Разработка методов контроля качества структуры паковок крестовой намотки

The process of winding is one of the principal processes in the textile industry. Quality of the formed packages largely defines the quality of the finished product in the textile industry, as well as labor productivity and equipment performance. Therefore, attention to analysis of processes of package formation, construction of new promising methods and designs of winding mechanisms, has been growing for many decades. We address issues related to the analysis of control methods over the structure of the cross-wound winding used in spinning production. The structure of winding is understood in the present work as the mutual arrangement of threads when they are laid on the surface of the package. Thus, the parameters of the structure include such quantities as a turn lifting angle, a distance between the points of turn reversal, a step in turns, etc.It is known that the mutual arrangement of turns on the winding body when packages are frictionally driven is not homogeneous. Under certain ratios between rotation speed of the bobbin and motion frequency of the thread guide, the threads are laid on the same place. In this case, the so-called braid formations are observed. If motion frequencies of the bobbin and the thread guide differ slightly from the multiple ones, turns are placed close to each other, in this case, a tape winding is formed. The braid winding is accompanied by a number of phenomena, which negatively affect quality of the formed packages. In this case, the shear and displacement parameters are determined based on empirical data. To substantiate the approach to choosing the technological parameters for such mechanisms, we performed a theoretical analysis of the process of braid structures formation in terms of the force interactions between threads. To make such a choice, it is necessary to have an instrumental procedure for quantifying the winding structure parameters, which is why we have in detail investigated methods for their registration.Процесс наматывания является одним из основных процессов текстильной промышленности. Качеством формируемых паковок в значительной мере определяется качество конечной продукции текстильной промышленности, а также производительность труда и оборудования. Поэтому внимание к анализу процесса формирования паковок, созданию новых перспективных способов и конструкций механизмов намотки не ослабевает уже многие десятилетия. Рассматриваются вопросы, связанные с анализом методов контроля качество структуры паковок крестовой намотки, используемых в прядильном производстве. Под структурой намотки в настоящей работе будем понимать взаимное расположение нитей при их укладке на поверхность паковки. Таким образом, параметрами структуры будут такие величины, как угол подъема витка, расстояние между точками разворота витков, шаг витков и т. д.Известно, что взаимное расположение витков на теле намотки при фрикционном приводе паковок не является однородным. При определенных соотношениях между частотой вращения бобины и частотой движения нитеводителя происходит укладка нитей на одно и то же место. При этом наблюдаются, так называемые, жгутовые образования. В случае, если частоты движения бобины и нитеводителя незначительно отличаются от кратных, витки укладываются вплотную друг к другу, в этом случае формируется ленточная намотка. Жгутовая намотка сопровождается рядом явлений, которые отрицательно сказываются на качестве формируемых паковок. При этом параметры сдвига и смещения определяются на основании эмпирических данных. Для обоснованного подхода к выбору технологических параметров таких механизмов проведен теоретический анализ процесса формирования жгутовых структур с точки зрения силовых взаимодействий нитей. Для проведения такого выбора необходимо иметь инструментальную методику количественной оценки параметров структуры намотки, поэтому подробно рассмотрены методы их регистраци

Analysis of the formation of filament winding in terms of force interactions between threads

