Fiber manufacturing

• 1. PRESENTATION onFIBER MANUFACTURING Presented by: MUHAMMAD UMAIR BUKHARIINSTITUTE OF ADVANCED MATERIALS

2. Muhammad Umair Bukhari [email protected] 03136050151 3. FIBER High strength to weight ratio High stiffness Corrosion resistant. Formable to Complex Shape Improve Fatigue Resistance Improve Creep resistance 4. TYPES OF FIBRE Natural fibers Advanced fibers 5. ADVANCED COMPOSITES FIBERS Carbon fiber Glass fiber Aramid ceramics 6. GLASS FIBERSMost versatile industrial materials known today.Produced from raw materials, which are available in unlimited supplyThey exhibit useful bulk properties such as Hardness Resistance to chemical attack Stability and Inertness, as well as desirable fiber properties such as strength, flexibility, and stiffness 7. GLASS FIBER TYPES Glass fibers fall into two categories, low-cost general-purposefibers and premium special-purpose fibers. Over 90% of allglass fibers are general-purpose products. These fibers are known by the designation E-glass and aresubject to ASTM specifications The remaining glass fibers are premium special-purposeproducts. Many, like E-glass, have letter designationsimplying special properties Some have tradenames, but not all are subject to ASTMspecifications. Specifically: 8. GLASS FIBER MANUFACTURING 9. ARAMID FIBERSARAMID FIBERS having the highest strength-to-weight ratio of any commercially available reinforcement fiber at the time of their first commercial introduction in the early 1970s.Characteristics light weight, high strength, and high toughnessUsed in tires, ropes, cables, asbestos replacement, and protective apparelThe disadvantage of aramid fibers is that they are difficult to cut and machine.Aramid fibers are produced by extruding an acidic solution (a proprietary polycondensation product of terephthaloyol chloride and p-phenylenediamine) through a spinneret. The filaments are drawn through several orifices.During the drawing operation, aramid molecules beome highly oriented in the longitudinal direction. 10. CARBON FIBER 11. CARBON FIBER MANUFACTURING Major raw materials PAN and pitch 90% of the carbon fibers are made from polyacrylonitrile(PAN). 10% of carbon fibers are made from pitch PAN is pre-manufactured synthetic fiber. Pitch is coal-tar petroleum product that is melted, twisted,and stretched into fibers. 12. CARBON FIBER MANUFACTURING Typical sequence of operations used to form carbon fibersfrom polyacrylonitrile (PAN): Thermoset treatment Carbonizing Graphitizing Surface Treating Epoxy Sizing 13. CARBON FIBER MANUFACTURINGTHERMOSET TREATMENT Fibers are stretched and heated to no more than 400 C. Cross-links carbon chains so that the fibers will not melt insubsequent treatments.CARBONIZING fibers are heated to about 800 C in an oxygen free environment. removes non-carbon impurities.GRAPHITIZING heats them to temperatures ranging from 1100 C to 3000 C. stretches the fibers between 50 to 100% elongation. The stretchingensures a preferred crystalline orientation 14. SURFACE TREATINGAfter carbonizing, the fibers have a surface that does not bond well with the epoxies and other materials used in composite materials. To give the fibers better bonding properties, their surface is slightly oxidized.provides better chemical bonding properties better mechanical bonding properties.The surface treatment process must be carefully controlled to avoid forming tiny surface defects, such as pits, which could cause fiber failure. 15. EPOXY SIZING Fibers are coated to protect them from damage duringwinding or weaving. This process is called sizing. Typical coating materials include epoxy, polyester, nylon, andothers. The coated fibers are wound onto cylinders called spools. The spools are loaded into a spinning machine and the fibersare twisted into yarns of various sizes. 16. CERAMIC FIBERSCERAMIC FIBERS are commercially available in two general classes for the reinforcement of ceramic-matrix composites. oxide fibers, based on the alumina-silica (Al2O3-SiO2) system non-oxide fibers, silicon carbide (SiC).Fibers are typically produced with small diameter (2000 MPa 17. CERAMIC FIBERS PRODUCTIONFor oxide fibers, sol-gel processing is used. sol- gel process uses chemical solutions or colloidal suspensions,which are shaped into fibers, then gelled (usually by drying) and heattreated to convert the gelled precursor to ceramic.In the case of fibers based on SiC and silicon nitride, fibers are twisted from organometallic pre-ceramic polymerprecursors, followed by cross- linking (curing) and heat treatmentsteps to convert the fibers to ceramic materials. 18. CERAMICS FIBER MANUFACTURING