Surface Quality Standards
(Scratch & Dig Sets)

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Basic Set

• The basic set, P/N 7641866, is used for compliance to MIL-O-13830.

Half Aluminized Set

• The half aluminized set, P/N 7641866A, is used for compliance to MIL-O-13830 and MIL-M-13508.

Restoration Services

• Brysen Optical can restore existing scratch/dig sets at a reasonable cost. Prices quoted upon evaluation.

Brysen Optical has engineered a new generation of surface quality standards to meet the needs of today’s modern optical requirements. These new standards are designed with an anodized aluminum housing for cleanroom compatibility and better handling. Gasketed high efficiency anti-reflective coated windows provide for better durability and visibility. New artifact design improves and accelerates scratch or dig comparison.

These Surface Quality standards are ideal for qualitative control and visual identification of scratch and dig surface defects on optical components. Repeatable and accurate evaluation of surface defects has long been a problem Quality Control Managers have had to face. Surface Quality refers to the cosmetic specifications for an optical element in terms of allowable surface defects. A scratch is any long mark or tear and a dig is any pit or divot in the surface. 

The scratch and dig numbers refer to the maximum allowable defect under particular lighting conditions. The dig number follows the scratch number; for example 60-40 denotes the 60 scratch & 40 dig specification. These Surface Quality standards are used in Quality Control departments to qualitatively ensure that fabricated parts are acceptable. Made in accordance with U.S. Army drawing 7641866 Revision R, these standards can be used for visual comparisons as described in MIL-PRF-13830B and MIL-M-13508. 

The scratches are scribed and the digs etched onto glass window blocks and covered with an anti-reflection coated window and mounted together in a lightweight, compact black aluminum housing. The individual window blocks are fixed inside their aluminum frame, so they cannot be removed or misplaced and are sealed from the outside elements. These separate scratch and dig frames are then shipped together as a set in one rugged, foam-padded plastic case for ease of storage and portability. 

The basic set, 7641866, includes 5 scratches (numbers 10, 20, 40, 60 and 80) and 5 digs (numbers 5, 10, 20, 40, and 50). The evaluation of reflective surfaces is facilitated by the use of the half-aluminized set, 7641866A. The 5 scratches in this version are aluminized over half their length and are approrpriate for in process and final inspection of opaque and mirror surfaces. Because the scratches are only half aluminized, this set can be used for evaluation of both reflective and transmissive optical elements.

Digs are certified based on direct measurement using a calibrated microscope. Scratches are certified based on comparison to previously certified scratch sets or direct measurement using the US Army owned Sira microscope image comparator. Certificate of Compliance is included with each set.

It is Brysen Optical’s goal to supply a standard that remains accurate in varying light levels, angles of view and will maintain this accuracy over a long period of time.

To view the Top 10 Scratch & Dig Questions click here.