Bearings in Implantable Medical Devices

Implantable medical devices require components that can perform reliably in highly demanding biological and mechanical environments. In applications such as micro-blood pumps, surgical support systems, prosthetic mechanisms, and specialized medical instruments, bearings may help enable smooth motion, low friction, precise positioning, and long-term mechanical stability.

For medical device OEMs, bearing selection is not only a question of size or load capacity. It also involves biocompatibility, corrosion resistance, lubrication strategy, surface finish, sterilization compatibility, wear behavior, and supplier quality control. The right bearing design can support device performance, while the wrong material or configuration can increase friction, contamination risk, premature wear, or maintenance concerns.

Leading bearing manufacturing companies like Myonic, NHBB, Barden, Timken, SKF, Schaeffler Group and NMB have led the revolution in the development of medical bearings.

Bearings in implantable medical devices require biocompatibility, longevity, and performance. 

This article looks at  the different types of bearings, bearing material, designs, and other key performance considerations for both standard and implantable medical devices.

To deal with the caustic issues bearings encounter in the human body manufacturers have turned to special materials like Cronidur® 30 Stainless Steel.

Cronidur®30 is a stainless martensitic steel, having greater corrosion resistance than 440C, and is longer wearing. Aside from enormous success in medical applications Cronidur is finding uses in aviation, Nascar racing engines and numerous industrial applications.  

Why is Cronidur®30 so successful in medical applications?  It is primarily due to its superior corrosion resistance, higher than 1.2083, 1.4112,1.4301, 1.4571. Cronidur has excellent machinability, high dimensional stability after heat treatment, excellent grinding and polishing to obtain optimal surface quality. Also due its high durability and maximum hardness it is useful in both static and dynamic situations.

Miniature bearings are used in all types of medical devices including implantable ones and some of the key applications include micro-blood pumps, surgical power tools, robot-assisted surgery, prosthesis and exoskeleton, respirators, analysis equipment, turbine and contra-angle handpieces, and handpieces for implantology and facial surgery.

Why Bearings Matter in Implantable Medical Devices

Bearings used in implantable and medical devices are designed to support controlled motion in compact spaces. Unlike industrial bearings, medical bearings often need to perform in environments where access for maintenance is limited or impossible. This makes reliability, cleanliness, and long-term material stability especially important.

Common performance priorities include:

• Low-friction movement
• Corrosion resistance
• Biocompatible or application-appropriate materials
• Resistance to bodily fluids, cleaning agents, or sterilization exposure
• Compact geometry for miniature assemblies
• Precision tolerances for predictable movement
• Long service life with minimal maintenance
• Compatibility with OEM design and validation requirements

For implantable applications, the bearing should be evaluated as part of the complete device system, including housing design, lubrication approach, expected duty cycle, load profile, and regulatory requirements.

Micro-Blood Pumps

Hospitals are now performing life saving heart surgeries employing the use of tiny ball bearings incorporated into implantable devices. Highly customized miniature bearings are important elements used in micro-blood pumps. Micro blood pumps are often compared to heart-lung machines but much less burdensome for the patient. Leading Bearing manufacturers like Myonic and NMB have developed specialized small bearings for exclusive use in medical device components.

Surgical Power Tools and Robot-Assisted Surgery

In certain medical applications like brain and eye surgeries the doctor must rely on the precision of the machine . Precision ball bearings are relied upon in these applications and are designed to hold a patient’s head perfectly still and in position during surgery.

Robot Assist Bearings

Dental Applications 

A dental bearing must be able to withstand the most extreme conditions and at the same time is one of the most decisive components for the performance of a dental instrument. To consistently improve this performance, an individual solution must always be sought and implemented consistently.

For decades, Myonic has supplied customers worldwide with its innovative and reliable dental bearings and has earned itself an exceptional market position.

Rotational speeds of up to 500,000 rpm, vibrations, superheated steam or different cleaning media as well as penetrating soiling such as blood and tooth dust are the biggest challenges for such special ball bearings.

Aside from the individual design, these challenges are met with a systematic selection of materials and lubricants.

The result is a product that is custom-tailored for this application and that meets all requirements over a long period. Challenge us! Our developers are looking for new, difficult problems to solve.

Prostheses and Exoskeletons

Myonic, NMB and other manufacturers offer specialized high precision ball bearings for use in prostheses and exoskeletons to help patients move comfortably again. Highly toleranced and precise bearings meeting the highest ABEC standard are often specified for use in prosthesis and exoskeletons.

Respirators

Myonic Bearing and NMB Bearing specialize in small ball bearings used in respirators. Quiet running , high precision, anti-corrosive features make for this life saving  device’s reliable operation. 

Scientific and Analytic Medical Equipment

Ball bearings are widely used also in medical laboratories. For handling and processing samples bearings must perform to exacting standards. Manufacturers like SKF, NMB and others provide the highest quality and precision required in scientific and analytic devices. 

