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Air supply

It is important that the air supply to the head is maintained while the head is powered as the air supplies the bearings and provides air for thermal management.

REVO-2 and air filter - labelled

Air filter maintenance

WARNING: It is vital that the supplied air filters are used for REVO-2 and that the filter unit is maintained to the filter manufacturer's specification. Failure to comply with the specification will invalidate the warranty and is likely to result in permanent damage to the REVO-2 head requiring replacement at full cost.

To maintain the air quality:

1. Ensure the air provided to the filtration system meets the specification given.

Incoming air supply specification:

Air pressure

5 bar - 8.5 bar*

Air consumption

Up to 50 litres per minute


Class 4

Particle size

15 μm

Dirt concentration

8 mg/m3

Dew point

+3 °C


5 mg/m3

* NOTE: The exact values are dependent on the inherent characteristics of the air pipe between the air filters and the REVO-2 head. Please ask the installer for the specification.

If the air pressure falls outside the range given, the head metrology results will be affected.

2. Regularly monitor the dew point indicator (see image below) and follow the instructions given in the table.

Maintenance of the REVO air filters 

For more information please visit the air filtration manufacturer's website and search for IDG5 filters. (Please refer to the section 'REVO air filter service kits' for details on air filter service kit part numbers).

Dew point indications and maintenance instructions

Grain colour




NOTE: The grains may be pink on delivery and can take up to 1½ hours to turn blue when air is connected.

Normal operation.

No action required.

Pink, white or brown

NOTE: If the grains are brown, then replace the indicator. If after 1 hour the grains in the new indicator turn brown again replace the indicator and membrane.

Water and oil flow into membrane air dryer.

1) Check and replace filters if necessary.
2) Check condition of inlet air for excess oil or water.

Pink or white

Input air temperature is too high.

Lower input temperature. Install in-line air coolers if necessary.

Pink or white

Purging air exit obstructed.

Check outlet of air purge port.


Membrane dryer near end of useful life.

Replace dew point checker.

Grains crushed

Water flow into membrane air dryer.

Replace dew point checker.

NOTE: Allow a minimum of 1 hour from start of air flow for the dew point indicator to change colour.

Air filter service kits

The Renishaw filter service kit (M-3060-0933) contains:

SMC part numberDescriptionQuantity
AF20P-060S5 μm filter element for use with AF20 unit1
AFM20P-060AS0.3 μm filter element for use with AFM20 unit1
AFD20P-060AS0.01 μm filter element for use with AFD20 unit1

We recommend that the above filter kit is replaced every two years.

The Renishaw membrane dryer service kit (M-3060-0943) contains:

SMC part numberDescriptionQuantity
IDG-EL5Membrane module kit for use with IDG5 unit1
IDG-DP01Dew point indicator kit for use with IDG5 unit1

We recommend that the above filter kit is replaced every four years.