In the era of intelligent manufacturing, industrial robots have become the backbone of automated production lines, undertaking tasks such as material handling, precision assembly, welding, and inspection with high efficiency and accuracy. Behind the stable and reliable operation of these robots lies the support of numerous key components, among which strong magnets play an indispensable role. As a critical functional material, strong magnets—primarily neodymium-iron-boron (NdFeB) permanent magnets, samarium-cobalt (SmCo) magnets, and ferrite magnets—are widely integrated into the core systems of industrial robots, such as drive motors, magnetic encoders, end effectors, and electromagnetic brakes. Their magnetic properties directly determine the performance indicators of industrial robots, including load capacity, movement precision, response speed, and energy efficiency. This article will delve into the application scenarios, technical requirements, technological evolution, and future development trends of strong magnets in industrial robots, aiming to comprehensively elaborate on their core value in promoting the advancement of intelligent manufacturing.

First, it is essential to clarify the definition and classification of strong magnets in the context of industrial robots. Strong magnets, also known as permanent magnets with high magnetic energy product, refer to magnetic materials that can maintain a stable magnetic field without an external power supply. Compared with ordinary magnets, they have the advantages of high remanence, high coercivity, and high magnetic energy product, which enable them to generate a strong magnetic force in a small volume. In industrial robot applications, the most commonly used strong magnets are neodymium-iron-boron magnets, samarium-cobalt magnets, and, to a lesser extent, high-performance ferrite magnets. Neodymium-iron-boron magnets, known as the "king of permanent magnets," have the highest magnetic energy product among all permanent magnet materials currently available. They are composed of neodymium (Nd), iron (Fe), boron (B), and other alloying elements, and their magnetic energy product can reach 280-450 kJ/m³. This makes them ideal for applications requiring high power density and miniaturization, such as the drive motors of industrial robots. Samarium-cobalt magnets, on the other hand, are composed of samarium (Sm), cobalt (Co), and other rare earth elements. They have excellent high-temperature stability (usable temperature up to 250-350°C) and corrosion resistance, making them suitable for harsh working environments, such as high-temperature welding robots or robots operating in corrosive chemical plants. Ferrite magnets, although having a lower magnetic energy product than rare earth magnets, are widely used in low-cost, low-power applications due to their low price, abundant raw materials, and good chemical stability, such as the auxiliary magnetic components of some lightweight industrial robots.

The most critical application of strong magnets in industrial robots is in the drive motor system, which is known as the "heart" of the robot. Industrial robot joints—whether Cartesian robots, articulated robots, or SCARA robots—rely on servo motors to drive their movement. These servo motors require high power density, high precision, and fast response speed to ensure the robot's flexible and accurate operation. Strong magnets are the core component of the permanent magnet synchronous motors (PMSMs) widely used in industrial robot servo systems. In a permanent magnet synchronous motor, the rotor is embedded with strong magnets (usually neodymium-iron-boron magnets), which generate a constant magnetic field. When the stator winding is energized, an alternating magnetic field is generated, and the interaction between the two magnetic fields drives the rotor to rotate. Compared with traditional induction motors, permanent magnet synchronous motors with strong magnets have significant advantages: higher efficiency (energy conversion efficiency can reach 95% or more), smaller volume, lighter weight, and better dynamic performance. For example, in a 6-axis articulated industrial robot, each joint is equipped with a high-performance servo motor. The use of neodymium-iron-boron magnets in these motors allows the robot to achieve a high torque output with a compact structure, enabling it to handle heavy loads while maintaining high movement precision. Taking the ABB IRB 6700 robot as an example, its servo motors adopt high-energy neodymium-iron-boron permanent magnets, which enable the robot to have a maximum load capacity of 150 kg and a repeat positioning accuracy of ±0.05 mm, meeting the needs of heavy-duty and high-precision assembly tasks in the automotive industry.

