تجزيه و تحليل عوامل موثر بر نيروي واردشده به سوزن در فرآيند سوزن ني مخمل

چكيده انگليسي :

Analysis of Factors Affecting Punching Force during Random Velour Needling Process Hasan Mashroteh Email mashroteh@yazduni ac ir Date of Submission April 6 2011 Department of Textile Engineering Isfahan University of Technology Isfahan 84156 83111 Iran M Zarrebini Email zarrebini@cc iut ac ir Department of Textile Engineering Isfahan University of Technology Isfahan Iran Abstract Random velour needling can be regarded as a modified technique of conventional needling process This modified technique results in occurrence of fundamental changes in initial orientation of fibers within the pre consolidated fibrous assembly As the consequence of these changes a dual fibrous structure comprising base and pile layers is created Random velour needling technology uses not only a modified needle loom in which the bed plate is replaced by a moveable brush conveyor but also specially designed needles known as fork needles are employed In this research forces experienced by individual fork needles were accurately measured A novel force measuring system enabling the momentary sensing of the forces was designed and developed using RVDT apparatus The results were analyzed by specifically written MATLAB based software known as force analyzing software FAS Analyzed results showed that needle experiences various forces due to its vibration and inertia and also frictional resistances offered by pre consolidated fibrous assembly and brush conveyor during a complete cycle of needle board reciprocation Needle also experiences a force during its dwell in the pre consolidated fibrous assembly when the needle board is at bottom dead center position The actual total needle force was considered to be composed of contact and non contact components While the former is due to generated forces due to contact between the fork needle and the pre consolidated fibrous assembly or the brush conveyor the latter is due to forces experience by the needle during times when it is not in contact with either pre consolidated fibrous assembly or the brush conveyor The results showed that non contact forces which are due to vibration and inertia of needles comprise significant proportion of actual total force experienced by individual needles Magnitudes of these forces are strongly dependent on stroke frequency of the needle board It was found that among contact forces the effect of pre consolidated fibrous assembly is dominant Quantification of the net punching force and the related factors are of vital importance in engineering design of fork needles and random velour looms These in turn lead to production of high performance products at lower costs Keywords Random Velour Dynamic Measurement Net Punching Force Needle Inertia Vibration Momentary Force Contact pre consolidated fibrous assembly Introduction Random velour fabrics are produced by a modified needling operation on a loom known as random velour needle loom In this type of needle loom a movable brush conveyor and fork needles have replaced the conventional lamella bed plate and barbed needles employed on conventional felting needle looms respectively Formation of velvet effect on the surface of random velour fabric is due to interaction between the fibers of a pre consolidated fibrous assembly and the fork needles on the surface of the brush conveyor This results in fundamental changes in initial orientation of fibers within the pre consolidated fibrous assembly Properties of the final velvet fabric are controlled by the structural alteration that takes place during this modified needling operation Fork needles not only serve as the principal element in occurrence of the structural alterations but also both transmit and influence the penetration forces that have to be conducted to the main frame of the loom 1 3 Therefore forces are generated by the re orientation of fibers in the pre consolidated

مشروطه، حسن

تجزيه و تحليل عوامل موثر بر نيروي واردشده به سوزن در فرآيند سوزن ني مخمل

منسوج نيافته , سوزن چنگالي , لايه تراكم اوليه , ارتعاش سوزن , اينرسي