Develop rimless and semi-rimless metal frames for an ultra-lightweight look.

Metal frames offer distinct advantages that cater to a specific market segment. They provide a sleek, minimalist, and professional aesthetic that is highly valued in business and formal settings. From an engineering standpoint, metal offers superior strength-to-weight ratios when using alloys like titanium, allowing for incredibly thin, lightweight designs that don’t sacrifice durability. Metal frames are also highly adjustable; opticians can precisely bend the bridge and temples for a perfect, customized fit—an option much more limited with plastic. For brands, offering metal frames positions your collection as premium, technical, and enduring, appealing to customers who value precision, understated style, and long-term value.

The best metals balance strength, weight, corrosion resistance, and skin safety. Titanium & Beta-Titanium: The gold standard. Pure titanium is exceptionally strong, lightweight, and 100% hypoallergenic. Beta-titanium offers more flexibility for spring hinges and comfortable temples. Stainless Steel: An excellent, cost-effective choice. It’s strong, corrosion-resistant, and can be made hypoallergenic with proper plating or using specific grades (e.g., 316L). Monel: A nickel-copper alloy known for its excellent malleability and spring-like properties, often used for durable, flexible core wires inside acetate frames or for sturdy hinge components.At Tuopu, we select the alloy based on the desired frame character—ultra-lightweight (titanium), value-engineered strength (stainless steel), or flexible component (Monel).

Ensuring hypoallergenic metal frames is a multi-step process. First, we source certified nickel-free alloys for titanium and specific stainless-steel grades. For components where other metals might be used, we employ advanced plating techniques—such as palladium-nickel plating under a final layer of ruthenium or gold—to create a complete, non-porous barrier between the base metal and the skin. All plating is tested for adherence and thickness. Furthermore, we design frames to minimize direct skin contact with metal; we use silicone nose pads and temple tips as standard. This comprehensive approach guarantees our metal frames are safe for even the most sensitive skin.

Metal frames are extremely durable, but their durability manifests differently than flexible plastics like TR90. Metal offers high tensile strength and fatigue resistance, meaning it can withstand repeated adjustments and long-term use without losing shape. It is less likely to snap under sudden impact compared to some plastics. However, unlike TR90 that bends and returns, a metal frame that is bent beyond its yield point may stay deformed (though it can often be adjusted back). The key is that metal’s durability is about structural integrity and precision over time. For a sleek, thin profile that maintains its shape for years, a well-made metal frame is exceptionally durable.

Absolutely. Metal is an ideal canvas for sophisticated customization. We can produce custom metal frame designs with unique wire shapes, intricate laser-cut patterns, or soldered decorative elements. Our finishing capabilities are extensive: we offer PVD (Physical Vapor Deposition) coatings in a vast spectrum of colors (black, gold, rose gold, gunmetal, blue) that are highly scratch- and fade-resistant. We also provide matte, polished, brushed, and two-tone finishes. For ultimate luxury, we can apply precious metal plating (gold, ruthenium). This allows you to create a metal frame collection with a distinct, high-end identity that stands apart from mass-produced options.

Manufacturing a metal frame is a process of precision joining. It typically starts with wire forming—bending flat or round metal wire into front rims and temples using precise CNC machinery. Components are then meticulously soldered or welded together at the bridge and hinge points, requiring skilled craftsmanship to ensure strength and alignment. Hinges are assembled with micro-screws. The frame then undergoes a series of surface treatments: polishing, plating, or PVD coating. Finally, nose pads and temple tips are attached. At Tuopu, each step is controlled and inspected. We use laser welding for clean, strong joints and automated plating lines for consistency, ensuring every metal frame meets exacting standards of fit, finish, and function.