Ceramic linear bearings

For decades PM is supplying linear bearings made out of full ceramic as well as hybrid versions. In 2005 PM was the first manufacturer introducing ceramic linear bearings in the market. On this page you find general information about the ceramics we are using. For more detailed information or advice for your application ask one of our experts or our local sales partner.

Why Ceramics

Ceramics are superior to steel in density and hardness. Because of their non-magnetic property they are an ideal material for use in non-magnetic or ultra-high vacuum environment in new generation machines. PM engineers have developed numerous of ceramics designs. We continue to focus on solutions that incorporate the silicon nitride (Si3N4) or oxide family (Alumina Al2O3 or Zirconia ZrO2) of ceramic compounds. The selection is made on operating conditions such as speed, temperature and surface finishing.

You want to use ceramic linear bearings?

Send us an email or call us to receive more information about the use of ceramic linear bearings.

Lightweight

Ceramics density is about 40%-60% percent of traditional bearing steel DIN 1.3505. Because force is directly proportional to mass, the low density silicon  nitride significantly reduces the starting force which is required to move the slide/stage. This enhances operations in high dynamic applications where the reduction of the mass-moment of inertia is an ongoing issue.

High Rigidity

Ceramic rails and balls (Silicon Nitride and Alumina) have a Youngs Modulus which is about 50% higher than steel. This make them an ideal linear bearing material for use in high-speed XY-stages as for wirebonding machines in the semi-conductor industry where rigidity and precision at high speed is required.

Increased Lifespan

The lifespan of linear bearings is directly related to hardness, the most critical mechanical property of a bearing material. With an impressive hardness of 78 HRc., twice as hard as many bearing steels - and a high compressive strength, about 5 to 7 times that of steel, silicon nitride improves wear resistance, minimizing the damaging effects of repeated surface contacts. The lifetime of ceramic bearings varies with the operating conditions. Results of a lifespan test of steel and full ceramic linear bearings without lubricaton are presented in the left figure.

Operation at high temp.

The mechanical properties of ceramic bearings does not change by extreme low (cryogenic) and extreme high temperatures - approximately 800ºC which makes it very suitable for use as heat resistant material. A major problem by such high temperatures is lubrication. Oil and grease can normally be used in temperatures up to 300ºC. When temperature exceed this, solid lubricants can be used. However, solid lubricant can only be used for temperatures up to 500ºC. Ceramic bearings can operate at temperatures up to 800ºC, exceeding the best high temperature bearing steels by a factor of three.

Speed vs Performance

Due to the material characteristics each ceramic offers specific benefits. Some materials perform better at high speed and some at lower speed. Other characteristics such as vacuum compatibility, less particle generation about 1/3 in both air and vacuum compared with stainless steel, chemically inert, corrosion resistant and electrical non-conductivity can enhance linear bearing performance in special applications. PM engineers can provide customer-focused bearing recommendations for challenging applications.

Design to client specification

Ceramic linear bearings and slides are manufactured on a make-to-order basis. In this way the ceramic bearing specifications can be matched with your system requirements such as speed, operating temperature and accuracy. Manufacturing starts after all technical details are cleared. Our engineers are on call to assist you to find the right linear bearing. They are ready to offer you the best solution, no matter how complex and unique your problems are. Contact us for more information about ceramic linear bearings.

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