Skip to content

Manufacturing Tolerances

Typical Manufacturing Tolerances
Tolerance Description Units Injection Molding Single Point Diamond Turning
Commercial Precision Commercial Precision
Radius of Curvature The radius of the optical surface % of Radius of Curvature ±1% ±0.5% ±0.5% ±0.1%
Center Thickness The thickness of the lens at the center mm ±0.025 ±0.015 ±0.020 ±0.005
Flange Diameter The outside diameter of the lens mm ±0.05 ±0.025 ±0.02 ±0.005
Concentricity Centering requirements typically refer to the position of one surface of a lens with respect to the second surface of the lens mm 0.025 0.015 0.005 0.002
Edge Clearance Edge clearance is the distance between the optical clear aperture and the physical outer dimensions of the part mm 0.5 0.25 0.05 0.01
Surface Form (Spherical) Power - maximum allowable deviation of the surface from its nominal shape based on an interferometer measurement Fringes at 632.8 nm for 25mm diameter 10 4 4 2
Irregularity (localized departure from nominal) in fringes Fringes at 632.8 nm for 25mm diameter 6 3 4 2
Cosmetics (Surface imperfection) Surface imperfection tolerances and the scratch-dig specifications standard for optical components MIL-PRF-13830B Scratch / Dig 60/40 40/20 60/40 40/20
Surface Roughness Surface roughness or surface texture measures small scale irregularities on a surface Å - RMS <75 <50 <100 <75
Material imperfections Material imperfections that may affect optical performance include stress birefringence, bubbles, inclusions, inhomogeneity, and striae. Due to the nature of manufacturing processes used for plastic optics, control of material imperfections is a challenge.
Surface treatment and coating Optical coating specifications should include performance requirements expressed as a percentage of reflectance and/or transmission over a specific spectral range and range of angles of incidence.

Please keep in mind that many of these parameters will highly depend on the size, shape and material of the design part. These tolerances are meant as guidelines for design and should be reviewed with Apollo Optical's Design Team during the technical review process.