Bearing Types Used in Implantable and Medical Devices

Pacific International works with the best bearing manufacturers like SKF, NMB, Myonic, Schaeffler Group, FAG, INA, and TPI. These are the very best manufacturers who design ball bearings especially for the high standards required in medical applications.

Medical applications often mean bearings come in contact with blood, caustic cleaning agents, high pressure steam sterilization and other bodily fluids. Bearings must be manufactured from materials like Cronidur30, and ceramics to overcome some of these challenges .

Ball bearing manufacturers supplying medical applications will employ some or all of the following features to achieve the best operating bearings.

Bearing Features required in implantable medical and other medical devices:

• NSF-certified cage materials and lubricants (e.g. H1/H2)
• Corrosion resistant ring- and ball steels
• Ceramics ideally suited for healthcare applications
• Media resistant shields and seals
• Biocompatible lubricants according to DIN EN ISO 10993

Implantable medical devices will use several types of bearings to facilitate motion within the device. Each type has its own merits and considerations, based on the specific application and requirements. Contact us at [email protected] for assistance in the type of bearing most suitable for your medical application. 

Dimensional Specifications

In implantable devices like pacemakers and cochlear implants, bearings are typically micro-sized, with diameters often ranging between 1mm and 5mm. The reduced size ensures the devices are compact enough for implantation, but this small scale introduces challenges in manufacturing precision. Standard tolerances for these micro-bearings fall within ±0.001 mm to ensure consistent rotational performance.

Material Selection and Properties

Material selection is one of the most important engineering decisions for bearings in implantable and medical devices. The selected material must support mechanical performance while also meeting the environmental demands of the device.

Common material considerations include:

• Corrosion resistance
• Biocompatibility requirements
• Wear resistance
• Hardness and fatigue life
• Dimensional stability
• Surface finish capability
• Compatibility with sterilization or cleaning processes
• Interaction with lubricants, coatings, or surrounding components

Cronidur® 30 Stainless Steel

Cronidur® 30 is often considered for demanding medical bearing applications because it offers strong corrosion resistance, wear performance, hardness, and dimensional stability. Compared with conventional bearing steels, it may provide advantages in environments where moisture, bodily fluids, or cleaning exposure are concerns.

For medical device engineers, Cronidur® 30 may be useful when a bearing requires both high mechanical performance and improved resistance to corrosion-related degradation.

Stainless Steel, Titanium, and Ceramic Materials

Medical-grade stainless steels, titanium alloys, zirconia, and alumina ceramics may also be considered depending on the application. Each material has different strengths and limitations, so the final choice should be based on the device environment, load conditions, life expectancy, and validation requirements.

Lubrication Considerations

Unlike conventional applications, implantable devices can’t undergo regular maintenance. Therefore, the initial lubrication needs to remain effective throughout the device’s operational lifespan, often exceeding 10 years. Self-lubricating materials, such as polytetrafluoroethylene (PTFE) coatings, can reduce the coefficient of friction to as low as 0.05, enhancing the wear lifespan of the bearing components.

FAQ

What types of bearings are used in implantable medical devices?

Implantable and advanced medical devices may use miniature ball bearings, precision ball bearings, ceramic bearings, hybrid bearings, or custom bearing designs. The best option depends on the device’s size, load, speed, material requirements, and operating environment.

What materials are used for medical device bearings?

Common materials include stainless steel, Cronidur® 30, titanium alloys, zirconia ceramics, and alumina ceramics. Material selection depends on corrosion resistance, biocompatibility, wear behavior, hardness, and sterilization or fluid exposure.

Why is corrosion resistance important for implantable bearings?

Corrosion resistance is important because implantable and medical bearings may be exposed to bodily fluids, moisture, cleaning agents, or sterilization processes. Corrosion can affect bearing performance, reliability, and service life.

Do implantable medical device bearings require lubrication?

Many bearings require some form of lubrication or low-friction surface strategy. In implantable or sealed medical devices, the lubrication must support long-term performance because regular maintenance may not be possible.

Can standard bearings be used in medical devices?

Some medical applications may use standard precision bearings, but many require custom materials, lubrication, dimensions, seals, shields, or documentation. For implantable devices, bearing selection should be reviewed carefully against device-specific requirements.

How can OEMs choose the right bearing for a medical application?

OEMs should evaluate the operating environment, load, speed, space limitations, material compatibility, lubrication requirements, expected lifespan, and quality documentation needs. Working with an experienced bearing supplier can help reduce selection and sourcing risks.

Why Work With PIB for Medical Bearing Selection?

Pacific International Bearing Sales Inc. works with leading bearing manufacturers and supports OEMs that need precision bearings for medical, dental, robotic, and high-performance applications. PIB can help engineers evaluate bearing types, materials, tolerances, lubrication options, and custom design requirements for demanding medical environments.

If your team is developing or sourcing bearings for an implantable medical device, surgical instrument, prosthetic system, respirator, or analytical medical device, PIB can help review your application requirements and identify suitable bearing options.

Contact PIB to discuss your medical bearing application or request engineering support for bearing selection.