Choosing the Correct Magnet. Think Like an Engineer
By: Michael Brand, President, SM Magnetics
Magnets have become the perfect addition to many crafts, DIY projects and fun. Give a kid a magnet and watch their mind go into creative overdrive. Give an adult a magnet and, well, the same thing happens. Creativity and problem-solving start to reign.
Below are some considerations when choosing a magnet for your craft or DIY project. These considerations may even be incorporated into some engineering projects.
Completely Define the Purpose of the Magnet
Start your creative thinking with this simple question…. “What do I want the magnet to do?” The real purpose of this question is dig into the details. For example, instead of saying “the purpose of the magnet is to hold something to a steel plate,” start to define things like the weight the magnet must hold, the kind of steel plate that it will hold against, the size of the area you would like the magnet to be, the location of the magnet in the application, and even the surrounding materials. This might be a craft or DIY project but summon your inner engineer and start to think though the details.
Define the Environment of the Magnet
For craft projects, the environment is usually pretty harmless to the magnet. Examples would be refrigerator magnets and magnets that hold paper to a steel plate (remember all of those grade school projects that you hang). These usually involve a ceramic magnet because the strength or the magnet is not very strong which means they are easier for children to handle and should not cause injury.
For DIY projects, or aspiring entrepreneurs, a stronger hold is usually required, and the environment of the magnet should be taken into consideration. While holding a door open with a magnet may seem like a simple application, consider if the door is inside or outside. If outside, the magnet will be exposed to elements like moisture, rain, sun, etc. It may also experience pounding from the door hitting against it which can cause cracking. Another example would be a jewelry clasp. This usually requires a higher holding force, but even as important as the definition of the holding force is the environment. Necklaces and bracelets experience sweat, snapping together, and specific coating requirements, but as long as you define the environment of the magnet then we can help with selection of the appropriate material and coating.
For engineers, the environment can be a more complex issue. Selecting a magnet involves a thorough review of the requirements of the magnet, the environmental factors, the surrounding materials, the manufacturing process, the assembly process, the storage and packaging, the chemicals (if any) involved in cleaning or during application, and the temperature exposure. Through simulation we can determine the best magnet for the application, but in the end a prototype is always recommended. Just like starting a business requires a good accountant, lawyer and banker, starting a design and engineering project requires the expertise of a magnet specialist.
Magnet Handling and Safety Should Be Considered
Due to their physical make up, magnets are brittle. This means they can break easily if not handled properly or protected properly in their application.
Craft magnets are usually ceramic magnets, which produce a low holding force but are an inexpensive solution. However, ceramic magnets can chip easily if they are continually hit or snapped onto a surface. But, with proper handling they will be a great choice.
DIY magnets usually involve a neodymium magnet. These are also brittle and can chip easily if hit or snapped together. However, neodymium magnets should also have a protective coating on them that can help protect them. While a good coating can help with chipping, the magnet can still be damaged if handled or used incorrectly.
Industrial magnets should be built to last with the proper coatings, housings, and material selection. When engineering a design, keep in mind every step in your manufacturing and assembly process to identify where the risks of magnet damage or demagnetization may occur. Working with our customers, we always suggest and recommend planning out the entire process very carefully to determine how to eliminate breakage, waste, and cost.
As you can see from the above information there are many factors that are involved with every design project. Of course, it all starts with planning and defining the end result, so take the time to be as detailed as possible so selection of all materials will be correct.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.