The Mirror Finish Starts Inside the Steel

S-Star is Daido’s 420 stainless refined by electroslag remelting, an internal matrix that polishes to lens-grade mirror finishes at 50 to 53 HRC.

S-Star reaches the ultra-high mirror-finish class on Daido’s machine-lapping chart, a class the standard pre-hardened mold grades on the same chart do not reach. The remelt happens at the mill, so the finish the polisher pulls from the cavity matches the finish on the print.

What a Cleaner Matrix Does for the Mold

· Mirror class: Lens and optical cavities polish to the chart’s highest class at 50 to 53 HRC

· Corrosive service: Medical, cosmetic, and food-container molds keep their finish

· Approved resins: PVC, PF, PMMA, PC, and flame-retardant compounds are on the application list

· Minimal distortion: Heat treatment moves the block less than 0.03 percent, so finish work happens once

· Uniform texture: Photo-etched and EDM patterns come out even across the cavity

· Chemistry carries the finish: 13.5 percent chromium with vanadium in the mix, stocked as pre-hardened rounds at 30 to 34 HRC and annealed plate ready for heat treat.

The right steel decision happens before the block is cut. IMS, Daido’s U.S. partner since 1991, assigns application engineers to match S-Star to the resin, the finish spec, and the heat-treat plan.