| Abstrakt: |
Today, large aircraft components rely on automated fiber placement (AFP) processing followed by an autoclave cure. High-speed AFP processing has proven very effective for insitu layup using thermoset materials on latest generation AFP equipment. There remains, however, a substantial opportunity to utilize thermoplastic pre-impregnated (prepregs) for large structural components in commercial aircraft. Thermoplastics have an advantage of weldability as compared to thermoset materials. This advantage hasn't been realized because most thermoplastic research has centered around full insitu consolidation intending to eliminate post-processing for curing. The main restriction of full insitu consolidation is on the speed (and productivity) of the AFP process, which is limited by the physics or chemistry of thermoplastic materials. This method places all the demands of final part quality (low porosity, proper crystallinity and autohesion) on the AFP process. In addition, the insitu consolidated AFP process is further complicated by being sensitive to the quality of the raw material, which can vary greatly from supplier to supplier and for each material matrix. In the continual pursuit of cost and production time reductions, the efforts to optimize thermoset AFP processes have focused on advances in higher processing reliability and automated in-process inspection methods continue to increase AFP cell utilization to AFP4.0 levels. Specifically, for thermoplastic materials, new advances, like the Variable Spot Size (VSS) laser, enable thermoplastic material to better compete with thermosets. There are also new Out-of-Autoclave (OOA) postprocessing methods being developed that can achieve the proper crystallinity and autohesion while reducing cure time. By implementing these advances together, AFP4.0 can achieve 4x-6x increases in rates and the advantages of thermoplastic materials can be realized for large structural parts. [ABSTRACT FROM AUTHOR] |
