Dokuma koşullarında ipliklerin yassılma özelliklerinin belirlenmesi ve ölçümü üzerine araştırma
Küçük Resim Yok
Tarih
1990
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Ege Üniversitesi
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
ÖZET Dokuma ve Örme kumaşların temel yapı elemanı olan iplik şekil değiştirerek kumaş yapısını oluşturur. Bu şekil değişikliği daha çok ipliğin eğilmesi biçiminde olmakla birlikte, kumaş oluşumu sırasında ipliğin uzaması ve yassılması da söz konusu olmaktadır. Oluşan kumaş yapısı içinde ipliklerin aldığı biçimlerin belirlenmesi kumaş geometrisini ortaya koymaktadır. Dokuma kumaş geometrisini etkileyen parametrelerin başında ise iplik çapı gelmektedir. Ne varki, dokuma kumaş yapısı içinde iplik kesiti yuvarlak kalmayıp yassıldığından kumaş kesitinde kumaş düzlemine dik doğrultudaki küçük çapın belirlenmesi Önem kazanmaktadır. İki paralel yüzey arasında bu yüzeylere dik doğrultuda bir basınç kuvvetinin etkisi altında yassılan iplik çapının ölçümü için çeşitli ölçü aletleri yapılmış ve yassılma ile basınç arasındaki ilişkiyi analiz eden bazı teoriler geliştirilmiştir. Ancak dokuma kumaş yapısı içinde iplik kesitleri, bir eğri biçimini alan ve dik yönde kesişen ipliklerin birbirlerine uyguladıkları basınçla şekil değiştirmektedir. Diğer yandan, dokuma kumaşın oluşumu sırasında iplikler gergin durumdadırlar. Bu nedenle dokuma koşullarında yassılan iplik çapının ölçümü için bir yöntem bulunması önemlidir. Bu çalışmada biri serbest koşullarda gerilimsiz ve gergin olarak, iki paralel plaka arasında basınç altında yassılan iplik çapını ölçen, diğeri dokuma koşullarına benzer koşullarda birbirleri; el kesişirken yassılan iplik çaplarının Ölçümünü sağlayan iki aparatın tasarım ve yapımı ile Ölçüm tekniklerinin geliştirilmesi ve her iki aparatla aynı iplikler üzerinde yapılan ölçümlerin karşılaştırılması amaçlanmıştır. Serbest koşullarda iplik yassılmasını ölçen aparat kaldıraç ilkesine dayanmaktadır. Bu yanda kaldıraç kolunu oluşturan vidalı mil 90üzerinde hareket ettirilen bir ağırlık diskinin değiştirdiği moment, öbür yanda kaldıraç koluna asılan bir silindirik ağırlık blokunun alt yüzeyi altındaki sabit blokun yüzeyine yerleştirilen ipliğe bir basıncın uygulanmasını sağlamaktadır. İpliğe gerginlik uygulanması da sağlanmış ve ağırlık blokunu taşıyan uzun kaldıraç kolu ucunun hareketini Ölçen bir optik düzenek yapılmıştır. Dokuma koşullarında kesişme noktasında yassılan iplik çaplarının toplamını ölçen bir ikinci aparat atkı ve çözgüyü temsil eden ipliklerin takıldığı U biçimli biri diğerine bağlı fakat düşey yönde bir vida kanalı içinde hareket ettirilebilen, diğeri ise eklem düzenlemeleriyle birbirlerine dik üç yönde dönebilen iki elemandan oluşturulmuştur. Düşey yönde hareket eden elemana atkıyı temsil eden iplik sabit uzunlukta tesbit edilirken, diğerine takılan çözgüyü temsil eden ipliğin ucuna bir ağırlık asılarak değişik gerilimler uygulanabilmektedir. Oluşturulan örgü açıları ve kesişen ipliklerin çap toplamları optik bir düzenleme ile bir ekrana gölge düşürülerek ölçülmektedir. Her iki aparatın da kalibrasyonu yapılmış deney materyali olarak seçilen 24 Ne, 36 Ne pamuk uplikleri ile 52/2 Nm yün ipliği kullanılarak yapılan örnek deneyler sonucu aparatların güvenilir Ölçümler sağlandığı ortaya konulmuştur. Serbest koşullarda iplik çapını ölçen aparatta hem 5g gerilim altında ipliklerin normal ve yassılmış çapları hem de 60 g a varan gerilimlerde normal ve yassılmış çapları ölçülmüştür. Dokuma koşullarında çaplar toplamını Ölçen aparatta ise çözgü ipliğine çeşitli gerilimler uygulayarak ve Örgü açısını değiştirerek oluşturulan çeşitli basınçlar altında ölçümler yapılmıştır. Ekranda uygun ve oldukça güvenilir ölçüm yapılmasını sağlayan görüntüler elde edilebilmiştir. Tasarlanan iki aparatta benzer koşullarda elde edilen ölçümlerin karşılaştırılmasından, birinci aparatta ölçülen mekanik çapların ikinciaparatta Ölçülen optik çaprara (çaplar toplamının yarısı) oranla daha düşük değerlerde elde edildiği, ipliklere uygulanan gerilimin çapı büyük ölçüde etkilediği ve gerilim altında yassılmanın aynı basınçlar altında daha düşük oranlarda gerçekleştiği görülmüştür. Örgü açısı yassılma oranları elde edildi gide gözlenmiştir. -92
