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The document discusses elastomers, reinforced plastics, and honeycomb materials. Elastomers are synthetic rubber-like materials that can be easily deformed and return to their original shape. Reinforced plastics use fibers embedded in a plastic matrix to increase strength. Honeycomb materials use a cellular structure similar to a honeycomb to reduce weight while maintaining stiffness.
Parasentation
- 1. :Elastomer :Reinforced Plastic :Honeycomb Material Topic
- 2. Members • Imtiaz Ahmad(BSME01113115) • Khawer Saeed(BSME01113139)
- 3. Elastomer • Synthetic-rubber like material which, at room temperature, can be easily bent, stretched, twisted, or deformed and, when released, quickly returns to its approximate original dimensions and shape.
- 4. Elastomeric Materials • Highly amorphous • Highly random orientation • High elongation
- 5. Elastomeric Materials Metals Strain Conventional Plastics Stre ss Elastomers
- 6. Elastomeric Materials No Stress Stressed In tension
- 7. Elastomer Unsaturated rubber that can be vulcanized (Thermosets) are 1=>Natural rubber(NR) 2=>Polyisoprene(IR) 3=>polybutadiene(PB) 4=>choloprene rubber(CR) Saturated rubber 1=>Epichlorohydrin rubber(ECO) 2=> Silicone rubber(SI) 3=Flourosilicone rubber(FVMQ) Thermoplastic
- 8. Aliphatic Thermoset Elastomers • These are the most common elastomers • These have a double bond after polymerization has occurred • These are noncrystalline • These are highly flexible
- 9. Polyisoprene structure Cis-poliisoprena Trans-poliisoprena (Hevea rubber) (Gutta percha)
- 10. Natural Rubber H H Gutta percha or Balatta C H (trans-polyisoprene) H C H C H C C H H H H H H C H C Hevea Rubber C (cis-polyisoprenene) H C C H H H
- 11. Natural Rubber • Raw material extracted from trees
- 12. Natural Rubber • Material is processed
- 13. Thermoplastic Elastomer (TPE) • These materials are not crosslinked, have some distinct processing advantages over traditional thermoset elastomers and physical properties of vulcanised elastomers • TPEs are able to be molded like thermoplastic (injection molding, extrusion, etc) • Thermoplastic elastomers are more temperature sensitive • Scrap and reject of these materials can be recycled-environmetal friendly behavior • Normal crosslinked polymers cannot be recycled because they don't melt. They don't melt because the crosslinks tie all the polymer chains together, making it impossible for the material to flow.
- 14. PROCESSING OF ELASTOMER Common machine used for rubber compounding:- 1. Banbury mixer 2. 2-roll mill
- 15. Manufacturing of Elastomer • Calendaring • Extrusion screw extrusion ram extrusion • Compression molding Horizontal injection molding • Transfer molding
- 16. calendaring • Calendar is consist of rollers(known as Bowls) by using this we can control the thickness of elastomer sheat.the bowls can be horizontal of vertical the material from the mixer is fed between the nips of the bowls. the desiered sheet thickness can achieved by adjusting the nips. typical calendar
- 17. Extrusion • Screw Extrusion The elastomer is first fed into the barrel via a hopper and then forced down the barrel by the screw whilst heat is added (created by the shearing action and via the heated barrel and screw). At the end of the barrel, in the extruder head, is a die through which the material is forced out.
- 18. Extrusion Ram Extrusion For a ram extruder the elastomer needs to be rolled and warmed, usually by placing it in a bath of hot water or taking it directly from the mill/calender. This roll is then placed into the cylinder housing the ram. The head of the extruder containing the die is then locked in place at the front of the extruder and the ram traversed forward, forcing the material out of the die orifice.
- 19. Compression Molding Compression moulding describes the forming process in which an elastomer profile is placed directly in a heated mould, then softened by the heat, and forced to conform to the shape of the mould as the press closes the mould.
- 20. Injection Molding • Injection molding is a process where heated elastomer is injected into a closed cavity via a runner system. Uncured elastomer is fed into the injection cylinder where it is preheated and accurately metered into the mould. This is done by controlling the pressure, injection time and temperature.
- 21. Transfer Molding Elastomer of set weight is placed in the transfer pot, and, as with compression moulding, the pot is closed by the press forcing the elastomer down the sprues and into the cavity. A small amount of excess material flows out of the cavity through vents, with other excess material lying in the sprue grooves and a mat of material left in the transfer pot.
