environmental engineering

Cell phone designers should think trash

H Kim Six_1

“As environmental regulations urge stronger stewardship for product retirement, recovering used products has become a field of rapidly growing interest for product manufacturers,” says Harrison Kim (above). “Recovery options—including reuse, repair, refurbishment, and recycling—enable companies to comply with legislation while also gaining some economic advantage. At comparatively little cost, companies can utilize many of the resources remaining in used products.” (Courtesy: U. Illinois)

U. ILLINOIS (US)—Out of the millions of cell phones retired each year only a small fraction—less than 5 percent—are recovered, which means that most end up in a landfill.

“People think that returning it to Best Buy is enough,” says Harrison Kim, assistant professor of industrial and enterprise systems engineering at the University of Illinois. “But if a product’s components are not designed to be replaced or reused, it is unlikely that it can be recycled efficiently.”

To make a product easy to recover, Kim says, manufacturing companies first need to understand the links between product design and recovery profit and be able to evaluate which design is better than others and why.

“As environmental regulations urge stronger stewardship for product retirement, recovering used products has become a field of rapidly growing interest for product manufacturers,” Kim adds.

“Recovery options—including reuse, repair, refurbishment, and recycling—enable companies to comply with legislation while also gaining some economic advantage. At comparatively little cost, companies can utilize many of the resources remaining in used products.

“As a result, more companies have been choosing product recovery instead of disposal as their primary retirement strategy,” Kim says. “Accordingly, engineering methods for maximizing recovery profit have come into increasing demand from industry.”

Kim and his colleague Deborah Thurston have developed a framework for analyzing how design differences affect product recovery and what architectural characteristics are desirable from the end-of-life perspective.

“As an illustration, we did a comparative study of cell phones types,” Kim says. “Three cell phone handset designs that share the same design concept but have different architectural characteristics. Ultimately, the optimal product design is the one that offers the greater recovery profit.”

Kim points to three reprocessing options: reuse, refurbishment, and recycling.

A reused item can be used for its original purpose without repair. A refurbished item maintains its identity and structure and is repaired or remanufactured as a like-new product. This usually includes disassembly, overhaul, and replacement.

“Component recovery is another option that can be more worthwhile than product recovery, especially when parts or modules account for most of the residual value,” Kim says.

In the case of a cell phone, the case may be worn or outdated, and perhaps the keyboard is too worn for reuse. However, the LCD screen may be perfectly useable in a rebuilt product.

This same concept can be applied to most manufactured items, Kim says.

“Caterpillar rebuilds diesel engines and certain automotive parts such as starters, transmissions, and oil pumps are routinely refurbished and reused.”

A product can be recovered not only in the form of a product but also of a module, a component, or a material. Multiple operations may be required to transform a unit into a desirable form, and different recovery plants can be required to accommodate necessary operations.

After all reprocessing is complete, recovered units are sold to demand sites, such as manufacturing plants and used-product markets.

The parts that cannot be reused can often be recycled to recover raw materials. Incineration of parts that are not reusable produces heat and electricity. When a company does not carry out any recycling on its own, dedicated recyclers are the demand sites for these materials.

To determine the economic viability of the different options, Kim created a mathematical matrix that takes into account numerous variables including the product design and production costs as well as the costs of the recovery network for collection, transportation, disassembly, repurposing of component parts, and recycling or disposal of unusable elements.

“We also looked at the volume of units involved to develop an optimization model for recovery profit evaluation.” Kim adds. “The results show that the framework can highlight preferred design alternatives and their design implications for the economic viability of end-of-life recovery.”

“The outcome of this research will ensure that sustainable product portfolio design will be realized at a much faster pace with economic justification, as well as environmental stewardship with regulatory compliance,” Kim says.

“It will also provide a new business model whereby a company is compelled to close the loop of product design and recovery by making recovery a part of the business model, due to its potential profitability, rather than outsourcing or ignoring it.”

University of Illinois engineering news: http://engineering.illinois.edu/

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