FANUC has built intelligent robots to perform several tasks for stringer manufacturing in the aerospace industry. The robots affix the stringers to be trimmed and cut and routered with the proper holes using fixtures – devices that hold the composite parts in place. Since the composite parts are often flexible, the fixturing needs to be flexible, too. “You have to consider the stresses that you put on the part when you’re manufacturing. You don’t want to cause damage to the part when you’re fixturing it,” says Blanchette. Robots can also build up or sand down the parts based on feedback from tactile sensors, prep their surfaces for painting and precisely control paint application.
“You can reduce the amount of paint on the surface, significantly improve the appearance and still have the same protection and effect, thus further reducing the weight of the end product,” says Blanchette.
Using robots for many different tasks in metal parts production is a familiar practice for the automotive industry, observes Chris Greaves, operational manager at Factory 2050 at the University of Sheffield’s Advanced Manufacturing Research Centre (AMRC) in England. However, many of the jobs that robots have traditionally performed – pick and place, spot welding, gluing – require repeatability but not accuracy.
For a project with an automotive manufacturer, however, Factory 2050 researchers wanted to use a robot as a stand-in for a large CNC machine for edge-of-part trimming. That required greater accuracy. The AMRC team recalibrated the robot’s programs, relying on its repeatability. If the robot always missed a particular point by a millimeter in a certain direction, the researchers moved it the same amount in the opposite direction.