Some application fields for hydrostatic units are as follows:

 Ultra-high precision grinding of brittle materials.

The materials like quartz, glass, ceramics, tungsten carbide are very brittle and to get required excellent surface finish using the grinding process is really a very challenging task. Unique combination of ultra-high rotational accuracy with extremely high vibrations resistance makes hydrostatic grinding spindle an optimal choice for this particular application;

 Hard turning

Hard turning is a high precision turning of hardened steel that in some cases is used to replace the grinding. The same as in the previous paragraph, the combination of accuracy and vibration resistance allows the turning process reaching the same (or often even better) geometrical accuracy and surface finish as compared to the grinding process.

 Diamond Turning

Diamond turning is usually a prerogative for the air static spindles. However, if the machined part is heavy, the stiffness, as well as a load capacity, have to be taken in consideration and hydrostatic spindles should be used.

High precision internal grinding

High speed hydrostatic spindles can be very effectively used for high precision internal grinding, especially in mass production. Combination of accuracy, stiffness and vibration resistance allows significantly to increase grinding productivity (throughput). It makes it possible to reach required geometrical accuracy and surface finish for a much shorter time as compared to the ball bearing spindles. Examples of such parts are fuel injectors components or bearing rings for high precision ball and roller bearings.

High precision boring

As it is clear from the boring process kinematics, roundness of the machined hole is to a large extent defined by the boring spindle rotational accuracy. The unique set of hydrostatic spindle advantages allows to reach simultaneously a very high geometrical accuracy, an excellent surface finish and to reduce the machining cycle time. 

High precision workhead grinding spindle in the cylindrical grinding machine

In the cylindrical grinding process, the two rotating spindles are involved: grinding spindle with mounted grinding wheel and the workhead spindle in which the ground part is mounted. While the grinding spindle is mainly responsible for the surface finish and for the grinding productivity, the workhead spindle is mainly responsible for the geometrical accuracy of the ground part. Usage of the workhead spindle with hydrostatic bearings allows significantly to reduce the out of roundness. Roughly speaking, the out of roundness can’t be lower than a synchronous error motion of the workhead spindle.

Truing spindles

Truing spindles are used to condition the surface of the grinding wheel and to get a required shape for the grinding wheel that will be concentric to the axis of rotation. Truing process starts when the truing wheel is touching the grinding wheel. To accurately define the moment when the truing wheel is touching the grinding wheel are used the acoustic emission sensors mounted inside the truing spindle. Because hydrostatic bearings, in contrast to the ball bearings, have an extremely clean spectrum, it allows to define the moment of touching with very high accuracy.

Inspection of the ball and roller bearings performance.

To inspect the performance of the ball bearing, it is mounted on the flange of the test spindle, and vibrations of the tested bearing are measured.  If for the test spindle the ball bearings are used, it becomes a very challenging task to separate vibrations of the test spindle bearings from vibrations of the tested bearing. However, if the hydrostatic bearings with a very clean spectrum are used to support a shaft of the test spindle, the measured vibrations will be related to the tested bearing only.