
Independent thesis Advanced level (degree of Master (One Year)), 20 credits / 30 HE creditsStudent thesis
This report contains the development and construction of a new patented doctor blade. A doctor blade is used when creping soft paper from a large rotating Yankee cylinder. At the current state the doctor blade are in use for four to six hours before it needs to be switch due to wearing, stopping the production of soft paper. The new idea is to have a very long and small blade that will slide into a fixed blade and be continuously pulled when creping paper. The company CS Production had a concept of the fixed blade but wanted to further develop it since the blade was too wide.
Measurements where done with the old blade and with the old testing device to measure the pull force required to pull the blade. New concepts where made by the method of brainstorming and evaluated with an elimination matrix. Rivet joints where selected as the joining technique for the new design. The new concept contains one dominant blade that smaller parts were assembled to form the final blade. The material selected for the dominant blade and the section blade was a cold rolled stainless spring steel strip and for the middle disc the material was aluminum bronze string casted. Test on the pull force required where done with the new doctor blade in the new test rig. FEM simulation where done on a small part of the blade to see where stresses are occurring in the blade. The FEM result showed that no stresses where on the middle discs, rivets or section blades. This is not reliable results because the small doctor blade is pushing down onto the middle discs and stresses should be occurring on the discs. Further testing is needed to see if the blade can withstand the forces applied to it.
Place, publisher, year, edition, pages
2014. , 40 p.
Doctor blade, Design, Development
Mechanical Engineering Materials Engineering
IdentifiersURN: urn:nbn:se:kau:diva-33183OAI: oai:DiVA.org:kau-33183DiVA: diva2:732794
Subject / course
Engineering: Mechanical Engineering, spec. in Materials Engineering (300 ECTS credits)
Thuvander, Fredrik, Professor
Bergström, Jens, Professor