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Active Disassembly. Self Disassembly Electronics. Labour for disassembly represents a large fraction of recycling electronics Products that can non-destructively take themselves apart?? Active Disassembly with single generic trigger Not necessary to have records or plans on how to disassemble.

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Presentation Transcript
self disassembly electronics
Self Disassembly Electronics
  • Labour for disassembly represents a large fraction of recycling electronics
  • Products that can non-destructively take themselves apart??
  • Active Disassembly with single generic trigger
  • Not necessary to have records or plans on how to disassemble
smart materials
Smart Materials
  • Two basic families of smart materials
    • Shape Memory Alloys
    • Shape Memory Polymers
  • Below a certain “transformation temperature” (Tx) they behave as standard engineering materials & can be used in the normal way
  • Above this critical temp they undergo a shape change that can be reversible if the temperature is lowered again
  • Tx can be controlled within a wide range of temperatures
  • Proper use of different activation temperatures can enable a designer to create a product that could take itself apart sequentially
shape memory alloys
Shape Memory Alloys
  • A group of metals made up of two or more metallic elements with particularly remarkable shape-changing and force provision properties
  • As the temperature crosses or changes across a critical value (Tx), known as Austenite Finishing Temperature they undergo a large and predictable shape change the so called Shape Memory Effect (SME)
  • Corrosion resistant and biocompatible
  • Mechanical strength to form fasteners
  • Tx can be placed between -190 C to 190 C
shape memory polymers smps
Shape Memory Polymers (SMPs)
  • Small group of plastics that can be formed using the normal processes
  • SME in SMP is different from SMA and is not well understood
  • Above their transformation temperature or glass transition temperature (Tg) SMPs loose their mechanical strength and return to their original formed shape after external forces are removed
  • SMP has a very narrow Tg range ~1C.
  • Unlike SMA plastics provide no significant force
shape memory effect
Shape Memory Effect
  • One way
    • Material recovers to the original form one or more times but must be forcibly reshaped
  • Two way
    • Material can recover many times to original shape and deform again to a secondary form after exposure to second stimulus
  • Multi-way
    • Same response as two way but with multiple shapes reacting to multiple stimulus
sma actuators
SMA Actuators
  • Released socketed IC’s from PCB’s
  • Disassembly of product housings
  • Nested Disassembly
  • Keyboards
  • CD Players
  • Video games
  • Telephones
sma actuators1
SMA Actuators
  • Characterisation
    • Non-destruction
    • Cost effectiveness
    • Range of permissible temperatures
    • Triggering temperatures
  • Heat Sources
    • Air
    • Steam
    • Infrared
    • Water Baths
smp releasable fasteners
SMP Releasable Fasteners
  • SMP screws placed inside the candidate product so that at Tg the device exhibits considerable mechanical property loss
  • Effect of “letting go”
  • Returned to their original shape after active disassembly
looking forward
Looking Forward
  • Materials expensive
  • Single Suppliers, Multinationals very slow to get involved
  • Developed SME in conventional materials
  • Need to get recyclers to adapt
  • The science and technology of building devices, such as electronic circuits, from single atoms and molecules.
carbon nanotubes
Extraordinary Strength

Conductor and Semiconductor Properties, Electrical Conductivity 1000 times greater than copper

Can be configured to be almost frictionless

Can be configured to be excellent thermal conductors or insulators

Carbon Nanotubes
  • Ultimate aim is to manufacture and assemble objects one molecule at a time (bottom up manufacturing).
    • Reduced resource consumption through dematerialisation
    • Reduced chemical pollution through material substitution
    • Conversion of current waste into new resources
    • Enabling recycling at consumer household level
  • Near zero tolerances
  • Stronger, lighter and purer than current materials
    • Much greater efficiency in moving parts
further reading

Further Reading

Chapter 23 Goldberg