Out-Draw Texturing - Nylon

Integration of these two processes offered substantial reductions in labour costs and capital equipment investment. For polyester and 'high speed spun' nylon feedstock (P.O.Y.), a technology was developed overseas for an integrated drawtexturing process. This method was known as 'in-draw' because the yarn drawing occurred simultaneously with the heating and twisting elements of the process. Unfortunately, low orientation nylon yarn does not respond well to this technique, because it is difficult to optimize properties such as extensibility, shrinkage and bulk in a single operation.

To overcome these difficulties with 'slow spin' nylon yarn, Fibremakers developed an integrated 'out-draw' process for the Barmag texturing machine, where a separate drawing step precedes the heating/twisting stage.

The main problem was to optimize the draw ratio and yarn tension so as to maintain threadline control but avoid overstressing the yarn, which results in broken filaments and low quality yarn. A further problem was a tendency towards lean (thinner) ends (high twist/low bulk) arising from the sensitivity of the process to any misalignment of the casablancas. This was overcome by replacing the casablanca system by a string up using a single wrap around a nip roll, which gave complete threadline control.

Australian Academy of Technological Sciences and Engineering