Air rings

HOMMEL-ETAMIC AG200 air rings with open air jets are used to measure diameters of continuous or shouldered shafts.

The diameter is established using two or three non-contact air jets, offset against the inner guide diameter of the air ring. Measurements can take place either statically or dynamically.

Workpieces can be rotated in the AG200 air ring to determine out-of-roundness and advanced through the ring to determine conicity. On request, the air ring can be fitted with additional air jets for increased measurement capability, such as X and Y diameter measurement, ovality, etc.


Our standard air tooling sizes range from 3 mm to 150 mm in diameter, with measuring ranges of 0.010 mm to 0.160 mm respectively.

There are two different standard versions of AG200 air rings. One with two jets diametrically opposed for diameter and out-of-roundness or the other with three jets at 120° for measurement of average diameter and triangulation.

The type of jets used depends on the diameter, the surface structure of the workpiece to be measured, and the required measuring range.

The position of the air jets depends on the type of ring being used. There are two types of tooling: ‘S’ (standard, with centered jets for continuous shafts) or ‘TP’
(jets located near the ring end for shouldered shafts).

AG200 air rings can be connected to all standard Hommel-Etamic measuring instrumentation. In the case of portamic, C61, and pneutamic displays, the
AG200 air rings are directly connected to each device. Alternatively, they can be used indirectly via an electro-pneumatic converter (ARC99, TPE99 or TPE70/3). In
this case, the measurement results can be displayed on an ESZ800, CMZ200, CMZ250 or ESZ400 industrial controller.

Hommel-Etamic air rings are extremely reliable and robust. They can be used hard mounted inline or on a bench, as well as on semi-portable handles for operational flexibility. AG200 air tooling is ideal for manual measurement of shafts in production lines, for automatic or semiautomatic measuring stations, and for the quality lab (subgroups or 100% monitoring).

Thanks to the pneumatic principle (high pressure), any special maintenance processes are eliminated – a simple cleaning is all the tooling requires.

To ensure the selection of the ideal air ring for your application,
the following information is required:
– Drawing of the workpiece to be measured
– Diameter, tolerance, and surface structure of the shaft
to be measured
– Type of shaft (continuous or shouldered)
– Type of material required for the air ring: hardened steel
(100,000 workpieces to be measured) or surface-treated steel
(1,000,000 workpieces to be measured)
– Required measuring range
– Pneumatic combination, if the air ring is to be connected to
an existing device

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