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News Programmable Magnets
Correlated Magnetics Research (CMR) demonstrates new Coded Magnet™ technology that enables designers to tailor the behavior of a magnets’ attract and repel forces to meet specific application requirements.
Jan. 29, 2010, Orlando, Fla. - Magnets are an important part of our daily lives, serving as essential components in everyday items such as electric motors, computers, compact disc players, microwave ovens, automobiles as well as in specialized equipment such as test and measurement apparatus, instrumentation, robotic equipment and advanced imaging systems.
For mechanical applications, ordinary magnet pairs will either attract each other or repel each other depending on the spatial orientation of their dipoles. However, magnet designs have been limited by the assumption of an indirect relationship, which describes the force as inversely proportional to the linear distance between the magnets. 
Because of this limitation, design engineers have long relied on materials science and advanced manufacturing techniques to produce magnets with appropriate attract and/or repel force performance characteristics required for particular applications.
The force curve shown in Fig.1 describes the repel force profile for two standard neodymium iron boron (NdFeB) N42-grade disk magnets 1-1/2” diameter by 1/8” thick. Two magnets are shown with north poles facing each other thereby producing a repel force that varies indirectly with separation distance. Correlated magnetics technology removes this limiting assumption by enabling the programming of magnetic devices to precisely prescribe magnetic fields and therefore magnet behaviors. Specifically, magnet designers can now use patterns of grouped and/or alternating magnetic elements – or maxels – that behave individually like dipole magnets, but can exhibit many different behaviors as a whole. The shape of a force profile is controlled by a number of design parameters, including total number of magnetic elements, polarity, amplitude, and the size, shape and location of the maxels.
The amount of maxel polarity variation per unit area (code density) on a magnet surface affects the level of the peak force at contact. The code density also affects the residual level of force at the far-field and the rate of decay, or slope, of the force curve. As the code density increases, so does the peak attraction force. However, the attraction force decays more rapidly, and the far-field force is significantly reduced.
Fig. 2 depicts multiple force curves produced by varying the code density of the maxels programmed into the magnet pair using instances of a simple alternating polarity code. In this case, the material is NdFeB N42-grade 3/4” square magnets at a thickness of 1/8” and code density is varied from conventional magnet (code density = 1) to 256 maxels on the Coded Magnet™ surface.
While code density affects the severity of the slope of the force curve, as well as peak and far-field force levels, maxel size, shape and amplitude affect the engagement distance of the forces programmed into the magnet pair. Opposing forces can be employed simultaneously (attract and repel), providing the designer the ability to impart inflections into the force curve.
The amplitude of each maxel is adjusted by varying the input power on the induction coil as the magnets are being ‘printed,’ which in turn affects the shape of the force curve. The attract and repel forces can be increased or decreased and the inflection point can be prescribed to meet specific application requirements.
Fig. 3 depicts the force profile for two magnets programmed with CMR’s RepelSnapTM code using CMR’s proprietary magnetizer induction coil. This profile demonstrates a multi-level magnetism where the repel force increases, peaks and then transitions to an attract force as the Coded Magnet™ pair approach
This programmable force behavior empowers design
Fig. 4 illustrates the effect of varying input power on the shape
For comparison, the force curve for conventional magnets is also
Fig. 5 shows the RepelSnapTM demonstrator built by CMR engineers to highlight the functional differences between conventional magnets and Coded Magnets™, where disk magnets adhered to the bottom surface of four solid cylinders interact in a manner similar to springs with magnets fitted at the bottom of four cylindrical tubes.
The force curves below each cylinder describe the nature of the repel force experienced as the magnets travel vertically down the shaft. The far-left cylinder features two conventional magnets that exhibit a progressively-stiffer resistance as the magnets approach contact. The other three cylinders each feature RepelSnapTM programmed magnet pairs that provide a progressively stiffer resistance up to an inflection point at approximately 6/10 of an inch from surface contact.
Fig.5 At this point, the resistive force declines and actually transitions to an attract force at approximately two-tenths of an inch from surface contact, where the magnet pair then snap together and bond. The difference in resistance offered by the higher and lower power attract-force codes can be noticeably felt in your fingers. The far-right cylinder illustrates a ‘breakaway cushion’ behavior. The cylinder travel is limited by a spacer such that the magnet pair cannot enter the attract force region. The net effect is that the repel force declines to near zero, yet the cylinder will return to its starting position when released. Thus, new cushioning devices can be designed to give way after a prescribed force is reached.
  
Because force curves are now programmable, designers can tailor the magnetic behavior to match application requirements and to support new magnet applications. Conventional magnets that have strong magnetic fields can adversely affect credit cards, cell phones, pacemakers, etc. because of the linear reach of the magnetic fields. For the same reason, these magnets can also be very dangerous to handle.
In contrast, the custom designed magnetic fields employing correlated magnetics technology can exhibit a stronger peak force with a very short ‘throw,’ rendering a much safer magnetic device. Magnets may now include combinations of attract and repel forces that enable entirely new application areas. Programming magnets and their force curves provides a powerful new capability for product innovation and increased efficiencies across industry.
Magnetics 2010 conference attendees, presenters and vendors alike showed enthusiastic interest in Correlated Magnetics’ new programmable magnet technology. Among the excitement at the CMR booth we heard these audience comments:
“Wow!…. programmable force curves!” “The number of applications seems to be endless...” and “Correlated magnetics is to mechanical engineering what the integrated circuit was to electrical engineers.”
CMR intends to license the programmable magnets technology to manufacturers in the automotive, aerospace, defense, energy, environmental, construction, biomedical, consumer products, chemical process, robotics, security and transportation industries. CMR has 69 patents filed with the U.S. Patent Office as well as international patent organizations. For more information about programmable magnets, contact CMR representatives or visit the CMR website at www.correlatedmagnetics.com.
About Correlated Magnetics Research, LLC: CMR was founded in 2008 to pursue research and development activities in the field of correlated magnetic structures. HoverfieldTM, RepelSnapTM, and Coded MagnetsTM are registered trademarks of Correlated Magnetics Research, LLC.
North America Ron Jewell, Correlated Magnetics Research, LLC TEL: 678-528-4113
United Kingdom Matthew Scherba, Tx3 Solutions, Ltd TEL: +44 (0) 207 297 2036
Denmark Ole Toft, OLETO Corporation TEL: +45 2922 6564 |
| Copyright 2010 Correlated Magnetics ResearchTM LLC. All Rights Reserved. |