Flynn, R., Payton-Stewart, K., Brewer, P., and Davidge, R., "Unique Material Handling and Automated Metrology Systems Provides Backbone of Accurate Final Assembly Line for Business Jet," SAE Technical Paper 2016-01-2104, 2016, doi:10.4271/2016-01-2104.
Figure 1Global 7000 Business Jet. Photo credit: Robert Backus.The customer’s assembly philosophy demanded a fully integrated flexible pulse line for their Final Assembly Line (FAL) to assemble their new business jets. Major challenges included devising a new material handling system, developing capable positioners and achieving accurate joins while accommodating two different aircraft variants (requiring a “flexible” system). An additional requirement was that the system be easily relocated to allow for future growth and reorganization.Crane based material handling presents certain collision and handover risks, and also present a logistics challenge as cranes can become overworked. Automated guided vehicles can be used to move large parts such as wings, but the resulting sweep path becomes a major operational limitation. The customer did not like the trade-offs for either of these approaches. A unique conveyance system (ATLAS) based on in-floor rails was developed to offer a solution that provides highly controlled, low risk and accurate moves that allow workers and tools to remain in the assembly area. Positioners were developed, some of which include a driven passive axis (DP axis), useful in certain conditions for driving positioners in their passive axis.Accurate and rapid joins required an advanced metrology solution. Integrating this automated metrology based positioning system posed a challenge. The accuracy requirement meant that the system had to measure and accommodate slight differences between the incoming parts i.e., be an “adaptive” system. A Human Machine Interface (HMI) was developed to enable de-skilled automated metrology and to communicate with the metrology and PLC systems. The HMI presents a virtual task checklist and restricts the user from deviating from the order of operations or omitting any tasks. Established tolerances must be achieved before proceeding to the next task. A robust architecture allows failed tasks to be re-attempted without restarting the join process, resulting in a forgiving and flexible process. Integrated supervisor-override privileges make it possible to execute alignment adjustments if dictated by engineering or circumstance.