Design for Disassembly

Editor’s note: This is an excerpt from “Design Is the Problem,” the latest book by Nathan Shedroff, chair of the MBA in Design Strategy program at the California College of the Arts in San Francisco. Contrary to the book’s title, Shedroff presents practical, specific and executable solutions to designing for sustainability, covering topics from biomimicry and life cycle analysis to dematerialization.

Recycling is an important tenant of sustainability, but in order to be effective, products need to be easily disassembled into component parts and separated by material. If this is difficult, these products simply end up in the landfill instead.

The worst parts, in terms of recycling, are those made from two different materials bonded together, because they can’t be easily separated. The Cradle to Cradle framework designates these as “monstrous hybrids.” A good example of this type of hybrid would be milk and juice cartons that come with circular pour spouts and caps built into the side. The plastic cap and spout can’t be recycled with the waxed cardboard, and yet there are no easy ways for recyclers to separate these quickly. While this design is particularly convenient for some users, it makes recycling nearly impossible (a good example of opposing goals). The only way to recycle these is for users to cut the plastic spout from the rest of the container before placing them both in a recycling bin.

Likewise, most modern clothing presents a particular challenge since so much of it is blended from natural and artificial fibers. That shirt with 80 percent cotton and 20 percent rayon can’t be recycled in either compost or recycling bins. Currently, it can only go into the trash bin (and, thus, the landfill) since we have no economical way of separating the two materials.

The next most difficult materials to recycle are products that can’t be taken apart easily (therefore, they go into the trash instead of being recycled). Any product with parts that are bonded together or sealed so that they can’t be disassembled at all are not going to be recycled. Likewise, products assembled with complex assemblies or requiring custom or multiple tools aren’t likely to be recycled either. If it takes too long for workers to disassemble, they just won’t do it. In addition, these same products likely won’t get repaired often (or ever) for the same reason, which makes them difficult to endure or reuse. Design for disassembly is often the same as design for assembly. Improvements that designers and engineers make toward the end goal of ease of disassembling a product often take into account – and improve – how that product is assembled in the first place.

Disassembly, Step by Step

It’s not too difficult to design more easily disassembled products when it’s part of the initial phase of the design specification and goals. However, once engineering, design and production are already checked, it’s nearly impossible to redesign for easy disassembly.

To whatever extent possible, designers and developers can increase the likelihood of their products being recycled by using the following techniques:

Pure-material parts: These are parts made from only one material that doesn’t need to be separated. For most products, it’s unlikely that the whole product can be made from the same material, but if a product’s parts are at least uni-material, then each can be recycled easily.

Fewer parts: Where possible and applicable, reducing the number of parts can reduce the time and cost of disassembly and also affect the overall environmental impact of potentially reducing the amount of materials used.

Batteries and other electronics that are easy to remove: These components are often the most hazardous in terms of toxic chemicals, and they should be separated from the rest of the waste stream as early as possible. Ideally, they should be recycled separately, which isn’t possible if users can’t pull them out of the product easily.

Standardized fasteners: Have you ever tried to assemble a piece of furniture or tried to repair an electronic product only to find that there were many different fasteners used through the product? It sometimes feels like each bolt or screw has a unique length, size, and head configuration needing a unique tool to deal with each. While this is often a deterrent on the part of the manufacturer to prevent users from repairing their own products, it also increases the complexity (and likelihood to mistakes) in terms of assembly and repair for the manufacturer too. This is just one of the many other benefits that standardization can create.

Accessible fasteners: Anyone who has ever tried to change the oil filter on a typical small car, or a fuse in just about any car, knows the pain involved when parts aren’t easily accessible. There’s no reason why this is the case except that their developers simply didn’t consider putting these parts in more accessible places. The same is true of fasteners. Even if you’ve standardized and reduced the number of fasteners in a product, if you don’t make them accessible, the parts will likely not be separated or recycled. Making any metal fasteners magnetic can both ease disassembly and increase the likelihood that the fasteners themselves will be recovered for reuse or recycling.

Standardized components: Standardization can make components easier to replace and repair. It can help products be more easily used and understood, as well as upgraded. Most electronics would not be possible without a vast number of standards for everything from hard-drive sizes to file formats to transistor connectors and power outlets. Modular components can extend this technique to make products more easily understood, used, serviced, repaired, and ultimately recycled.

No fasteners: Sometimes, cases and components can be designed to clip together without the need for fasteners like screws. For example, many mobile phone cases (like those for the Nokia 6200) do this to allow a plethora of third-party custom case designs. The Macintosh IIcx and IIci family excelled in this respect as well. Hard drives, fans, power supply, motherboard, and other components simply snapped into place with plastic tabs molded into the case itself. These bent just enough to allow them to be held aside for the components to be removed. Parts can be glued or bonded, but only where they are recyclable together because they are identical materials.

Part material labels: No matter how the parts are assembled or how easily disassembled, if the materials for each aren’t immediately identifiable, they won’t be recycled. Recyclers can’t take many chances in contaminating their material streams. If they don’t know that the part is a specific type of plastic or alloy of aluminum, for example, they won’t throw it in the right bin. Instead, they’ll usually divert it to the trash or to the shredder (where it may get contaminated even more, requiring it to be further downcycled). Each part should be clearly marked with an internationally understood label or icon declaring what it is. If some parts are just to tiny (like screws), they should all be made of the same material (so someone could safely assume that they’re all the same material). If a part is made from an unexpected material or a material that looks like something else, this is even more critical. Metals that use alloys (like aluminum cases) should also be labeled by the alloy. It’s not enough to just say “glass” or “aluminum” if it’s a special kind that shouldn’t be mixed with others. There are several commonly understood labels and indicators for just these purposes. For example, the most commonly occurring plastics use a series of seven numbers within a recycling symbol (how’s that for clear?). This system, though less common, extends to glass, metals, batteries and other materials.

A 15% discount on Shedroff’s book is available from the publisher at , using the code ATISSUE.

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