Automatic Spar Assembly Tool 4

Boeing C17

Electroimpact designed and manufactured an Automatic Spar Assembly Tool (ASAT4) for Boeing's C17 program. ASAT4 is based on the concept of "in jig" assembly with a vertical yoke assembly machine. This ASAT configuration was initially implemented for the Boeing 737 and 757 programs. ASAT4 however offers an unprecedented level of flexibility along with many new features for improved process speed and control.

ASAT4 consists of a vertical traveling yoke machine which straddles the spar fixtures. Two fixtures placed end to end form a system approximately 220 feet in length which is serviced by a single machine. This allows manual operations, e.g. load and unload, to be performed on one spar while the machine works in the adjacent cell. Each fixture can accept any of the six C-17 spars. Fixture reconfiguration between spars is completely automatic. The single three axis yoke machine, the E5000, travels the full system length. The yoke is simply supported on the side of a rigid gantry structure. The E5000 has completely redundant tool heads on both legs of the yoke. This permits drilling and fastener insertion from either side of the spar.

  • Completely dual process
  • All tools are available on both spar surfaces with offset capability from either side
  • Tool transfer heads use dual linear motors with transfer speeds of 60 inches per second
  • Electroimpact 20,000 RPM spindles with automatic power drawbar and HSK50 tooling
  • Precision linear scales on all machine axes
  • X axis scales are 220 feet long
  • Rollup floors pass through the gantry