Polymagnets are stirring the imaginations of enterprising designers with their ability to be engineered to custom requirements, but their potential to add value to products has barely been tapped.
By Mark Shortt
If you’ve never heard of Polymagnets® before, you may be surprised when you see them in action. Polymagnets may look like traditional magnets, but their similarity stops there. These versatile, permanent magnets can be programmed to attract at a distance, repel up close, and attach to steel with up to four times the force of traditional magnets—all without damaging electronics that are sensitive to magnetic interference.
Polymagnets, also called Smart Magnets, are the brainchild of Larry Fullerton, co-founder and chief scientist of Correlated Magnetics Research (CMR), a Campbell, Calif., company that is reported to have accumulated more than 120 patents for its work in magnetic technology. While trying to create a self-assembling toy for his grandchildren, Fullerton arranged magnets in patterns, or “codes,” to create complex magnetic fields. He later encoded magnets based on these experimental magnetic arrays, crafting the technology that led to the development of CMR.
Polymagnets are unlike conventional magnets in that they have multiple north and south poles, rather than just a single north and south pole. The surfaces of these multi-pole magnets are encoded with patterns of small magnetic elements called maxels, creating magnetic fields that can be tailored, via software, to enable spring or latch features, super-strong attachment or holding force, and precise alignment. The magnets can also be tuned for subtle differences in how a product feels, allowing products to snap together crisply, for example, or release softly from a point of attachment.
Although Polymagnet Smart Magnets are found in tablets, laptops, and other consumer electronics devices today, their potential to add value to products has barely been tapped, according to Andy Keane, CEO of CMR. To help product designers learn how smart magnets can be used to customize the behavior, function, and feel of new products, CMR has launched the Polymagnet Smart Magnet online design tool and catalog at www.polymagnet.com.
“Developing with Smart Magnets is relatively new to most product designers and mechanical engineers,” said Keane in a January release. “So we created a place where developers of all types can discover the wide variety of Smart Magnet behaviors and combinations. Our online selection tool quickly narrows down design options and puts real engineering data in the hands of designers.”
Correlated Magnetics Research has invented what it describes as a software-driven magnetizer, a machine called the MagPrinter®, to print customized maxel patterns onto the surfaces of the magnetic materials. Although not visible to the naked eye, these magnetic patterns can be seen with the aid of a high-resolution magnetic viewing film, which contains microscopic iron filings suspended in an oil between a couple of layers of film.
“If you and I looked at a Polymagnet without that film, they don’t look any different from a normal magnet,” said Paul Hardy, Polymagnet brand manager for Industrial Magnetics, Inc., in a phone interview. Industrial Magnetics, a Boyne City, Michigan company that strongly advocates the benefits of Polymagnets for design engineers, provides permanent magnets and electromagnets for use in work holding, lifting, fixturing, conveying, and magnetic separation. “But with that film, you can see the different patterning that we can put on the Polymagnet, and also some of the different sizes of the dots that we can put on there,” Hardy added. “The iron filings move around to the strong points of the magnets and kind of surround every individual magnetic field, and that’s what creates the little white lines that you see.”
Paul Hardy spoke with D2P recently about how Polymagnets are made, how they work, and how they can help make a design engineer’s life a little easier. Following is an edited transcript of our conversation.
D2P: When you hear the word ‘Polymagnets’, what’s the first thing that comes to mind?
Paul Hardy: When most people hear Polymagnets, they immediately relate ‘poly’ to plastic, but in this case, it actually means ‘many magnetic fields.’ As we take magnet material, it usually has one pole on each of its faces, and we modify it so that it has many magnetic poles, or fields, on that face.
D2P: Through what process is that modification done?
PH: We create the pattern with software, and the process actually involves what we call the MagPrinter®, which, mechanically, is very similar to a dot matrix printer. But instead of imprinting with ink, we’re actually using positive and negative electrical charges to create either north or south magnetic fields on the face of the material.
D2P: How does the MagPrinter work?
PH: Basically, we’re not actually making the magnet material; we’re imprinting or modifying that magnet material with multiple polarities. The printer is basically like a spot magnetizer, so we can decide which polarity we want to put in a specific spot on the surface of that magnet material. By doing that, we can create many small magnetic fields, which, in a lot of cases, enhances the energy that is already there in that material, to make it more effective when attracting to, say, thin metals. And it also will make a pair of magnets react differently to each other than was possible in the past.
Without this process, two magnets will either repel each other or attract each other, depending on which side you have them flipped on. With Polymagnets, with those multiple dots magnetism, we can actually make magnets that will, say, attract from a distance, and then, once they get really close, will actually go into a repel position. And we can do the opposite as well, where they will repel at a distance and then, if you push through that repel, physically, you can make them go to an attract position.
