by Jeremy Faludi

This week’s episode of green design for Exbiblio is about metal. They recently decided to change plans about how the first release of the oPen will be made–instead of the whole body being recycled injection-molded plastic, most of the body will be an aluminum extrusion with holes machined into it for the screen and buttons, and there’ll just be plastic bits on the ends, much like an iPod Nano. The reasons for this had to do with schedule and design flexibility–we have a very tight schedule to make, and need to get to production as soon as possible, but still have not nailed down all of the design considerations. Using an extrusion with machined holes gives us a great deal of flexibility, as machining can be reprogrammed at any time to cut different holes, and extrusions are fast and easy to get into production–easier than injection-molding.

Using aluminum instead of plastic does increase the device’s environmental impact, in three ways: first, aluminum is more energy-intensive to produce than plastic; second, it’s more energy-intensive to manufacture with and requires harder tooling; third, having the case be made out of multiple different materials makes it harder to recycle because it needs to be more carefully disassembled and sorted. With a device this small, we need disassembly time to be extremely short, otherwise it won’t be worth anyone’s while to recycle it, because the amount of plastic and metal you get for the amount of time spent is small. I’ll talk more about design for disassembly in a later post.

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