Product System Life Extension

Extending the life of a product can directly reduce environmental impact. In many cases, longer-lived products save resources and generate less waste because fewer units are needed to satisfy the same need. Doubling the life of a product translates into a pollution prevention of 50% in process transportation and distribution and a waste reduction of 50% at the end of the product's life.

Understanding why products are retired helps designers to extend the product system life. Reasons why products are no longer in use include:

• Technical obsolescence

• Fashion obsolescence

• Degraded performance or structural fatigue caused by normal wear over repeated use

• Environmental or chemical degradation

• Damage caused by accident or inappropriate use

To achieve a longer service life, designers must address issues beyond simple wear. A discussion of specific strategies for product life extension follows.

(a) Conventional Design

(a) Conventional Design

Municipal

Solid

Waste

(b) Green Design

Energy Efficiency Energy Efficiency

(b) Green Design

Energy Efficiency Energy Efficiency

FIG. 3.5.1 How product design affects material flows. Making changes in a product's design reduces overall environmental impact. The green design emphasizes the efficient use of material and energy, reduction of waste toxicity, and reuse and recycling of materials. (Reprinted from U.S. Congress Office of Technology Assessment 1992, Green products by design: Choices for a cleaner environment [U.S. Government Printing Office].)

Design for Recycling

Design for Reuse

FIG. 3.5.1 How product design affects material flows. Making changes in a product's design reduces overall environmental impact. The green design emphasizes the efficient use of material and energy, reduction of waste toxicity, and reuse and recycling of materials. (Reprinted from U.S. Congress Office of Technology Assessment 1992, Green products by design: Choices for a cleaner environment [U.S. Government Printing Office].)

Appropriate Durability

Durable items can withstand wear, stress, and environmental degradation over a long useful life. Development teams should enhance durability only when appropriate. Designs that allow a product or component to last beyond its expected useful life are usually wasteful.

Enhanced durability can be part of a broader strategy focused on marketing and sales. Durability is an integral part of all profitable leasing. Original equipment manufacturers who lease their products usually gain the most from durable design.

For example, a European company leases all the photocopiers it manufactures. The company designs drums and other key components of their photocopiers for maximum durability to reduce the need for replacement or repair. Because the company maintains control of the machines, they select materials to reduce the cost and impact of disposal.

Adaptability

Adaptability can extend the useful life of a product that quickly becomes obsolete. To reduce the overall environmental impact, designers should design a product so that a sufficient portion of it remains after obsolete parts are replaced.

Adaptable designs rely on interchangeable components. For example, an adaptable strategy for a new razor blade design ensures that the new blade mounts on the old handle so that the handle does not become part of the waste stream.

A large American company designed a telecommunication control center using a modular work station approach. Consumers can upgrade components as needed to maintain state-of-the-art performance. Some system components change rapidly, while others stay in service for ten years or more.

Reliability

Reliability is often expressed as a probability. It measures the ability of a system to accomplish its design mission in the intended environment for a certain period of time.

The number of components, the individual reliability of each component, and the configuration are important aspects of reliability. Parts reduction and simplified design can increase both reliability and manufacturability. A simple design may also be easier to service. All these factors can reduce resource use and waste.

Designers cannot always achieve reliability by reducing parts or making designs simple. In some cases, they must add redundant systems to provide backup. When a reliable product system requires parallel systems or fail-safe components, the cost can rise significantly. Reliable designs must also meet all other project requirements.

Reliability should be designed into products rather than achieved through later inspection. Screening out potentially unreliable products after they are made is wasteful because such products must be repaired or discarded. Both environmental impact and cost increase.

For example, a large American electronics firm discovered that the plug-in boards on the digital scopes it designs failed in use. However, when the boards were returned for testing, 30% showed no defects and were sent back to customers. Some boards were returned repeatedly, only to pass tests every time. Finally, the company discovered that a bit of insulation on each of the problem boards' capacitors was missing, producing a short when they were installed in the scope. The cause was insufficient clearance between the board and the chassis of the scope; each time the board was installed it scraped against the side of the instrument. Finding the problem was difficult and expensive. Preventing it during design with a more thorough examination of fit and clearance would have been simpler and less costly.

Remanufacturability

Remanufacturing is an industrial process that restores worn products to like-new condition. In a factory, a retired product is first completely disassembled. Its usable parts are then cleaned, refurbished, and put into inventory. Finally, a new product is reassembled from both old and new parts, creating a unit equal in performance and expected life to the original or currently available alternative. In contrast, a repaired or rebuilt product usually retains its identity, and only those parts that have failed or are badly worn are replaced.

Industrial equipment or other expensive products not subject to rapid change are the best candidates for re-manufacturing.

Designs must be easy to take apart if they are to be re-manufactured. Adhesives, welding, and some fasteners can make this process impossible. Critical parts must be designed to survive normal wear. Extra material should be present on used parts to allow refinishing. Care in selecting materials and arranging parts also helps to reduce excessive damage during use. Design continuity increases the number of interchangeable parts between different models in the same product line. Common parts make re-manufacturing products easier.

For example, a midwestern manufacturer could not afford to replace its thirteen aging plastic molding machines with new models, so it chose to remanufacture eight mold-ers for one-third the cost of new machines. The company also bought one new machine at the same time. The re-manufactured machines increased efficiency by 10 to 20% and decreased scrap output by 9% compared to the old equipment; performance was equal to the new molder. Even with updated controls, operator familiarity with the remanufactured machines and use of existing foundations and plumbing further reduced the cost of the remanufac-tured molders.

Reusability

Reuse is the additional use of an item after it is retired from a defined duty. Reformulation is not reuse. However, repair, cleaning, or refurbishing to maintain integrity can be done in the transition from one use to the next. When applied to products, reuse is a purely comparative term. Products with no single-use analogs are considered to be in service until discarded.

For example, a large supplier of industrial solvents designed a back-flush filter that could be reused many times. The new design replaced the single-use filters for some of their onsite equipment. Installing the back-flush filter caused an immediate reduction in waste generation, but further information about the environmental impact associated with the entire multiuse filter system is necessary to compare it to the impact of the single-use filters (Kusz 1990).

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