Scratch & Dig Sample Sets from Davidson Optronics enable inspecting and characterizing surface quality of finished optical components (lenses, prisms, mirrors, reticles, windows and wedges) in accordance with MIL-13830, MIL-C-48497 and the new ANSI/OEOSC OP1.002:2008. The samples serve as direct visual comparison standards.
Each set consists of ten individual samples in a fitted hardware case. Samples are hermetically sealed as stand-alone pieces with a size of 1.5 x 1.5 x 0.375 inch (38 x 38 x 10 mm)
Values are: Scratch 10 – 20 – 40 – 60 – 80 | Dig: 5 – 10 – 20 – 40 – 50
Order set D-667, or D-667A, for a set with half-aluminized scratch samples (useful for characterizing highly reflective and/or polished metal surfaces).
- Ground glass with strips for inspecting to MIL-O-13830
- Overhead fluorescent lamps for inspecting to MIL-C-48497
- Curtain conforms to MIL-C-48497
- Overall size (H x D x W): 20 x 19 x 20 inch
- (508 x 483 x 508 mm)
- Weight: 30 lbs (17 kg)
- Shipping Weight: 42 lbs (19 kg)
- Shipping Box: 32 x 32 x 32 inch
- (813 x 813 x 813 mm)
Use of samples: Designation of defect size. Limiting size of surface defects is designated on the applicable drawings by two numbers which refer to the graded sets of surface quality standards; e.g. 80/50. The first number refers to scratches and the second number refers to digs.
Scratches: Any marking or tearing of the surface. Scratch types are identified as follows:
- Block Reek – Chain like scratch produced in polishing.
- Runner Cut – Curved scratch caused by grinding.
- Sleek – Hairline Scratch.
- Crush or Rub – Surface scratch or a series of small scratches generally caused by mishandling.
Digs: Small rough spots on the polished surface, similar to pits in appearance, generally caused by mishandling.
Bubbles: Internal inclusions in the glass are classified as digs and are added to the other surface defects.
Inspection method #1
The element to be inspected and the applicable sample are viewed against a ground glass or opal surface illuminated from behind by a 40 watt lamp approximately 3 inches (76 mm) from the surface under examination.
Inspection method #2
The light through ground glass from a 40 watt bulb shall be passed through the element and sample. Defects are observed by light scattered from the surface while viewing it at approximately 90° to the path of the beam against a dark background.
Cleaning: Scratch/Dig Samples have been sealed and their surfaces may be cleaned with a mild detergent and warm water solution. Wipe dry with a lens tissue or lint free cloth. Avoid use of chemical solvents as the sample seals could be affected.