Dave,
Per our conversation earlier today regarding teledyne conf
coating issue, I contacted Fred Gross for some answers. See Below for issues
and solutions.
1) 4 hr Bake out of Assembly
prior to coating. Bake out to be 4 hrs @ 93C.
* Per Fred Gross the 60 minute cure @ 125c prior to coating is
equivalent to the required 4 hr
bake out.
2) Measuring the thickness
after application can be achieved by several methods:
* Using a coupon for measuring the cured material
* applying tape to the edge of the assembly and measuring tape
after application
* Using a wet thickness gauge.
Fred has provided us with information for the gauge manufacturer.
(KTA-TATOR)
1-800-433-5477
3) The thickness requirement
for polyurethane is .001-.005 per NASA-STD-8739.1
* If for some reason Teledyne cannot meet the .005 maximum
thickness requirement there needs to be
a deviation waiver submitted stating that the requirement
cannot be met and some mass and design
evaluations will be required. Hopefully with the proper tolls
the thickness measurements will be
easier to obtain and will meet the specified requirements.
4) The use of an
Ultra-Violet light source for inspection.
* The material being used contains the light tracer needed to
perform ultra-violet inspection.
Therefore, the only materials needed would be the actual
light source the Darkened area in
which to perform the inspections. Additional training will be
required for all
personnel that will be performing the inspections.
5) All acceptance and
rejection criteria shall be derived from either NASA-STD-8739.1 or the
amended document that Nick Virmani sent you referencing the
J-STD series for assembly and coating
applications. There are
some requirements not called out in the amendment that need to be included
( coating thickness ). Please use both documents when detailing
a process for Teledyne conf coating
applications.
Please let me know if I can be of any further help in establishing
this process.
Tracy L. Shepherd
Sr. Quality Engineer
GSFC-NASA Mission Assurance
GLAST Large Area Telescope
Project
Stanford Linear Accelerator
Facility
2575 Sandhill Rd.
Menlo Park, Ca 94025
650-926-2812 Phone
650-926-4979 Fax
888-264-9421 Pager