Industrial Lens Edging Mechatronics: 3D Stylus Frame Tracing & Diamond CNC Beveling

The edging process begins with a 3D patternless frame tracer (such as Briot, Essilor, or Nidek). A motorized ruby or tungsten-carbide mechanical stylus engages the internal bevel groove of both the right and left frame eye-wires.

As the stylus rotates 360 degrees, optical encoders record over 16,000 spatial coordinate points mapping:

1. The radial distance from the boxing center: $r(\theta)$.
2. The vertical groove elevation (frame curvature/base curve): $z(\theta)$.
3. The bridge distance (DBL) and three-dimensional frame wrap.

This generates a complete 3D topological mathematical model of the frame rim, ensuring perfect bilateral symmetry.

Next, the lens is placed on a digital video centering device. Using high-resolution telecentric lenses, the machine superimposes the patient's exact monocular Pupillary Distance (PD) and Optical Center (OC) fitting height over the lens markings, applying an adhesive vacuum mounting block precisely along the cylinder axis.

The blocked lens is clamped into the CNC edger spindle and rotated against a series of high-speed diamond grinding wheels spinning at 3,000 to 5,500 RPM under high-volume water coolant:

• Roughing Wheel: Electroplated coarse diamond grit (120–140 mesh) rapidly removes 80% of excess polymer bulk.
• Beveling Wheel: Fine diamond grit (400–600 mesh) grinds the edge profile: standard $110^\circ$ V-bevel for full metal frames, mini-bevel for slim acetate, or flat grooving for semi-rimless nylon cord frames.
• Safety Bevel & Polish Wheel: High-grit polyurethane wheels polish the rimless edges to water-clear transparency and apply a microscopic $0.3$ mm chamfer to eliminate sharp edge chippings.

For three-piece rimless and screwless silhouette frames, the edger engages a motorized multi-axis diamond end-mill drill:

$$(x_d, y_d, \theta_d)$$

The drill interpolates exact coordinates for nose-bridge and temple holes, drilling at perpendicular or tilted entry angles with $0.05$ mm positional accuracy.

Furthermore, the machine dynamically calculates the bevel curve to match the frame's natural front curvature. If a flat base-curve 2 lens is forced into a curved base-curve 6 frame, the eye-wire will bend, pinching the lens and inducing severe mechanical stress birefringence that causes headaches and lens crazing. ELLASUV precision edging guarantees stress-free optical mounting.