Flexible fabrication of microlens array surface on mold steel by magnetic field-assisted self-assembly electrode

Mold steel, like H13 and M2, are widely used in critical industrial applications due to their excellent wear resistance and thermal hardness. Electrical discharge machining (EDM) is an effective method for fabricating structured surfaces on conductive materials. However, significant electrode wear and a complex replacement process result in high fabrication costs and low production efficiency. Therefore, EDM with a magnetic field-assisted self-assembly electrode （MASAE） was proposed for creating microlens array surfaces on H13. However, significant electrode wear and a complex replacement process result in high fabrication costs and low production efficiency. Therefore, EDM with a self-assembly electrode was proposed for creating microlens array surfaces on H3 mold steel. The MASAE consists of an array of ferromagnetic metallic balls held together by a magnetic field from a permanent magnet. By adjusting the position, number, and size of the metallic balls, various MASAEs can be created. After the EDM process, various microlens arrays on H13 can be fabricated. The shape evolution and surface roughness of the microlens array were investigated by ContourGT-X 3D optical profile and scanning electron microscope (SEM). The results indicate that self-assembling ball electrodes offer significant advantages in machining microlens array structure.