Design and Analysis of a Controllable Magnetic Blank Holder System with Magnetorheological Elastomer for Sheet Metal Forming

Abstract

To tackle the issue of magnetic force loss caused by the air gap in the electromagnetic permanent magnet (EPM) blank holder process magnetorheological elastomer (MRE) is used to fill the air gap of the magnetic circuit as magnetic matrices. This allows for the construction of a controllable magnetic force blank holder system with magnetorheological elastomers (EPM-MRE) for sheet metal forming. Additionally, EPM-MRE blank holder deep drawing tools were designed. MREs with different mass ratios were developed and tested for their magnetic properties. Air and MREs of varying mass ratios were filled into the magnetic circuit gaps of a four-pole magnetic force model, and a finite element analysis of the magnetic force coupling field was conducted, followed by experimental verification. The results show that the inclusion of MRE in the magnetic circuit gap can significantly enhance magnetic force, with an increase of over 50% across gaps ranging from 0.5 mm to 3.0 mm, and the enhancement effect becomes more pronounced as the gap widens, and the enhancement effect of the prepared MREs with different mass fractions is not significantly different, with the difference being no more than 1%. The EPM-MRE blank holder process was further verified through deep drawing experiments and the results demonstrate that the designed process device can be matched with the press to effectively complete the drawing process. At last, the energy consumption using the EPM-MRE blank holder technique is predicted, and it is estimated to save more than 50% of energy compared with EMP blank holders and more than 80% of energy compared to conventional blank holders.