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Lecturer(s)
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Bílek Martin, doc. Ing. Ph.D.
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Kovář Šimon, Ing. Ph.D.
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Course content
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Lectures: 1. Binding point models (Peirce's and Olofsson's one), comparison of models' correctness. 2. Beat-up mechanism, beat-up force and weaving resistance, parts of the beat up mechanism, types of mechanisms, force between the reed and the front of the fabric, weaving resistance, beat-up pulse, mathematical model of the beau-up force. 3. Beat-up process modelling. 4. -5. Shedding mechanism, analysis of the movement of the heald of the weaving machine, mathematical model. Shed forming mechanisms, force and deformation of warp threads eye. 6. Force compensation during the weaving cycle, basic function of the back rest on the weaving machine. 7. Mathematical models of the back rest, static and dynamic model of the back rest. Force compensation using active back rest. 8. Means of external control of weaving process, scheme of weaving machine as a regulated system, External control, Substitutive scheme of controlled system, Relations for description of controlled system. 9.-10. Weft insertion systems with rigid carriers I. - shuttle, projectile and rapier weft insertion system. Tensograph and tachograph. Weft insertion phases. Kinematic quantities of motion of carrier and weft. 11. Jet weft systems I. - Water-jet weft insertion, Determining outlet velocity of water flow, Water flow and weft velocities, Equation of motion of piston as well as weft, Tachograph and tensograph of water-jet weft insertion. 12. Jet weft systems II. - Air-jet weft insertion, Velocity field of main nozzle, Solution of weft motion, tachograph and tensograph of air-jet weaving machine 13. Impact forces in weft insertion, Comparison of impact effects of air-jet and rapier weft insertion systems, Dynamic model of impact force, Means for reduction of impact force. 14. Multi-shed weaving machines, Weaving cycle and continuous proces, Continuity of weft distribution, Basic conflict of weaving and multi-shed weaving machine, Circular, planar serial and parallel multi-shed weaving machines. Practices: 1. Analysis of the history of non-woven weaving, development of weaving technology in the Czech Republic. 2. Kinematic parameters of basic mechanisms of the weaving machine, inertial forces, substitute dynamical effects, equation of motion. 3. Determining the size of the weaving resistance for the specified parameters of the geometry, calculating the magnitude of the force for the parameters of the beat-up pulse, and the rigidity of the warp and the fabric, determining the minimum preload of the warp threads. 4. Calculation of warp extension and weft slippage. 5. Comparison of single-lift and double-lift systems, Exciting of elastic forces through heald motion, Forces and deformation of warp thread. 6. Example of the mathematical model of the shedding mechanism and the heddle frame. 7. Analysis of single-roller and double-roller free back rest with spring, Ensuring the fabric take-up without slip, Condition of self locking state. 8. The weft motion equation, acceleration and braking phase of weft insertion, mathematical description of the acceleration phase of the weft start, determination of the weft stopping force. 9. Introduction to measurement of basic parameters of the weaving process, selection of sensors, measurement accuracy, static and dynamic characteristics of sensors. 10. Strain gauge sensors, calibration of sensor, setting of measuring unit for measuring thread tension, practical demonstration of measurement. 11. Measurement of forces in warp threads, definition of concepts (elastic forces, kinematic excitation), adjustable force, force excitation through shedding mechanism, beat-up mechanism and movement of the back rest. 12. Measuring velocity of the weft during weft insertion process, determining the average weft velocity. 13. Measuring of the forces in the weft yarn, comparing the tachographs with and without WBS activation. 14. Analysis the measurements results and reports preparation.