- 22. Application of Elastomers • Automotive Tuned mass dampers, rubbers seals, tyre and tube manufacturing, pipes and hoses, boots, sleeves and covers. • Aerospace Air management ducts, diaphragms, interior foils, hose and hoselines, air spring systems. • Defense Coating for radar and other defense equipments
- 23. Application Of Elastomer • Biomechanics and the medical/dental professions Surgery devices, prostheses, orthopedics, orthodontics, dental implants, artificial limbs, artificial organs, wheelchairs and beds, monitoring equipment • Highway safety and flight safety Seat belt design, impact absorbers, seat and padding design, passenger protection • Sports and consumer Helmet design, shoe design, athletic protection gear, sports equipment safety • Others • Dental Products, paints and coatings, cement and concrete adhesives, special wood protection coatings, biocompatible materials, medical and dental adhesives
- 24. Comparison B/W thermoplastic and Thermo sets Thermoplastic Thermosets • These soften and melt on heating. • These do not soften on heating but rather • These can be remolded recast and reshaped become hard in case prolonged heating is done • These are less brittle and soluble in some these start burning. organic solvents. • These can not be remolded or reshaped. • These are formed by addition polymerization. • These are more brittle and insoluble in organic • These have usually linear structures.Ex. solvents. Polyethylene, PVC, Teflon. • These are formed by condensation polymerization. • These have three dimensional cross linked structures. Ex. Bakelite, urea, formaldehyde, resin.
- 25. Industries In Pakistan Ideal Industry Mailing Address: Plot # 109, Kerbath Soling, 1 km Off Main Bedian Road, Lahore Pakistan. Pabx: 92 42 35600211/12 Cell: 92 344 6001111 Fax: 92 42 35600209 Email: sales@idealindustriesm.pk Rainbow Rubber Industry Factory Address: Near Rabbani Masjid, Mirza Adam Khan Road, Karachi-Sindh, Pakistan Telephone: 0092.21.32521070 & 0092.21.32542033 Fax: 0092.21.32542033 Director Marketing's : 0092.300.9279057 Director Product's : 0092.300.2172782 Email: contact@rainbowrubberindustry.com contact@rainbowrubber.net
- 27. Composites • Composites can cut weight by not being isometric and still maintain the strength in the desired directions • Composites are, by definition, solid materials composed of more than one substance in more than one phase
- 28. Composites
- 29. Processes • Thermoplastic processes –Very short fibers • Matched die/compression molding • RTM • Spray-up • Hand lay-up for wet and prepreg materials • Filament winding and fiber placement • Pultrusion
- 30. Matrix Materials • Resins – Both thermosets and thermoplastics can be used – Short fibers are generally used in thermoplastics – Long fibers are generally used with thermosets
- 31. Matrix Materials • Short fiber composites – Less than 0.2 inches (whiskers) – Processed through standard thermoplastic processes • Must pass through gates, runners, and gap between processing screw and barrel walls – Thermoplastics generally benefit greatly from even the short reinforcement materials
- 32. Matrix Materials – FRP • Intermediate length fiber reinforcement – The longer the fibers, the more difficult it is to coat the fibers enough to reap strength benefits – Low viscosity thermosets ―wet-out‖ the materials better than high viscosity thermoplastics – Generally use unsaturated polyester and vinylester resins for FRP
- 33. Reinforcements • Three main types of fibers – Fiberglass – Carbon fiber or Graphite – Organic fibers, aramids (kevlar)
- 34. Fiberglass • Spin molten glass • Different types of glass can be made – E-glass (improved electrical resistance) – S-glass (high strength) – C-glass (high chemical resistance)
- 35. Carbon or Graphite Fiber • Originally some distinction was made—now the two refer to the same material • Made from PAN fibers, pitch or rayon fibers • Through heating, raw material looses most non-carbon atoms in the chain • Processing also aligns carbon chains • Carbon fibers have very high modulus (stiffness)
- 36. Organic Reinforcement Fibers • Aramid fibers have greatest strength and modulus properties of organic fibers • Kevlar is the most commonly used aramid fiber • Aramids are strong and stiff but their greatest value is in impact applications – Front of airplane wings – Armor applications
- 37. Reinforcement Forms • Fiber manufacturers package the fibers on spools called tows • Fibers are generally converted to other forms after manufacturing – Chopped fibers (including whiskers) – Mat (random) – Woven fibers – Tapes – Prepregs
- 38. Manufacturing Methods • Thermoplastic processes using short fibers – Injection molding – Extrusion – Minor changes are made to accommodate the fiber reinforcements • All gaps in flow path should be increased • A resin viscosity decrease may be necessary
- 39. Manufacturing Methods • Matched die or Compression molding – Reduced flow path over injection or extrusion – SMC compression molding allows for continuous fibers, mats or weaves – These processes offer parts that are finished on both sides where most other composite processes do not
- 40. Manufacturing Methods • Resin transfer molding – Fiber preform is placed in the mold cavity – Preform doesn’t move—resin is pulled/pushed in
