Optical Target Care

1238888

Optical Target Care Overview

Optical Targets, such as the spherically mounted retroreflector (SMR), are an important part of the FARO Laser Tracker. Handle SMRs with great care to ensure accuracy and longevity.

Target care includes:

• Never touching the optical surfaces of the target.

• Never dropping the target.

• Keeping the target free of dust and moisture by storing it in the case when not in use.

• Cleaning the target only when there are problems acquiring the target or the Operational Checks indicates cleaning is necessary.

• Always using the proper cleaning materials and procedure when cleaning is required.

If the FAROLaser Tracker does not lock onto the target, use the Operational Checks command to check your SMR. If the Return Power value is “GOOD” your SMR does not need cleaning.

Unnecessary cleaning will degrade the reflective surface of the SMR and can cause damage to the coatings on silver surfaces that will eventually destroy the SMR. Only clean SMRs when required for good measurement and accuracy performance, not based on cosmetic conditions.

Cleaning Optical Targets

In many cases, the optical surfaces of the target are simply dusty and just require cleaning with compressed air from a can.

Do not clean with compressed air available from a hose in a workshop - the air is seldom clean and may coat the SMR with oil or some other contaminant.

• Spray the air away from SMR for a few seconds before spraying it onto the optical surfaces to remove any propellant in the can from the air nozzle. This prevents the propellant from being sprayed onto the SMR's optical surfaces. Always hold the can upright and never shake the can when spraying compressed air.

If the target is still not functional after blowing off any dust, use the following target specific procedures.

Never use a dry cotton swab or tissue to clean the optical surfaces because these will scratch the optical surfaces. Cleaning with any improper chemicals will destroy the reflective surface.

1. Breathe on the optical surfaces. The moisture in your breath will form a layer of condensation on the optical surfaces.

2. While condensation is still on the glass surface, gently slide a cotton swab in one direction while rotating it in the opposite direction. Use very little pressure; do not push the cotton swab onto the surface. Use one cotton swab for each pass and then discard it. You may need several swabs to clean the optical surfaces thoroughly. Using a cotton swab more than one time can cause debris to scratch the coatings. For silver SMRs, a scratch can lead to oxidation under the coatings and destroy the SMR.

3. If this does not successfully remove the residue, clean the optical surfaces with Optima Grade acetone for oil based residue or denatured alcohol for water based residue.

4. Moisten a clean cotton swab with solvent.

5. Gently slide the cotton swab in one direction while rotating it in the opposite direction. Use very little pressure; do not push the cotton swab onto the surface. Use one cotton swab for each pass and then discard it. You may need several swabs to clean the optical surfaces thoroughly.

6. Remove any remaining cotton dust with canned compressed air.