Development of a model for automated determination of the ideal lubricant layer thickness for hot forging processes

• Applicant: Professor Dr.-Ing. Bernd-Arno Behrens
• Subject Area: Primary Shaping and Reshaping Technology, Additive Manufacturing
• Term: since 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 524639810

In their industrial areas of application, minimum quantity lubrication offers several advantages over conventional lubrication. For example, the successful implementation of MQL contributes to more environmental protection and employee health protection through lower emissions of vapors and impurities. Due to the significantly reduced use of lubricants, for example, the disposal costs for excess lubricants and the cleaning costs for dirty tools can also be reduced. A particular problem with the application of minimum quantity lubrication in the area of hot forging results from locally varying tool loads. These occur because the individual tool areas are exposed to different levels of wear and different friction loads. This is due to the respective component geometry. Ideally, therefore, adaptive lubrication must be used for these tool areas. The aim of the proposed research project is therefore to develop a model for the automated determination of the ideal lubricant layer thickness for hot forging applications as a function of the component geometry and the locally different tool loads. Four subgoals are pursued to achieve this goal. The first subgoal is to determine ideal base lubricant layer thicknesses for hot forging processes based on established ring upsetting tests. A spray system must be developed and designed for uniform and reproducible application of the lubricant. The basic lubricant layer thickness is the thickness of the lubricant layer, which leads to minimum coefficients of friction during ideal forming. The second subgoal is to investigate the causes of lubricant film breakoffs in the die, the effects of the breakoff on the die surface and the development of a function to predict lubricant film breakoffs as an essential failure or avoidance criterion of MQL. For this purpose, a test tool will be designed, and experimental tests carried out. Subgoal 3 deals with the development of an algorithm for the automated determination of the adapted lubricant layer thickness. Therefore, the results of subgoals 1 and 2 are combined and applied to a real forming process to obtain an ideally lubricated process. Based on these results, the algorithm is developed as a model for calculating the ideal lubricant layer thickness. The fourth objective is the calibration and verification of the developed algorithm by experimental tests. The scientific question of the project is divided into two areas. First, the interactions between the occurrence of a lubricant film break in the die during hot forging and the process parameters during die forging are investigated. Subsequently, it will be investigated how an ideal adapted lubrication can be calculated for use in drop forging in hot forging.

• DFG Programme: Research Grants
• Co-Investigator: Dr.-Ing. Malte Stonis