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Porous Ceramic Hydrostatic
Bearing Technology

Porous Ceramic Hydrostatic Bearing Technology has been developed at Cranfield Precision in conjunction with Cranfield University. A collaborative project saw the design and manufacture of a set of ultra precision spindle bearings for a porous ceramic hydrostatic spindle. The project was for Lawrence Livermore National laboratory's Precision Optical Grinder And Lathe (POGAL) machine concept project.

The main requirement for the ultra precision spindle bearings was very low radial error motions. Porous Ceramic bearings are ideal for this application as they are not limited by some of the geometric design features inherent in traditional fluid film bearings.

Traditionally, air bearing spindles have been preferred over oil hydrostatic designs because of the lower asynchronous noise, however extremely low radial error motions and carefully tuned hydrostatic oil systems allow for high load capacity, extremely low radial error motion with minimal asynchronous noise.

Porous Ceramic Hydrostatic Bearing Systems are ideal for applications requiring

  • Extremely low Radial Error Motions
  • High Load Capacity
  • Ultra Precision
  • High Damping
  • Good Thermal Stability

The major technical challenge was producing a manufacturing method that allowed you to achieve the specified permeability of the ceramic material in conjunction with tightly controlled dimensional tolerances. Achieving both of these difficult criteria and producing bearings to a desired specification was overcome by Cranfield Precision. A manufacturing process was developed that allowed us to exploit this technology and has enabled us to develop the technology further for use in new machine concepts and spindle bearing designs.

Porous Ceramic Bearings

Porous Ceramic
Hydrostatic Bearings



Ultra Precision Spindle

Ultra Precision Spindle