MAGNETOFORMING COILS WITH A LONG LIFETIME: LNCMI TO CEMENT TIES WITH Bmax

Since 2013, the LNCMI is collaborating with the Toulouse company Bmax / I Cube Research to design magnetoforming coils with long lifetime. Durability is a crucial issue for using electromagnets at an industrial scale, requiring the production of parts in large quantities with extreme precision and at controlled cost. To generate very strong magnetic fields, it is necessary to use conductors that combine good electrical conductivity with very high mechanical strength. In addition to the magnet production, the LNCMI has its own wire-drawing workshop and is able to manufacture the conductors necessary for the fabrication of coils which can resist long-lasting magnetic fields (several tens of milliseconds) up to the 100 T range. It is this expertise that attracted Bmax / I Cube Research, a specialist in magnetoforming. Magnetoforming is a technique that makes it possible to manufacture precise parts with shapes that cannot be obtained by other methods at reasonable costs. The pulsed electromagnets that are designed for this purpose generate very short and strong magnetic field pulses, which induce a current in the metal part to be molded. The part is then projected at very high speed onto a mold, which gives it the desired form. This technique is called direct, as opposed to indirect, magnetoforming where a punch is set in motion by magnetic forces, hits the material to be modeled and projects it to the mold. The operation takes place in a few tens of microseconds, and offers a level of precision in the shape of the parts that meets the expectations of very demanding sectors such as luxury, aeronautics, and automotive industry. However, the pulsed electric currents that make this process possible impose enormous magnetic, mechanical, and thermal stresses on the electromagnet. The challenge is, therefore, to produce coils with conductive materials that are sufficiently resistant to sustain these stresses in order to use them on industrial production lines without the need of frequent replacement. Starting with a few hundred pulses realized a few years ago, the LNCMI, therefore, has optimized the electromagnets to withstand more than 30,000 pulses, which corresponds to a 50-times longer lifetime. Based on this success Bmax / I Cube Research is now in a position to extend its magnetoforming applications and to conquer new markets. Initially financed by funds of Bmax / I Cube Research, the partnership with the LNCMI was recognized institutionally and has been sponsored as part of local (NEXTMAG, LABEX NEXT), regional (MAG-IC, Région Occitanie), national (SIgMA, ANR), and European (ISABEL, H2020) projects.