The Tube magnet is defined as a hollow cylinder that has an outer diameter that is smaller than its length.
Many industries utilize tube magnets due to their versatility and direction of magnetization possibilities. The food and beverage industry use tube magnets as separators and filter against contaminated ferrous materials. While motor companies use diametrically magnetized tubes to produce 2-pole motors.
This article looks at the most common questions regarding tube magnets:
- What does the field profile look like for a tube magnet?
- What direction of magnetization do I use?
Below we take a look at the magnetic field profiles of 3 common types of magnetization direction of neodymium tube magnets.
The first view shows a tube magnetized through the length. The bright read arrows located on the face indicate the highest locations of magnetic field. This is the magnets strongest location and where the poles wrap around to reach each other. The shades of blue and green indicate lower magnetic fields. As the distance from the magnet surface increases the weaker the field becomes. Tube magnets with a Direction of Magnetization through the length tend to be used for consumer electronics and medical applications.
Our second view shows a diametrically magnetized tube. The greatest strength of this magnet is located on the outside diameter of the tube magnet. This direction of magnetization is important for separators, filters and motors. Separators and filters use the magnetic properties on the outer length of tubes to remove contaminants and ferrous material. This direction of magnetization is a major part of the Motor industry as it is what gives many motors their motion and power to turn electrical energy into mechanical energy.
The final field profile shows a radial direction of magnetization that is unique to only a fraction of tube magnets. Radial Magnetization is a special process that involves advanced production and magnetization techniques and usually come with added costs. A radially oriented magnet has all of the same pole on the OD, with the opposite pole on the ID. This can be accomplished with multiple pieces or in some cases a single piece. The image to the right is a single piece. Much of the Radially Magnetized tubes are used in research projects to balance and focus a beam through a magnetic field.
If you would like to get more information, are not sure if you should use a tube magnet in your application, or which direction of magnetization to use, we can help assist you in your magnet selection and design.
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.