Testing of Lubricants for DIC Tests to Measure the Forming Limit Diagrams of Aluminum Thin Sheet Materials

We investigated lubricants and thin teflon foils that can be applied in the formability testing of aluminum sheets used electronics automotive industries. For tests, thirteen different industrial (oils greases) (i.e., L1–L13) two Teflon films 0.08 0.22 mm thick) were applied. The authors conducted an Erichsen test, thickness reduction discs was measured first. In forming-limit curve (FLC) it is crucial stresses are localized central area specimen during forming biaxial deformation maintained throughout, if possible. aimed to achieve fulfill this task. To perform measurement, GOM ARAMIS measuring system utilized. It optical based on digital image correlation (DIC) principle, capable both displacements real time. A specific validation method also developed qualify DIC system. concluded there a 5% difference indentation (IE) number diagrams between best (L12) worst (L4) cases for oils tested, which significant plates. found value could increased improved by using discs. Furthermore, localization stress maxima, i.e., centering cracks specimen, achieved combining L12 lubricant (with appropriate layer order), significantly aids recording standard FLC diagrams. Using advantageous because they readily available, have no expiry date, less environmental concern.