Magnetics Business & Technology - Summer 2012 - (Page 19)

FEATURE ARTICLE ders for RE bonded magnets, whether isotropic or anisotropic, and covering NdFeB, SmCo and SmFeN, has an extraordinarily high utilization of the starting alloys. Figures in the high 90s percentage are normal, and then looking at scrap and wastage in the production of magnets from these powders, the overall efficiency of converting alloy ingot to finished product would normally be >95 percent. This is a hugely beneficial feature of these products, particularly when comparable figures in sintered magnet manufacture can be as low as 30 percent. This brings us to the final “RE” – REcycle. The increase in metal costs has given a renewed impetus to recycling processes. Whether this is recovery of the RE content of grinding sludge through fairly complex chemical means, or the identification of block material after parts have been cut from it, there is activity at every level within the magnet manufacturing process. Once the components get into devices though the story is a little different, with usually only a minimal consideration, if at all, of how the magnets can be removed at the end of the product life. Some situations are hopeless, such as the tiny vibrator motor built into some makes of toothbrush. The small sintered NdFeB cylindrical magnet ends up in someone’s bathroom trash can after a few months, and there is no hope of recovery. Some areas are brighter, such as the work by the University of Birmingham in the UK, who are developing processes to not only extract the voice coil magnets in hard disk drive head assemblies, but to convert the magnet into a hydrided powder at the same time, ready for incorporation back into new magnets. The auto industry is also putting pressure on designers to enable reprocessing of the materials used. An example of this is a seat motor housing, where the ring shaped bonded neo magnet is held in place purely by the differential expansions and contractions after the uncured magnet is pressed directly into the pole housing, and then put through the curing cycle. At the end of life, a slight crushing of the housing causes the magnet to break and fall out, no coating, no glue, ready for grinding up and using again. In summary, try to think about how to be more effective in the grades and shapes of material that get designed into products, and then how to get them out again so that someone else can give them a second life. Find out precisely how the components are made and challenge producers to find more efficient, lower cost methods. Ask how much scrap is produced, where it goes and how much you are paying for it. Be smart with your material choices and there will be more than enough price competitive material to go around. MagnetoDynamics is a magnetics consultancy business, assisting clients with challenges in both permanent magnets and in magnetic sensors. Contact James@MagnetoDynamics.com. www.MagneticsMagazine.com Summer 2012 • Magnetics Business & Technology 19 http://www.newenglandwire.com http://www.newenglandwire.com http://www.MagneticsMagazine.com

Table of Contents for the Digital Edition of Magnetics Business & Technology - Summer 2012

Magnetics Business & Technology - Summer 2012
Editor's Choice
Injection Molded Magnets for Electrical Machines
The Process of Developing and Testing a New Transformer
Rare Earths & Corporate Social Responsibility
Research & Development
RE-use, RE-duce, RE-cycle, RE-place
Magnets • Materials • Measurement
Application • Component Developments
Industry News
Rare Earth Crisis Dissected: Securing the Future
Marketplace
Advertising Index
Spontaneous Thoughts: The End of Axial Pressing?

Magnetics Business & Technology - Summer 2012