AbstractThis bachelor thesis has been assigned by the company ACG Nyström, Borås. ACG Nyström is working in cooperation with a Swiss company named Jentschmann AG. Jentschmann is a manufacturer of ultra sonic welding machines which ACG Nyström is marketing in Scandinavia and the Baltic States. On behalf of Jentschmann AG the company has the aim to introduce the ultra sonic welding technique to new companies.The aim of this thesis is to compare traditional sewing machines with ultra sonic welding machines within two textile areas, protective clothing and outdoor living.Two investigative questions have been formulated for this purpose: what are the differences between a sewing machine and an ultra sonic welding machine? Is it possible to replace the sewing technology with ultra sonic welding? These stand as guidance for this paper.To gather knowledge interviews, literature studies, and tests on two different ultra sonic welding machines were performed. Ultra sonic welding is a technique which generates inner friction inside the material when it is exposed to pressure. The inner friction creates heat which melts the material and bonds it together. The bond needs time to stabilize before the product can be used. Not all textile materials have the contingency to bond; in this scenario tape has to be added.Ultra sonic welding machines have the same appearance as traditional sewing machines, even the sewing process is similar. Another similarity is the capacity of the two machines, which is almost identical. The sewing machine technology has one advantage: the experience and research from several centuries. Industrial sewing machines usually have the ability to perform only one task whereas an ultra sonic welding machine can perform more than one operation.One reason why ultra sonic welding machines are being used within different textile areas is the water and UV-resistance of the bond (depending on choice of material). When compared, an ultra sonic welding bond is preferable. The bond has a cleaner and daintier appearance from a designing point of view. Our research in this thesis shows that most sewing processes on the chosen products have the ability to be replaced with ultra sonic welding. / Uppsatsnivå: C