For carbon-fiber structural content of the A350, the assembly issues with composites must be overcome. “It´s a costly problem” said Maria Weiland, R&T director at Saab Aerostructures and coordinator of the EU-funded Low Cost Manufacturing and Assembly of Composite and Hybrid Structures (Locomachs) project.
An example of the issues encountered in composite assembly is the vertical tail plane (VTP) of the A350.
Composite Technology Center (CTC) Stade, an Airbus company in Germany with Spanish Tier1 Aciturri, developed the next-generation carbon-fiber VTP, which is designed for highly automated assembly.
But problems with process stability and rate capability were encountered early in production, said Joachim Piepenbrock, head of production composite systems at CTC Stade, speaking at the JEC Europe 2015 composites-industry show in Paris in March.
The cost of “non-quality” –the costs incurred by having to inspect and sometimes scrap parts- was greater than 25% and the deviation in skin thickness ranged from +10% to -15%.
CTC embarked on a process optimization and rebalanced VTP production to a 2-shift from a 3-shift operation.
Vacuum bagging for autoclave curing of the parts was simplified and skin thickness adjusted, and “within 3 months we got to more than 90% good parts and a cost of non-quality less than 5%”, he said.
Locomachs tackles the assembly problem in many ways, from designing more integrated structures with fewer interfaces between parts that need to be measured, drilled, shimmed and joined, to robots collaborating with humans to move and position parts and drill&join structures in areas that are hard for person access.
The project is developing simulation tools to predict gaps and design shims for rapid additive manufacture, mobile systems for faster nondestructive inspection to keep parts moving, and flexible assembly tooling that can accommodate variations in part geometry.
Based on the article “Faster Carbon” published in Aviation Week.