Homes
> Blog
> Blog Details

How to Select the Right Magnets for Robots: Performance, Safety, and Cost Considerations

To select the right magnet for...

Jump to Section

To select the right magnet for a robot, you need to weigh three critical factors: performance (magnetic strength and size), safety (temperature and corrosion resistance), and cost (material and manufacturing constraints).

For example, neodymium (NdFeB) magnets offer high torque in compact spaces but may fail under heat.

Samarium cobalt (SmCo) handles extreme temperatures but comes at a premium, while ferrite magnets are cost-effective for basic tasks with lower power needs.

This guide draws from real-world engineering applications in robotic motors, grippers, sensors, and actuators, and is built with insights from YQ Magnetic’s team, who specialize in matching magnet materials to robotic use cases in industrial, medical, and mobile automation.

You’ll learn:

● How different magnet materials (NdFeB, SmCo, Ferrite, Electromagnets) impact performance and reliability

● The pros and cons of each magnet type across robotic use cases

● How to avoid common mistakes like demagnetization or signal interference

● How coating, grade, and placement affect long-term efficiency and safety

the Right Magnets for Robots

Why Magnets Play a Critical Role in Robotics

Magnets really form the backbone of how robots move and interact with the world. Magnetic fields let robots transfer force and information without physical contact.

This approach cuts down on wear and friction, and it lets engineers design more compact systems. Electric motors show this best—most robots use permanent magnet motors like brushless DC or permanent magnet synchronous motors.

Neodymium or ferrite magnets sit in the rotor, generating torque when the stator coils energize. The result?

Smooth motion, precise speed control, and less power loss than you’d get from induction motors.

Magnetic actuation brings controlled movement without gears or belts. Linear actuators and magnetic couplings apply force with aligned fields, so you end up with fewer parts to break and quieter operation in tight spaces.

Sensors lean on magnets for accuracy. Hall effect and magnetoresistive sensors pick up changes in magnetic fields to track position, speed, or angle, and because they don’t touch anything, they last a long time.

Grippers often have magnets at the end of a robotic arm. Electromagnetic grippers switch on and off with current, while permanent magnetic grippers use mechanical releases. This setup gives you quick, predictable holding force for metal parts.

For deeper detail, see How Permanent Magnets Drive Modern Robots.

the Right Magnets for Robots

Common Types of Magnets for Robots

The magnets used in robotics generally fall into two broad categories: Permanent Magnets (which are always "on") and Electromagnets (which can be turned on/off).³

1. Permanent Magnets

These are the most common magnets in robotics, primarily used in the motors that drive robot joints and wheels. They provide a constant magnetic field without requiring electricity to maintain it.

A. Neodymium Iron Boron (NdFeB)

● The Powerhouse: These are the strongest commercially available permanent magnets ("Rare Earth" magnets).
● Role in Robotics: Because they are incredibly strong for their size, they are the standard for high-performance brushless DC (BLDC) motors, servo motors, and stepper motors. They allow robot arms to be lightweight yet powerful.
● Pros: Highest magnetic strength-to-weight ratio; compact.
● Cons: Vulnerable to corrosion (usually nickel-plated); loses magnetism at high temperatures (standard grades lose strength above ~80°C/176°F, though specialized high-temp grades exist).
● Common Use: Drone motors, robotic arm joints, walking robots (like Boston Dynamics' Spot).

B. Samarium Cobalt (SmCo)

● The High-Temp Specialist: Another type of Rare Earth magnet, slightly weaker than Neodymium but much more stable.
● Role in Robotics: Used in industrial robots that operate in extreme heat or aerospace robotics where temperature fluctuates wildly.
● Pros: Excellent temperature stability (works up to 300°C); highly resistant to corrosion (needs no coating).
● Cons: More expensive than Neodymium; very brittle and prone to chipping.
● Common Use: Welding robots, aerospace actuators, Mars rovers.

C. Ferrite (Ceramic)

● The Budget Option: Made of iron oxide and strontium/barium carbonate. These are the dark grey magnets you see on refrigerators.
● Role in Robotics: Used in low-cost hobbyist robots or heavy industrial stationary robots where weight is not a concern.
● Pros: Very cheap; highly resistant to corrosion.
● Cons: Heavy; weak magnetic field (you need a large magnet to get the same power as a tiny Neodymium one).
● Common Use: Conveyor belt motors, cheap hobby servos, magnetic sensors.

