||Technology in Australia 1788-1988
Table of Contents
I 1788 - State Of The Art In Textile Technology
II Australian Textiles - The Early Days
III Australian Textiles - The 20th Century
IV Australian Textiles - To Date
i Narrow-tape Weaving Loom and the Nyguard Zipper
ii Vacuum Packaging System for Knitting Yarns
iii 'Computer' Socks
iv 'Jumbo Cakes' (Large Cheeses of Spun Yarn)
v Out-Draw Texturing - Nylon
vi 'Bored-Out' Pack
vii Computer Control of Heat-Setting Conditions for Synthetic Yarns
Out-Draw Texturing - NylonEarlier in the history of false-twist texturing, when only 'slow spin' feedstock was available, a two-stage process was used -draw-twisting of the spun yarn on one machine followed by texturing the drawn yarn on another machine.
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.
Organisations in Australian Science at Work - Fibremakers Pty Ltd
© 1988 Print Edition pages 303 - 304, Online Edition 2000
Published by Australian Science and Technology Heritage Centre, using the Web Academic Resource Publisher