Efforts Grow to Design for Disassembly

November 19, 2007

7 Min Read
Efforts Grow to Design for Disassembly

Keep an eye on design for recycling. It’s long been a backburner issue at the great majority of American companies, but that may change.

Two new directives require companies to take responsibility for their products sold in the European Union after their useful life. The Waste Electrical and Electronic Equipment Directive (WEEE), which was enacted as European Union Law in 2003 along with RoHS, is finally starting to grab hold after member states dragged their heels on implementation.

OEMs, distributors and others are required to develop an infrastructure to collect computers, household appliances, cell phones, lighting equipment, medical equipment and other electronic waste and then to recycle or re-use as much of the material as possible. The law became effective in the United Kingdom on July 1. Manufacturers are paying a fee to cover the cost of collection and recycling of goods they produce.

Producers in countries such as Germany are already taking responsibility for post-consumer waste by collecting products at municipal waste sites. It behooves them to make their products as recycleable as possible to reduce costs of the process.

Three states in the U.S. have promulgated electrical waste legislation and bills are pending in a dozen others. The most important law, in California, requires consumers to pay a recycling fee at the time of purchase and does not create an incentive for OEMs to design products differently.

The European Union (EU) is also ramping up recycling targets in its End-of-Life vehicle directive from 75 to 95 percent through 2015. Another factor that will encourage design for recycling is the soaring cost of materials. Price escalation in aluminum, steel, copper and zinc is “scary,” says Bo Andersson, General Motors’ top buyer. While GM is already a leading recycler, the economic incentive is growing for other OEMs.

Hewlett Packard’s Headstart

One of the leaders in design for disassembly and recycling globally is Hewlett Packard, one of the founding members of the European Recycling Platform, which is establishing the framework for WEEE compliance in much of Europe.

Hewlett Packard established a goal in 2004 to recycle 1 billion lb of electronic waste (including printer cartridges) and hit that target last summer, six months ahead of schedule. Its new target is another billion pounds by the end of 2010.

“Starting 15 years ago there was very conscious effort to design products so that they could be recycled,” says John Frey, who chairs HP’s Environmental Strategies Council. “And the reason for that is we had started recycling 20 years ago and we were running into difficulties with the ways things were put together.

In HP’s view, design for easier disassembly required embracing simpler solutions to assembly.

“We now use a common screw form factor all the way through,” says Frey. “In the good old days, subassemblies might have been held together with a Phillips head screw; main assemblies might have been held together with a flathead or a torque screw. So what we found in dissembling is that the person had to keep switching screw drivers.”

The cases for desktop PCs used to be held together with five screws. “Now a lot of business PCs have a latch where you pull the latch and the whole side comes off,” says Frey. Battery case covers are now designed so they are integral to the battery, rather than functioning as a separate piece.

Other changes:

• No more adhesives.
• Use of more metals, which are more easily recycleable than plastics.
• Use of plastics families, rather than chemically disparate plastics, such as aromatic-based and olefin-based.
• More snap fits.
• Clear markings indicating types of plastic used.

HP prefers to use simple, off-the-shelf assembly technology. For the most part, new assembly technology has not been developed specifically for design for recycling. However, significant technology has been developed for design for disassembly for maintenance purposes.

One example of a new product that serves both purposes well is the Avdel Rivscrew, which combines the speed of rivet placement with the removability of a screw. Phil Szuba, general manger of Avdel North America told Design News that Rivscrew PL fasteners are up to six times faster to install than self-tapping screw and nut or screw and washer assemblies. They’re targeted at a variety of applications, including several in the automotive and electronics categories, such as computer printers. The screws are aimed at plastic assemblies.

PennEngineering also has several products aimed at design for disassembly, whether for maintenance or recycling purposes. The primary product line, self-clinching fasteners, provides permanent threads in thin metal sheets. Only mating hardware is needed for final assembly — and disassembly is just as simple, says a PEM spokesman. The line extends to inserts for plastic assemblies, too, with all the disassembly benefits.

In addition, some standoff fasteners (for stacking or spacing PC boards) allow users to “snap boards on” and then “snap them off” without tools.

“First and foremost we design for assembly,” says Leon Attarian of PennEngineering, Danboro, PA, “but the reverse of that can also be true. We are trying to eliminate a lot of the loose hardware, nuts, bolts, washers, things like that, so that when you’re putting things together you don’t have to deal with all of these components. And at the other end of it, when you are disassembling you don’t have to worry about stuff falling all over.”

Another company that offers products for fast disassembly is Asymmetric Fasteners Inc. of Hackettstown, NJ. Referring to a product called Torksleeve M, President Tad Staniszewski says “To disassemble these components from the shaft or disassemble shafts from metal or plastic wall takes seconds. Just loosen up the nut (½ to ¾ turn) and slide components from the shaft.”

Keep It Simple

Design for disassembly isn’t so much a matter of special technology, however.

“Our view of design for disassembly is very much as it is for the design for assembly,” says Winston A. Knight, professor of industrial and systems engineering at the University of Rhode Island and author of several books on industrial design. “If you concentrate on simplifying the overall product by reducing the number if parts then this has just as much impact on disassembly as it does on assembly.”

Knight helped develop a software package on design for disassembly for software firm Boothroyd Dewhurst Inc. of Warwick, RI. It was first rolled out in the 1990s and is being revved up again in anticipation of increased interest because of the EU directives. “The thinking is that if you want to meet the EU directives, a company is going to have to say that a certain percentage of this product is recycleable or reusable,” he says. The software also provides information on financial impact of disassembly and disposal for different design options.

One of the key aspects of the program indicates materials preferences and their recycling potential. Design engineers get quick alerts to avoid materials such as lead that are restricted substances. Other materials such as polyvinyl chloride and plastics with brominated flame retardants are indicated as non-preferred.

Materials selection is also a big part of the Hewlett Packard approach. HP has phased out brominated flame retardants and most PVC. Power cables are jacketed with PVC at HP and elsewhere because no safe alternative exists. The materials push at HP is to take its own recyclate back and use it in high-end applications, sometimes even above its original use. Recycled polyethylene from HP printer cartridges is compounded with glass fiber, recycled polyethylene terephthalate (PET) from soda bottles and other materials into a plastic that replaces polycarbonate on a piece that holds the light source on optical scanners. “The structural stability of that piece is very important for optical clarity,” say’s HP’s Frey. It’s not only a good environmental move; the cost of the new compound is less than PC. The recycled material is referred to as RPET.

The design for recycleability process requires a rigorous design engineering protocol, particularly considering much of electronics design now takes place by third parties all over the world.

“One of the things we recognized early was the necessity to embed our design for recycleability standards in our design standards in each of our groups designing new products,” says Frey. Environmental managers participate in new product development with design engineers.

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