In addition to drive motors, strong magnets also play a crucial role in the position sensing system of industrial robots—magnetic encoders. Position sensing is a key link to ensure the precise movement of industrial robots, as it needs to real-time detect the position and speed of the robot's joints and feed back the information to the controller for closed-loop control. Magnetic encoders use the magnetic properties of strong magnets to achieve high-precision position measurement. Their working principle is: a small strong magnet (usually a neodymium-iron-boron magnet) is installed on the rotating shaft of the robot joint, and when the shaft rotates, the magnet generates a periodic magnetic field change. The magnetic sensor (such as Hall sensor or magnetoresistive sensor) installed near the magnet detects the change of the magnetic field and converts it into an electrical signal, which is then processed by the signal processing circuit to obtain the precise position and speed information of the rotating shaft. Compared with optical encoders, which are commonly used in traditional robots, magnetic encoders have the advantages of strong anti-interference ability (not affected by dust, oil, and vibration), high reliability, and long service life, making them more suitable for the harsh working environments of industrial production sites. For example, in the welding robot working in the automotive welding workshop, the environment is filled with dust, spatter, and vibration. If an optical encoder is used, its precision will be seriously affected, and even failure will occur. However, the magnetic encoder using strong magnets can maintain stable and precise position sensing, ensuring the welding quality and efficiency of the robot. In addition, with the continuous improvement of the magnetic properties of strong magnets and the advancement of sensor technology, the precision of magnetic encoders has been continuously improved, currently reaching the level of 16-bit to 24-bit, which is comparable to that of high-end optical encoders, and has been widely used in mid-to-high-end industrial robots.

Another important application scenario of strong magnets in industrial robots is the end effector, also known as the robot gripper. The end effector is the part of the industrial robot that directly contacts the workpiece, and its performance directly determines the robot's ability to handle different workpieces. Magnetic grippers based on strong magnets are widely used in the handling of ferromagnetic materials (such as steel plates, iron parts, and magnetic components) due to their simple structure, strong clamping force, and high reliability. The working principle of the magnetic gripper is: the strong magnet (usually a neodymium-iron-boron magnet) is installed in the gripper, and the magnetic force generated by the magnet is used to adsorb the ferromagnetic workpiece to achieve clamping and handling. According to the control method, magnetic grippers can be divided into permanent magnetic grippers and electromagnetic grippers. Permanent magnetic grippers use the inherent magnetic force of strong magnets for adsorption, which has the advantage of no power consumption during the clamping process, and even if a power failure occurs, the workpiece will not fall, ensuring high safety. They are suitable for long-term clamping and handling tasks, such as the handling of steel plates in the stamping workshop of the automotive industry. Electromagnetic grippers, on the other hand, use electromagnets (which are essentially coils wound around a magnetic core made of strong magnetic materials) to generate magnetic force when energized, and the magnetic force disappears when de-energized. They have the advantage of being able to quickly release the workpiece and are suitable for fast-paced handling tasks, such as the sorting of small magnetic parts in the electronic component manufacturing industry. In addition, with the development of intelligent manufacturing, magnetic grippers are also developing in the direction of intelligence. For example, some magnetic grippers are equipped with pressure sensors and magnetic field sensors to real-time detect the adsorption force and the position of the workpiece, realizing adaptive clamping of workpieces of different sizes and weights, improving the flexibility and versatility of the robot.

Electromagnetic brakes in industrial robots are another important application field of strong magnets. Industrial robots need to maintain a stable position when stopping or in case of emergency, to prevent the robot arm from falling due to gravity or external forces, which may cause damage to the workpiece, equipment, or even personal injury. Electromagnetic brakes use the magnetic force of strong magnets to achieve the braking function. Their working principle is: when the robot is working normally, the coil of the electromagnetic brake is energized, generating a magnetic field that attracts the armature, compressing the spring, and the brake is released, allowing the robot joint to rotate freely. When the robot stops or an emergency occurs, the coil is de-energized, the magnetic field disappears, and the spring pushes the armature to press the brake disc, generating friction torque to stop the joint from rotating. The magnetic core of the electromagnetic brake is usually made of high-permeability strong magnetic materials (such as silicon steel sheets with strong magnetic properties or permanent magnet materials), which can enhance the magnetic field strength generated by the coil, improve the braking force and response speed of the brake. For example, in the vertical articulated robot, the joints of the arm are subject to large gravitational torque. The electromagnetic brake using strong magnetic materials can generate sufficient braking force in a small volume to ensure that the arm remains stable when stopping, avoiding accidental falling. In addition, the electromagnetic brake has the advantages of fast response speed (response time up to a few milliseconds), small volume, and long service life, which is an important guarantee for the safe and reliable operation of industrial robots.

