Goal: Reinvent part geometries to save material
One way to reduce the environmental impacts embodied in your product is by reducing the amount of material in your product. For vehicles (especially cars and airplanes), lightweighting is often by far the top priority for sustainability, because it saves fuel, which is usually a vehicle’s biggest impact. For other products, lightweighting is often less effective than sharing the product among many people: if ten people share a product, it uses 1/10th as much material per unit service, while the best engineer might be lucky to reduce material use 10–30% through lightweighting. Consider both to improve your whole system.
Here is a video Introduction to Lightweighting:
One way of lightweighting is removing as much material as possible, and reinforcing the few areas that need more support:
You can also lightweight structures by following lines of force:
Finally, “tensegrity” is a powerful way to reinvent for lighter weight:
For more thoughts on saving material and prioritizing reduction of certain materials, see these resources:
- Natural Capitalism (Hawken, Lovins, and Lovins), Chapter 4. This chapter describes the “hypercar” plan for lightweighting vehicles, the importance of measuring to find opportunities, net-shape production, and more.
- The Klagenfurt Innovation – Transnational Report (Schmidt-Bleek et. al., 1999). This paper explored ways to reduce material inputs per unit of service (MIPS). The document is quite academic, but p.10 contains a table that lists resource intensity of various materials and pp. 14-25 contain worksheets and checklists for exploring your options. In addition, you can consult the table on p.49 of Calculating MIPS (Ritthoff et. al., 2002), which shows material intensity factors. These are similar to LCA lookup tables.
- The Ecological rucksack for materials used in everyday products (NOAH–Friends of the Earth Denmark, 2005). This paper provides easy-to-understand explanations of MIPS calculations for various commonly-used materials.
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