W.A. Ag Dept research shows an 85% correlation between increasing CV and reducing then the lower CV will have a beLter Spinning Fineness and hence spin better. crimp frequency in raw wool. Huacaya fibre – products too heavy) and of course that “crimp frequency is a reliable WHAT IS THE DIFFERENCE BETWEEN MERINO WOOL AND HUACAYA? data indicates that the fineness for huacaya tends on average to gradually. Fleece tip (dust and water penetration, tip weathering, top/noil ratio). Unevenly sized fibres produce crimps of uneven length and depth which give For e.g. a 20 micron wool with an 18% C of V, has the spinning qualities (or fineness) of a 19 to staple crimp characteristics, particularly crimp frequency - for as frequency.
In severe cases, they can be pre-emptive of the future increase in the average micron of that sheep.What is WOOL CLASSING? What does WOOL CLASSING mean? WOOL CLASSING meaning & explanation
The coarse edge qualifies and fine - tunes the C of V assessment. This is helpful in determining those animals with a left hand shift on their histograms. Spinning Fineness - is a numeric calculation that relates C of V to the actual micron in terms of spinning ability.
The spinning qualities of wool are enhanced by a low coefficient of variation, which enables the wool to be processed at standards less than the given micron. Yield measures the "true wool" by eliminating the grease, swint, wax and dirt. Fibre Curvature - is a new approach to measuring "crimp" in wool, and recent evidence shows that curvature is probably the third most important fibre specification after diameter and length.
What use is curvature? Curvature relates strongly to staple crimp characteristics, particularly crimp frequency - for as frequency increases, the fibres are increasingly curved. But curvature is not the same as character staple crimp definitionwhich is a measure of how well aligned fibres are. Fibre alignment and thus staple crimp definition does however relate to the CV of curvature, since it is physically hard to align fibres differing in curvature. Figure 1 illustrates these points: Recent scientific evidence confirms that wool fibre curvature influences processing efficiency, particularly during topmaking and spinning operations, yarn thickness and evenness and fabric thickness, handle and quality.
Wools of high crimp curvature tend to show increased fibre breakage during carding, relative to wools of low crimp curvature. Wools of poor crimp definition high CV of curvature tend to show increased fibre breakage in processing, in comparison to wools of good character. As fibre curvature increases, yarns become progressively more uneven, thicker, and show a progressively increasing frequency of faults. As fibre curvature increases, fabrics become increasingly thick and rigid.
As fibre curvature increases at a constant diameterwool becomes increasingly hard to compress, displays increasing bulkiness, develops an increasingly noticeable texture, a dry feel, and generally feels increasingly harsh. By comparison, cashmere renowned for its silky softness represents the combination of low average fibre diameter and low average fibre curvature. Measurements of fibre curvature have the potential to have a major positive impact on the ability of our wool to deliver to consumers the soft, lightweight and easy care fabrics consumers increasingly demand.
Measurements of fibre curvature could therefore be a useful means of identifying and specifying wools of particular style, such as Superfine wools, or the target wool type of the Soft Rolling Skin Sheep selection system.
Lower rainfall areas will handle both low and higher figures. REMEMBER do not neglect the basic need for wool production - select for productive wool cutters and frame, then fine - tune the wool to suit your own environment.
This enables the buyer and manufacturer to forecast with a high degree of accuracy the processing results which could be obtained from every purchase. It should then be evident that clip preparation and a sound classing technique must similarly depend on an appreciation of the same criteria the buyer uses to select and value his wool.
This infers that within any clip good classing relies on an appreciation of the extent to which various wool characteristics are important in determining the price. It may be worthwhile for woolgrowers to consider some of the more important characteristics of greasy wool that are of importance in processing and the quality of the end product.
YIELD The wool processor is interested in the quantity of pure wool fibre in the raw wool he buys and the greater the yield of fibre which he can obtain from the fleece, the more will be its economic advantage as far as he is concerned. Yield can be determined in two ways, that is by estimating the yield subjectively traditional method or by laboratory analyses.
Estimating the yield is as old as the wool trade itself. It is a subjective method and calls for a lot of experience.
Today buyers are making more and more use of the actual yield, that is a laboratory determined yield which is part and parcel of objective measurement implemented in July Raw wool consists of pure wool keratin and natural impurities such as wool wax grease and suint as well as acquired impurities such as vegetable matter, dirt, dust and sand. These different impurities may vary in different proportions and thus influence the clean yield of the wool.
The yolk wool wax and suint is, however, considered necessary to coat and also to bind the fibres together into staples preventing the fibres from falling open and being damaged deeper into the staple by the sun. Wools deficient in yolk normally also feel harsh. An increase in the iodine number indicative of a fluid wool wax was considered of more value. This increase in wool wax consequently caused a sharp decline in the yield percentage of the wool of rams.
Generally, the weight of vegetable matter is small and has little influence on yield. The greater percentage of vegetable matter is removed mechanically in the carding and combing processes. In considering clean values of wools which in the greasy form contain vegetable material, account must be taken of the additional loss of fibres which cling to vegetable material, such as burr, during carding and also the additional fibre breakage when beating the burr from the wool.
