Production Implementation of a Multi Spindle Flexible Drilling System for Circumferential Splice Drilling Applications on the 777 Airplane

With the recent development of a multi spindle flex track drilling system for aerospace applications, the challenges of testing and implementation on existing airplane programmes require unique technical methodologies and solutions. This paper discusses the technical approach, problems encountered and methodologies/solutions used to successfully implement a multi spindle flex track drilling system for circumferential splice drilling on the 777 airplane. The multi spindle system uses varieties of flex track carriages attached to flexible vacuum tracks for wide inside drilling. The hardware and software challenges encountered during the interfacing of the multi spindles are discussed as well as the complex problem of indexing and locating all detailed components of the splice accurately and with high repeatability. Design changes completed to make the equipment production ready along with the key hole feature probing hardware (Renishaw, Laser & Vision) and techniques are also presented in this paper. The usage of carbide drills with unique carbide material specification and drill geometry design is presented as part of the tool life optimization process. NC programming techniques and algorithms used to compensate for contour variability on circumferential splices are also discussed. Material handling equipment design and implementation process for this multi spindle flex track drilling cell is provided. The detailed test plan along with the incremental implementation methodology used to establish first a stable, then a robust and ultimately a completely optimized process with all technical variables accounted for is presented through the body of this paper.