Custom Magnet Shapes
By: Michael Brand, President & COO
Advancements in magnet fabrication have led to advancements in producing virtually any shape and size of magnet. Yes, there are definitely some limitations, but if you can dream it, we can try to make it.
Some examples of magnets shapes that we have designed are below. This will give you an idea of the possibilities, and some real examples of the shapes that we have produces for our customers.
This list is definitely not “all inclusive” as there have been many other unique requests. We work with some very talented and innovative engineers and designers, and they continue to develop new ideas every day.
Neodymium Magnets and Industries Served
Technology in almost every industry is pushing the limits of magnet design, size and shape. The Consumer Electronics industry requires smaller magnets which reduce the size and weight within their application. This holds true in the medical, speaker, sensor and robotics industries also, which is spawning the need for micro magnets. The medical industry needs magnets with a focused field or specific shapes to inject into the body. The motor industry is more “old school” with arc magnets, rectangle magnets, and square magnets (although we have made skewed shapes too). But whatever the industry or application, there is always a specific reason for a specific shape.
Consideration of Magnet Shape & Size
When selecting a specific shape for your applications, remember to select the correct magnet material also. In an earlier blog Magnet Materials were discussed, and a quick review of that article, Understanding Magnet Grades and Magnet Tables, should help tie together the magnet material needed, and Shape and Size considerations.
For this article we will look at a few unique magnet shapes and why they were considered in a specific application.
A Pyramid Magnet starts with a wide base and tapers to a smaller top. This design allows a larger concentration of flux at the top. These are usually better in applications where a bigger magnet is possible and a focused field is required. The trade-off is that these magnets require extra manufacturing processes, which means an increase in cost over a traditional square.
Like the Pyramid Magnet, the Cone Magnet starts with a wider base and tapers towards the top. The difference is that a cone magnet usually tapers to a tip, which produces a high magnetic field at that exact point. For Research & Development and the Medical Industry, these magnets could be just what the doctor ordered. Combined with another magnet or steel, and this shape can find the tip even a bit stronger. Cost is a consideration of this shape since it usually requires extra tooling and precise fabrication.
A Countersink Hole Magnet is usually used in holding applications. This magnet is usually used in an application where a mechanical hold is required so the magnet does not dislodge from steel due to a rougher working environment. With some motors having RPMs reaching high numbers, designers want to ensure that a magnet stays attached. This is a great option as a mechanical hold, but remember that magnets are brittle and can easily break. For this reason, it will be important to take extreme care not to over torque a holding screw into the through hole.
A tube magnet is basically a cylinder magnet with a through hole in the center. Tube magnets are usually used in an application where a post or wires have to run through the center of the magnet. Since this magnet can be magnetized through the length or across the diameter, it gives flexibility. Tube magnets work very well as a sensor magnet that needs to move internally toward and away from a sensor. Small motors use tube magnets that are magnetized across the diameter so there are 2 poles on one magnet.
Your Custom Magnet
Picking the right shape, size, tolerance, material, and surrounding materials are all considerations when choosing a magnet. Definitely consider the magnet and magnetic assembly as a critical part in any design. Ask us about the materials, considerations and options.
About SM Magnetics: SM Magnetics is privately owned company, providing assistance with permanent magnets, magnetic design & optimization, engineering support, and production. SuperMagnetMan is the online retail division of SM Magnetics offering neodymium magnets and other materials.