Fluctuations of material properties are one reason for the occurrence of cracks and waviness in series production of car body parts. Especially fluctuating tribological conditions have an effect on the friction behavior and thus on the material flow. So far fluctuating material properties are not considered in the standard FE-simulation and consequently not in the tool design. In order to enhance the accuracy of the simulation result and thus improve the tool design regarding a robust process, the appearance of batch fluctuations has to be consistently understood. Therefore, the impact of varying lubricant quantities and roughness have been investigated. Several batches have been analyzed to identify the main influencing parameter regarding the friction behavior. Flat strip-drawing tests have been performed to determine the friction coefficient. The investigations have been performed by using material from the series production, as delivered. Since the amount of lubricant turns out to be the main influencing factor, the characteristics and appearance of the lubricant distribution has been analyzed in a further step. The analysis has shown that the distribution of the lubricant changes within one coil over the coil width and length. In addition, the time of storage has been identified as one main influencing factor on the homogeneity of the lubricant distribution over the coil width. Based on these findings, a method has been developed to map the series production conditions regarding the friction conditions in the simulation. Hence, simulations were performed using a side frame blank with different friction conditions, to investigate the impact on the forming result. The results reveal that by considering realistically existing tribological conditions, more scrap is to be expected compared to the conventional simulation. This leads to the conclusion that previous simulation results are too optimistic. Consequently, the introduced method offers the potential to optimize the tool design by considering fluctuating tribological conditions already in the process of development. Thus, it is possible to reduce scrap and increase productivity.

材料性能的波动是在车身零件的批量生产中出现裂纹和波纹的原因之一。特别是波动的摩擦条件会影响摩擦性能，进而影响材料流动。到目前为止，在标准有限元仿真中并未考虑材料的波动，因此在工具设计中也没有考虑。为了提高模拟结果的准确性，从而改善有关稳健过程的工具设计，必须始终了解批次波动的出现。因此，已经研究了润滑剂量和粗糙度变化的影响。已经分析了几批以识别有关摩擦行为的主要影响参数。已经进行了扁平带材拉拔试验以确定摩擦系数。已经使用批量生产的材料（已交付）进行了调查。由于事实证明润滑剂的量是主要的影响因素，因此已在下一步中分析了润滑剂分布的特性和外观。分析表明，润滑剂的分布在一个线圈内沿线圈的宽度和长度变化。另外，存储时间已被确定为在线圈宽度上润滑剂分布均匀性的主要影响因素。基于这些发现，已开发出一种方法来映射有关模拟中摩擦条件的批量生产条件。因此，使用具有不同摩擦条件的侧架毛坯进行了仿真，以研究对成形结果的影响。结果表明，与常规模拟相比，通过考虑现实中存在的摩擦学条件，可以预期会有更多的废品。由此得出结论，先前的仿真结果过于乐观。因此，通过考虑已经在开发过程中引起的摩擦条件的变化，引入的方法提供了优化工具设计的潜力。因此，可以减少废品并提高生产率。通过考虑开发过程中已经出现的摩擦条件变化，引入的方法为优化工具设计提供了潜力。因此，可以减少废品并提高生产率。通过考虑开发过程中已经出现的摩擦条件变化，引入的方法为优化工具设计提供了潜力。因此，可以减少废品并提高生产率。