Understanding Holding Force and Shear Force: Why They Matter

When discussing magnetic fastening solutions, two critical parameters often surface: holding force and shear force. These terms define the performance and applicability of magnetic products, playing a pivotal role in ensuring their safety and reliability. Let’s break down what these forces mean and why they are so important in magnetic assembly design and application.

What is Holding Force?

Holding force refers to the vertical force required to detach a magnet from the surface it is attached to, typically measured in Newtons (N) or kilograms (kg). It represents the magnet’s ability to resist being pulled directly away from its contact surface.

Factors Influencing Holding Force:

1. Magnetic Material: Stronger materials like neodymium produce greater holding forces compared to ferrite or alnico magnets.
2. Surface Contact: A clean, smooth, and flat ferromagnetic surface maximizes holding force.
3. Air Gap: Any distance, such as coatings or uneven surfaces, reduces the holding force.
4. Temperature: High temperatures can weaken the magnet’s performance, reducing the holding force.

What is Shear Force?

Shear force measures the force required to slide a magnet across the surface it is attached to, typically in a horizontal direction. Unlike holding force, which resists perpendicular movement, shear force addresses lateral stability.

Factors Influencing Shear Force:

1. Surface Friction: The coefficient of friction between the magnet and the surface plays a crucial role. Higher friction increases shear resistance.
2. Magnet Coating: Rubber or other high-friction coatings can enhance shear force.
3. Load Distribution: Unevenly distributed loads may reduce the effective shear resistance.

Why Are These Parameters So Important?

Understanding and optimizing holding and shear forces are essential for designing magnetic products that meet specific application requirements. Here’s why these parameters matter:

1. Safety and Reliability

In applications like wind turbines, construction, or industrial automation, magnetic fasteners must securely hold heavy or sensitive equipment. Insufficient holding force can lead to detachment, causing operational failure or accidents.

2. Application-Specific Requirements

Different applications impose unique demands on magnetic fasteners. For instance:

• In vertical mounting, holding force takes precedence to prevent objects from falling.
• In horizontal mounting, shear force becomes critical to resist lateral displacement.

3. Material and Cost Optimization

By understanding the required holding and shear forces, manufacturers can optimize the size and material of magnets, reducing costs without compromising performance.

4. Durability in Harsh Environments

Industries like oil and gas, wind energy, and automotive require magnetic fasteners to perform under extreme conditions. Evaluating these forces ensures magnets maintain their effectiveness, even with exposure to vibration, temperature fluctuations, and corrosion.

Designing Magnetic Products with These Forces in Mind

At WZ Magnetics, we design magnetic assemblies with precise consideration of holding and shear forces. For example:

• Rubber-coated magnets enhance shear resistance, making them ideal for delicate surfaces or applications requiring extra grip.
• POT magnets concentrate magnetic strength to maximize holding force, ensuring secure attachment in high-stress environments.

Conclusion

Holding force and shear force are foundational to the performance and safety of magnetic products. By understanding these parameters, businesses can choose or design magnetic fasteners that meet their specific needs, ensuring reliability and efficiency in various applications. Whether it’s securing cables in wind turbines or supporting fixtures in industrial settings, mastering these forces is key to unlocking the full potential of magnetic technology.

If you’re looking to learn more about magnetic fastening solutions or need assistance selecting the right product, feel free to reach out. Let’s engineer solutions that stick—securely and reliably!