Herrmann Marius, Beckschwarte Björn, Hasselbruch Henning, Heidhoff Julian, Schenck Christian, Riemer Oltmann, Mehner Andreas, Kuhfuss Bernd
Bremen Institute for Mechanical Engineering-Bime, University Bremen, 28359 Bremen, Germany.
MAPEX Center for Materials and Processing, University Bremen, 28359 Bremen, Germany.
Materials (Basel). 2020 Nov 3;13(21):4939. doi: 10.3390/ma13214939.
Electromagnetic forming is a high-speed process, which features contactless force transmission. Hence, punching operations can be realized with a one-sided die and without a mechanical punch. As the forces act as body forces in the part near the surface, the process is especially convenient for embossing microstructures on thin sheet metals. Nevertheless, the die design is critical concerning wear like adhesion. Several die materials were tested, like aluminum, copper as well as different steel types. For all die materials adhesion phenomena were observed. To prevent such adhesion an a-C:H-PVD (Physical Vapor Deposition)-coating was applied to steel dies (X153CrMoV12) and tested by embossing aluminum sheets (Al99.5). By this enhancement of the die adhesion was prevented. Furthermore, the die surface was structured with tribology-effective patterns that were generated by micro hard milling. The embossing quality was topographically analyzed with respect to different initial surface states of the sheets. It was identified that thicker sheets facilitate better embossing results. Moreover, the initial sheet surface has a decisive influence on the embossing quality, whereby the characteristic of the topography showed different susceptibility on the initial sheet surface state.
电磁成形是一种高速加工工艺，其特点是无接触力传递。因此，冲孔操作可以通过单侧模具实现，无需机械冲头。由于力在靠近表面的零件中作为体积力起作用，该工艺对于在薄金属板上压印微结构特别方便。然而，模具设计在诸如附着力等磨损方面至关重要。测试了几种模具材料，如铝、铜以及不同类型的钢。对于所有模具材料，都观察到了附着力现象。为了防止这种附着力，在钢模具（X153CrMoV12）上应用了非晶碳氢物理气相沉积（a-C:H-PVD）涂层，并通过压印铝板（Al99.5）进行了测试。通过这种方式防止了模具附着力。此外，模具表面采用了通过微硬铣削产生的具有摩擦学效果的图案进行结构化处理。针对板材的不同初始表面状态，对标压印质量进行了形貌分析。结果表明，较厚的板材有助于获得更好的压印效果。此外，板材的初始表面对压印质量有决定性影响，其中形貌特征对板材初始表面状态表现出不同的敏感性。
