How to Measure Flatness, Parallelism, and Height of Air Bars

New Way Air Bearings’ products provide exceptional flatness and parallelism, but in order to achieve the specifications listed on our product pages, all New Way products must be placed directly against a precision ground guide surface. Before any measurements are taken, the surfaces should be cleaned in accordance with our Care and Air guidelines, namely using 70% isopropyl alcohol only.

Surface Flatness Requirements for Air Bars

Per our Application and Design Guide, we recommend a surface finish of 16 RMS or better. Local flatness, which we define as the flatness under the bearing at any one time, should always remain below 50% of the designed air gap. This is a worst case scenario, and it is relatively easy to stay within 10% of the air gap height.

Measuring Air Bar Parallelism With the Guide Surface

With your New Way product directly placed on a precision ground surface, parallelism shall be measured by use of a displacement gauge, mounted to an armature and free to slide on the precision ground surface to which your bearing or air bar is mounted. If the bearing or air bar must be elevated, it shall be placed on precision gage blocks, with a graded tolerance. Zero the gauge against one corner of the surface which is parallel with your guide surface. Take measurements along this surface, paying special attention to measurements at the corners of the air bar surface. The largest difference between measured values is the parallelism between your bearing and the guide surface.

Measuring Air Bar Flatness

Flatness shall be measured by use of a displacement gauge, mounted to an armature and free to slide on the precision ground surface to which your bearing or air bar is mounted. Zero the gauge against one end of the surface for which you wish to measure flatness, and then take measurements in regular intervals along the surface. The largest difference between measured values represents the flatness of the component. Of note, the air bar, air bearing or other component must be placed directly upon a precision ground surface and parallel with the guide surface in order to take accurate measurements on flatness deviations of the bearing surface.

Measuring Air Bar Height

Bearing height shall be measured with your height gage placed directly on the precision ground surface to which the bearing or conveyor bar is mounted. With the bearing leveled in accordance with our Application and Design Guide, zero your height gage against the top surface of the mounting block, and then lower the probe tip onto the upper surface of the air bar. Dimensioning of an air bar’s thickness can also be accomplished through use of a micrometer, placing the micrometer anvil face and spindle on opposite sides of the bearing, and measuring the distance between them.