D-667 SCRATCH / DIG SAMPLES
Inspecting surface quality of finished optical components e.g.: lenses, prisms, mirrors, reticles, windows and wedges in accordance with MIL-0-13830 and MIL-C-48497 is easily accomplished using these Scratch/Dig Samples. The samples serve as direct visual comparison standards.
Each set consists of ten individual samples in a fitted hardwood case. Samples are hermetically sealed, size 1 1/2" x 1 1/2" x 3/8" - Values are: Scratch: 10 - 20 - 40 - 60 - 80; Dig: 5 - 10 - 20 - 40 - 50.
Order Set D-667 or D-667A for aluminized.
Ground glass with strips for inspecting to MIL 0-13830
- Overhead fluorescent lamps for inspecting to MIL C-48497
- Overhead 40 watt incandescent lamp for inspecting to MIL 0-13830
- Curtain to conform to MIL C-48497
- Overall size: (H x L x W) 20" x 19" x 20"
- Weight: 30 lbs.
- Shipping Weight: 42 lbs.
- Shipping box size: 32" x 32" x 32"
D-667-11 Viewing Fixture
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.
- 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.
Scratches: Any marking or tearing of the surface. Scratch types are identified as follows:
Digs: Small rough spots on the polished surface, similar to pits in appearance, generally caused by mishandling.
Bubbbles: Internal inclusions in the glass are classified as digs and are added to the other surface defects.
WHEN USING THE D-667-11 VIEW FIXTURE:
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" from the glass.
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.
Scratch/Dig Samples have been sealed and 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 sample seal could be affected.