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9.2 Guidelines

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9.2.2 Engaging Reversible Joining Systems From the disassembly point of view, the joints are classified as reversible or permanent. Unlike permanent ones, reversible joints can be removed and re-used without damaging the joint itself. It is easy to realise that reversible joints are more convenient for disassembling. Especially if it is disassembly for extending a product’s lifespan, then damaging the components would compromise their re-use. In respect of extending the material lifespan, this issue is not so strict; in fact, if of recycling is more important to acquire the materials as clean as possible and unbroken, the components are not end in themselves. Then the joining system can be permanent, as long as the materials are easily separable. Let us take a look at some indications with regard to different reversible joining systems: Snap-fit assembly: two way1 snap-fits are probably ideal joints for DFD strategies, as they allow easy, fast and repeated separation of components. Besides, they have integrated with components and therefore do not increase the amount of components or compromised materials (Fig. 9.4). Screws and bolts 2: we should give some clarification about using screws. Compared with snap-fit assembly, a screw obviously increases the number of components and different materials3. But actually, it is a good reversible fastening system and appropriate for frequent disassembling/re-assembling, which is especially recommendable in cases of components that are frequently repaired and replaced. Fig. 9.4 Two-way snap-fit that is easily opened with a screwdriver

1 Two-way snap-fit can be opened from the outside with a tool that lifts the snap’s hook. For this, one of the two components must have a fissure to allow the tool (usually a screwdriver) to be pushed in and then to lift the components apart. 2 Here, bolts refer to the set of screw, nut and washer. 3 This problem might not even arise if the component consSolls of the same material as the screw.

Design for Environmental Sustainability  

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Design for Environmental Sustainability  

Download: versi pdf [http://www.ziddu.com/download/12569881/DesignforEnvironmentalSustainability.pdf.html] versi zip [http://www.ziddu.com/...

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