1 From "Can Fit" to "Fitted Skillfully": The Demand for Ultra-Thin Bearings in the Era of Modern Precision Equipment Design

The design of modern precision equipment is undergoing a profound transformation. Industrial robots are evolving from bulky six-axis mechanical arms to lightweight collaborative robots. Semiconductor equipment is striving for higher wafer processing density in clean rooms, and medical imaging equipment needs to achieve precise rotation within limited spaces - these trends collectively point to a core demand: equipment is becoming increasingly compact, leaving less and less space for bearings, but the requirements for rotational accuracy and rigidity are continuously increasing.

 

Traditional bearing designs prioritize bearing capacity, and the size is often larger. In extremely constrained spaces, designers face a dilemma: either sacrifice some performance by using smaller bearings or maintain performance by expanding the size of the equipment. Ultra-thin precision bearings were specifically designed to break this deadlock.

 

The core feature of NMT ultra-thin precision bearings lies in: the cross-sectional height is much smaller than the inner diameter of the bearing, with extremely thin walls and light weight. Under the same inner diameter conditions, the radial space occupied by them can be reduced to one-third or even less of that of conventional bearings. This "thin" characteristic allows equipment designers to regain design freedom - it is no longer a question of "can it fit", but "how can it be fitted more skillfully".

 

From a value perspective, the significance of ultra-thin bearings goes beyond simple size reduction. It brings a series of chain optimizations: smaller joint volume → more compact overall layout → lighter equipment weight → lower drive energy consumption → higher motion response speed. This is an indispensable underlying lever for precision equipment in the competition for miniaturization and lightweighting.

 

2 Product Structure and Core Operating Principle

NMT ultra-thin precision bearings adopt a compact ring-shaped design, consisting of high-stiffness inner and outer ring bases, high-precision rolling elements, ultra-thin cages, and lightweight sealing components. The core technological breakthrough lies in: under the significant reduction of cross-sectional height, by optimizing the diameter and quantity ratio of rolling elements, precisely controlling the curvature radius of the raceways, and selecting high-strength bearing steel or ceramic composite materials, the bearing still maintains sufficient radial rigidity and bearing capacity under the extremely thin wall thickness condition.

 

Rolling elements and ultra-precisely polished raceways achieve low-friction rolling contact, smooth operation, low friction torque, and can effectively save equipment drive energy. NMT ultra-thin bearings adopt a uniform cross-sectional design and special carburizing process, further enhancing the rigidity and reliability of robot joints and reducing maintenance costs.

 

The global ultra-thin bearing market is in a stage of steady expansion. The global sales revenue of ultra-thin bearings reached 7.735 billion yuan in 2025 and is expected to reach 11.10 billion yuan in 2032. The global market size of ultra-thin spherical bearings is approximately 1.083 billion US dollars, and it is expected to reach 1.555 billion US dollars in 2032. The sales revenue of ultra-thin bearings for industrial robots in 2025 was 542 million US dollars, and it is expected to reach 753 million US dollars in 2032. This growth trend confirms that ultra-thin bearings are moving from "special selection" to "mainstream configuration".

 

3 Core Performance Highlights of the Product

Extremely thin cross-section, extreme compression of space: The cross-sectional height of the bearing can be compressed to one-third to one-fifth of that of conventional bearings with the same inner diameter, achieving reliable rotational support in extremely limited radial space, significantly releasing the internal space of the equipment, and providing a structural basis for miniaturization and integration design.

 

Light weight, small rotational inertia: The dual weight reduction of the thin-walled structure and lightweight materials significantly reduces the overall weight of the bearing, with a small rotational inertia, and the acceleration and deceleration response of the equipment is more rapid, especially suitable for precision equipment with frequent start-stop and high-speed reciprocating operations. High rigidity without compromise: Despite the extremely thin wall thickness, NMT ensures excellent radial rigidity and anti-deformation ability under thin-wall conditions by optimizing the rolling element geometry parameters and the rolling body arrangement density, and selecting high-rigidity bearing steel or silicon nitride ceramic ball materials. This meets the strict requirements of precision equipment for supporting rigidity.

 

Smooth operation with low friction: The raceways are processed by nano-level ultra-finishing, with extremely low surface roughness. Combined with low-viscosity special lubricating grease, the running friction torque is small, the temperature rise is low, effectively reducing equipment energy consumption and improving transmission efficiency.

 

High precision level, strong rotational stability: The product precision can reach P5 and P4 levels. The rotational runout and end face runout are controlled at the micron level, ensuring the rotational accuracy and repeat positioning accuracy of the equipment during high-speed operation or precise positioning.

 

4 Core Application Scenarios

4.1 Industrial Robot Joints: The wrist, elbow, shoulder joints of six-axis robots and collaborative robots, as well as humanoid robots. The ultra-thin structure significantly reduces the radial size of the joints, providing a structural basis for the compact and lightweight design of robots, while maintaining high rigidity to meet dynamic load requirements. Thin-wall cross roller bearings and thin-wall four-point contact ball bearings are the two main types of bearings for industrial robot joints.

 

4.2 Semiconductor Manufacturing Equipment: Wafer handling robots, transfer platforms, precision stages of lithography machines, vacuum chamber rotating mechanisms, etc., which have strict requirements for cleanliness, precision, and space. The ultra-thin bearings have the characteristics of low dust emission, high precision, and space-saving, meeting the extreme design requirements of semiconductor equipment. In semiconductor manufacturing, wafer equipment faces "three high" challenges - high precision, high cleanliness, and high density.

