On Airbus aircraft, the undercarriage reinforcing is attached through
the lower wing skin using bolts up to 1- inch in diameter through as much
as a 4-inch stack up. This operation typically takes place in the wing
box assembly jigs. Manual hole drilling for these bolts has traditionally
required massive drill templates and large positive feed drill motors. In
spite of these large tools, the holes must be drilled in multiple steps to
reduce the thrust loads, which adds process time.
The GRAWDE (Gear Rib Automated Wing Drilling Equipment) is a wing-drilling
machine specifically designed for operations in the gear rib area of the
A380 wing. The machine drills fastener holes for the purpose of fastening
the gear rib reinforcing through the skin into the rib spar structure matrix.
Fastener holes in this area of the wing are as large as 1 inch in diameter
and 4 inches deep. Manually cutting these large holes is a multi-step process
using numerous pneumatic drill motors and drill templates. In the assembly
jig, this area of the wing extends just below factory floor level. High
fastener density, numerous drill motors and templates, and restricted worker
access to the reinforcing area for the workers creates a rate-limiting step
in the wing assembly process. The GRAWDE was designed to address these
challenges.
The GRAWDE can precisely position countersunk
fastener holes up to 1.25 inches in diameter through a 4-
inch stack. It has the ability to re-synch to a feature on
the wing or in the jig, drive to a precise location, adjust
for normality and drill a hole in a single shot. It
eliminates the use of pneumatic drill motors and
templates. It reduces drilling time to less than one
minute per hole, while producing superior quality holes.
The mobility of this machine provides maximizing of a
valuable capital asset over multiple parallel work zones.
When operating the GRAWDE, the operators stand on a moving platform 250 mm below factory floor and 500 mm above
the machine beds. From the platform, operators can reach the wing surface, operator controls and quill box for
changing tools. The platform has handrails and a gate on two sides, to protect the operator from falling and
to protect from shear points between the GRAWDE and assembly jig components. Manual access can also gained
by driving the GRAWDE away from the immediate area and standing directly on the machine bed.