6-Step Optical Refurbishment & Authentication SOP
Executed at DAG BAU GmbH Optical Laboratory, Hammer Str. 19, Düsseldorf, Germany under DIN EN ISO 12870 standards.
Step 1: 40kHz Ultrasonic Cavitation Deep Cleanse
Each pre-owned frame is immersed in our German Bandelin / Transsonic ultrasonic tank containing non-corrosive optical surfactant. High-frequency cavitation waves dislodge sweat, grime, and oils from microscopic hinge recesses without abrading vintage cellulose acetate or gold plating.
Step 2: Digital Lensmeter & UV400 Spectrophotometry
Lenses are analyzed on Topcon / Nidek digital lensmeters to verify dioptric power, optical prism balance, and zero optical distortion. A dual spectrophotometer tests UV cutoff at 400nm, ensuring 100% UVA/UVB eye safety.
Step 3: Microscopic Engraving & Provenance Audit
Our master opticians examine factory stamps (e.g. B&L Ray-Ban bridge markings, IC! Berlin patent codes, Cartier serial numbers) under 40x optical stereomicroscope to confirm authenticity and detect counterfeit replica traits.
Step 4: Hinge Alignment & Dynamic Torque Calibration
Hinge screws are ultrasonically cleaned, treated with optical threadlocker, and calibrated to 0.12 - 0.18 N·m opening torque. Frame geometry is aligned using heated sand baths for perfect anatomical symmetry.
Step 5: Medical-Grade Silicone Pad Replacement
All nose pads showing cosmetic aging are replaced with hypoallergenic medical-grade German silicone pads matching original factory specifications.
Step 6: Tamper-Evident Optical Security Sealing
Every verified pair is tagged with a serialized hologram security seal and packed into rigid shockproof packaging before handoff to DHL Paket.