 

4.3 Medical Devices: Surgical robot joints, CT machine rotating frames, precision turntables of medical detection equipment, rehabilitation equipment adjustment mechanisms, etc. The ultra-thin bearing structure is compact, runs smoothly, and has low noise, meeting the multiple needs of medical equipment for cleanliness, quietness, and compact space.

 

4.4 Precision Optical Instruments: Optical adjustment tables, laser alignment mechanisms, microscope rotating carrier tables, spectral analyzer dividing turntables, etc. The ultra-thin bearing ensures the position accuracy and optical path stability of the optical system during fine adjustment and rotation.

 

4.5 Precision Turntables and Gearing Devices: Gearing tables of CNC machines, precision measurement turntables, azimuth drive mechanisms of radar antennas, photoelectric tracking equipment, etc., which require high rotational accuracy and compact structure.

 

5 Scientific Selection and Standardized Assembly Guidelines

5.1 Precise Selection Criteria

 

Before selection, it is necessary to clearly define the radial size limit of the equipment installation space and the load type and size required by the bearing. The inner diameter size should match the installation shaft diameter, and the outer diameter size should be controlled within the maximum radial space allowed by the equipment. The load type is mainly radial load, supplemented by axial load. The ultra-thin bearings mainly undertake radial support functions. The rotational speed requirement determines the bearing precision grade and lubrication method. High-speed precision equipment should select P5/P4 grade high-precision products. Environmental factors: Cleanroom environments can use open-type or low-dust sealed types, while dust or humid environments require contact-type sealing structures. The installation of thin-wall bearings has extremely high requirements for mating tolerances and assembly accuracy. When selecting, the feasibility of the assembly process should also be considered simultaneously.

 

Thin-wall four-point contact ball bearings are mostly used in the waist, elbow, and wrist parts of industrial robots due to their strong ability to withstand combined loads, high precision, small friction torque, light weight, and smooth operation. Cross roller bearings are characterized by the 90° cross arrangement of rollers and line contact bearing. They are particularly suitable for joint parts that need to withstand both radial, axial, and overturning moments.

 

5.2 Standardized Assembly Specifications

 

Before assembly, it is necessary to thoroughly clean the dust, oil stains, and metal debris on the shaft necks of the installation shafts, the inner holes of the bearing seats, and the assembly contact surfaces. The thin-walled bearing rings have relatively weak rigidity. During assembly, the bearing rings or rolling elements should not be struck directly. Special pressing tools or hot assembly processes should be used to ensure that the pressure or thermal expansion acts uniformly on the bearing end face, avoiding deformation of the rings. After assembly, manual rotation tests should be conducted to confirm smooth operation, no sticking, and no abnormal sounds. After installation, radial runout and end face runout should be inspected to ensure they meet the equipment precision requirements. The assembly accuracy of thin-walled bearings directly affects the rotational accuracy and service life of the entire machine. Each assembly step must be strictly controlled.

 

6 Lubrication Maintenance and Daily Inspection Standards

6.1 Fine Lubrication Management

 

Due to the extremely limited internal space of ultra-thin precision bearings, the filling amount of lubricating grease needs to be precisely controlled. Excessive filling will lead to increased temperature rise and increased resistance, while insufficient filling will accelerate wear. It is recommended to use low-viscosity, low-volatile, and wide-temperature-range special lubricating grease, which is suitable for the high-speed and long-life requirements of precision equipment. For equipment with long-term operation, the lubricating grease condition should be checked regularly, and timely supplementation or replacement should be carried out.

 

6.2 Routine Inspection Focus

 

The key points of daily operation and maintenance include monitoring the bearing operation noise, temperature rise, rotational smoothness, and rotational accuracy. If abnormal sounds, overheating, sticking, or excessive runout are detected, the lubrication status, seal integrity, and bearing wear conditions should be promptly investigated. Regularly inspect the seal condition to prevent impurities from entering the raceway and extend the bearing service life. For semiconductor, medical, and other highly clean environments, special attention should be paid to the dust emission of bearings, and particle emissions should be regularly tested.

 

7 Core Advantages and Supporting Guarantees of the Product

NMT ultra-thin precision bearings have been deeply involved in the field of thin-walled precision bearings. Relying on high-precision processing equipment and strict quality control systems, every step from steel material selection, heat treatment, grinding processing to ultra-precision grinding is strictly carried out according to standardized processes to ensure the dimensional accuracy, rotational accuracy, and service life of the products. Taking the 618 series ultra-thin cross-section products as an example, while maintaining the standard inner diameter, the cross-sectional height is reduced, and it is combined with P5-level precision design to provide the possibility for the compactification of precision instruments.

 

The cross-sectional height of the product covers various specifications, and the inner diameter covers the mainstream installation requirements of precision equipment, suitable for various robot joints, semiconductor equipment, medical devices, and optical instruments. The brand has a regular inventory of mainstream specifications, which can quickly respond to batch purchases and emergency maintenance needs, shortening the enterprise's procurement cycle. NMT provides reliable thin-walled rotating support solutions for various precision equipment with stable quality, compact structure, and excellent high rigidity performance.