Additive Manufacturing of Tailored Blank for Sheet-Bulk Metal Forming Processes

Functional integration and lightweight construction pose increasing demands on manufacturing processes and require innovative approaches. In this context, sheet-bulk metal forming combines the advantages of conventional sheet and bulk forming processes expanding the limitations of these particular processes. However, the intended three-dimensional material flow contains major challenges regarding the material flow control. To enhance material flow control and part quality the application of process-adapted semi-finished products is an expedient approach for sheet-bulk metal forming processes. So-called Tailored Blanks have a process-adapted sheet thickness profile or combine different mechanical properties within a single blank and were applied in the 1980s for the first time. Since then tailored approaches gained in importance and find broad application in research and industry. At present, various technologies are used to manufacture Tailored Blanks. The Tailored Blanks applied in sheet-bulk metal forming are often manufactured by sheet-bulk metal forming processes themselves. The achievable gradient in thickness depends on various factors but is eventually constraint by the material volume of the initial blank. In this regard, Additive Manufacturing offers new possibilities to overcome those limitations and to expand the limits of sheet-bulk metal forming processes further. Additional material can be allocated with high geometric flexibility. Besides the allocation of additional material, this technology allows the manufacturing of discrete functional elements within the production of Tailored Blanks. In this investigation, Tailored Blanks made out of stainless steel are produced using sheet material and additively manufactured elements. These Tailored Blanks are processed in a deep drawing and a subsequent upsetting operation to manufacture a functional component with an external gearing. Conventional sheet material is also processed to compare the resulting part properties and to evaluate the different semi-finished product strategies. For this purpose, an analysis of geometrical as well as mechanical Tailored Blank properties is conducted. Furthermore, the part properties after deep drawing and upsetting are analysed. The investigation evaluates the potential for Tailored Blanks consisting of sheet metal with additively manufactured elements in sheet-bulk metal forming and conclusively points out the need for further research in this field.