2. Electromagnets

Unlike permanent magnets, these require an electrical current to generate a magnetic field.

This allows the robot to control the magnetism dynamically.

● The Dynamic Gripper: The primary use of electromagnets is in End-Effectors (the robot's "hand").
● Role in Robotics:

○ Pick-and-Place: A robot turns the magnet on to pick up a steel part, moves it, and turns the magnet off to drop it.
○ Holding: Locking joints in place (magnetic brakes) when the power is cut to prevent the robot from collapsing.

● Pros: Controllable on/off; variable strength.
● Cons: Requires constant power to hold (unless it's an "electro-permanent" magnet); can generate heat.

3. Specialized Magnetic Sensors

While not "lifting" or "moving" parts, these small magnets are the robot's nervous system.

● Hall Effect Sensors: These use small permanent magnets to detect position and speed. As a motor spins, the sensor detects the passing magnet to calculate exactly where the robot arm is.
● Magnetic Encoders: Used in robot wheels to measure distance traveled (odometry).

the Right Magnets for Robots

Different Types of Magnets For Robot Comparison Table

Magnet Type	Strength	Cost	Temp Resistance	Primary Robot Application
Neodymium	Very High	Moderate	Low (std) to Med	High-performance motors (arms, drones)
Samarium Cobalt	High	High	Very High	Industrial/Aerospace (welding, space)
Ferrite	Low	Low	High	Low-cost motors, heavy machinery
Electromagnet²⁰	Variable²¹	Moderate²²	Variable²³	Grippers (picking up metal), Brakes²⁴

Key Factors to Consider When Choosing a Magnet for Robots

Magnet material really shapes performance. Neodymium (NdFeB) magnets offer high force for their size, so you can shrink motors or grippers without losing torque. Samarium cobalt (SmCo) magnets handle higher heat—up to 250 °C—so they’re great for robots working near hot spots.

Magnetic strength and size need to match the job. Magnet grades like N35 to N52 set the maximum energy product in MGOe. Higher grades mean more force, but also higher cost, so it’s worth sizing the magnet to fit the load and budget.

Temperature limits affect reliability. NdFeB magnets start losing magnetization above 80–150 °C, depending on grade. SmCo magnets hold up better at higher temps, which helps prevent sensor drift or grip loss during long use.

Coating and corrosion resistance matter, too. Nickel-copper-nickel and epoxy coatings keep moisture and chemicals out, so the magnets last longer in humid or wash-down settings.

Permanent magnets vs. electromagnets really comes down to control. Permanent magnets give you constant force with no power, while electromagnets need current but let you turn them on and off. That choice impacts energy use, safety, and control design.

Matching Magnet Type to Robotic Application

Different robot tasks need different magnets. Every application brings its own demands for strength, size, heat resistance, and cost. If you line these up early, you’ll save space, cut power use, and avoid early failures.

Neodymium (NdFeB) magnets work well for industrial arms and grippers. They deliver high energy density—often over 35 MGOe—so you can get big torque from small motors and keep joints compact.

Samarium Cobalt (SmCo) magnets are a good fit for medical and high-temperature robots. They keep their magnetic properties up to around 300 °C and don’t need coatings to resist corrosion. This means stable fields during heat cycles, like sterilization, so sensors and motors stay accurate.

Ferrite magnets are common in mobile robots or budget systems. They’re not as strong, but they’re cheap and easy to replace, and they use iron oxide with barium or strontium to keep costs down.

Alnico magnets show up in sensing and positioning. They handle heat well and give a nice linear field, which makes sensor readings more predictable over time.

Robotic Application	Common Magnet Choice	Practical Reason
Industrial arms	NdFeB, SmCo	High torque in limited space
Cobots	NdFeB, coated ferrite	Balanced strength and cost
Mobile robots	Ferrite, Alnico	Lower cost and power use
Medical robots	SmCo	Heat and corrosion resistance
Grippers	NdFeB with coating	High holding force, better grip

Common Mistakes When Selecting Magnets for Robots

Chasing only magnetic strength can backfire. Someone might grab a high-pull neodymium magnet but forget about its max operating temperature—standard NdFeB grades only go up to 80 °C. Motor heat can easily pass that, leading to permanent demagnetization.

