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Powder metallurgy

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3_plastics.ppt
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Powder metallurgy

  1. 1. NAME:-TIVADI JEET SATISH KUMAR EN:-216400319213 SUB:-ME-1
  2. 2. Powder Metallurgy, Manufacturing with Ceramics Fine powder (plastic, ceramic, metal) Join powder particles(heat to just below melting point) balls used in ball-pointpens gears, cams cuttingtools (inserts) porousmetal filters oil-impregnated bearings piston rings in engines Shape by compacting in a die
  3. 3. P-M: (1) Powder Production Atomization:Spray liquid metal using high-pressure water, inert gas Chemicalmethod:Pass CO or H2 gas over powdered Metal oxide (reduction) Electrochemical action: Solutionof metal salt → Current → Metal depositson cathode water atomizer air atomizer
  4. 4. P-M: (2) Powder Blending, (3) Powder Compaction Blending • Mix different sizes of powder homogeneously • Add lubricant to improve compaction die life Compaction: produces green mold
  5. 5. P-M: (4) Sintering, (5) Finishing Green compact → heated in oven to 70% ~ 90% of melting point → Diffusion weld Sintering: 3-stage Sintering furnace: burn off lubricant→ sinter → cool down Finishing: 1. Coining and sizing: forging die to improve dimensional accuracy 2. Impregnation: e.g. oil impregnation for self-lubrication bearings 3. Infiltration: e.g. brazing of steel powders to add strength
  6. 6. Manufacturing with Glass (and Ceramics) Glass Sheet making: Rolling operationusing molten glass Lenses, Headlamps manufacture:Moldingprocess Glass tubes and rods: Drawing process using molten glass
  7. 7. Bottle manufacture heated glass 3-piece mold (a) Thehollowpiece of heated glass (parison) is first created bya blowmold (see text-book Fig 17.25) (b) Themold is put together (c) Plunger and hot air pushthe glass up (d) Hot air blows the glass out towards themold surface (e) Mold comes apart, bottle is removed heated glass 3-piece mold (a) Thehollowpiece of heated glass (parison) is first created bya blowmold (see text-book Fig 17.25) (b) Themold is put together (c) Plunger and hot air pushthe glass up (d) Hot air blows the glass out towards themold surface (e) Mold comes apart, bottle is removed Blow molding source: http://www.pct.edu/prep/bm.htm
  8. 8. Traditional Manufacturing Processes Casting Forming Sheet metal processing Cutting Joining Powder- and Ceramics Processing Plastics processing Surface treatment
  9. 9. Plastics History
  10. 10. Generalproperties:more durable,harder, tough, light. Typicaluses:automobile parts, constructionmaterials. Plastic types: Thermosets Examples: Unsaturated Polyesters:lacquers, varnishes, boat hulls, furniture Epoxies and Resins: glues, coating of electrical circuits, composites: fiberglass in helicopter blades, boats, …
  11. 11. Plastic types: Elastomers Generalproperties:these are thermosets, and have rubber-likeproperties. Typicaluses:medical masks, gloves, rubber-substitutes Examples: Polyurethanes: mattress, cushion, insulation,toys Silicones: surgical gloves, oxygen masks in medical applications joint seals
  12. 12. Generalproperties:low melting point, softer, flexible. Typicaluses:bottles, food wrappers, toys, … Examples: Polyethylene: packaging, electrical insulation, milk and water bottles, packaging film Polypropylene: carpet fibers, automotive bumpers, microwave containers, prosthetics Polyvinyl chloride (PVC): electrical cables cover, credit cards, car instrument panels Polystyrene: disposable spoons, forks, Styrofoam™ Acrylics (PMMA: polymethyl methacrylate): paints, fake fur, plexiglass Polyamide (nylon): textiles and fabrics, gears, bushing and washers, bearings PET (polyethylene terephthalate): bottles for acidic foods like juices, food trays PTFE (polytetrafluoroethylene): non-stick coating, Gore-Tex™ (raincoats), dental floss Plastic types: Thermoplastics
  13. 13. Plastics Processing: Extrusion p e lle t s o p e n c r o s s - s e c t io n s ( c h a n n e ls ) c lo s e d c r o s s - s e c t io n s ( t u b e s , p ip e s ) p e lle t s o p e n c r o s s - s e c t io n s ( c h a n n e ls ) c lo s e d c r o s s - s e c t io n s ( t u b e s , p ip e s )
  14. 14. Plastics Processing: Blow molding heated glass 3-piece mold (a) Thehollowpiece of heated glass (parison) is first created bya blowmold (see text-book Fig 17.25) (b) Themold is put together (c) Plunger and hot air pushthe glass up (d) Hot air blows the glass out towards themold surface (e) Mold comes apart, bottle is removed heated glass 3-piece mold (a) Thehollowpiece of heated glass (parison) is first created bya blowmold (see text-book Fig 17.25) (b) Themold is put together (c) Plunger and hot air pushthe glass up (d) Hot air blows the glass out towards themold surface (e) Mold comes apart, bottle is removed - similar to glass blow-molding-

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