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Design News, May 2013

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functional requirements. When this about having to remove a front tire and happens, the batteries can no longer its fender well liner in order to access a power an automobile, but they still have car's battery or its headlight. How many usable life: in some estimates, up to 70 times have we had to switch between percent of the original charge. metric and standard tools while workOne application GM is investigating ing on one product? In addition, conis bundling the batteries and creating sider all the products we buy with plasbackup power systems for homes. From tic cases that have no visible fasteners or the reports, the Volt batteries themselves snap-fits, the ones that cannot be pried will not have to be modified to serve open even with a vise and a screwdriver. this new function. They will merely re- Virgin polypropylene (PP) resin (left) comes For these and any other products that quire removal from the Volt and ship- in uniform pellets. Grinding plastic products are difficult to disassemble, it doesn't ment to an assembly operation to be in- down for recycling creates irregular shaped nyh7matter what pearl of technology tegrated into the new product. is contained within: if it's not worth the and sized pieces (right). Virgin pellets are From the standpoint of labor and or- combined with the regrind to be molded into time investment, the product will at best ganization, reclamation for refurbish- new products. be tossed whole into a shredder and ment is usually more complicated than repurposing. In order reduced to its component materials, or at worst, end up in a to mine usable components from damaged, non-functioning, landfill. or simply discarded products, the products need to be disasMaterials recycling can be undone by one element: consembled, and the individual components tested, sorted, and tamination. For materials like plastic, separation into pure stored. material streams can be extremely difficult. Even metal fragFor any given component, recycling centers conduct time ments in plastic, the most basic of separations, can be missed studies to establish the return on the time investment needed by equipment designed to catch them. A small amount of to accomplish these steps. Markets exist for these components metal contamination in the plastic can damage an injectionand sub-assemblies, functional or not. Some recycling centers molding machine or a mold, while a mixture of dissimilar will even create refurbished product themselves, assembling plastics can cause material weakness and product failure. end products from their inventory of working components. Designing for Disassembly (DfD) can help address these In all of these cases, parts that would have once ended up in a concerns by minimizing the complications of component landfill now have a new life. removal and reducing the opportunities for contamination of Materials recycling is generally the most familiar form of materials. I've found that DfD principles can be successfully reuse, and ideally can be the most basic. In the simplest terms, incorporated into the overall design process in eight distinct products are separated by material type, which are then repro- ways: cessed into usable raw materials. While the purposes behind these 1 Combine functions of components end-of-life strategies seem straightforwithin the assembly ward and simple, it does not take a lot r 3FEVDFT UIF OVNCFS PG QBSUT to make their implementation messy, r .BZ BMMPX UIF SFEVDUJPO PG EJTTJNJMBS costly, and financially untenable. materials Repurposing and reclamation for 2 Reduce the number of assembly refurbishment only work when the reoperations by using subassemblies or moval of the components intended for modules reuse is financially viable. This viability r 'FXFS QBSUT UP BTTFNCMF is challenged by anything that complir 'FXFS GBTUFOFST cates that removal. Complications could r 4IPSUFS BTTFNCMZ UJNF include: the component is impossible to r "MMPXT GBTUFOFST UP CF QMBDFE JO FBTJMZ remove from the assembly; it requires accessible locations the disassembly of too many other com3 Use quick, finger-release fasteners ponents to access it; or it requires the use All accessory components of Schaefer's r 3FEVDFT UIF OFFE GPS UPPMT of multiple tools because a mix of fas- CF Collapsible Containers line of totes are r 4QFFET SFNPWBM tener types was used. 4 Use common fasteners when posmade of the same material as the box. This Day-to-day experiences demon- eliminates the possibility of material cross- sible and stick to either the English or strate that these complications are com- contamination that can arise from using metric standard and one head type, monplace. We've experienced or read metal rod hinges or nylon pivot pins. e.g., Allen or Phillips. Source: Schaefer Systems International Materials & Assembly Design News | MAY 2013 | w w w. d e s i g n n e w s . c o m –46– magenta cyan yellow black ES244374_DN1305_046.pgs 05.02.2013 05:22 UBM

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