Experimental Investigation of Energy Savings during Table-Top Hemming of Aluminum Alloys

Abstract

The organization of workflow and design of tools and processes in automotive manufacturing will become even more dominated by topics of energy efficiency due to increasing environmental requirements in the future. From this point of view a detailed analysis of all manufacturing processes in the body shop, taking into account the reduction of energy consumption and required area covered by equipment, is necessary. In automotive manufacturing welding and gluing processes as well as metal forming processes are commonly used for joining of single parts to an assembly group, such as doors or closures. In order to determine typical process characteristics as well as to develop more efficient hemming solutions an experimental study was performed in this paper. Using a modular hemming test, representing a conventional table-top hemming process for hang-on parts, theoretical energy consumption during flanging, pre-hemming and final-hemming was determined experimentally. The forming force characteristic shows typical process related development of each single operation. Based on these findings a first experimental parametric study was performed to determine the significance of single material and hemming parameters regarding energy consumption of the entire process workflow. The most significant hemming parameters also were quantified. In a further investigation the identified parameters were used to improve efficiency of the single forming operations (flanging, pre-hemming and final hemming). Therefore are more detailed DoE study was performed considering hemming tool and process parameters. In the final step of the investigation all process steps were combined to a high efficient hemming routine and positive and negative interactions of single steps were considered. For the evaluation of efficient hemming process the quality of the hemming rope was analyzed.