When a joint has to run without grease — vacuum, cleanroom, or simply a grease life shorter than the maintenance interval — ceramic balls are the way out. Robotics & Automation duty is high cycle count, oscillating motion and zero tolerance for play; the material is what decides whether the bearing survives it.
| Industry duty | very high duty cycle, small oscillating displacements and stiffness demands |
|---|---|
| Typical media | clean air, occasional grease starvation at reversal points |
| Housing temperature | 0 to +60 °C |
| Material and grade | silicon nitride ceramic (hybrid) — Si3N4 |
| Hardness | 1500 HV |
| Temperature ceiling | 800 °C for the balls, rings limit the bearing |
| Corrosion / chemical | none — inert to water, acids and coolant |
| Relative cost | ≈8–15× of a standard 52100 bearing |
A vacuum robot cannot have grease: it outgasses and deposits on the wafer. A cleanroom axis cannot have grease either, for a different reason. Ceramic balls with a PEEK cage and a bonded dry film run with a friction coefficient low enough to survive millions of cycles, and the ceramic does not cold-weld to the raceway the way steel does at low film thickness.
| Position | Bearing type | Material / finish | Why it works there |
|---|---|---|---|
| Vacuum transfer axis | Deep groove ball | Si3N4 hybrid, PEEK cage, dry film | No grease vapour in the chamber. |
| High-cycle pick and place | Deep groove ball | Si3N4 hybrid, 2Z, low-torque grease | Lower friction means lower temperature at 300 cycles per minute. |
| Semiconductor stage | Linear guideway | Ceramic balls in 440C blocks | Non-magnetic and low particle generation. |
| Material | Fit here | Choose it when |
|---|---|---|
| Si3N4 | Best fit | Vacuum, cleanroom or high cycle rates where grease is the limit. |
| 440C | Workable alternative | Washdown without the vacuum requirement. |
| 100Cr6 / 52100 | Workable alternative | Standard grease-lubricated axes below the grease life limit. |
With a bonded dry film and a PEEK cage, yes, at moderate load and speed. Without the film, the first few thousand cycles wear the raceway until a transfer layer forms.
Silicon nitride is, which is why it appears in semiconductor and MRI-adjacent equipment. The steel rings are not, so the assembly is only partly non-magnetic.
A crash. Ceramic balls crack instead of brinelling, and a cracked ball destroys the bearing within seconds.
Hardness, temperature, corrosion and equivalents for silicon nitride.
Read →Typical duty, recommended types and suffixes for robotics.
Read →Joints & reducers — robot joint reducers, harmonic drive supports and linear axis carriages.
Read →Cleanroom & washdown — cleanroom, pharmaceutical and food-handling robots.
Read →Send the position, bore size, quantity and the medium it sees. We reply with the material certificate, clearance class, lubricant and price within 30 minutes on working days.