Wool that cannot be cleansed mechanically has to be carbonised.
Importance of certain greasy wool characteristics
In the carbonising process the wool is treated with diluted sulphuric acid. Wool treated in this way becomes inferior because of the damage sustained by the fibres. The presence of vegetable matter is a problem in the processing of wool and high degrees of contamination with burr and fine grass seed should be avoided as far as possible.
Dirt, dust and sand - anyone or all together - varies most of all foreign matter in the fleece. LENGTH The length of the wool fibre largely determines whether it will be manufactured on the woollen or the worsted system. Wools up to about 35 mm in length are manufactured on the woollen system and are referred to as clothing wools, whereas wools longer than 35 mm are processed on the worsted system. The latter wools are known as combing wools.
It must be remembered that there is staple length as well as straight fibre length to consider. The evidence is overwhelming that there is a close relationship between the length of staples and the mean straight length of the fibres within the staples. Due to this close relationship between mean fibre length and staple length a wool clip can be successfully classed for length if there are staple length differences between fleeces. Some variability of fibre length is important because it enables the spinner to spin more evenly and to enable him to blend properly.
Understanding Wool Test Results
However, a great variation in length results in weaker and less extensible yarns Walls, As a rule the longer the wool, the longer and also stronger and more uniform yarn can be spun from a given weight of wool. The carding operation is a very severe one and a large percentage of fibres is broken.
This results in a decrease of average fibre length and an increase in the percentage of short and very short fibres. The term 'tearage' refers to the removal of the very short fibres in the combing process. It is an important subject both from the standpoint of costing and from its effect upon the spinning property of the wool.
Fleece Testing Reporting Functions
The short fibres which are removed during combing are known as Noil and the remaining longer fibres are known as the Top. As noil has less than half the value of top, the percentage of wool removed as noil has considerable commercial significance and therefore in estimating the value of any lot of wool, it is necessary for the buyer to examine the wool for this feature in addition to those previously mentioned.
Walls stated that when there is no break in the wool, the finer and hence weaker fibres tend to give more noil than the coarser fibres. A break in the staple results in increased fibre breakage and a higher percentage of noil.
Seasonal changes cause a thinning of the fibres that is enhanced by poor nutrition, but the final stimulus causing the break is usually a stress condition brought on by disease or sudden exposure to wet cold conditions, etc. Weathering also has a marked adverse effect on the soundness of wool. Degradation of wool, especially in the tip portion of the staple, takes place on the back of the sheep and to a lesser extent on the other parts of the body of the sheep due to exposure to sunlight, dust and heat.
It was found that the wool component in the card losses come mainly from the staple tips which had been weathered during growth. In an open fleece the fibres maybe more deeply damaged than in the case of a dense fleece.
In order to produce a sound root to tip wool the weathering of the wool on the sheep's back should be limited as far as possible. Consequently, the penetration of dirt into the wool staples promotes damage Le Roux, The adaptability of the animal to a certain environment also proved to have an effect on the degree of weathering Snyman, Severe weathering of the extreme tip usually occurs during the hot summer months.
During this period long wool is liable to be more deeply weathered than shorter wool. Deeper weathering of the wool in the staple can be limited by selecting and breeding for better substance and a better staple formation. From a management point of view the degree of weathering deeper into the staple can be reduced by changing the shearing time: The availability of shade in camps especially trees or open sheds is recommended as the most practical method Venter, ; Venter, Nel and Edwards, It is thus clear that a sound, well nourished wool with a good tensile strength from base to tip is the ideal from the manufacturer's point of view as it will give the least fibre waste and cause the least problems during manufacture and will result in a high quality end-product.
Superfine wool is used for the manufacturing of very light materials, while strong wool is used for coarser materials such as blankets and carpets. Wiggens stated that mean fibre diameter determines the spinning performance of wool for fine yarns and in fabrics it is associated with softness, warmth and flexibility. It is also known that finer fibres result in smoother and softer handling fabrics. Finer wools are also more valuable than thicker wools as stated by Whan The impact of fibre fineness on wool values is much more pronounced in the superior styles and between finer counts.
However, there are realistic differences in wool values, even in the poorer styles, which stem directly from fibre fineness effects. The relationship between spinning count, fibre thickness and number of crimps per inch 25,4 mm crimp frequency as compiled by Duerden led to the use of crimps per inch 25,4 mm as an indication of the fineness of wool.
Whitely pointed out that in practice the classer is forced to rely on the relationship between staple crimp frequency and diameter. A large variation in the nature of crimping in relation to fibre thickness generally occurs.
As far as South African Merino wool is concerned, Bosman showed that the Duerden relationship only holds in 28 percent of the cases while 36 percent proved to be over-crimped and 36 percent under-crimped. Corresponding deviations were noted by Lang in Australian Merino wool and appeared to vary within flocks and different strains.
Lately, various studies showed that the South African wool clip is to a large extent undercrimped. The commercial wool producer and stud breeder have for years emphasised the production of a good quality wool kind handle.