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  • Slide 1
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:1 Environmentally Conscious Design & Manufacturing Class 18: Recycle Prof. S. M. Pandit
  • Slide 2
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:2 Agenda Definition of recycling Hierarchy of recycling Design for recycling Recycling metals, plastics & forest products Economics
  • Slide 3
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:3 Definition of Recycling American Automobile Manufacturers Associations definition A series of activities, including collection, separation, and processing, by which products or other materials are recovered from or otherwise diverted from the solid waste stream for use in the form of raw materials in the manufacture of new products.
  • Slide 4
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:4 Some Myths - 1 Recycling should pay for itself -Bias in data collected, and the inability to recognize large scale impact has led to reports of expensive recycling -$200 of energy is saved per ton of material recycled
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  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:5 Some Myths - 2 Environmental impacts of manufacturing are included in the products -Cost = function of: supply & demand governmental policy problems with assigning cost
  • Slide 6
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:6 Source: Bishop, Pollution Prevention: Fundamentals and Practice Life Cycle of a Product
  • Slide 7
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:7 Recycling World Categories: -Portable high value (computers, auto parts) -Metals -Plastics -Paper -Chemicals & glass -Food waste -Used equipment -Building material
  • Slide 8
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:8 Typical Value for Vehicles
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  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:9 Hierarchy of Recycling Options Source: Bishop, Pollution Prevention: Fundamentals and Practice
  • Slide 10
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:10 Steps of Recycling For remanufacture and reuse: Disassembly Cleaning Sorting and inspection Part renewal Re-assembly
  • Slide 11
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:11 For material recycling: Separation Discrete subassemblies / joining techniques Sorting Group or classify Reprocessing technology Steps of Recycling (cont.)
  • Slide 12
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:12 Possible Separation for Materials Source: Bishop, Pollution Prevention: Fundamentals and Practice
  • Slide 13
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:13 Example: Polymer Recycling
  • Slide 14
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:14 Design for Recycling Multiple objectives Minimize variety of materials & components Avoid use of toxic materials Ease of disassembly of dissimilar materials
  • Slide 15
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:15 Disassembly Design for Disassembly (DFD) Ease of Disassembly -Preferred design: snap-fit, pop-in, pop-out, bolted or screwed components -Difficult design: welded, adhesive, threaded connections
  • Slide 16
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:16 Disassembly (cont.) Simplified Design -Reduce the number and types of parts -Reduce product complexity Modularity Design Material Selection -Facilitate identification of materials (e.g. Marking plastics) -Use fewer types of materials -Use similar or compatible materials
  • Slide 17
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:17 Disassembly (cont.) Non-Destructive Disassembly (NDD) -Minimize the destruction of the product -Maximize the potential of material resource and sub-component reuse Destructive Disassembly (DD) -Destroy one or more components so that the others can be disassembled -Save more expensive components -Recycle materials
  • Slide 18
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:18 Disassembly (cont.) Disassembly Strategy - Analyze feasibility of part reuse and materials recovery - Generate optimal disassembly sequence - Disassembly optimization (Lower disassembly cost, higher rate of component reuse, higher rate of material recycling, etc.)
  • Slide 19
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:19 Recycling Metals Mixed metals (plating) - expensive Pure metals - very inexpensive Separation techniques: -Manual -Automated magnetic separation -Chemical separation Pyrometallurgy, hydrometallurgy, electrometallurgy
  • Slide 20
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:20 Recycling Plastics Thermoplastics - easy -Polyethylene terepthalate, polyvinyl chloride, low density polyethylene, polypropylene Thermoset plastics -Phenolics, polyesters, epoxides: - crosslinking, need pyrolysis / hydrolysis to reduce mol. Wt.
  • Slide 21
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:21 Recycling Rubber Mechanical Recycling Feed Stock Recycling Energy Recovery Use as is (Retreaded tired, fishing banks, etc.) Powdered rubber (Block, road paving, etc.) Reclaimed rubber (Devulcanization by the PAN reclaiming Thermal decomposition, etc Recovery of heat energy Source: Otsuka et al., SAE 2000 world congress
  • Slide 22
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:22 Recycling Forest Products Paper -Fibers get shorter with use & recycling White bond Colored bond newspaper grocery bags toilet paper
  • Slide 23
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:23 Economics Recycling must be profitable Revenue from recycling: -High value, reusable subassembly and parts -Recycled materials and energy Cost incurred by recycling: -Investments in recycling equipment -Labor cost -Other cost such as transportation, equipment operating
  • Slide 24
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:24 Economics (cont.) Number of Disassembly Steps Cost Landfilling Cost Disassembly cost
  • Slide 25
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:25 References Graedel & Allenby, Industrial Ecology, 1995 http://minerals.usgs.gov/minerals/pubs/commodity/recycle/index. html http://doemetalsrecycle.ornl.gov/ http://www.edf.org/pubs/reports/armythfin.html http://www.recycle.net/recycle/ http://mime1.marc.gatech.edu/Courseware/autorecycling/MatRecy c.html http://srl.marc.gatech.edu/education/Recycle/EnergRec. html
  • Slide 26
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:26 Homework #6 1How is the manufacturing economics affected by environmental considerations? (Illustrate your answer by using machining as an example) 2What steps would you take in a quantitative decision making process? What are the different tools available in this process? 3Compare and contrast traditional and ECDM guidelines for material selection.
  • Slide 27
  • Environmentally Conscious Design & Manufacturing (ME592) Date: April 17, 2000 Slide:27 Homework #6 4Why is recycling of plastics so important for the ECDM efforts? Give relevant statistics to support your answer. 5What are the major hurdles in recycling of plastics? How can they be overcome?

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