Fabrication Of Composite Tape From Thermoplastic Powder-Impregnated Tows

Recent automated manufacture of thermoplastic matrix composites has focused on the use of multi-tow heated head placement machines employing narrow consolidated ribbon. Use of narrow ribbon allows small turning radii and less edge scrap when cutting and adding individual tows. However, in applications where only moderate curvatures exist, such as aircraft wings and fuselages, narrow ribbon placement is inefficient Placement of wide tape is one way to achieve the high lay-down quantities per hour needed for commercial applications. Benefits also include fewer gaps and laps between sequentially placed material and correspondingly better quality.As part of ongoing composite materials forms research at NASA Langley Research Center, a previously developed process for making narrow thermoplastic ribbon was modified and extended to make a 7.6 cm (3 in)-wide tape. Improvements were made in tow heating, design of the holder for the stationary bars, and design of the contoured nip-rollers. A processing window for producing high quality well-consolidated tape was established. Tape samples were hand laid and compression molded into laminates that exhibited good mechanical properties.