Unit 7 Manufacturing Processes: Plastics and Composites

1. Unit 7Manufacturing Processes:Plastics and Composites Processing of Plastics and Composites

2. http://www.youtube.com/watch?v=PSxihhBzCjk

3. Processing of Plastics and Composites • Composites: • A materials category that consists of a matrix or base material reinforced by another material. • The materials maintain their original identification but the properties of the combination are improved.

4. Processing of Plastics and Composites Composites: • Matrix: • In composite materials the matrix is the outer layer of material in which the reinforcement is contained. • In metals, the background phase in which another phase is contained; steel is the matrix in which graphite flakes are present in gray cast iron.

5. Processing of Plastics and Composites Three Types of Composites: • PMCs – (Polymer Matrix Composites) composite materials that have a reinforcing material in a polymer matrix. • MMCs – (Metal Matrix Composites) composite materials that have reinforcing material in a metallic matrix. • CMCs – (Ceramic Matrix Composites) composite materials that have reinforcing material in a ceramic matrix.

6. Processing of Plastics and Composites Three Types of Composites: • Although the three types of composites have some significant differences, they are similar in their general makeup. • Each has a polymer, metallic, or ceramic matrix. • The reinforcements used inside these matrices can vary.

7. Processing of Plastics and Composites Reinforcements: • The material added to the matrix of a composite to improve its properties, usually the strength or stiffness.

8. Processing of Plastics and Composites • Composites differ from alloys, polymers, and ceramic compounds in that the matrix and reinforcement are separate from each other. • A material may be added to a metal, polymer, or ceramic for strengthening purposes and the material becomes part of the original material; reinforcements do not.

9. Processing of Plastics and Composites • Reinforcements: • Vary from short or chopped fibers, flakes, and particles to filaments and wires to continuous woven fibers and honeycombs. • Short, discontinuous reinforcements increase mechanical strength • Better – continuous reinforcements which can transfer or redistribute a load throughout the composite.

10. Processing Methods for Plastics: Blow molding Injection molding Extrusion Processing of Plastics and Composites

11. Processing of Plastics and Composites • Blow Molding: • Air is used to force a mass of molten plastic against the sides of a mold shaped in the form of the desired end product. • Examples include: milk bottles, soft drink bottles, etc.

12. Extrusion Blow Molding http://www.youtube.com/watch?v=ynsS2afrUzE

13. Processing of Plastics and Composites • Injection Molding: • A process in which the material to is heated sufficiently to become fluid and then injected under pressure into a mold cavity. • There, it is cooled sufficiently to take the shape of mold, and then removed from the mold; polymers and ceramics are processed in this manner. • Metal die casting is very similar to injection molding.

14. Plastic Injection Molding http://www.youtube.com/watch?v=jYkKBUFORco&feature=related

15. Processing of Plastics and Composites • Extrusion: • Usually under high pressure and at elevated temperatures, forcing materials through a die containing the shape desired so that a shaped product is produced. • Metal and polymer shapes are produced using this method.

16. Extrusion http://www.youtube.com/watch?v=WaB-dsB1Kfk&NR=1

17. Other Molding Processes: Compression Molding Thermoforming Transfer Molding Rotational Molding Processing of Plastics and Composites

18. Plastic Thermoforming http://www.youtube.com/watch?v=U60mdDW5Ulc

19. Composites • Plastics and composites are fast replacing metals in a vast array of manufactured products • Why? • Because of the often high cost of metals and the large energy requirements in metal processing, and the high strength and light weight of plastics and composites.

20. Composites NASA 360 Video http://www.youtube.com/watch?v=tZhH2B-EI1I Or

21. Composite Processing Methods • Methods to create and/or form the three types of composites: • PMCs – • Prepregs • Sheet-molding compound • Molding • Hand layup

22. Methods for forming Composites • To form PMCs (Polymer Matrix Composites) • Prepregs • Sheet-molding compound • Molding • Hand layup • Pultrusion • Filament Winding • Lamination

23. Methods for forming PMCs • Prepregs – an intermediate preimpregnated product: • Continuous strands of fiber are carefully aligned and then coated with the appropriate thermoplastic or thermoset resin • Made into sheets or tapes used to form a laminated product which is heated for curing

24. Pre-preg Materials http://www.youtube.com/watch?v=IeST0vfDuhw&feature=related

25. Methods for forming PMCs • Sheet-molding compound : • Made from chopped fibers that are deposited, with random orientation, on a resin-covered carrier film, such as polyethylene. • Another layer of resin covers the fibers • Then a top sheet or film (e.g. polyethylene) covers the resin.

26. Methods for forming PMCs • Sheet-molding compound : • The resulting sandwich is pressed between rollers and coiled or kept as flat sheets. • Kept in a controlled environment for 24 hours to cure.

