Production of substrates
Raw glass
Pre-cut in rough shape
- from a melt (Fused Silica) or a crystal boule (CaF2, Sapphire)
- made at glass companies like Schott, Heraeus, Ohara, Corning
- a stock of common glass types from different suppliers is available for quick turnaround
Cutting
Cut into blanks
- by diamond-studded blades
- for round optics: edge grinding or CNC milling into round and plano blanks
- for curved optics: premanufacture radius by CNC processing
- the alternative to processed blanks are preformed moulded blanks
Chamfering edges
Chamfer sharp edges by grinding or milling
- prevents handling damages and gives a cleaner appearance
- done in an early stage to avoid damaging during later ones
Grinding
Approach the dimensional tolerances
- after fine grinding the substrate still is intransparent, but already has precise dimensions
- quality aspects like parallelism, radius or surface figure are already being monitored throughout the process
- CNC combines several grinding steps in one machining center
Polishing
Polish to our standard P4
- using pitch as carrier for the polishing agent leads to a very good surface quality
- using a polishing foil can reduce process time and costs significantly and can get to similar results
- polishing for super-polished optics (roughness RMS < 0.1 nm) can take twice as long
- CNC can help in all stages to handle larger quantities and to reduce processing times and cost
Cleaning
Clean off processing residues
- using multi-frequency ultrasonic and various baths with different chemical add-ons
- details about automatic ultrasonic and manual cleaning on