Ignoring the magnetic circuit wastes efficiency. Magnets don’t work in isolation—they depend on steel backers, air gaps, and geometry. Overlooking these means you’ll need a bigger or higher-grade magnet for the same torque, which drives up size and cost.

Skipping magnetic interference checks creates headaches. Strong stray fields can mess with encoders, Hall sensors, and nearby PCBs. That can cause unstable readings or false triggers unless you add spacing, shielding, or use lower-grade magnets.

Picking the wrong coating shortens the magnet’s life. Nickel-plated NdFeB handles light humidity, but epoxy or Parylene coatings are much better for wet or corrosive places. The wrong choice leads to corrosion, swelling, and failure.

Skipping quality control is risky. Magnets without grade markings, tolerance data, or batch tests can vary in strength and size, leading to inconsistent robot performance.

How YQ Magnetic Helps Engineers Choose the Right Magnet

YQ Magnetic supports robot design from the first sketch to the final build. Their team focuses on material data, operating limits, and how magnets fit your system, not just vague specs.

They manufacture custom NdFeB, SmCo, ferrite, and AlNiCo magnets—with the grades, shapes, and magnetization directions you need. You can specify flux density, temperature rating, and coatings like NiCuNi or epoxy, so you balance torque, size, and corrosion risk without going overboard.

YQ Magnetic also offers engineering consultation during selection and design. Their team reviews your load, speed, and temperature range, helping you pick the right magnet grade and avoid demagnetization. That means fewer test cycles and less risk of losing magnet strength during hot runs or current spikes.

They support simulation and prototype builds before you commit to production. You get to see how the magnet behaves in your real assembly—testing pull force, air gap sensitivity, or back-EMF—instead of just trusting a datasheet.

● Industrial automation: magnets sized for continuous cycles and stable torque
● AI robotics: compact magnets that boost sensor accuracy and quick response
● Motor drive systems: grades chosen to resist demagnetization at high temps

Need help picking the right magnet for your robot? Contact YQ Magnetic’s engineering team for a custom solution.

FAQ

1. What are the key factors when selecting magnets for robots? You must balance three core elements:
● Magnetic Strength: NdFeB magnets are ideal for compact joints because they offer high flux density (often >1.2 Tesla) in small sizes.
● Temperature Rating: Standard magnets lose strength above 80°C. Motors near heat sources require high-temperature grades (e.g., SH, UH series) or materials like SmCo.
● Environment: For outdoor or humid environments, corrosion-resistant coatings (like Nickel-Copper-Nickel) are essential to prevent rust.

2. How do Neodymium magnets compare to Ferrite or SmCo?
● Neodymium (NdFeB): The strongest option. Best for high-torque, compact motors where space is limited.
● Ferrite: Lower cost and good heat resistance (up to 250°C), but weaker. Best for larger, cost-sensitive robots.
● Samarium Cobalt (SmCo): Excellent heat resistance (up to 300°C) and corrosion immunity. Ideal for medical or aerospace robots, though more expensive.

3. How are magnets integrated into robot motors for better performance? Magnets are typically arranged in Surface-Mounted (SPM) or Interior Permanent Magnet (IPM) designs.
● IPM Rotors: Placing magnets inside the steel rotor protects them from centrifugal forces and generates extra "reluctance torque," improving efficiency at high speeds.
● Grade Selection: Using high-grade NdFeB (like N42 or N48) boosts air-gap flux, delivering more torque without increasing the motor's size.

4. How do magnet shape and size affect robot functionality?
● Shape: Dictates the magnetic field direction. Ring magnets provide even flux for rotary encoders and motors, while Block magnets offer directional pull for grippers and linear actuators.
Size: Directly impacts inertia. Smaller, lighter magnets allow robotic joints to start and stop faster, significantly improving precision in pick-and-place tasks.

Want to Know More About Our Products

View All Products Now