Flexible laser welding of tailored blanks in small batch series

Abstract

In a EU Craft project including eight partners in five countries, the most important aspects regarding efficient and low cost manufacture by small and medium sized enterprises (SME) of tailored blanks has been systematically investigated. In this paper, small batch series laser welding of tailored blanks in SME will be described. This includes the design, development and systematic use of a flexible and low cost clamping device as well as the practical experience obtained on the job shop through systematic optimization of welding of tailored blanks with even and uneven thickness (0.75 and 1.25 mm). A clamping device that is able to hold finished parts up to 1 x 1 m is successfully manufactured and tested. A special arrangement with alignment needles along the weld line is used to precisely position the sheets. These needles are turned into the clamping device during welding, where root shielding is employed. Hydraulic presses hold down the sheets, so they move less than 0.01 mm during welding. High quality tailored blank welds are successfully manufactured in ten different combinations, including mild steel and medium strength steel with even and uneven thickness with and without zinc coating.