Production of substrates

Raw glass

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
 
Cut into blanks

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
 
Chamfer sharp edges by grinding or milling

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

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 figu re are already being monitored throughout the process
  • CNC combines several grinding steps in one machining center
 
Polish to our standard P4

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 < 1.5 Å rms) can take twice as long
  • CNC can help in all stages to handle larger quantities and to reduce processing times and cost
 
Clean off processing residues

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

more about cleaning

 
Inspect for all given specifications

Inspection

Inspect for all given specifications