Hair severity: a new yarn hairiness parameter

Introduction:

Hairiness denotes the extent to which fibres protrude from the yarn body. Hairiness is an important surface property which has a direct impact on the performance of the yarn in the subsequent processes. It also has a bearing on the feel and appearance of the fabric. Certain minimum amount of hairiness is desirable for converting the yarn into fabric. However, when the length of the protruding hair crosses a critical limit, it poses severe constraints during fabric formation in Weaving and Knitting. The fabric quality also gets degraded due to Pilling and Fuzzy appearance created by the longer hairs.

Hairiness is a highly variable parameter which is influenced by various factors like Raw material quality, Process parameters in Spinning preparatory, Ring frame and also at Winding. Controlling longer length hairs is of primary importance for a yarn to perform better in subsequent processes. Increased production rates and Compact Spinning technology necessitates precise measurement of yarn hairiness deviation.

An innovative concept of estimating the Hair Severity (HS) has been dealt here.

The need for a New Hairiness Parameter:

• Improved measurement of true hairs
• Selection of suitable yarn for subsequent processes
• For easy internal process control

Hairiness index, is not the true representation of Hair count distribution, as hairs irrespective of its length are related over one centimeter length of the yarn. This effectively means that hairs of longer length are not significantly represented here. Similarly Hair Count from 3mm to 10mm involves a complex procedure to analyze and then relate it with practical Spinning mill environment. H3 the associated parameter with Hair Count is also losing its importance as it is increasingly getting difficult to monitor and analyse a 3~4 numeric digit as the value changes to a great extent. Since the application of both the Hair Count and H3 often calls for skilled technicians to decide upon a comprehensive solution, Premier has evolved a new parameter Hair Severity (HS).

Two yarn samples may have similar Hairiness Index value, but they will have different HS value based on the hairs distribution. For the spinner, HS serves as an excellent process control tool For the yarn buyer, HS helps to distinguish yarns for a given end use, whether it is for Knitting or Weaving. An example of HS is given below.

Yarn Count: 40s Nec

In the above example there is not much difference in the Hairiness Index values. Although there is a difference in H3, these values fluctuate to a great extent which makes it difficult to monitor and use it as a tool. But there is significant difference in the Hair Severity values.

Testing Hair Severity at high speeds:

Premier iQ Qualicenter & Tensomaxx 7000 together make the most versatile yarn testing equipment

Studies on Hair Severity

Studies were conducted across the different Count and Material. 73 mills participated in this study and Hair Severity has been computed based on the mills information. All samples were tested under controlled Lab environment. Samples were tested at 400mpm and 50mpm. Good Co-relation has been observed as shown below.

Premier recommends testing of Hair Severity (HS) at 400mpm, which is a universally acceptable testing speed for testing Yarn Hairiness Index (HI) and Hair Count (HC), Evenness and Imperfections simultaneously. Similarly controlled studies have also been conducted to find out the effect of Ring frame process parameters on HS and also the effect of HS on Knitting and Weaving performance.

HS Statistics 2007

Distribution across count and material

Tool to understand the prevailing Quality level

Bench mark the quality against the best

Count wise HS

Hair Severity has been arrived at and the HS value has been plotted across four different Count and Material. The percentage level for Hair Severity has been plotted. The three levels represent the levels achieved by 5%, 25% and 50% of the mills who have participated in the study. The comparative Hairiness Index and H3 values for these three levels are also given in the numerical table. Hair Severity (HS) has a very good Co-relation with the Raw material Quality, Process parameters in the Spinning preparatory and the Ring frame.

40s CW   Level HI H3 HS 5% 3.17 61.6 3.7 25% 4.94 143.5 8.9 50% 4.48 188.4 11.5

40s CW   Level HI H3 HS 5% 3.17 61.6 3.7 25% 4.94 143.5 8.9 50% 4.48 188.4 11.5

20s CHY   Level HI H3 HS 5% 4.54 305.5 18.8 25% 6.41 320 19.9 50% 6.03 418.3 46.4

60s CW   Level HI H3 HS 5% 3.49 119 7.3 25% 3.8 151.4 9.3 50% 4.27 231.3 14.1

Note: The Y axis, represent the HS value of mills who have participated.

More information on HS:

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