Want to produce a more eco-friendly car, computer or toaster? Be sure to check out these design tools and “green” tips.

For manufacturing and design engineers, being “green” is not as complicated as they might suspect. In fact, many manufacturers around the world are already getting a head start, examining their products’ environmental impact, incorporating more recycled materials and developing products that can be reused and recycled.

In addition, a growing number are taking a more holistic approach to being “green.” Some manufacturers are studying how their products affect the environment throughout their entire life cycle, from raw material production to use and eventually, disposal. Others are even revamping their business models. Rather than simply selling their products, some are implementing a service business model—accepting used products and either refurbishing them or recycling them for new products.

Indeed, these examples illustrate the basic ways that companies can help protect the environment. Whether compelled by legislation or driven by a sense of responsibility, these firms’ actions underline a deepening urgency to be “green.”

“The vast majority of what we consume is not returned to the natural system,” says Jonathan G. Overly, a research associate at the Center for Clean Products and Clean Technologies at the University of Tennessee. “It’s put in the ground as solid waste or it’s burned. With that in mind, individuals and corporations need to think about what we are doing to this planet. We have to come up with more sustainable ways of doing business.”

Fortunately, there are several tools that can help manufacturing and design engineers do just that, allowing them to determine their product design’s effect on the environment.

Checklists and Scorecards

Checklists are one example of a simple but effective tool. They pose basic questions about a product, including:

1) What kinds of plastic are used to make the product? And in what amounts?
2) How much waste does the manufacturing process produce?
3) What packaging materials are utilized for shipping and retail display?
4) Are any of the components reusable?
5) Are any of the materials recyclable?

Also helpful are scorecards or matrices, which allow engineers to assess the environmental effect of their products and the way they are manufactured using subjective numerical values.

For example, the West Michigan Sustainable Business Forum produces a scorecard that evaluates a product on 14 environmental concerns, such as resource depletion, worker health, manufacturing energy, durability and recyclability. For each issue, the product is graded on a scale of 0 to 5, with 0 meaning “good environmental performance” and 5 signifying “very poor environmental performance.” All of the values are then added up to arrive at a benchmark figure. This measurement allows engineers to address individual issues to attain the best possible overall score.

You can obtain checklists and scorecards from a number of academic, governmental and corporate sources in the U.S., Canada and Europe. They include the Minnesota Office of Environmental Assistance in St. Paul and the Industrial Research Assistance Program of the National Research Council of Canada in Ottawa.

Design for Environment (DFE) Software

Engineers can also rely on a more sophisticated “green” tool—the Design for Environment (DFE) software from Rhode Island-based Boothroyd-Dewhurst Inc. The software simulates the dismantling of a product at its life’s conclusion, showing the design’s cost benefits and environmental impacts. With this quantitative data, engineers can make adjustments during initial design stages.

The DFE software can be integrated with Boothroyd-Dewhurst’s Design for Manufacture and Assembly (DFMA) software, allowing initial disassembly sequences to be automatically created from the DFMA assembly list. Thus, users can organize the DFMA assembly list into groups of items that will not be dismantled once they’re obsolete.

Aside from allowing engineers to sort out the DFMA assembly list, the software also figures out how much time will be needed to take a product apart. Moreover, by considering the value of recovered materials against the costs of dismantling the product and disposing of the remainder, the software issues financial and environmental assessments.

“As the software simulates assembly and disassembly, it raises questions about how to improve things environmentally,” says Winston A. Knight, one of the DFE software authors and a professor of industrial and manufacturing engineering at the University of Rhode Island.

Life-Cycle Assessment

An even more complex tool is life-cycle assessment. Using this tool, engineers can determine the environmental effect of every phase in the product’s life cycle—from production of raw materials to manufacturing, from use to obsolescence.

For instance, a life-cycle assessment of a toaster would first examine the cost and environmental impact of manufacturing the toaster’s plastic parts, including such processes as oil refining, resin processing and injection molding. Then it would delve into the energy efficiency of different designs for the heating elements. Third, the assessment would weigh the costs of making and using the toaster against the duration of its usefulness. Finally, it would consider how to dispose of the toaster once it reaches the end of its life cycle.

