Naslov
A Contribution to the Investigation of the Factors Influencing the Quality of Knitewear

Autori
Ujević, Darko ; Rogale, Dubravko

Vrsta, podvrsta i kategorija rada
Sažeci sa skupova, sažetak, znanstveni

Izvornik
3rd International Conference on New Products and Production Technologies for a New Textile Industry / Kiekens, Paul - Gent : Universiteit Gent, 1999, 353-354

Skup
New Products and Production Technologies for a New Textile Industry

Mjesto i datum
Gent, Belgija, 01.07.1999. - 02.07.1999

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
Knitwear; softeners; sewing needle penetration force; knitted loop damages

Sažetak
Sewing needle penetration force is of utmost importance in the process of sewing knitwear, primarily because of its direct impact on the incidence of loop damages. Investigations performed by various researchers indicate there is a noted correlation between the needle penetration force and the demages that occur on the knitted loops, which is especially pronounced in seam construction on knitted garments. Lower penetration force definitely means lower incidence of loop damages in knitwear sewing. Optimization of various technological procedures lead to further improvement in sewing, with practically no demaged loops on the knitwear, the goal being to attain a high degree of quality, in accordance with contemporary standards for knitted garments. Sewing needle penetration force results from frictional resistance and the force of pushing, by which the workpiece resist the penetration of the needle. Determination of knitted fabric loop damages ond measuring penetration force differ in the approach and the measuring method used, as well as in later data processing. Loop damage determination and measurements of needle penetration force in sewing are done by varying certain factors, such as the type of the knitted fabric used, fabric finishing, type of the softener used, amount of the softener, sewing needle gauge, number of layers, needling or topstitching of the samples. It should be noted that softeners tend to lower considerably the level of the penetration force, meaning the incidence of loop damages is also much lower when softeners are used. Sewing needle penetration force measurements described here were done on the ITV measuring system, in the company of CHT R. Beitlich GmbH in Tübingenu, Germany. The determination of knitted loop damages, in relation to the penetration force, were done in the Department of Clothing Technology, Faculty of Textile Technology, University of Zagreb. New, more precise equipment was constructed for the purpose of these measurements. The geometry of the knitted loop is changed, as certain parts of the loop are stretched and the other relaxed. The seam and the area near it are of especial interest, as the yarn tends to yield here, due to the needle penetration force, which can lead to loop damages. If the above stretching and load are known, loop damages can be rather precisely detected, and the point where the needle penetration force has damaged the yarn in the area of the seam indicated, along the length of the seam on a sample of two, three, or four layers. The damages in the seam and the area surrounding it are particularly visible after the cycle of 30 consecutive movements of the upper clamp has been completed. Due to the variable load on the knitted fabric, the fibbers in the yarn yield, or are sometimes completely broken. A magnifying glass of proper characteristics is used to determine precisely the extent of the knitted loop damages. Knitted fabric samples are topstitched or needled on the sewing machine. Penetration force is measured using a measuring plate and tenziometric tapes, connected with the sewing needle signal sensors. The variation of the tenziometric tape resistance in transformed into the variation of electrical resistance, using a Wheatstone bridge. Under the Wheatstone bridge there is an analogue filter and signal amplifier. Color monitor gives the values of sewing needle penetration force. A part of the system is also a computer, with A/D converter (IBM PC compatible), a keyboard, a printer and a power source. The system for measuring sewing needle penetration force is situated in an air-conditioned labaratory, with the temperature of 20oC to 21oC, and relative humidity of 60 %. On the basis of the results obtained, a high degree of positive correlation between the loop damage incidence and the level of sewing needle penetration force is established. It can be concluded, that the quality of knitwear can be significantly improved by the optimization of certain parameters of manufacture.

Izvorni jezik
Engleski

Znanstvena područja
Tekstilna tehnologija

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