Method and apparatus for spreading fiber bundles

摘要

A system for spreading a multi-filament bundle of fibers such that most of the individual fibers are exposed for various treatment and coating processes is described. The system is particularly suited to, but not limited to, carbon fiber applications. In such applications it is desired to spread carbon fiber tows consisting of anywhere from less than 1,000 to in excess of 144,000 individual filaments such that a significant portion of the filaments are exposed for processing. A spreading system can consist of one or more individual spreaders placed in series to achieve a desired spread. Each spreader consists of expandable bands, an expandable tube, or a compressible and expandable piece of foam placed between two angled support discs. The discs are angled away from each other such that the bands, tube, or foam between the closest points of the angled discs will stretch or expand as the support discs rotate about their respective axes. The fiber bundle enters the spreader at the point where the discs are closest together and exits at the point where the discs are furthest apart. The bands, tube, or foam therefore support the incoming fiber bundle and stretch or expand to an established width, thereby separating a portion of the individual filaments. Changing the angle of the support discs can control the amount of stretch. As the angle is increased, the overall stretch or expansion that the bands, tube, or foam are subjected to will increase, thereby increasing the filament separation of the fiber bundle. One or more spreaders can be placed in series to obtain a desired spread beyond the capabilities of a single spreader. The spreaders can be free spinning or motor driven depending upon the application.