In order to discuss the influence of the top cradle on yarn quality,the function of the top cradle in the drafting system and the technological properties requirements of the top cradle in the drafting system are introduced.The shortcomings of 6833 series top cradle,such as large running resistance of upper apron,unreasonable distribution of friction field in the middle and anti-enveloping arc on the front cot are analyzed in detail.The technological performance,tech-nical advantages and existing problems of 6839 series and 6839PLS extended top cradle are compared.Through spinning cases,it is shown that 6839 and 6839PLS extended top cradle have advantages in improving yarn evenness irregularity,nubs and fine ends,neps and so on.The matters needing attention in using extended top cradle are summarized.It is pointed out that the yarn quality can be effectively improved by optimizing the key dimension parameters design of extended top cradle and conforming to the concept of flexible drafting.In using,the coordina-tion of various process parameters should be paid attention to,and the critical drafting process state should be avoided,ensuring the long-term stability and consistency of spinning quality.
extended top cradle6839PLSfriction fieldfloating areaaprondrafting forcecon-trolling force
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