Round optical frames with a keyhole bridge feature a geometric harmony between circular lens rims and a contoured, indented bridge profile. Within optical collections, this silhouette serves as a core staple for vintage-inspired and intellectual eyewear lines.

Key Structural Features

Round Lens Geometry
The rounded lens outline offers a softer, balanced facial contour compared to angular frames. Evaluated alongside rim thickness and eye size (lens width), it ensures structural rigidity, particularly when housing high-index or thicker prescription lenses.

Keyhole Bridge Construction
The upper inner edges flare outward, forming a traditional keyhole contour that redistributes contact points along the nose. Bridge width and depth must match specific demographic fitting requirements, as the keyhole shape alone does not universally fit all nasal profiles.

Technical Specifications & Reference Tolerances

Parameter	Specification / Standard Industrial Range
Product Type	Round Optical Eyeglass Frame
Bridge Design	Keyhole Bridge
Lens Width (A)	Customizable (Typical range: 46mm – 52mm)
Bridge Width (DBL)	Customizable (Typical range: 18mm – 22mm)
Temple Length	Customizable (Typical range: 140mm – 150mm)
Frame Front Width	Matched to eye and bridge size
Hinge Type	Standard Barrel Hinge, Spring Hinge, or Custom Rivet Hinges
Rim Construction	Full-rim
Surface Finish	Hand-polished tumbling (Acetate) / Electroplated or Ion-Plated (Metal)
Customization	Laser-engraved logo, foil-stamped temple logos, custom color plating/dyeing
Quality Compliance	Conforms to international optical frame dimensional and safety benchmarks

Material & Construction Options

Material Category	Key Sourcing & Processing Characteristics	Best Suited For
Cellulose Acetate	Excellent color depth, rich laminations, and superior adjustment capability via heat. Allows varied rim profiling and hand-polishing.	Premium vintage collections, independent designer brands, and tactile retail lines.
Injection Plastic (TR90 / Propionate)	Lightweight, highly flexible, consistent mold replication, and cost-effective for high-volume programs.	Everyday budget-friendly optical lines and active lifestyle frames.
Stainless Steel / Monel	Slim-profile construction, high tensile strength, precise laser-cut shapes, and clean architectural lines.	Minimalist optical frames and lightweight professional wear.
Titanium / Beta-Titanium	Exceptional strength-to-weight ratio, corrosion resistance, hypoallergenic properties, and high-end positioning.	Ultra-lightweight luxury collections and high-end optical retail.

Optical Workshop & Glazing Guidelines

Groove Depth & Profile: Standard V-bevel and U-groove tolerances must accommodate standard 1.50, 1.60, 1.67, and 1.49 polycarbonate lens bevels without edge chipping.

Heat Activation Limits: For acetate frames, ensure proper heating thresholds (typically 65°C to 70°C) during lens insertion to prevent bridge distortion or keyhole deformation.

Base Curve Alignment: Frame front curvature should align with standard single-vision and progressive lens base curves (typically 4 to 6 base) to avoid stress fractures along the eyewire lock screws or rim joints.

OEM & Customization Workflow

Specification Review: Submit technical drawings, reference samples, or modifications based on existing portfolios.

Material & Component Confirmation: Select material grades, color references (Pantone / Acetate swatches), and hardware components.

Sample Development: Production of pre-production physical samples for dimensional, fit, and aesthetic verification.

Master Sample Approval: Signed physical samples serve as the strict quality benchmark for bulk production.

Batch Production & Quality Inspection: Full manufacturing under strict internal QC protocols.

Factory Quality Control (QC) Protocols

Dimensional Verification: Vernier caliper checks on lens width, bridge span, temple length, and diagonal symmetry against approved blueprints.

Hinge Endurance & Alignment: Testing smooth opening/closing cycles and verifying that temples rest flat without vertical misalignment.

Stress & Tension Testing: Evaluating frame flexibility and structural resilience around the bridge and rim locking areas.

Finish & Cosmetic Inspection: Checking for surface blemishes, tool marks, uneven polishing, and color consistency under standardized lighting.

FAQ

Q: Can these frames be glazed with prescription (Rx) lenses?

A: Yes. The frames are constructed with standard optical rim grooves designed for prescription lens fitting by a licensed dispensing optician or optical laboratory.

Q: What is the standard sample lead time and cost?

A: Standard sample development takes approximately 7 to 14 days depending on material availability and custom tooling requirements. Sample fees are typically refundable upon placing a confirmed bulk production order.

Q: Can custom frame colors be matched from a Pantone code or fabric swatch?

A: Yes. For acetate frames, block or gradient color sheets can be custom-mixed. For metal and injection plastic frames, color matching can be executed via Pantone references.

Q: What is the Minimum Order Quantity (MOQ) for private label production?

A: MOQ varies by material and specific tooling requirements (e.g., custom metal molds vs. existing acetate cutting dies). Specific target quantities should be provided during inquiry to establish precise thresholds.

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