The application of strong magnets in industrial robots puts forward strict technical requirements for their magnetic properties, mechanical properties, and environmental adaptability. First, in terms of magnetic properties, high remanence (Br) and high coercivity (Hc) are required. Remanence determines the maximum magnetic flux density generated by the magnet, which directly affects the power density and torque output of the servo motor. Coercivity determines the ability of the magnet to resist demagnetization. In the process of robot operation, the magnet is subject to factors such as temperature rise, vibration, and external magnetic field, which may cause demagnetization. Therefore, the magnet must have high coercivity to ensure stable magnetic properties during long-term use. For example, the neodymium-iron-boron magnets used in servo motors usually require a remanence of 1.2-1.5 T and a coercivity of 800-1200 kA/m. Second, in terms of mechanical properties, strong magnets need to have sufficient mechanical strength and toughness. Industrial robots are in high-speed movement and frequent start-stop during operation, and the magnets in the motor and other components are subject to large mechanical impact and vibration. If the magnet is brittle and easy to crack, it will affect the normal operation of the robot. Therefore, some strong magnets (such as neodymium-iron-boron magnets) need to be subjected to surface treatment (such as electroplating nickel, zinc, or epoxy coating) to improve their mechanical strength and corrosion resistance. Third, in terms of environmental adaptability, strong magnets need to have good high-temperature resistance and corrosion resistance. In some special working environments, such as welding workshops and chemical plants, the temperature can reach above 150°C, and there are corrosive gases and liquids. Samarium-cobalt magnets with high-temperature resistance are usually used in these environments, while neodymium-iron-boron magnets need to be modified (such as adding dysprosium, terbium, and other elements) to improve their high-temperature resistance. For example, the high-temperature resistant neodymium-iron-boron magnets can be used at temperatures up to 200°C, meeting the needs of most industrial robot working environments.

With the continuous development of industrial robot technology towards high precision, high speed, miniaturization, and intelligence, the technological evolution of strong magnets is also advancing in tandem. One of the main development directions is the improvement of magnetic energy product and high-temperature performance. Researchers are exploring new alloy compositions and preparation processes to further improve the magnetic energy product of neodymium-iron-boron magnets. For example, through the optimization of the smelting process and the addition of trace elements (such as gallium, copper, etc.), the magnetic energy product of neodymium-iron-boron magnets can be increased to more than 500 kJ/m³, which will help to further reduce the volume and weight of servo motors and improve the load capacity of robots. At the same time, in order to solve the problem of poor high-temperature performance of neodymium-iron-boron magnets, researchers are developing new rare earth permanent magnet materials, such as samarium-iron-nitrogen (SmFeN) magnets. Samarium-iron-nitrogen magnets have high magnetic energy product and good high-temperature performance (usable temperature up to 200-250°C), and their raw material cost is lower than that of samarium-cobalt magnets, which is expected to replace part of samarium-cobalt magnets and high-temperature resistant neodymium-iron-boron magnets in the future. Another development direction is the integration of strong magnets with intelligent sensing technology. For example, the combination of strong magnets and magnetoresistive sensors can realize the integration of drive and sensing, simplifying the structure of the robot joint and improving the integration level and reliability of the system. In addition, the development of nanocomposite permanent magnet materials is also a research hotspot. Nanocomposite permanent magnets combine soft magnetic materials and hard magnetic materials at the nanoscale, which can give full play to the advantages of high saturation magnetization of soft magnetic materials and high coercivity of hard magnetic materials, and have the potential to achieve higher magnetic energy product and lower cost.

