Journal of the Textile Machinery Society of Japan

The effects of the cylinder speed (250 to 600rpm), taker-in speed (600 to 1, 500rpm), doffer speed (15 to 33rpm), sliver weight (4 to 8g/m) and production rate (16 to 34kg/hr) were investigated on a high production card with the following results:
1) The optimum speeds of the cylinder and the taker-in are 400rpm and 1, 000rpm, respectively, from the viewpoint of yarn quality.
2) Increasing the sliver weight up to 6g/m does not deteriorate the yarn.
3) Increasing the production rate in proportion to the doffer speed does not deteriorate the yarn.
4) Keeping the sliver weight at 6g/m and using a high speed web doffing unit may increase the production rate up to 57kg/hr without deteriorating the yarn.

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The question of why thick and thin places are produced in fabrics during weaving still awaits a complete solution. In an effort at a solution, we have analyzed warp tension.
We believe thick and thin places are produced mainly by variations in warp tension which are generated by the dynamic displacement of tension rollers of the free-oscillation system.
Acting on this belief, we have analysed the relation between warp tension and factors which generate the dynamic displacement of tension rollers.
The analysis has led to a basic theory on the causes of thick and thin places. From it we have deduced the following conclusions.
(1) Analytical equations have been deduced, which have been proved, by measurements, to be useful for clarifying the causes of thick and thin places.
(2) Warp tension in thin fabrics is influenced mainly by external force generated by shedding. Warp tension is given nearly exactly from the difference between variation in warp lenght and tension roller displacement.
(3)Variations in warp tension at the start or at a stop differ from that in stationary running state. This difference presumably influences set-mark in fabric.
The analytical equation which enables variations in warp tension theoretically to be described is believe, to serve as a means to prevent set-mark.

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