27. Sheet Molding Compounds http://www.youtube.com/watch?v=IxaTwSBWz14

28. Methods for forming PMCs • Molding: • Some molding methods previously discussed take advantage of the prepregs and molding compounds are compression and transfer molding. • In these cases the reinforcements are placed into the mold cavities before or during the application of the polymer.

29. Methods for forming PMCs • Hand Layup: • The most common application of Hand Layup is the use of fiberglass. • Alternating layers of glass fiber fabric and resin are coated over a mold or form built in the shape of the desired end product. • Boat manufacturing is a popular application.

30. Automated Composite Lay-up http://www.youtube.com/watch?v=y_TDd3bzDeM

31. Methods for forming PMCs • Pultrusion: • Fibers are pulled or drawn through a liquid resin and then through a heated die that forms the desired shape. • Very much like extrusion except for the pulling rather than pushing of the material through the extrusion die.

32. Pultrusion http://www.youtube.com/watch?v=4MoHNZB5b_Y

33. Methods for forming PMCs • Filament Winding: • Fiber is wound back and forth on a cylindrical form. • This method is used to produce cylindrically shaped products such as tanks or other pressure vessels.

34. Filament Winding http://www.youtube.com/watch?v=iOZl3v4RC18

35. Methods for forming PMCs • Lamination: • Laminating alternating layers of resin containing the structural fiber. • Similar to the technique used with fiberglass; however, here the fibers are continuous throughout the material (in fiberglass, short pieces of glass fiber are randomly distributed throughout the resin).

36. To form MMCs (Metal Matrix Composites) Liquid Matrix Powder-Metallurgy Techniques Liquid-Solid Processing Methods for forming Composites

37. Methods for forming MMCs • Liquid Matrix – the typical MMC methods involve casting the molten matrix around solid reinforcements: • Using conventional casting techniques • Or, by using pressurized gas on the liquid matrix to force it into and around a preformed reinforcement • Reinforcements are often made of metal sheet or wire, or a ceramic fiber.

38. Liquid Matrix Molding http://www.youtube.com/watch?v=o0PGDRjoDUc

39. Methods for forming MMCs • Powder-Metallurgy Techniques • The reinforcement fibers, whiskers, or particles are carefully mixed with the powdered metallic matrix so that they are uniformly distributed in the mixture. • The mixture is then compacted, • Then sintered

40. Methods for forming Composites • To form CMCs (Ceramic Matrix Composites) • The most common process used in producing CMCs is slurry infiltration, in which the slurry contains the ceramic matrix powder. • A fiber pre-form of the desired product is hot pressed and impregnated with the slurry, then sintered.

41. Tool and Die Making • Specialty tooling is required to hold or form plastic materials until steps are taken in the process that alter the state of the material to make it rigid. • Thus, Tool and Die Making – the processes of building specialty production tooling to support manufacture of a product – is an integral and indispensible part of forming plastics and composites.

42. Unit 7Manufacturing Processes:Plastics and Composites Processing of Other Industrial Materials

43. The more important industrial materials used in manufacturing include: Glass Ceramics Wood, wood products, and paper Fabrics Rubber Natural materials Constructions materials Other Important Industrial Materials

44. Nonmetallic materials are used in conjunction with metals in all types of products. In many cases these materials are replacing metals because they are: More economical Stronger Lighter Easier to process Other Important Industrial Materials

45. Other Important Industrial Materials • Glass: • Consists primarily of fused silica (SiO2), a major constituent of beach sand. • Glass withstands chemical attack and large variations in temperature • Lead added to glass provides shielding from ionizing radiation • Can be fashioned into optical lenses

46. Other Important Industrial Materials • Glass: • A relatively new/developing technology in the use of glass is fiber optics. • Glass Manufacturing Processes include: • Pressing • Blow and Blow Operations • Press and Blow Operations

47. Other Important Industrial Materials • Ceramics: • Ceramic engineering materials are among the most researched and developing technologies in modern production. • Ceramics are made from the metallic oxides of such metals as silicon, aluminum, and magnesium. • Clay-based ceramics are becoming increasingly popular.

48. Other Important Industrial Materials • Ceramics: • Important properties of ceramics include: • Resistance to high heat levels • High strength • Chemically inert • Heat reflective • Can be as hard as diamonds and as light as aluminum.

49. Other Important Industrial Materials • Wood, wood products, paper: • Structural lumber for construction • Plywoods and other laminates • Hardwoods (furniture and flooring) • Paper

50. Other Important Industrial Materials • Fabrics: • Clothing and upholstery • Natural • Cotton, wool, flax, silk • Synthetic • Polyesters, nylons, other plastic polymers