SUMMARY A yarn which provides the basic structural component for woven and.nitted fabric, forms the fabric structure by changing its shape. Although this change of shape takes place as the bending of the yarn, the extension and flattening of the yarn during yarn formation are also in question. The determination of the configurations taken up by the yarn in the fabric structure gives birth to a cloth geometry. As the forerunner of the parameters affecting cloth geometry comes the yarn diameter. Yet, as the yarn cross section in the woven fabric structure does not remain circular, and thus, flattens, it becomes important to determine the small diameter in the perpendicular direction to the fabric plane. Various measuring instruments have been constructed to measure the diameter of the yarn flattenning between two parallel surfaces under the influence of a pressure force in perpendicular direction to these surfaces and certain theories analysing the relationship between flattenning and pressure have been developed. However, the yarn cross sections in the woven fabric structure change their shape as a result of the pressure that the yarns intersecting at right angles and taking a curved shape exert on each other. On the other hand, the yarns, during fabric formation, are in tight state. As a consequence it is vitally important that a method is found for the measurement of the flatternning of the yarn diameter in the weaving conditions. It has been the aim of this work to design and construct two apparatuses, one measuring the yarn diameter being flattened between two parallel plates under pressure in free condition with and without tension, the other enabling the yarn diameter to be meausured, which flattens under alike weaving conditions while intersecting, and also to develop measuring techniques and compare measurements made on the same yarns with both appratuses. The apparatus which measures the yarn diameter, in the free conditions is based on the lever principle. The moment changed by moving a counter weight disc on a screw shaft forming the lever arm on one side enables a pressure to be exerted on the yarn, which is below the lower surface of a cylindirical counter weight block hung on the lower arm of the other side, which is placed on the surface of a stationary block underneath. The application of tension to the yarn was also provided for and an optical arrangement was set up which measured the movement of the tip of the lower lewer arm which carried the counterweight block. A second apparatus which measures the sum of the diameters of the flattened yarn at the point of intersection in weaving conditions was constructed of two "U" shaped components to which the yarns representing the warp and weft were attached, the one being linked to the other but 93 -being able to move in the vertical direction in a screw channel, the other being able to move in three dimensions by means of joint arragements while the yarn representing the weft is attached to the component that can move vertically in constant length. Varying tensions can be applied by hanging a weight on the end of the yarn representing the warp which interlaces with the other. The weave angles thus formed and the sums of diameter of the intersecting yarns could be measured by obtaining a shade image on a screen by an optical arrangement. Both apparatuses were calibrated and as a result of sample experiments carried out with 24 We,36 Ne cotton and 52/2 Nm worsted yarn chosen as experimental materials, it was shown that the apparatuses provide trus table measurements. In the apparatus measuring the yarn diameter in the free conditions the diameters of the normal and flattened yarns at both 5 g tension and at tensions reaching 60. g were measured. In the apparatus which measures the sum of diameters under weaving conditions, on the other hand, measurements were made under various pressures obtained by applying various tensions on the warp, yarn and by altering the weave angle screen images which enabled suitable and quite trustable measurements to be made could be obtained. As a result of a comparison between the measurements made on the two apparatuses designed, it was found that the mechanical diameters measured with the first apparatus were obtained at lower values than the opticial diameters (half of the sum of diameters) with the second apparatus; that the tension applied on the yarns affected the diameter greatly and the flattening under the same pressures but under tension occurred at lower rate, it was also observed that as the weave angle increased greater rates of flattening were obtained, again, under the same pressures.
