How Do Magnets Work? A Technical Guide to Magnets
Magnets are essential industrial tools with a wide range of applications. Beyond attracting and repelling, they also play a role in energy transformation. Available in various shapes and sizes, magnets can be tailored to suit nearly any application.
When selecting a magnet, consider the part’s shape (e.g., round, convex, concave) and surface condition (rough, rusty, dirty, or oily), as both can create air gaps that reduce magnetic holding power. These factors, along with the guidelines in this section, will help you choose the right magnet for your application.
Note: Air gap refers to the space between the magnet and the part, often caused by coatings such as paint, plating, galvanizing, or protective films.
Uses for Magnets
Securing metal sheets and components
Mounting safety shields and removable panels
Supporting overhead conveyor racks
Separating stacked sheet metal
Die inserts
Paint and plating fixtures
Spot welding setups
Hand assembly jigs and fixtures
Shearing, punching, and forming operations
Press and Burn Table feeding operations
Capturing or separating metal
Cleaning or lifting metal from floors & more
Maximum vs. Average Pull Strength
Maximum and average pull values are based on the same magnet but reflect different testing conditions. In our catalog, we list average pull for user safety and practical relevance. Maximum pull measures under ideal lab conditions—by pulling a new magnet perpendicularly from a freshly machined, thick steel surface. This value represents the peak force (in pounds) required to separate the magnet. However, ideal conditions are rare in real-world applications. To account for common variables such as surface irregularities and part shape, we list average pull, calculated at 50% of the maximum. Doing this provides a more realistic expectation of performance in the field. Refer to the “Magnet Selection Factors” section for how shape and surface condition affect magnetic holding force.
Materials
Flexible Magnetic Strips
Made from ferromagnetic powder bonded with polymer, flexible magnetic strips are low-energy magnets that resist demagnetization and won’t chip, crack, or shatter. They conform to curved surfaces and are ideal for office use, manufacturing, inventory labeling, appliances, and advertising. Flexible magnets can be easily cut, drilled, or shaped.
Maximum operating temperature: 160°F (70°C)
Ceramic Magnets
Made from Strontium Ferrite (SrFe) through a sintering process, ceramic magnets are widely used in electronics, automotive, medical, mining, industrial, and oil industries. They offer medium magnetic strength, excellent resistance to demagnetization, and long-term stability, losing only 0.5% of their magnetic strength over 100 years. Ceramic magnets are brittle and must be cut with diamond-tipped tools.
Maximum operating temperature: 350°F (176°C)
Alnico Magnets
Composed of aluminum, nickel, and cobalt (AlNiCo), these magnets are produced through casting or sintering. Alnico magnets perform well in high-temperature environments, offering medium magnetic strength and the best temperature stability of all standard magnet materials. They have moderate resistance to demagnetization and are extremely hard and brittle; machining or drilling requires specialized equipment.
Maximum operating temperature: 800°F (427°C)
Rare Earth Neodymium-Iron-Boron (NdFeB) Magnets
Also known as Neo magnets, NdFeB magnets are available in sintered and bonded forms. They offer the highest magnetic strength of any material and excellent resistance to demagnetization—making them ideal for applications requiring maximum force in limited space. Due to their high iron content, Neo magnets are typically coated or plated to prevent oxidation. Grinding is not recommended.
Maximum operating temperature: 200°F (94°C)
Rare Earth Samarium Cobalt (SmCo) Magnets
Manufactured similarly to Neodymium magnets, SmCo magnets combine high magnetic strength with excellent temperature resistance. They are ideal for applications demanding strong magnetic performance in high-heat environments.
Maximum operating temperature: 392°F (200°C)
Permanent Magnetic Material Properties
Type | Components | Magnetic Strength | Maximum Temperature | Resistance to Demagnetization | Color | Machineable |
|---|---|---|---|---|---|---|
Flexible | Ferrite Magnetic Powder with a Polymer Bonding | Very Low | 160°F (70°C) | Low | Dark Brown | Drill, Scissors |
Ceramic | Strontium Ferrite | Low | 350°F (176°C) | High | Dark Gray | Diamond Wheel |
Alnico | Aluminum-Nickel-Cobalt | Medium | 800°F (427°C) | Medium | Silver | EDM |
Rare Earth | Neodymium-Iron-Boron Unplated | Very High | 200°F (94°C) | Very High | Dark Green | Avoid Grinding |
Rare Earth | Samarium Cobalt | Very High | 392°F (200°C) | Very High | Dark Gray | Avoid Grinding |
Rare Earth | Neodymium-Iron-Boron Nickel Plated | Very High | 200°F (94°C) | Very High | Bright Silver | Avoid Grinding |