Knowledge of problems, even relatively minor items, is essential for improve-
ment in the NDI program, the materials specification, and qualification
testing. Information copies of written correspondence concerning unsatisfac-
tory penetrant materials SHALL be furnished to AFRL/MLSA, 2179 Twelfth
Street, Ste. 1, Wright-Patterson Air Force Base, OH 45433-7718.
Unsatisfactory materials SHALL be reported in accordance with T.O. 00-35D-54 (Air Force) or AR 735-11-2
(Army). A copy of the quality conformance test report SHALL be included as substantiating data. Air Force
NDI Program Office, AFRL/MLS-OL, 4750 Staff Dr., Tinker AFB, OK 73145-3317; DSN 339-4931 is the item
manager for penetrant materials. They may be contacted for assistance when preparing a material
deficiency report. (For Navy: Commanding Officer Naval Aviation Maintenance Office, Attn.: NDI PM,
Patuxent River, MD 20670; for Army: Commander, AVSCOM, Attn.: AMSAV-MC, 4300 Goodfellow Blvd., St.
Louis, MO 63120-1798).
Monitoring Process Performance (Stationary Inspection Units).
Description of Process Monitoring Device.
An example of a process monitoring device is the Penetrant System Monitor (PSM), also known as the star
burst panel. The PSM is alternatively specified as Pratt and Whitney TAM Panel 146040, Sherwin
Company P/N PSM-5 and Magnaf lux Company P/N 198055. The panel is especially suitable for high volume,
semi-automated, and fully automated depot systems. It is intended to be used as a daily or weekly monitor of
the entire penetrant process. When properly used, the PSM will signal changes that would affect the
integrity of a penetrant inspection process, changes that may have occurred in the materials, equipment or
procedures. It is not a substitute for the cracked chrome plate panels that are used to compare the
performance of the materials in terms of sensitivity.
The PSM is a stainless steel panel measuring 4 inches wide by 6 inches long. A chrome-plated strip runs the
length while the other side is a medium roughness, grit blasted surface. The chrome-plated strip contains
five, evenly spaced, crack centers. The crack centers are in circular patterns varying in size from about 1/4-
inch diameter down to about 1/32-inch diameter, and are arranged in order of magnitude. The cracks radiate
from the center in a star or sunburst pattern. No two panels are completely identical. Crack patterns and
sizes vary from panel to panel. The panels are supplied in sets of two, with the supplier matching the panels
as closely as possible. One panel is reserved for use as a reference or transfer standard while the other is
the working panel.
The PSM can monitor the entire process because it can be processed directly in the working tanks along with
production parts. In addition, the grit blasted strip will separately indicate the effectiveness of just the
removal process steps. One disadvantage is that small or gradual changes are not readily noticed.
Furthermore, as with cracked chrome plate panels, the PSM indications deteriorate with handling and
repeated use. Also, the PSM panel can retain large amounts of residual penetrant, so careful and thorough
cleaning is mandatory.
The 50m and 30m panels are usually used with low and medium sensitivity penetrants. The 20m and 10m
panels are usually used with high and ultra-high sensitivity penetrants. The standard panel is the 20m
panel. After the 2.80 inch wide plate is plated and cracked, it is cut in half, lengthwise. This produces two
panels containing symmetrical crack patterns in each panel. Since the cracks extend across the original
panel, the two panels are provided as a set with each panel measuring 3.94 inches (100 mm) long and 1.38
inches (35 mm) wide.