The etching process for metal spectacle frames constitutes a precision subtractive manufacturing technique based on chemical corrosion principles, particularly suited to processing thin metal sheets with thicknesses ranging from 0.3 to 1.5 millimetres. The process sequence primarily comprises: Pre-treatment of stainless steel/titanium alloy sheets → Application of double-sided photosensitive resin coating → High-precision ultraviolet exposure → Development → Precise chemical etching → Resist removal and cleaning → Surface post-treatment. Utilising high-resolution photolithographic masks, metal spectacle frames can achieve intricate patterns with line widths as fine as 0.08mm, complex openwork areas, and locally varying depths in semi-etched structures.

The defining characteristic of this metal frame processing lies in its entirely non-contact, stress-free nature. This eliminates burrs, deformation, heat-affected zones, and internal stress accumulation inherent in traditional stamping, wire-cutting, or CNC milling. Consequently, the frames retain exceptional elasticity and fatigue resistance even in ultra-thin configurations. The etching process can be performed bilaterally in synchronisation, enabling the simultaneous formation of intricate three-dimensional features on components such as temples, frames, nose pads, and brow bridges. This particularly facilitates the creation of extremely fine decorative openwork patterns, brand logo light-transmitting apertures, and gradient thickness transitions – outcomes virtually unattainable through conventional machining.

Post-etching edges naturally form smooth rounded corners (typically ≤5μm radius), eliminating the need for subsequent deburring or chamfering. This delivers exceptionally comfortable tactile feel, avoiding the skin irritation caused by sharp edges from conventional processing. Surface roughness is controllable between Ra 0.4–0.8μm, enabling direct subsequent surface treatments such as PVD coating, anodising, brushing, or sandblasting to achieve premium finishes including mirror, matte, or coloured effects. Metal eyewear frame processing exhibits exceptional material adaptability, accommodating virtually all metals commonly used in spectacles: 304/316 stainless steel, pure titanium, beta titanium, nickel silver, cobalt-chromium alloys, etc. Even high-hardness, high-elasticity titanium alloys can be etched to a high standard.

A further distinct advantage of metal eyewear frame etching lies in its exceptional design flexibility and minimal tooling costs. Production requires only photolithographic masks (film or glass plates), with design modifications achieved through simple pattern updates without tooling changes. This makes it particularly suited for high-end bespoke eyewear production involving small batches, diverse styles, and rapid iterations. During mass production, metal spectacle frames exhibit exceptional dimensional consistency, with tolerances maintained within ±0.02mm. This meets the stringent precision requirements of international luxury brands. Furthermore, the etching process offers high production efficiency, particularly for large-area thin-sheet batch manufacturing, where unit costs are significantly lower than CNC machining per piece.

In practical production, metal frame etching enables functional structural enhancements. Examples include locally thinning the nose pad area for greater flexibility, incorporating ventilated cut-outs on the temple tips to reduce weight, and etching concealed hinge mounting slots at the brow bridge. These intricate designs directly elevate the eyewear's wearability and functionality. Overall, chemical etching offers a manufacturing pathway for metal spectacle frames characterised by high precision, zero defects, lightweight construction, artistic expression, and exceptional consistency. It has become the core processing technology enabling the pursuit of ultimate design and unparalleled comfort within the modern high-end eyewear industry.