Sheet trimming is an important forming operation in stamping industry. However, trimming of automotive magnesium sheet materials is not well understood. The objective of present study was to investigate the trimming behavior of AZ31 and ZEK100 automotive magnesium sheet materials using a laboratory-based experimental set-up and complementary finite element (FE) simulations of the lab-based experiments. The effects of the trimming process parameters that included tool setup configuration, punch speed, clearance, sheet thickness and sheet orientation (rolling and transverse directions) on the quality of trimmed edge were analyzed. Experimental results indicated that the trimmed edge quality depended strongly on the trimming conditions. The optimal trimming parameters for AZ31 and ZEK100 sheets were experimentally obtained. Interrupted trimming experiments were conducted to examine crack initiation and development, the mechanism of fracture, and the generation of the fracture profile of the trimmed edges. The R-value as a measure of material anisotropy and fracture strain of both materials were measured using uniaxial tension and plane strain tests and incorporated in the FE model. General purpose Finite Element software ABAQUS/Explicit was employed to simulate the trimming process where five different fracture criteria and element deletion method were used to predict profile of trimmed edge and the fracture initiation and development during the trimming process. Good general agreement was observed between experiments and FE simulations. However, some discrepancies were also observed. These are presented and discussed in the thesis. / Thesis / Master of Applied Science (MASc)

Under höstterminen 2013 har Stefan Erlandsson och Louise Andersson, designingenjörsstudenter på Högskolan i Skövde, utfört ett produktutvecklingsprojekt i samarbete med entreprenören Lars Willebrand. Målsättningen för projektet var att utveckla ett lyftverktyg som ska komplettera Willebrands produktserie bestående av; travers, svängkran, plåtbyrå och lyftverktyg. Lyftverktyget ska vara anpassat för att användas i kombination med en plåtbyrå, vilket innebär att det kommer användas till att lyfta material från höga och låga höjder. Lyftverktyget måste därmed konstrueras i syfte att underlätta för användaren och undvika arbetsskador som kan uppstå vid dessa lyft. Lyftverktyget ska även kunna anpassas till kunder som endast avser att lyfta skivformade produkter i midjehöjd. Projektet inleds med en förstudie där mycket fokus läggs på ergonomi och användaren. Förstudien har gjorts genom fördjupning i relevant litteratur, kontakt med industriföretag och genom att analysera konkurrerande lyftverktyg. Resultatet från förstudien har sammanfattats till en kravspecifikation som legat till grund för konceptframtagningen. Konceptframtagningen har skett stegvis, där lyftverktygets huvudfunktioner utvecklats var för sig. De funktioner som utvecklats är justering av sugkopparnas position, manövrering och lyft vid hög/låg höjd. Alternativa lösningar har tagits fram och utvärderats för att hitta den lämpligaste lösningen på varje enskild funktion. När de bästa lösningarna hade tagits fram sattes dessa samman till ett slutgiltigt koncept. Det slutgiltiga konceptet har analyserats och detaljutvecklats. För att underlätta tillverkning och tillgodose kundens behov har många av lyftverktygets delar anpassats och ritats om. För att säkerställa att lyftverktyget lever upp till kravspecifikationen har hållfasthetsberäkningar och en antropometrisk analys genomförts. Projektets process och resultat sammanfattades och diskuterades. Slutligen gavs förslag på rekommendationer för fortsatt utveckling av lyftverktyget. / During the second semester of 2013, product design engineering students Stefan Erlandsson and Louise Andersson have been involved in a project in cooperation with entrepreneur Lars Willebrand. The main objective of this project has been to develop a lifting tool for sheet materials. The lifting tool is one of four different products developed by Lars Willebrand. The line of products also includes an overhead crane, a slewing crane and a storage drawer for metal sheets, which are already fully developed and ready for production. The purpose of this lifting tool is to be used along with the storage drawer which means that is has to be optimised for lifting sheet materials from different heights. This means that the lifting tool has to be designed with regards to the users working postures. Human factors such as ergonomics have to be taken into account as well. The initial part of the project is a pre-study with focus on ergonomics and human factors. This pre-study included a study in relevant literature, contact with a manufacturing company and an analysis of the possible competitor’s lifting tools. The results from the pre-study have further been used to define the specification of requirements, which is the foundation for the concept development. The concept development has undergone a number of different phases. All of the lifting tool’s main functions were broken down and developed individually. The functions were as follows; adjustment of the suction cups, lifting from different heights and handling. The most suitable solution for each main function were chosen and assembled into one final concept. The final concept has been analysed and further developed in order to please the employer and the users of the lifting tool. Some details in the design have been changed in order to ease the manufacturing of the lifting tool. To ensure that the final concept matches the specification of requirements, strength calculations and FEM analysis have been made and anthropometrical measurements have been taken into account. The final chapters include a discussion and recommendations for further development of the lifting tool.