Poka-yoke design of rubber rail for holding and transversal sealing of packages

Abstract: This report is the result of a bachelor thesis project conducted as the final part of the education in Innovation technique and Design at Karlstad University. The project itself was carried out at Tetra Pak, Lund and consisted of re-designing a component used in packaging machines, with the purpose of making it fool proof in terms of assembly. The mis mounting of this component could lead to inferior sealing quality in packages produced and in worst case leakage and spoiled content. The issue of the mis mounting has been raised by several customers and Tetra Pak is looking for a solution to improve the mounting.   The methods used in this project are common in product development, such as the use of a design specification, generating solutions by various brainstorming methods and evaluating these concepts by different forms of matrices. In addition to common product development methods, other suiting methods such as CAT (Consensual assessment technique) has been used and theory in Poka-yoke solutions as well as Cognitive ergonomics has been studied. In the pre-studies, a rather wide study of different sources has been made to gather information on this technically advanced target component and converged them all by the principles of data triangulation. By involving user centred design theory, the entire methodology also extends to using the view of the users in all steps along the way. The resulting solution has been filed as a report of invention by Tetra Pak along with two other concepts which were deemed valuable for the company by the supervisor at Tetra Pak. This proposed concept is not only physically impossible to misplace, it also displays by colour marking how it is to be placed and reminds the assembler of the process by nearby instructions. The resulting CAD model shows this solution as technically fit for the machinery and a simple mock-up of the physical function of the solution shows how it would be impossible to mount incorrectly. The project resulted in 39 different concepts of various function, documented in an idea archive. This project has developed a proposed Poke-yoke solution which matches the product specification set by the company as well as two other solutions deemed of value by the company in terms of future use. The proposed use of the main solution shows potential in solving the issue at a reasonable expected cost while theoretically improving user cognition. The solution also requires very little physical change in the component and surrounding machinery, thus giving it great potential for retrofit ability.