Friot, D., Meiffre, L., and Vandaele, C., "LISI#OneSide, a Set of Solutions for Efficient Blind Fastener Installation," SAE Technical Paper 2017-01-2098, 2017.
With air traffic demand constantly increasing and several years of aircraft production in their backlog, major aircraft manufacturers are now shifting their focus toward improving assembly process efficiency. One of the most promising solutions, known as “One Side Assembly”, aims to perform the whole assembly sequence from one side of the structure (drilling, temporary fastener installation and removal, blind fastener installation, assembly control) and with a high level of integrated automation.A one-sided, or blind fastener that is capable of matching the performance of current two-sided structural fasteners while meeting volume and cost objectives can be a major driver for assembly process efficiency improvements. To achieve a blind fastener assembly capable of both fully automated and manual installations while providing robust cycle times and assembly cost reductions is full of challenges. Figure 1OPTIBLINDTM fasteners familyThe first key challenge to overcome is at the mechanical interface between the end-effector and the blind fastener being installed. One can imagine the ease with which human operators can hold a fastener with complex geometry and introduce the fastener to a hole regardless of direction and orientation. In a simple example of being unable to maintain coaxial alignment between the blind fastener and installation nose of the end-effector, the robot can bump into the structure and potentially cause damage or cycle interruption. To overcome this challenge, both the end-effector of the robot and the blind fastener need to be perfectly in sync to repeatedly and reliably pick up and install the blind fasteners.Another important challenge is to provide real-time control and validation of the assembly and installation. Because of the lack of visibility to the blind side of the assembly, it is difficult for human operators to visually check the fastener installation with traditional gages. In order to overcome the challenge of providing assembly installation control, the blind fastener design should take advantage of predictable material deformation properties, and the installation tools should record key installation parameters through sensors and logic integration. With this combination, real time installation analysis of a blind fastener assembly becomes a reality.This presentation will focus on technologies developed by LISI AEROSPACE to bring about a breakthrough “One Side Assembly” based on the combination of OPTIBLIND™ fasteners and a variety of tooling options integrating features and controls necessary to overcome the main challenges of full one-side automation.