We investigated a problem of filament winding formation in terms of force interactions between threads. It was established that at certain ratios between the frequency of bobbin rotation and the frequency of thread feeder motion the threads are laid on the same place. This results in the formation of the so-called filament winding. In this case, in an extreme case, a turn of the thread is laid exactly on the place of the preceding one. This phenomenon, however, occurs only if the thread is considered ideal, that is, it has no thickness. It is shown that due to sufficient complexity of actual processes a thread cannot be placed exactly on the place of the one laid earlier, which results in that it flies off it. In this case, the turn laid earlier acquires the role of a spreader, that is, it defines the place of laying a thread on the bale. This place can differ significantly from that set by the motion of a thread feeder, resulting in the formation of chords, which cause breaks of thread at subsequent unwinding of the bobbin. It is proposed, in order to eliminate the specified defects of winding in the form of filaments and chords that accompany them, to reduce to the permissible minimum the distance from the eye of a thread feeder to the point of attack. We describe conditions under which a fly-off of the turn occurs, based on which it becomes possible to determine the number of turns, laid with a breach of the kinematic conditions, as one of the basic parameters of the process. The latter means that there is no need for the thread feeder to control it. It is shown that a given parameter depends on the inclination angle of the turn, and the application of the resulting analytical description of this relation does not present any practical difficulties because all actual values of its constituent magnitudes, except for thread twisting stiffness, are known when designing a winding mechanism. It was established that in addition to the proposed design solution it is necessary to maintain the tension not less than 20 sN for the yarn 225´2 tex. In the case of other linear densities, this parameter can be calculated based on the obtained analytical dependences for a thread inclination angle and duration of torsional oscillations of a homogeneous rod suspended in the middle. Such results form the basis of requirements to the design of a winding mechanism, which are aimed at reducing the number of uncontrollably placed turn

Аналіз формування жгутової намотки з точки зору силових взаємодій ниток

We investigated a problem of filament winding formation in terms of force interactions between threads. It was established that at certain ratios between the frequency of bobbin rotation and the frequency of thread feeder motion the threads are laid on the same place. This results in the formation of the so-called filament winding. In this case, in an extreme case, a turn of the thread is laid exactly on the place of the preceding one. This phenomenon, however, occurs only if the thread is considered ideal, that is, it has no thickness. It is shown that due to sufficient complexity of actual processes a thread cannot be placed exactly on the place of the one laid earlier, which results in that it flies off it. In this case, the turn laid earlier acquires the role of a spreader, that is, it defines the place of laying a thread on the bale. This place can differ significantly from that set by the motion of a thread feeder, resulting in the formation of chords, which cause breaks of thread at subsequent unwinding of the bobbin.It is proposed, in order to eliminate the specified defects of winding in the form of filaments and chords that accompany them, to reduce to the permissible minimum the distance from the eye of a thread feeder to the point of attack. We describe conditions under which a fly-off of the turn occurs, based on which it becomes possible to determine the number of turns, laid with a breach of the kinematic conditions, as one of the basic parameters of the process. The latter means that there is no need for the thread feeder to control it. It is shown that a given parameter depends on the inclination angle of the turn, and the application of the resulting analytical description of this relation does not present any practical difficulties because all actual values of its constituent magnitudes, except for thread twisting stiffness, are known when designing a winding mechanism.It was established that in addition to the proposed design solution it is necessary to maintain the tension not less than 20 sN for the yarn 225´2 tex. In the case of other linear densities, this parameter can be calculated based on the obtained analytical dependences for a thread inclination angle and duration of torsional oscillations of a homogeneous rod suspended in the middle. Such results form the basis of requirements to the design of a winding mechanism, which are aimed at reducing the number of uncontrollably placed turns. Исследован процесс формирования жгутовой намотки с точки зрения силовых взаимодействий нитей. Установлено, что  при определенных соотношениях между частотой вращения бобины и частотой движения нитеводителя происходит укладка нитей на одно и то же место и формируются жгутовая  намотка. Для устранения дефектов в виде жгутов и сопровождающих их хорд предложено  уменьшить до возможного минимума расстояние от глазка нитеводителя до точки набеганияДосліджено процес формування жгутовой намотування з точки зору силових взаємодій ниток. Встановлено, що при певних співвідношеннях між частотою обертання бобіни і частотою руху нитководія відбувається укладання ниток на одне й те саме місце і формується джгутове намотування. Для усунення дефектів у вигляді джгутів та супроводжуючих їх хорд запропоновано зменшити до можливого мінімуму відстань від вічка нітеводителю до точки набіганн