TM-1-1500-344-23-2
AIRCRAFT VOLUME II
TECHNICAL MANUAL; CLEANING AND CORROSION CONTROL
APRIL 2009
TM-1-1500-344-23-2 - Page 233 of 240
B-31
NAVAIR 01-1A-509-2
TM 1-1500-344-23-2
15 April 2009
c. Dust Monitor. The dust monitor equipment shall
be capable of continuously monitoring explosive
conditions of air in the facility.
d. Safety. Walk-in room operator safety equipment
shall include a carbon monoxide monitor, respiratory
equipment, blast hood and hearing protection. Safety
equipment shall be as specified by the cognizant Safety
and Industrial Hygiene Department.
e. Maintenance. The Walk-In Facility shall be
operated and maintained in accordance with the
equipment manufacturer's instruction manual.
B-27.5. PMB PROCESS.
B-27.5.1.
General Requirements.
B-27.5.1.1.
The PMB blast shall be kept moving in an
even sweeping motion and not allowed to dwell over
one spot while maintaining stand off distance and
nozzle angle.
B-27.5.1.2.
The PMB operator shall stop the process
immediately when any abnormality in the process is
observed or damage to the substrate is noticed.
Sometimes the coating scheme may be different than
expected, media characteristics may change, air
pressure may fluctuate, etc. The anomaly shall be
corrected or appropriate changes made before
proceeding.
B-27.5.1.3.
An operating procedure or processing
sheet shall be developed for each part and shall include
the following:
a. P/N, substrate (including plating), and
identification of film to be removed (indicate limitations).
b. Part preparation, including cleaning and masking.
c. Media type, specification.
d. Air pressure.
e. Flow rate.
f. Stand off distance.
g. Angle of impingement.
h. Maximum dwell time.
i. Post processing cleaning, inspection, flow.
j. Special instructions.
NOTE
The aircraft component DMWR or TM may
exclude certain parameters as stated above,
as required.
B-27.5.1.4.
The air pressure selected for removal of
organic coatings shall be within 25-40 psig, unless
otherwise specified in the aircraft component DMWR or
TM.
B-27.5.1.5.
The air pressures selected for general
cleaning and removal of oxides and carbon deposits
shall be within 15-25 psig, unless otherwise specified in
aircraft component DMWR or TM.
B-27.5.1.6.
The angle of impingement shall be within
45-90 degrees, unless otherwise specified in aircraft
component DMWR or TM.
B-27.5.1.7.
The minimum stand off distance of nozzle
to work place shall be 2 inches unless otherwise specified
in aircraft component DMWR or TM.
B-27.5.1.8.
Metal parts with wall thickness less than
0.032 inch shall not be PMB processed.
B-27.5.1.9.
Parts and components must be free of oil,
grease, dirt, or other contamination, and shall be air
dried prior to PMB blasting.
B-27.5.1.10. Masking of aircraft component parts shall
be as required in order to protect sensitive areas, areas
that do not require PMB, or that require a different PMB
process, and to avoid media intrusion in internal
passages or bearing surfaces. The following masking
methods are acceptable as required.
a. Tape, impact resistant, 3M 500, BT 100, or
equivalent.
b. Plugs, oversize, tapered, made from Neoprene
rubber are recommended.
c. Bags.
d. Fixtures and covers.
e. BER mating parts.
f. Molds.
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