Tuesday, March 18, 2008

Nokiainside - Pop Goes to Cell Phones


Nokiainside - Tips



As TechOnline points out, "In less than five minutes, trained workers at recycling centers can manually disassemble a computer and sort all of its plastics and its ferrous and nonferrous metals in preparation for recycling." But five minutes costs money. Today most cell phones and other small electronics are shredded instead of taken apart for recycling, because the disassembly time is too expensive for the amount of material reclaimed.


What if the product disassembled itself, in one second?

That's what Active Disassembly is all about. Screws that lose their threads and lengthen to push themselves out. Hooks that straighten to unhook and push the other piece away. Adhesives that melt or dissolve. Plastic parts that depolymerize into powder. All these and more are not just fantasies, they've been done in the lab for a couple years, and are getting closer to hitting the shelves:

Nokia has prototyped a cell phone that pops itself apart in two seconds, as opposed to the two minutes normally required for manual disassembly. Their diagram shows how they use shape memory alloy springs to push apart the snap-together plastic case and pop the circuit board off, use shape memory polymer screws which lose their threading, and use shape memory polymer screw bosses which expand to release the now unthreaded screws.

All of these shape memory materials are actuated by heating them up with a laser. The temperatures involved are around 60-150 ÂșC, cool enough to not melt the surrounding plastic but hot enough to not be easily triggered accidentally. ...Though in many parts of the world you'd have to watch where you set your phone on a hot sunny day. I know this isn't a problem in Finland, but they'll have to do some environmental testing before wide release--having software crash is one thing, but having your phone / laptop / camera / car spontaneously collapse into its component parts is a whole other level of "usability issue".

Nokia is not the first player in this game: various academic research has been done, and there is at least one company--Active Disassembly Research--that works exclusively on this. Active Disassembly does technology, logistics, and policy-related work in the field, and they have a great video gallery showing how some of these things work: screws unthreading, rivets and hooks unhooking, reversible glues sloughing off, ribbons and washers becoming springs to push components apart, etc.

Because many of these methods use snap-together fasteners that release on cue, it could also help manufacturers improve assembly times as well. Traditionally one of the reasons to avoid snap-together systems is the difficulty of disassembly for repair and maintenance, but if service technicians had portable devices to set off the active fasteners (probably just a heater of some sort, since most of these shape memory materials are heat-activated), this problem could be avoided. Plus, if the actuator were specialized (say, inductive or laser heating), it could allow products which are easily opened up by official service technicians but unopenable by the average consumer. Although the hackers and open-sourcers among us cringe at that, many companies would love the idea.

Whatever the specific incarnations of active disassembly, reducing breakdown time from minutes to seconds can make product recycling much more viable. With the WEEE and other take-back legislation coming down the pipe, the manufacturers will have to start paying for that time instead of governments or third-party recyclers, which is why manufacturers are starting to get interested in Design for Disassembly. We'll no doubt begin seeing spontaneous pop-apart products along with the myriad other strategies.

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