Are ceramic bearings more beneficial for surgical robots? Not necessarily!

Medical robots are a new and popular track in the robotics industry. Last year, several global medical robot companies received hundreds of millions of yuan in financing. According to the forecast of the overseas data agency GlobalData, the medical robot market will be worth 4.7 billion US dollars in 2020, and the compound annual growth rate from 2020 to 2030 is expected to exceed 11%. Based on this, the global output value of medical robots may exceed 12 billion US dollars in 2030.

There are many types of medical robots. The mainstream products on the market are surgical robots that help perform minimally invasive surgeries and exoskeleton robots that help with rehabilitation. An ordinary surgical robot system may cost millions of dollars. Surgical robots require extremely high precision, and an inconspicuous component plays a big role: the bearing.

Bearings have the important task of supporting and guiding the key components of the robot, such as supporting the rotation and movement of the robot arm , so that the robot can accurately perform surgical operations; at the same time, during the movement of the robot, bearings can effectively reduce friction and wear between mechanical parts, and by providing a smooth moving surface, bearings help reduce energy loss.

Today, most surgical robots use steel bearings, which are made of high-purity metals such as martensitic stainless steel using traditional metal processing methods. Steel bearings are strong and can withstand high pressures and loads, while being relatively inexpensive, but they may not meet the stringent hygiene requirements of medical environments and are susceptible to particle contamination.

The latest research has found that bearings made of zirconium oxide (ZrO2) or other special ceramic compounds are more suitable for medical robots. Ceramic bearings are more resistant to the harsh chemicals that equipment needs to withstand during the sterilization process. In such an environment, steel bearings are prone to corrosion and their service life is not as good as that of more wear-resistant ceramic bearings.

Full ceramic bearings are harder than steel and have excellent corrosion and heat resistance, higher dimensional stability and lower density, but the performance improvement comes at a price, and ceramic bearings are much more expensive than steel bearings.

Take magnetic resonance imaging (MRI), for example, which uses strong magnetic fields to generate 2D or 3D images of any living object. Standard steel bearings cannot be used in these scanners due to their magnetic properties, so ceramic bearings are the best choice. Plastic ball bearings are also completely non-magnetic when mated with polymer, glass or ceramic balls. They are ideal for use in MRI equipment or sensors that do not experience any magnetic distortion .

Hospitals want to ensure these machines run efficiently without high-maintenance parts, so quality ceramic bearings are essential in these situations. Full ceramic bearings require no lubricant to operate, whereas steel alternatives may require routine maintenance to re-lubricate parts.

According to IOM3 (Institute of Materials, Minerals and Mining), ceramic bearings made from ZrO2 are extremely tough and have similar expansion characteristics to chrome steel and 440 stainless steel, but are 30% lighter.

But is it economically viable to spend more to manufacture ceramic bearings in order to improve performance?

Ceramic bearings have the advantages of being resistant to pollution, chemical substances, and not requiring lubrication. In medical environments that require high hygiene standards, such as operating rooms, ceramic bearings will not be affected by particle contamination, reducing the risk of failure of surgical robots due to contamination. These characteristics can reduce the frequency of maintenance and replacement of bearings, reduce maintenance costs, and the silent cost of downtime. Therefore, if the frequency of use of surgical robots is high, it may be more economical to choose ceramic bearings.

As the competition in the surgical robot market becomes increasingly fierce and technology continues to develop, the manufacturing cost of ceramic bearings may gradually decrease, making them more competitive. In addition, as the performance and reliability requirements for medical robots increase, more surgical robot manufacturers may choose to use ceramic bearings to enhance the market competitiveness of their products.

Although ceramic bearings have a higher cost, the material is still economical to use in a specific market environment, especially in the field of medical equipment that pursues high performance, high stability and low maintenance costs. Robot manufacturers can reasonably arrange their different product matrices according to the market demand of their own products.