In the beginning there was an altimeter - Meggitt PLC

TONY’S TOUR
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urethane. The orientation of the fabric ply,
its thickness and the way it is woven is the
secret of impact resistance and strength.
McCann is also keen to draw attention
to the challenge—not shared by many other
Meggitt facilities—that material instability
presents to continuous improvement
initiatives. Fabrics and other materials
must be refrigerated in rolls and boxes to
keep them fresh and stable before being
acclimatised for manufacturing. He explains:
“After you cement two pieces of rubbercoated
nitrile fabric together, there is a point
when you peel them back, when you will see
spider legs. That’s the optimal time to stick
the fabric together. If you do it too soon, you
won’t get it and if you do it too late it won’t
work either.”
Another set of variables arises during
manufacture. Until recently, a MPC
Rockmart tank was made from
start to finish by one person. Now, teams
are increasingly being brought into play in
new ‘start’ and ‘build’ areas where batch
production (one person: one tank) is being
exchanged for flow set-ups (one tank: five
people). “Visibility boards” (white boards
constantly updated with output data) and a
system of little coloured flags highlighting
the completion of a manufacturing
sequence—or a problem—evidences this
step-change in manufacturing process.
Using the production metronome of ‘Takt
time’ to pace key stages of production using
a team, McCann expects to double output.
He points to five stations in a straight line.
“On this programme, we will be able to shoot
a tank out every 90 minutes instead of five
tanks a day.” With demand for the life-saving
military tanks high and competition never far
away, around 20 fuel tank programmes are
being converted now. Virtually all production
will be converted to flow over time. (See ‘Why
Sam got rhythm” and “What the coach said”
on pages 30 and 31).
With fuel cell production process spread
over multiple floors, much creativity has to be
employed to create flow. The MPC Rockmart
team seems to be infinitely resourceful.
“You wouldn’t build a factory like this now,”
McCann says, before recalling: “A couple of
years ago, I was really proud of our crew—
we shuffled around 140,000 square feet of
building to bring in the KC-135 programme
and expand our ice guards business.”
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REVIEW | WINTER 2010
McCann highlights the plant’s training
area, a space off a long corridor, and with
great affection its original—and gleaming—
hardwood floor made from Canadian lumber.
Refurbished in 2009, training houses a
conference room and offices for four fulltime
trainers and a part-time retiree with
35 years’ invaluable experience. Operators
receive extensive training before they go on
to the shop floor, every six months after that
or when they go into a new area.
Exceptional attention to detail must
be paid at every stage of the tank-making
process. McCann explains: “It takes real
dexterity and workmanship to make these
components and not everyone is suited
to it. There is a skill to putting this cloth
on to meet the requirement and if you get
overgenerous with your cement or get sloppy
with your plies, the tank will be overweight
and have to be scrapped.”
Each fuel cell type requires its own
set of manufacturing instructions and
Rockmart’s industrial engineers work closely
with the training department to standardise
and document the build, sequencing,
measurement and positioning of components
so fundamental to McCann’s pursuit of flow
production. Now all first-time programmes
are developed by trainers and operators and
‘debugged off-line’. McCann explains: “In the
past, we would get a tank out on the shop
floor and iterate a process there. Now the
tank form follows the specification—not the
other way round.”
Patterns for fuel tank and ice guard
moulds and a seemingly infinite
range of composite product shapes
are downloaded from the engineering
department in an adjacent building, captured
by a giant digital camera and fed to the
cutting centre here in the old mill. Multiple
automated cutters cut anything from single
to multiple ply coated fabrics, cardboard,
gum for self-sealing fuel tanks and collars
for tank fittings. To minimise waste, digitised
patterns that can be cut in the same material
are nested by engineers using real-time
digital feedback. These machines, which
originated in the garment manufacturing
industry, resonate with the factory’s textile
history, just like the software used to make
the fuel tank’s fabric flanges: when 30 holes
are cut for bolts in a fuel tank flange, a machine
ingeniously adapted by MPC Rockmart engineers,
thinks it is cutting 30 shirt button-holes.
Visitors are always
overwhelmed by the Who’s
Who of the US defence
industry present in tanks for
UAVs, missiles, military jets
and helicopters covering all
branches of the services
McCann explains that the iterative
prototyping enabled by these cutting
machines is a vast improvement on his
earliest days at Rockmart, which involved
clicking dies—giant steel cookie cutters
for cardboard, cloth and fabric still used
for product lines not yet converted for
computerised modelling.
Today, MPC Rockmart’s engineers
create a solid model of the cavity that will
hold a fuel tank. Software enables it to be
‘unfolded flat’ in the form of data sent to the
cutting room where the cut-out is crafted
into a 3-D shape. After minor modification,
Part of MPC Rockmart’s art is the design of fittings for very complex
contours and dimensions, adapting a process that harks back to
tyre-making in the Goodyear days
this prototype will be ready for production
tooling, “minus the imperfection we had to
work around in the old days,” says McCann,
emphasising: “These days, we won’t hard
tool anything until we get it the way we want.”
Customers commonly provide the
specification of a cavity but MPC Rockmart
engineers will challenge the spec if airframe
and cavity modifications will enable lighter
constructions, devoid of heavy corner and
edge reinforcement, that still meet the
customer’s specification.
Large wooden structures are used to
create disposable cardboard forms for the
largest tanks. Operators nail a jigsaw puzzle
of pre-cut cardboard pieces around them and
line interiors with foam or cardboard. Once
assembly is complete, the structure is removed,
leaving the disposable cardboard tool.
The grind of circular saws and the
smell of dust announces the shop where
operators “curf” (buff and grind) the edges
of cardboard forms intensively to create the
smoothest possible surface. “It is always
amazing to me what we are able to make
in terms of complex shapes. Our operators
do some miraculous things with cardboard
and masking tape,” says McCann. Layers
of cardboard are removed gingerly without
breaking the skin of the form and key
surfaces are taped over tightly—any defect in