D2P: Industrial Magnetics custom fabricates different types of magnetic assemblies. How would you describe your business model beyond that, and how do Polymagnets fit into what you’re doing?
PH: Our business model, in the past, was to provide mostly industrial customers with magnetic solutions—for holding applications, lifting, and fixturing, and for separating steel—for applications or needs within their manufacturing processes. The Polymagnets are unique for us, in the fact that we’re providing magnets to help other people create their own unique new solutions, using magnet material. One thing that helps Industrial Magnetics succeed at this is that we have 50 years of background in making magnetic assemblies and magnetic circuit design. So that makes our knowledge useful in guiding product designers and developers to get them to more practical solutions faster.
D2P: What are some of the major applications in which Polymagnets are currently being used?
PH: Polymagnets are being used for improvements in accessories for things like mobile electronic devices. The Polymagnets are stronger when attracting to steel, or to each other, than traditional magnets are, especially thin steel. And with the multiple fields that the Polymagnets have on their surface, the depth of those fields is also much shallower, which means that there’s a lot less chance of magnetic interference with electronics that are sensitive to magnetics, such as cell phones and electronic devices, as well as credit cards.
So if you’ve got a Polymagnet, say, on an accessory for your phone, in your pocket close to your wallet with your credit cards, there’s a lot less chance of a Polymagnet wiping out your credit cards than the traditional magnet.
On the function side, they’re also being used as attach and latch type magnets, and align magnets. There are people using those to create closures for things like small appliance doors and some other devices that are proprietary. I can’t go into detail about it, but they act as a torsion spring that actually slows the door’s movement as it closes. It also has set stop positions, where it will hold the door in two different positions securely. But Polymagnets do this differently than traditional mechanical devices in that they’re using the magnetic field to do that, so there are no components that will wear out.
D2P: Is there any size range or restriction for these types of magnetic parts?
PH: It’s pretty broad, but the more maxels we can have on the surface of the magnet, the more function we can get out of it. The more we can increase the strength of it because we have more surface area to work with, more things we can change and edit. But on the small size, from a half inch to 2 inches in diameter is a pretty good working range for Polymagnets.
D2P: They could go into a larger component, right?
PH: Yes. We can put multiple Polymagnets in a bigger assembly, and we can make bigger Polymagnets than the 2-inch that I mentioned, but that’s just from a product designer’s standpoint. For other folks using these, that half inch to 2-inch range is a good practical range for fitting into their products, and also from a cost standpoint. It makes it affordable and even practical.
D2P: What do you think a design engineer should know about Polymagnets that they may not know?
PH: Design engineers should know about Polymagnets, in my opinion, because they create new ways to use magnets that really couldn’t be used practically in the past, such as the function magnets, which can create kind of a unique feel to a product. The way that the magnetic hinges work, they have a feel to them that’s different from anything mechanical that’s out there. So if they used the Polymagnets, it helps them take a function that their product already had, and give it a unique feel towards a competitor’s, to achieve that same function.
The other thing that they should know is that if we simply just replace the magnet they use—if, say, they’re attaching to steel with a Polymagnet—we can now make that even stronger for them. So it can be new and improved without changing anything physically. And if they wanted to look at possible cost reduction, size reduction, or weight reduction, a lot of times, we can make a Polymagnet that’s as strong or stronger in a much smaller size. So it gives them an opportunity to reduce the size of their product, possibly, the weight of their product, or maybe the number of magnets needed to achieve their goal.
D2P: What are some of the other major benefits that Polymagnets offer design engineers?
PH: These are made from what are called permanent, rare earth magnets. Permanent magnets only lose one half of one percent of their strength every 100 years. So when you create a Polymagnet that [mimics] a mechanical device, that magnet is permanent in the respect that it’s only going to lose that amount of strength—one half of one percent of their strength every 100 years. So, compared to a spring or mechanical latch, or other mechanical devices, it really isn’t going to wear out, especially if you think about small products. A lot of them have plastic catches and plastic latches, and eventually, that plastic will either break or just not work anymore. The Polymagnet isn’t going to wear out like that. So I think the wear characteristics are probably one of the best things they should know about.
D2P: Polymagnets are said to transform ordinary magnets into “precision-tailored magnetic systems that produce complex functions not possible with conventional magnets.” What are these complex functions that are not possible with conventional magnets?
