ISO Spindles

Professional Instruments Company’s ISO spindles are designed to complement our BLOCK-HEAD® spindles while expanding the range of capabilities in some important areas. The spindle properties specifically addressed by the ISO line of spindles are speed and radial load capacity. It may be helpful to think of BLOCK-HEAD® and ISO spindles as being the inverse of one another. The BLOCK‑HEAD® spindles have proportionally higher thrust capacity at the expense of radial properties, while the ISO spindles give up some thrust capacity to allow for higher speed operation and greater radial capacity.

ISO spindles use long radial journal bearings separated by a central thrust, captured on both sides by air bearing surfaces. Air is ported to annular feed grooves that distribute it to both the thrust and radial bearings. The long, widely separated journal bearings provide substantial tilt capacity and exceptional radial loading. The thrust plate diameter is sized to minimize heating while still providing superior axial load capacity and stiffness. The central stiffness properties of Professional Instruments Company’s ISO spindles easily exceed those of our competitors. Error motions in our ISO spindles are held to the same exacting standards as our BLOCK‑HEAD® spindles. Radial, axial, and tilt errors are specified to be better than 25.4 nanometers (one-millionth of an inch).

Professional Instruments Company currently manufactures ISO spindles in two standard sizes:

ISO 2.25 - 60,000 rpm
ISO 5.5 - 10,000 rpm

Professional Instruments Company’s standard line up of ISO spindles are supplied with brushless DC motors, PWM drive amplifiers and precision encoders. Thermal growth in these spindles is controlled through the use of integral cooling jackets which surround both the air bearing spindle and the brushless DC motor. The level of spindle thermal growth control is only limited by the capacity and sophistication of the chiller unit used to control the temperature of these spindles.

Professional Instruments ISO precision air bearing spindles are being used in many machining applications such as the direct machining of optics as work spindles and flycutting spindles, raster flycutting of optical molds, grinding of SiC optical molds and a wide variety of ID and OD grinding applications in many materials.

The full range of Professional Instruments Company spindle attachments including piloted chucks, rotary unions, rotor grounding systems, and other enhancements is available. All of the spindles are dynamic two-plane balanced to ensure smooth, vibration-free operation.

Special versions of these spindles are being used extensively by the computer disk drive industry. If your spindle requirements can not be handled by our standard line of spindles please feel free to contact us for custom designs.