The pills are formed only during wear ,wash and tear due to abrasion affectingappearance, touch and handle of fabrics. The mechanism of pilling goes through thefollowing four stages:1. Fuzz formation on fabric surface.2. Entanglement of fibers in the fuzz with each other.3. Densification of these entanglements into small balls called pill.4. Shedding away of pills.4. Factors Affecting Pill Formation : Pills build up is affected by Number of protruding fibre ends Fibre linear density Fibre length Fibre cross sectional shape Fibre strength modulus Friction Yarn twist levels Fabric construction Dyeing Finishing Fibre Parameters: 1. Stages in life span of pills: surfacing of fibres Entangling of surfaced fibres Wearing-off or build from fabric. In a fabric construction, the physical and mechanical properties of fibre determine the rate of above stages. Breaking strength of fibres determines the limit of applied force during surfacing of fibres. Fibre ParametersFibre Parameters: Fibre linear density cross section modulus, bending rigidity and elongation determine the degree of entanglement. Fibre breaking strength and abrasion resistance control the pill break off rate. 2. Fibre type Fuzz tendency of various fibres is given in Table. Dacron (Polyester) and nylon fibres show high pill formation due to high strength and abrasion resistance. Fibre ParametersFibre Parameters: Orlon (acrylic) show high tendency of pill buildup than viscose due to higher abrasion resistance. In general, pills are removed during wear by the breakage of anchoring fibres. Above the minimum strength, abrasion resistance is the controlling factor in pill wear-off. Due to different surface finishes on man-made fibres, pill formation may differ. Fibre ParametersPowerPoint Presentation: Fibres Flex life Cycles Tenacity Modulus Friction (mg) Fuzz (mg) gf /den gf / tex gf /den gf / tex Nylon 26,000 4.5 0.50 6 0.67 0.29 6.0 Viscose 70 2.6 0.29 69 7.66 0.22 4.4 Dacron 13,000 3.9 0.43 29 3.22 0.35 3.1 Orlon 1,870 2.2 0.24 52 5.77 0.35 3.1 Wool 3,620 1.4 0.16 24 2.66 0.15 0.4 Acetate 20 1.4 0.16 13 1.44 0.30 0.4 Table 2. Fuzz Tendency of Various Textile FibresFibre Parameters: 3. Fibre length No pill formation generally takes place in long continuous filament fibre. Longer staple in yarns show low pilling tendency. Variation in length of constituent fibres in blend yarns give more tendency to pill formation 4. Fibre friction and cross section Coarser fibres have low tendency to pill. Fineness of individual fibres in blended yarn should be more or less equal to each other to avoid pilling. Fibre ParametersFibre Parameters: Circular cross section of fibres with smooth surfaces give more pilling Pilling tendency falls with an increased flatness of fibres. 5. Fibre tenacity and bending resistance Weaker fibres with lower bending resistance give lower pilling. 6. Inter fibre friction High inter fibre friction reduces pilling. 7. Fibre crimp Higher fibre crimp increases pilling. Fibre ParametersYarn Parameters: 1. Yarn type If ring-spun, rotor-spun and airjet -spun yarns are compared, airjet yarn is the most pill resistant, and rotor-spun is the least. (Fig 8, 9, 10 & Table 3) The difference is spinning systems cannot be over come by changing material properties. 2. Yarn Count Finer the count lower the pilling. Yarn ParametersYarn Parameters: 3. Twist Higher the twist lower the pilling. Increased twist level of yarn containing synthetic fibres above the standard values can reduce pilling. At higher twist level pilling decreases at all production speeds. 4. Blend Lower the content of synthetic fibres in blended yarn lower the pilling Intimate blending may give lower pilling Yarn ParametersYarn Parameters: 5. Yarn hairiness Lower the hairiness, low is the pilling (Table 4) 6. Yarn Doubling Double yarns give low pilling in fabrics Yarn ParametersPowerPoint Presentation: Cotton Variety Fibre Length (mm) 2.5% span length Mean number of pills/Unit Area Varalakshmi 37.3 5 Sankar 4 31.6 15 Table 4: Effect of length on hairiness of blendsFabric Parameters: 1. Fabric type Knitted fabrics pill more as compared to woven fabrics Pilling reduces by increasing yarn twist level and tightness factors of fabrics. 2. Fabric cover factor Compact fabrics give low pilling. Soft and fuzzy surface pill more. Reduced length of floats reduces pilling Fabric ParametersFabric Parameters: 3. Fabric structure Plain fabric show lower pilling than twill and satin fabrics due to more interlacing and short cross lengths. 4. Fabric weight An increase in fabric weight reduces pilling tendency. Fabric ParametersDyeing and Finishing Parameters: Singeing reduces pilling Shearing and cropping reduces pilling in polyester/wool fabrics. Heat-setting at higher temperature for suitable duration reduces pilling. The cellulosic materials in super steam for heat setting should be preferred for reduction in pilling. Low heat setting temperature for longer duration in polyester/cotton fabric reduces pilling Effect of heat setting of a polyester fabric under tnesion at different temperature is given in table 5 Dyeing and Finishing ParametersPowerPoint Presentation: Heat Setting Temperature ( o C ) Pill/Unit Area Heat-set only Boiled-off and Heat-set Control 6.5 10.2 120 - 9.9 140 11.9 8.6 160 11.6 7.8 180 7.8 7.1 200 8.5 5.2 220 5.0 6.4 Table 5: Fuzz tendency of heat-set fabrics5. Control of Pilling : Selecting the correct raw materials (fibre). Manufacturing yarn through proper pill resistant steps Constructing fabrics with suitable parameters Using finishing and dyeing techniques for reducing pilling Pilling on finished fabric is on the average 85% less than in grey state. In polyester/ cotton fabric singeing, shearing and cropping and heat setting reduces pilling tendency. Enzyme treatment given low pilling i.e. Bio-polishing. 5. Control of PillingFabric handling and pilling performance are two keycharacteristics to be considered by the buyers ofpolyester / viscose blended fabrics. The choice of softenersis of paramount importance as the pilling performance ofa fabric is one of the major requirements of customersalong with the fabric handle. In this study, it wasconcluded that certain softeners, which decrease ?bre-to-?bre friction by internal lubrication, such as nonionicorgano-modi?ed silicone microemulsions and aminofunctional polysiloxanes, result in a decrease in fabricpilling performance. Furthermore, as far as polyester /viscose blended fabrics are concerned, sanforisingtreatment also results in an increase in pilling propensity.Fabric fuzziness is a property which affects the appearance, handle, thermal insulation and other fabric features; it also leads to pilling that is a serious problem for the apparel industry. fabric fuzziness with increase of viscose ratio has ascending trend in different abrasion cycles. The abrasion resistance of a faupon many factors, including fibstructure and size, fabric weigfabric finishes including lubriagents, and the type of abradant The comparison between the mean of fabrics fuzziness in whole of abrasion cycles shows that the fabrics with 87.5% viscose content has most fuzziness, that is not significantly different from the fabrics with 50%, 75% and 100% viscose content. Also the fabrics with 0 and 12.5% viscose ratio have the least amount of fuzziness. This shows that fabrics with higher viscose ratio generate more fuzziness.The results show that the fabrics including more viscose content tend to have more fuzziness in various stages of abrasion. This is in accord with surface and mechanical characteristics of polyester and viscose fibers reported in the literature. Also the fabrics with 50/50 polyester/viscose show high fuzziness before abrasion and after the second stage. This may be because of fibers interaction in yarn structure.