- 41. Manufacturing Methods • Spray-up – Fibers are chopped, coated with resin and sprayed onto the mold
- 42. Manufacturing Methods • Hand Lay-up (wet and prepreg) Wet Prepreg
- 43. Fiber Orientations • Isometric materials have equal strength in all directions • Composites can be lighter weight by not having strength in the directions that it is not needed • Lay-up still has to have some balance and symmetry
- 44. Vacuum Bagging • Provides for increased part consolidation • Reduces matched die mold costs
- 45. Manufacturing Methods • Filament winding and fiber placement – Fiber placement has greater accuracy – Fiber placement can wind on less symmetrical and even partially concave mandrels • Tubes, tanks, wind turbine blades and rockets
- 46. Manufacturing Methods • Roll wrapping – Faster than filament winding – Limited to symmetrical mandrels
- 47. Manufacturing Methods • Pultrusion – High volume production – Comparable to extrusion but the main processing force is tension – Profile is pulled from the machine
- 48. Plant Concepts • Many of the processes require considerable space • Curing equipment for large parts can be very large (and expensive) • Controlling volatiles (solvents and resins) must be taken care of • Molds can be both expensive and fragile
- 50. Honeycomb structures are natural or man-made structures that have the geometry of a honeycomb to allow the minimization of the amount of used material to reach minimal weight and minimal material cost. The geometry of honeycomb structures can vary widely but the common feature of all such structures is an array of hollow cells formed between thin vertical walls.
- 51. Today honeycomb cores are manufactured via the expansion process and the corrugation process from composite materials such as glass-reinforced plastic (also known as fiberglass), carbon fiber reinforced plastic, Nomex aramide paper reinforced plastic, or from a metal (usually aluminum)
- 52. Recently a new process to produce thermoplastic honeycombs has been implemented, allowing a continuous in-line production with direct lamination of skin to cost efficient sandwich panel production. Continuous in-line production of metal honeycomb can be done from metal rolls by cutting and bending. Today, a wide variety of materials can be formed into a honeycomb composite. For example paperboard honeycomb is used in paper pallets and package cushioning, blocking and bracing
- 53. Manufacturing method Expansion method corrugation process slotted metal strips
- 54. Expansion method • In this process thin metal sheet is first cut into panels and strip bonded • This process is referred to as the ―honeycomb before expansion‖ or HOBE method. This can be cut and stretched perpendicular to the strip bonds to create a hexagonal structure. The expansion process requires moderately high inter-sheet bond strengths (sufficient to enable sheet stretching). For low density honeycombs with very thin webs
- 55. Corrugated method • In this approach, a metal sheet is corrugated, and then stacked into a block. The sheets are bonded by welding (or any suitable method) together and the core sliced to the desired thickness and the corrugated layers either adhesively bonded or welded to face sheets.
- 56. Corrugated method • the process for forming a hexagonal honeycomb core; however this process may be used for numerous additional topologies including square and triangular shaped cells
- 57. Slotted metal strips • slotted metal strips can be assembled in the form of square and triangular honeycombs • Since no metal bending is required, this slotted sheet process is also well suited for making honeycombs from low ductility materials. The honeycomb cores are bonded by welding/brazing (or any suitable method) together and bonded to face sheets to form a sandwich structure. Even brittle composite or ceramic honeycombs can in principle be made by this approach.
- 58. Application of honeycomb Composite honeycomb structures have been used in numerous engineering and scientific applications.
- 59. Application of honeycomb Lightweight honeycomb solutions are used in a wide range of industries, including the aerospace, marine, military, construction and automotive markets. Aluminum honeycomb, for example, is used as flooring material in various aircrafts, as it provides exceptional strength and low weight. It is also suitable for use at high temperatures and can withstand a variety of environmental factors
- 60. Application of honeycomb • Aramid fiber honeycomb is also used in aerospace applications, but often in more advanced capacities, such as missile and hull components. This type of honeycomb also finds use in various marine and military structures. Polypropylene honeycomb, on the other hand, is used in various noise and vibration reduction applications, such as acoustical panels. It also offers relatively high strength for its weight and is easily formed by various thermoforming techniques.
- 61. Application of honeycomb • Honeycombs utilize far less material than a solid panel but still provide exceptional strength, making it a highly economical option for many applications. In addition, the strength of the honeycomb increases with its thickness, meaning it is well suited to structures needing considerable core materials. Honeycombs are available in a wide range of standard and custom shapes and sizes.