![Optics surface flatness](https://sydor.com/wp-content/uploads/pitch-polishing-img1.jpg)
Surface Flatness
The highly skilled opticians at Sydor Optics have perfected the art and science of conventional pad and pitch polishing, also known as single-sided polishing. While surface flatness over a full clear aperture can be attained down to λ/20 PV, it is possible to reach surface flatness tolerances of λ/40 PV over smaller sub apertures.
![Optics surface roughness](https://sydor.com/wp-content/uploads/pitch-polishing-img2.jpg)
Surface Roughness
Opticians at Sydor Optics have passed down precision polishing techniques from generation to generation. Consequently, Sydor Optics’ proprietary techniques produce precision parts with surface roughness down to 3 Å RMS, ideal for laser applications requiring minimal scatter and maximum performance.
![Optics cosmetics polishing](https://sydor.com/wp-content/uploads/pitch-polishing-img3.jpg)
Cosmetics
Sydor Optics has years of experience producing precision-grade parts with cosmetics (scratch-dig) specifications as tight as 10-5, or as loose as 80-50. No matter the specified tolerance, trained metrology and inspection technicians at Sydor Optics are ready to verify that your parts meet the most rigorous quality guidelines.
![Pitch polishing](https://sydor.com/wp-content/uploads/prism-bg-1.jpg)
About Pitch Polishing
![Precision pitch polishing](https://sydor.com/wp-content/uploads/pitch-polishing-img4-1024x512.jpg)
Precision Pitch Polishing
Pitch polishing is similar to the double-sided process except that it only polishes optics one side at a time. Sydor Optics frequently uses single-sided polishing machines for wedged optics, optical components thicker than 25mm and larger optics up to 750mm in diameter. The single-side process is typically used only if one side of an optical component needs to be polished, or if a part is too large for the double-sided process.
Pitch polishing involves significant skill and craftsmanship and can achieve much tighter tolerances for surface flatness, surface roughness, parallelism and cosmetics. Parts typically polished on a pitch table include optical flats and mirror substrates. Notably, the pitch polishing process also minimizes surface deformation on the edge of a part also known as edge roll.
Pitch tables are hand poured and have a semi-malleable surface with a consistency similar to roofing tar. Proprietary grooves are hand cut to allow the polishing slurry to flow beneath parts resulting in exceptional surface flatness and surface roughness. Pitch polishing is a non-deterministic trial-and-error process and combines both art and science. The highly-experienced opticians at Sydor Optics have an innate understanding of the optical glass polishing process and can provide consistent, high quality parts.
Optical Glass Polishing Manufacturing Limits
Specifications | Measurements |
---|---|
Diameter | ≤ 650mm |
Thickness | ≤ 100mm |
Length / Width | ≤ 350mm x 350mm |
Surface Roughness | ≥ 3 Å rms |
Parallelism | ≤ 5 arc seconds |
Cosmetics (MIL-PRF-13830B) | 60-40 to 10-5 |
Reflected Wavefront Error (RWE) – before coating | ≥ 1/20 wave over clear aperture |
Transmitted Wavefront Error (TWE) – before coating | ≥ 1/20 wave over clear aperture |
Wedge Angle Tolerance | ± 5 arc seconds |
![Pitch polishing](https://sydor.com/wp-content/uploads/Small-flat-surfaced-optics-Alt.jpg)