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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. - PowerPoint PPT Presentation
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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
Active Disassembly
Active Disassembly
Active Disassembly
Active Disassembly
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
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 Alloys
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 Polymers (SMPs)
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
Released socketed IC’s from PCB’s Disassembly of product housings Nested Disassembly Keyboards CD Players Video games Telephones
SMA Actuators
Characterisation– Non-destruction– Cost effectiveness– Range of permissible temperatures– Triggering temperatures
Heat Sources– Air– Steam– Infrared– Water Baths
SMA Actuators
SMA Actuators
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
SMP Releasable Fasteners
SMP Releasable Fasteners
SMP Releasable Fasteners
Looking Forward
Materials expensive Single Suppliers, Multinationals very slow to
get involved Developed SME in conventional materials Need to get recyclers to adapt
Nanotechnology
The science and technology of building devices, such as electronic circuits, from single atoms and molecules.
IBM Xenon Atoms on Nickel Using Atomic Force Microscopy
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
Nanotechnology
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
Nanotechnology
Near zero tolerances Stronger, lighter and purer than current
materials– Much greater efficiency in moving parts
Further Reading
Chapter 23 Goldberghttp://www.activefasteners.co.ukwww.wikipedia.comwww.howstuffworks.com