technology today 2005 issue 4 - Raytheon

MATERIALS AND STRUCTURES
Engineering
Environmental
Performance
for Mission
Assurance
The ultimate goal of Mission Assurance in
engineering is to produce superior products
through engineering excellence. Every day
engineers integrate products from all
aspects of the product life cycle to create
the best final output that meets the customer’s
requirements and fulfills its end-use
objective. The evolution of environmental
compliance is a prime example of this in the
mechanical and materials area.
Environmental requirements are constantly
changing programmatically and globally;
our customers demand compliance without
compromising reliability or performance.
Engineering communities all over Raytheon
have been working these issues for over
10 years with the ultimate goal being to
balance environmental compliance and
performance. The following are some
examples of successes in this arena.
Network Centric Systems, Precision
Technology, Lemmon Ave, Dallas —
Eliminating Environmental Hazards
at the Design Level
Our process engineering efforts in Raytheon
Precision Manufacturing (RPM) include a
strong focus toward elimination of hazardous
materials. The approach includes our
process engineers, our Environmental
Health and Safety team and our operators.
A key place in the engineering process
where there is a large impact to environmental
requirements is the elimination of
materials used by design mandate. Through
concurrent engineering development of
new part designs, process engineers recommend
materials and processes that provide
the lowest net use of hazardous materials
while still meeting design performance
requirements. Making progress in these
areas requires coordination between
Design, Manufacturing and industry
specification organizations. Specific
examples include:
Replaced chromium plating with electroless
nickel plating in all but the most
demanding wear resistance applications.
At this point, we fabricate only two legacy
parts that require chromium plating.
22 2005 ISSUE 4 RAYTHEON TECHNOLOGY TODAY
Encouraged designers to select chemical
finishing process options that do not
mandate chromate seal steps (anodize,
passivate, etc.).
Developed two new aluminum casting
alloys (F357 and E357) to replace beryllium-containing
versions (A357 and D357).
Today, all castings sourced by RPM permit
the foundry to use the beryllium-free version.
As these new alloys become the primary
available material, future designs
will mandate the beryllium-free version.
Created a performance-based paint specification
(rather than “chemical formulation
based”), so designers can specify a
level of performance, yet allow manufacturers
to apply the most environmentallyfriendly
qualified paint system that meets
these requirements. This approach was
required due to the moving target of
paint formulations and air permit requirements
from state to state. The solution
involved a Joint Group on Acquisition
Pollution Prevention (JGAPP) Single
Process Initiative Block Change that
allowed implementation for the range of
programs we support.
This is not an exhaustive list, just a summary
of some of the projects supported. Our
process engineers keep these principles in
mind as they develop and maintain the
processes under their cognizance. Rich
Spitzer, process engineering manager for
RPM, can provide a more recent update.
Raytheon views the subject of hazardous
material elimination as a process — not a
destination. It is a marathon, not a sprint.
There will always be an opportunity to
make our designs better, our workplace
safer and our environment cleaner.
Space and Airborne Systems (SAS)
Engineering, McKinney, Texas —
Chromate Replacement on Fasteners
The F-16 MMC program out of SAS in
McKinney, Texas has recently completed an
effort to replace zinc chromate for wet
installation of fasteners. It was imperative
that our selection of an alternative needed
to survive future environmental restrictions,
such as VOC reduction and the elimination
of carcinogens and teratogens, while maintaining
the high standard of performance
we have delivered for decades. Engineering
analyzed several possible alternatives
against criteria in categories including environmental
health and safety (EHS), performance,
procurement and producibility.
Ultimately, MIL-PRF-85582 Class N was the
most environmentally friendly, however
water-borne primers are not recommended
for wet installation of fasteners. Therefore,
we decided to use MIL-PRF-23377 Class N
which has two vendors approved for the
qualified product list, was the next best
ranked in the EHS criteria, and outperforms
the baseline zinc chromate. Although the
MIL-PRF-23377 Class N still contains some
VOC, the elimination of hexavalent chromium
is an important step toward meeting all
of our future environmental compliance.
Integrated Defense Systems
Engineering, IADC, Andover, Mass. —
Water-Borne Chemical Agent Resistant
Coating
In 2005, Patriot, HAWK, CLAWS, SLAM-
RAAM, and JLENS changed the baseline
paint topcoat material used on all equipment
from a solvent-based coating to a
water-dispersible material. For the past 25
years, the Army has required that all ground
equipment be painted with a solvent-based
chemical agent resistant coating per specifications
MIL-C-53039 or MIL-C-46168.
Recently the Army Research Lab developed
a water-dispersible material which conforms
to specification MIL-DTL-64159. The performance
properties of the new material are
equal or better than the solvent-based system.
The water dispersible material offers
improved flexibility, color retention and mar
resistance. Material conforming to specification
MIL-DTL-64159 contains zero hazardous
air pollutants and 60 percent fewer
volatile organic compounds. In addition to
the environmental benefits offered by the
paint material as packaged, additional VOC
reduction is realized because the material is
thinned with water, and spray guns and
equipment may be cleaned up with water
as well. All future Army programs will incorporate
MIL-DTL-64159 into the design.
Robert Steffen
r-steffen@raytheon.com
Meredith Bonin
meredith_l_bonin@raytheon.com
Michael Chittick
michael_e_chittick@raytheon.com
YESTERDAY…TODAY…TOMORROW