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Learning activities and teaching methods
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Dialogue metods(conversation,discussion,brainstorming), Self-study (text study, reading, problematic tasks, practical tasks, experiments, research, written assignments), Demonstration, Laboratory work, Lecture, Practicum
- Class attendance
- 56 hours per semester
- Home preparation for classes
- 30 hours per semester
- Preparation for laboratory testing; outcome analysis
- 25 hours per semester
- Preparation for exam
- 50 hours per semester
- Presentation preparation (report)
- 10 hours per semester
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Learning outcomes
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The subject deals with the following issues: fabric forming, threading and deformation of the thread in the binding point; kinematic excitation of forces in threads movements of working members of fabric forming mechanisms; forces in warp and weft effectively used for fabrication, control of these forces on the weaving machine; elimination of the forces with compensators and regulators; modeling of the beat up process; compilation and use of discrete models of beat up process; weft insertion systems, motion equations, velocity and weft forces.
Deepening the knowledge in the field of weaving, namely: fabric formation, displacements and deformations of threads in the binding element; forces in the warp and weft effectively used for the fabric formation; weft insertion (picking) systems and their equations of motion; determining the speed of weft carrier and weft, determining the forces in the weft ; composition of weaving machine units in response to the changes of weaving process.
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Prerequisites
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Knowledge of the technological process of weaving, knowledge of the function of weaving machine, Mechanics: statics (equilibrium equation of forces) -kinematics ( kinematic quantities of general movement, structure of simple planar mechanisms, displacement laws, transfer functions) - dynamics ( equations of motion) ,- elasticity and strength ( relation of forces and deformations (strain) , tension, bending) Mathematics : differential equations ( of the 1st and 2nd order)
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Assessment methods and criteria
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Combined examination, Student's performance analysis
Credit: Participation in practices a lectures. Preparation of reports from measuring. Exam: written + oral
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Recommended literature
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Soubor českých přednášek na https://elearning.tul.cz/ - v sekci stávajícího předmětu Tkalcovství.
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Soubor českých přednášek na http://www.kts.tul.cz v sekci Podklady pro výuku.
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Webové stránky světoznámých výrobců tkacích strojů, žakárských prošlupních mechanizmů tkacích strojů (https://www.bonas.be/en https://www.staubli.com/cs-cz/textile/textile-machinery-solutions/ ; www.karlmayer.com https://www.lindauerdornier.com/en/ http://www.picanol.be/en ; www.knotex.de)).
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ADANUR, S. Handbook of Weaving, Sulzer Textile Limited. Boca Raton: CRC Press, 2001. ISBN 1-58716-013-7.
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BOWDEN F. P, TABOR, D. Friction and Lubrication of Solids. Oxford: Proc. RoySoc., Clar. Press.
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DVOŘÁK, J., BÍLEK, M., TUMAJER, P. Mechanické modely tkaní.. Liberec: VUTS, 2016. ISBN 978-80-97184-68-4.
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DVOŘÁK, J. Tkací proces a stroj.. Liberec: Technická univerzita v Liberci, 2006. ISBN 80-7372-099-X.
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CHOOGIN, V., BANDARA, P., CHEPELYUK, E. Mechanisms of Flat Weaving Technology.. Woodhead Publishing, 2013. ISBN 9780857097804.
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MASAJTIS, J. Dynamic disturbances of warp tension in weaving and behaviour of the letoff motion on the loom.. University of Gent, 1998. ISBN 83-908012-3-X.
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ORMEROD, A., SONDHELM, W. Weaving, Technology nad Operations, The Textile Institute. Manchester: Textile Institute, 1998. ISBN 187081276X.
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TALAVÁŠEK, O., SVATÝ, V. Bezčlunkové tkací stavy.. Praha: SNTL, 1975.
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TALAVÁŠEK, O. Tkalcovská příručka. Praha: SNTL, 1980. ISBN Typové číslo L21.
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TUMAJER, P., BÍLEK, M., DVOŘÁK, J. Základy tkaní a tkací stroje, Skriptum TUL.. Liberec: Technická univerzita v Liberci, 2015. ISBN 978-80-7494-215-0.
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VAN DE WIELE. Plain, Dobby & Jacquard Velvet Weaving Machine.. Belgium: Michael Van De Wiele, 2003.
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WILL, G. F. The woven figure: conservatism and America's fabric : 1994-1997.. New York: Scribner, 1997. ISBN 0-684-82562-7.
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