PH: One of them is the detent type function. When two flat surface magnets are programmed properly and rotated, you will feel what feels like a mechanical ball detent, or hard stop, which means this magnet has very strong holding at positions where that detent is. And in between, it’s easier to rotate it if you need to twist it, but it’s also easier to get those two magnets to pop apart between those detent spots. So you can create a function that’s something that a normal magnet will not do. Two normal magnets have no resistance to spin on each other, other than just the surface tension alone. But with a Polymagnet, you can prescribe that, and you can change the angles, positions, and number of detents as you rotate that around, based on what the application demands.
D2P: In your experience so far, how have design engineers received this new technology?
PH: When I show these at shows, I see a lot of excitement—people kind of having that ‘Aha!’ moment in their head where they go ‘Wow! I’ve got to think about this for a while’ because the possibility wasn’t there before they saw it, in their mind. And now they see it and they go, ‘Gosh, that’s really cool! I’ve just got to go back and figure out how I can implement this into my product.’
Usually, it takes a little while for them to kind of absorb what they’ve seen and felt at the trade shows, when I take these magnets out and they actually get to put their hands on them for the first time. After a while, the wheels turn long enough and they start to come up with great ideas.
D2P: I understand you have a demo kit that’s sort of a hands-on way for engineers to learn about the Polymagnets and check out different possibilities for them.
PH: Yes, the demo kit is a great idea generator for design engineers because they feel some of the basic functions, some of the first discovered functions, and a lot of times they can take that and go, ‘Okay, I really would like this function, but could you possibly combine two of these so it does both of these functions?’ And sometimes, that is possible, depending on the combination and the size of the magnet that they’re open to putting into their product.
D2P: What aspect of the Polymagnets do engineers find most surprising?
PH: The thing they seem to be most surprised about is the fact that we can make magnets that both repel and attract at the same time.
The first time I show somebody what’s called the ‘hover field demonstrator,’ or the ‘push latch demonstrators,’ where you’re both attracting and repelling within two magnets, they kind of go, ‘What?’ They kind of step back and take a look at it, and you can kind of see their eyes light up and go, ‘How is that even possible?’ That’s the question I get, so then I have to explain how it is possible.
D2P: What are some of the applications that you would like design engineers to become more aware of, going forward?
PH: That would depend on what their needs are. For the most part, there’s probably the most potential for this product, initially, in the Max-Attach™ line, where design engineers need to know that ‘Hey, I can get a stronger magnet in the same size as this magnet I’m already designing in. Or, I can potentially make the magnet smaller, so it’s either lighter or less expensive, or just takes up less real estate in my product design. So, that’s something that I think, initially, would be very helpful to design engineers.
And, just looking at it from a new product standpoint, there’s also the safety aspect of the shorter fields in those Max-Attach magnets. They have less chance to interfere with electronics, and less chance to interfere with medical related devices, credit cards, and other things that are sensitive to magnetic fields.
D2P: Could you give some examples of how these magnets are used for different functions?
PH: Yes. The spring type magnet, or hover field type magnet—I’ve had customers use those for vibration isolation. One of the customers was producing high-end audio equipment for DJs, and they needed to isolate vibration from the speakers to the equipment, so they used the magnets to basically kind of hover their equipment so that it wouldn’t absorb the vibration from the speakers.
For the detent/alignment, I have a customer who has a phone accessory mount that’s used initially for gun scopes and sighting scopes, and it has two detent positions that are 90 degrees from each other. So, in one position, the camera on your phone or your iPad can look down next to the scope and you could [record video of] say, a hunt, or birds, if you’re watching birds with your sighting scope.
D2P: Is the spring magnet programmed so that it would repel at a certain distance?
PH: Yes. It will attract from a long distance, and then it repels when it gets close, so it will kind of hover over the other magnet.
Or, if you don’t want your two items to spring apart, we can make it so it attracts in one position, and then as you rotate it a prescribed amount of rotation, it will go into what is called a relaxed state, so it doesn’t spring apart, but it’s very easy to pull apart.
D2P: Is there any one industry, or range of industries, that you see these magnets having the most application to?
PH: So far, I’d say probably the most prevalent is electronics accessories. That has probably been the dominant one.
There’s no limitation to the actual type of magnet material— ceramic, rare earth, samarium cobalt—that we can apply Polymagnet technology to. We can get into applications that don’t necessarily need a strong magnet, but need the Polymagnet technology. Or we can get into applications where samarium cobalt is the high heat magnet material, where we can do Polymagnets for high heat applications.
Some of the medical applications that I’ve started to do some work on need a high heat material because they need to put that magnetic device in an autoclave for cleaning. So it’s not just for rare earth material, which is the most prevalent thing we use them for, and all our standard Polymagnets are offered in rare earth. But we can also work with other materials as needed.