Electroimpact is improving the efficiency and reliability of the Boeing 777
spar assembly process. In 1992, the Boeing 777 spar shop installed Giddings
and Lewis spar machines with Electroimpact Inc. EMR (Electromagnetic Riveting)
technology. In 2011, Electroimpact began replacing the original spar
machines with next generation assembly machines.
The new carriages incorporate a number of
technical improvements and advancements over the legacy system. These technical
advancements have facilitated a 50% increase in average cycle rate, as well as
improvements to overall process efficiency, reliability and maintainability.
Boeing and Electroimpact have focused on several key technology areas as opportunities
for significant technical improvements.
As part of the spar assembly process, the machines must traverse a radial portion of the
box-way which follows a bend, or ‘kick’ in the 777 spar. The legacy machines are unable
to traverse this section at the standard cutting traverse of 400 Inches per Minute,
and instead must slow considerably during the kick motion. The new machines utilize the
high speed positioning capabilities of the Fanuc 30i controller, as well as using a
kinematic routine written by Electroimpact to facilitate motion through the kick of
at least 400 IPM.
Machine accuracy during spar assembly is highly critical, especially in areas where
reference holes (or ‘K’ holes) are drilled and later used to position aircraft components.
Compensation accuracy, and more importantly, flexibility was a key focus during the project.
In addition to this, the new carriages take advantage of a linear magnetic distance coded
scale which provides exceptional accuracy, reliability and flexibility, enabling the
operator to home the machine anywhere along the 50m long spar jig.
Finally, a critical development goal was to use the latest technology to enhance the
usability of the new system in an attempt to improve overall process efficacy. These
enhancements include a high resolution digital camera system and an advanced graphical
user interface for machine operation.