SUMMARY A yarn which provides the basic structural component for woven and.nitted fabric, forms the fabric structure by changing its shape. Although this change of shape takes place as the bending of the yarn, the extension and flattening of the yarn during yarn formation are also in question. The determination of the configurations taken up by the yarn in the fabric structure gives birth to a cloth geometry. As the forerunner of the parameters affecting cloth geometry comes the yarn diameter. Yet, as the yarn cross section in the woven fabric structure does not remain circular, and thus, flattens, it becomes important to determine the small diameter in the perpendicular direction to the fabric plane. Various measuring instruments have been constructed to measure the diameter of the yarn flattenning between two parallel surfaces under the influence of a pressure force in perpendicular direction to these surfaces and certain theories analysing the relationship between flattenning and pressure have been developed. However, the yarn cross sections in the woven fabric structure change their shape as a result of the pressure that the yarns intersecting at right angles and taking a curved shape exert on each other. On the other hand, the yarns, during fabric formation, are in tight state. As a consequence it is vitally important that a method is found for the measurement of the flatternning of the yarn diameter in the weaving conditions. It has been the aim of this work to design and construct two apparatuses, one measuring the yarn diameter being flattened between two parallel plates under pressure in free condition with and without tension, the other enabling the yarn diameter to be meausured, which flattens under alike weaving conditions while intersecting, and also to develop measuring techniques and compare measurements made on the same yarns with both appratuses. The apparatus which measures the yarn diameter, in the free conditions is based on the lever principle. The moment changed by moving a counter weight disc on a screw shaft forming the lever arm on one side enables a pressure to be exerted on the yarn, which is below the lower surface of a cylindirical counter weight block hung on the lower arm of the other side, which is placed on the surface of a stationary block underneath. The application of tension to the yarn was also provided for and an optical arrangement was set up which measured the movement of the tip of the lower lewer arm which carried the counterweight block. A second apparatus which measures the sum of the diameters of the flattened yarn at the point of intersection in weaving conditions was constructed of two "U" shaped components to which the yarns representing the warp and weft were attached, the one being linked to the other but 93 -being able to move in the vertical direction in a screw channel, the other being able to move in three dimensions by means of joint arragements while the yarn representing the weft is attached to the component that can move vertically in constant length. Varying tensions can be applied by hanging a weight on the end of the yarn representing the warp which interlaces with the other. The weave angles thus formed and the sums of diameter of the intersecting yarns could be measured by obtaining a shade image on a screen by an optical arrangement. Both apparatuses were calibrated and as a result of sample experiments carried out with 24 We,36 Ne cotton and 52/2 Nm worsted yarn chosen as experimental materials, it was shown that the apparatuses provide trus table measurements. In the apparatus measuring the yarn diameter in the free conditions the diameters of the normal and flattened yarns at both 5 g tension and at tensions reaching 60. g were measured. In the apparatus which measures the sum of diameters under weaving conditions, on the other hand, measurements were made under various pressures obtained by applying various tensions on the warp, yarn and by altering the weave angle screen images which enabled suitable and quite trustable measurements to be made could be obtained. As a result of a comparison between the measurements made on the two apparatuses designed, it was found that the mechanical diameters measured with the first apparatus were obtained at lower values than the opticial diameters (half of the sum of diameters) with the second apparatus; that the tension applied on the yarns affected the diameter greatly and the flattening under the same pressures but under tension occurred at lower rate, it was also observed that as the weave angle increased greater rates of flattening were obtained, again, under the same pressures.
Açıklama
Bu tezin, veri tabanı üzerinden yayınlanma izni bulunmamaktadır. Yayınlanma izni olmayan tezlerin basılı kopyalarına Üniversite kütüphaneniz aracılığıyla (TÜBESS üzerinden) erişebilirsiniz.
Anahtar Kelimeler
Tekstil ve Tekstil Mühendisliği, Textile and Textile Engineering, Dokuma kumaşlar, Woven fabrics, Yassılma, Flattening, İplik, Yarn
