| The manufacture of Carbon fibers composites , after a 40 year period of development, now is more mature on the technique. Because of its properties and characteristics of light weight, stiffness, anti-high temperature, high tensile modulus, Carbon fiber is widely used in a variety of applications, including aerospace, sporting goods, medicine and industry. Carbon Fiber Sheet, manufactured by special process is a single-ply, epoxy impregnated sheet. Because carbon fiber sheet material is flexible and will conform to almost any shape, the use of it for the strengthening/repair of bridge girders has been widely practiced in the world. Its reinforcement is a kind of graticule in shape of square and rhombus. The aim of this devise attempts to present a method of designing the graticule by textile technology, and develops a graticule shaping machine.This devise refers to parallel weft thread laying principle of warp knitting machine, designs a weft thread insertion arrangement for the weft thread magazine of this machine. The magazine includes a pair of endless continuously moving conveyors, each having a plurality of hooks for retaining weft threads in parallel and for delivering them to the next processing. Also the weft thread laying arrangement is operabal to transversely reciprocate between the conveyors and transport weft threads from one conveyor to the other. The weft insert carriage of the laying arrangement, having a plurality of thread guides for transferring weft threads around the hooks, is in conjunction and cooperation with the conveyors. Before each crossing of the carriage, a flat board holds down the weft threads, and a rake adjacent each conveyor extends each strand, relative to the conveyor, a distance of one band width from a first holding element to a second holding element upstream of the same conveyor. The thread guides, rake, flat board and conveyors are operated very well so that the lengths of strands extending between conveyors will be parallel for presentation to fabric forming means. The warp thread is conveyed over the conveyor by drive wheel with the same speed of the conveyor, laid on the tensing weft thread layer, form the thread graticule. Then the point of the crossing in the fabric is bonded by the certain glue. Finally the fabric is taken up, forming the reinforcement of the carbon fiber sheet.The drive of this project uses the advanced method, that is, three single AC servo drive systems to control conveyors, weft laying arrangement and the arrangement respectively. The driving shaft of conveyors is also looked as the main shaft, making the movement of thethread guide and taken-up arrangement synchronous with it. Particularly, the drive speed is not dependent on a sinusoidal function which is determined by the mechanical unit, by utilizing the servo drive, permitting entirely a new speed pattern, including three sections of an accelerate, even and decelerate movement. The actions of hold-down apparatus, thread guide and rake are all controlled by pneumatic cylinders, therefore, they form a pneumatic circuit. But acting time and direction of cylinders are determined by programmable controller(PLC).This device gives the detail calculation of driving parts. Also it develops the mathematical model of winding part, meeting the requirement of the constant tangent speed of winding.The relevant experiment of this project is fulfilled using the similar equipment of Germanic MALIMO stitch-bonding machine. The success of the experiment verifies the feasibility of this project.Because the study of Carbon fiber Composite in our country is later than that in advanced countries, this designation of graticule shaping machine not only has principle significance, but also has practical value. |
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