Reconfigurable Composite Tooling at Spirit Aerosystems
Spirit Aero and Spintech develop a new approach for complex structures
One problem in advancing uses of composites is the limitation on shapes imposed by tooling. Complex shapes are difficult to achieve and require purpose built tooling. In a press release dated June 17, 2013, Spirit Aerosystems announced “a new reconfigurable tooling technology for manufacturing complex composite aircraft structures. The solution uses re-formable, reusable mandrels to form complex, highly integrated composite structures, with features that are not possible with traditional tools.” The press release also noted that “Spirit's version of the technology, which includes enhancements to enable large, integrated, single-sided reinforced structures, is known as InflexionTM.”
The release quotes Bill Smith, acting director of technology development at Spirit: “The degree of integration of composite structural components has been limited to date by current tooling methods. InflexionTM breaks through this barrier by providing tooling that can change states through the layup and cure phases, allowing for extraction of the tool in spite of trapping features which would hinder current tooling methods. This enables, for example, the full integration of skins, stringers, and frames or ribs in one step.”
In related reporting, American Machinist (6/17, Brooks) reported that the technology is based on shape memory polymer technologies. “Shapes with complex geometries or “trapped features” are expensive and labor-intensive to produce, and with related low rates of production. Some such shapes cannot be produced at all. The reconfigurable tooling capability that Spirit has licensed from Spintech Ventures LLC changes these assumptions.”
According to the Spintech website, when a Smart Mandrels blank is heated above a transition temperature, it can be formed into shape and cooled. In its new, complex shape, it is then used to create parts using traditional automated lay-up techniques. When reheated, the mandrel recovers its original, simple shape for easy extraction and re-use.
Above a transition temperature, a flexible mandrel from Spintech Smart Tooling is pushed against a mold using interior air pressure. The mandrel is cooled in its new shape, which is recovered to its original tube when reheated.