A major benefit of life-cycle assessment is revealing how some seemingly “green” design changes may not be good for the environment in the long run. For instance, when you compare the two main materials for computer monitors—cathode ray tubes (CRTs) and liquid crystal displays (LCDs)—it may seem that LCDs have an edge because of several CRT drawbacks. For one, CRTs consume up to 10 times more energy when operating than similarly sized LCDs. What’s more, CRTs are filled with lead and release radiation. So LCDs are definitely the “green” choice, right? Wrong.

Using a life-cycle assessment, engineers will quickly realize that LCDs use mercury, which is more toxic than lead and can penetrate the ecosystem with greater ease when handled improperly. Engineers can thus tackle the issue from either side—attempting to either reduce CRTs’ energy consumption or remove mercury from LCDs.

Life-cycle assessment forces engineers to consider the big picture and adds perspective to decisions such as whether to use lead-free solder in electronic products. “There’s a big push to eliminate lead from electronic products because of its toxicity,” says Overly. “But if it takes three times the energy to produce a tin-silver-bismuth solder alloy, what have you gained?”

Cost Matters

A major component of these assessment tools is cost, says Bert Bras, Ph.D. and associate professor of mechanical engineering and director of the Institute for Sustainable Technology and Development at the Georgia Institute of Technology. “Cost plays a big role,” he points out. “Good companies always balance cost and the environment.”

For example, “green” products that cost a lot might not appeal to many and can end up being a waste of resources. Also, if an environmentally friendly design or process requires the complete revamping of an assembly line, companies could be inefficiently using resources as well. On the flip side, an inexpensive design could incur more costs in the long term because of its negative impact on the environment.

Indeed, before companies launch “green” products, they should undergo a cost analysis. “If you see a green product on the market, there’s usually a good cost story behind it,” says Bras.

“Green” Tactics

All of these tools share one significant side benefit; they inspire innovation. “By asking designers to assess the environmental impact of their products, you give them an excuse to rethink the entire design,” says Bras.

Engineers can greatly improve a product design’s “green” value with simple design changes. For instance, to make a product easy to take apart for remanufacturing or recycling, engineers can make sure it’s easy to assemble to begin with. To do so, they can decrease the product’s total number of parts or fasteners. “Too many fasteners are not good from an assembly standpoint, and they’re not good for disassembly either,” says Knight. “It’s much better to use some form of integral fastening, like snap-fit connections. It’s easier to break a snap-fit than it is to unscrew several fasteners.”

Of course, that doesn’t mean that engineers should avoid screws altogether; they are suitable for products that will be repaired, refurbished or remanufactured, says Bras. Indeed, aesthetic, financial and functional needs should never be overlooked when engineers make design decisions. In fact, in some cases, like choosing materials, these requirements usually override environmental issues, notes Bras.

After addressing these product requirements, then engineers can start considering some “green” tips. For one, Bras recommends that engineers maximize the use of recycled material and minimize the overall amount of material needed to manufacture the product. He says that when it comes to recycling, the less variety of plastics the better. “Using a variety of metals is not a problem, because sophisticated metal separation technology is available,” says Bras. “With plastics, however, try to stick with one plastic family.”

Engineers should also keep in mind that while life-cycle analysis can be insightful, it might not provide clear-cut answers. For example, while using more plastics in cars lowers total vehicle weight and bolters fuel economy, this material can have less desirable effects elsewhere. “There’s a penalty to pay with plastics, too,” says Jonathan W. Bulkley, Ph.D., a professor of civil and environmental engineering and co-director of the Center for Sustainable Systems at the University of Michigan. “Approximately 75% of a vehicle, by weight, is recoverable. The material that isn’t recovered is largely plastic and foam, which ends up in the landfill. You have to be careful that you’re not trading one problem for another.”

In the end, making products environmentally friendly is a delicate balancing act. And with assessment tools, engineers can take the various concerns into account and make the most informed decision.

Source: It Is Easy Being Green
John Sprovieri
Assembly Magazine, March 2003
http://www.assemblymag.com