A Systematic Approach to Analyse Critical Tribological Parameters in an Industrial Case Study of Progressive Die Sequence Production

In a production line that uses sheet metal forming technology, the surface quality of the final part and tool life depend significantly on the lubricant performance. Hazardous chlorinated paraffin oils have been widely used by manufacturers throughout the world for many decades. However, with growing environmental awareness, the trend is to substitute environmentally hazardous oils with environmentally friendly lubricants. Tribological conditions in forming operations depend on several parameters such as process speed, workpiece/tool interface pressure, workpiece/tool interface temperature and surface roughness of the parts. Prior to testing several tribo-systems in the laboratory to determine the limit of lubrication, it is therefore important to identify the tribological parameters in the production process.
This paper describes a generic methodology for such an investigation to determine the tribologically critical parameters in an industrial production line in which a progressive tool sequence is used. The current industrial case is based on multistage deep drawing followed by an ironing operation. Severe reduction in the ironing stage leads to high interface temperature and pressure. As a result, subsequent lubricant film breakdown in the production line occurs. The methodology combines finite element simulations and experimental measurements to determine tribological parameters which will later be used in laboratory testing of possible tribology systems.