The market demand for strong magnets in industrial robots is also showing a rapid growth trend driven by the continuous expansion of the global industrial robot market. According to the data released by the International Federation of Robotics (IFR), the global sales volume of industrial robots reached 517,000 units in 2023, and it is expected to exceed 600,000 units by 2025. The rapid growth of the industrial robot market has directly driven the demand for strong magnets. Taking neodymium-iron-boron magnets as an example, it is estimated that the global demand for neodymium-iron-boron magnets in the industrial robot field will reach 15,000-20,000 tons by 2025, accounting for about 10-15% of the total global demand for neodymium-iron-boron magnets. At the same time, the regional distribution of the market demand is also changing. With the acceleration of the intelligent manufacturing transformation in emerging economies such as China, India, and Southeast Asian countries, the demand for industrial robots in these regions is growing rapidly, which has also become an important driving force for the growth of the strong magnet market. However, the strong magnet market also faces challenges such as the shortage of rare earth resources and the fluctuation of raw material prices. Rare earth elements (such as neodymium, samarium, dysprosium, etc.) are the key raw materials for strong magnets, and their reserves are limited and unevenly distributed globally. The fluctuation of rare earth prices will directly affect the production cost of strong magnets and the stability of the industrial robot supply chain. Therefore, reducing the dependence on rare earth resources, developing low-rare-earth or non-rare-earth permanent magnet materials, and improving the recycling rate of rare earths have become important issues to be solved in the development of the strong magnet industry.

Looking to the future, the application of strong magnets in industrial robots will be more in-depth and extensive with the development of technologies such as artificial intelligence, the Internet of Things, and big data. On the one hand, in the field of collaborative robots, which are developing rapidly, the requirements for miniaturization, light weight, and low noise of robots are higher. Strong magnets with higher magnetic energy product and smaller volume will help to realize the miniaturization of servo motors and end effectors, improving the flexibility and safety of collaborative robots. On the other hand, in the field of mobile robots (such as AGVs and AMRs), the use of strong magnets in drive motors and magnetic navigation systems will help to improve the energy efficiency and navigation precision of mobile robots, enabling them to better adapt to the complex and dynamic production environment. In addition, with the development of intelligent manufacturing, the demand for industrial robots with higher precision and higher speed will continue to increase, which will put forward higher requirements for the magnetic properties and stability of strong magnets. Therefore, the research and development of new high-performance strong magnetic materials, the optimization of preparation processes, and the improvement of recycling technology will be the key directions for the development of the strong magnet industry in the future. At the same time, the deep integration of strong magnets with other technologies (such as sensor technology, control technology, and material science) will also promote the continuous innovation and upgrading of industrial robot technology, making greater contributions to the development of intelligent manufacturing.

In conclusion, strong magnets, as a key functional material, play an irreplaceable core role in the core systems of industrial robots such as drive motors, magnetic encoders, end effectors, and electromagnetic brakes. Their magnetic properties and performance directly determine the load capacity, movement precision, response speed, and safety of industrial robots. With the continuous development of industrial robot technology towards high precision, high speed, miniaturization, and intelligence, the technical requirements for strong magnets are getting higher and higher, which also promotes the continuous evolution and innovation of strong magnet technology. Although the strong magnet industry faces challenges such as the shortage of rare earth resources, with the progress of research and development and the improvement of recycling technology, it is believed that strong magnets will play a more important role in the field of industrial robots in the future, helping to promote the continuous development of intelligent manufacturing towards a higher level. Therefore, strengthening the research on strong magnetic materials, improving the independent innovation capability of the industry, and ensuring the stable supply of the industrial chain are of great significance for the development of the global industrial robot industry and the transformation and upgrading of the manufacturing industry.