The Importance of Proper Handling & Cleaning Procedures
After purchasing a glass or optical component, exercising proper care is necessary to maintain its quality and extend its usable lifetime. Use of proper cleaning supplies and techniques are
very important to avoid damaging the component. Improper handling and cleaning practices can damage critical areas by creating random scratches, pits, or chips.
General Glass Handling Guidelines
The following
guidelines are general rules that will help you avoid damaging critical areas. If at all possible, don't touch the critical areas of finished components; instead hold on unfinished surfaces. Don't slide glass components over any
other surface, and don't stack finished glass components one atop of another. Don't set a component down on a hard surface, since a very slight impact on a sharp edge will chip the glass. When components are clean and ready for
use, wrap in lint-free paper or store in a padded foam container until they are used; this will help protect it from contamination and damage.
General Glass Cleaning Guidelines
Materials commonly used for
cleaning glass & optical components include pressurized filtered dry nitrogen, lint-free lens tissue, reagent-grade isopropyl alcohol, reagent-grade acetone, lens cleaning solution, mild detergents, ultra-sonic baths, lint-free
cotton swabs, foam-tipped swabs, and a magnifying device. Dirt and oil from fingerprints can permanently damage components, so preventive measures (i.e. lint & powder-free gloves or finger cots) should be used. The following
are general guidelines and results may vary based on differences between components (i.e. glass type, coatings, and shape).
Non-coated Optics and Glass Components
Dust is the most common contaminant and can
usually be removed by blowing the parts off with pressurized nitrogen. If more cleaning is necessary, hold the lens in lens tissue or tweezers avoiding the critical areas if possible, and apply a few drops of reagent-grade acetone
or lens cleaning solution. Slowly turn the lens while using lens tissue or a cotton swab to apply pressure in the critical areas while working outward, to pull dirt off the lens instead of redistributing it on the surface.
Fingerprints on a coated lens should be cleaned as soon as possible to avoid staining or damaging the optic. Larger dirt particles, however, should be removed with a dust-free blower before attempting to clean the optic with lens
tissue, since they will scratch the surface you are attempting to clean when trapped under the cloth or swab. If the lens is still contaminated after using acetone (e.g. contamination was just redistributed and not removed), then a
mild detergent or lens cleaning solution can be used to gently wash the lens. Repeat the procedure with acetone to eliminate streaks and residue.
Coated Optics and Components
Dirt and fingerprints will
permanently damage special coatings, so measures to prevent fingerprints (i.e. lint & powder-free gloves or finger cots) should be used to prolong the lifetime of the coating. After blowing off particles with pressurized gas,
the drag method of cleaning can be used to remove fingerprints or other contaminants. In the drag method, lens tissue saturated with reagent-grade isopropyl alcohol or acetone is slowly dragged across the surface. If done
correctly, the solvent will evaporate uniformly without leaving streaks or spots. Bare metallic coatings are extremely delicate and should not be cleaned in this manner; instead use the same drag method with specialty foam-tipped
swabs.
Micro-Optics
These lenses may also be cleaned using acetone, but they require special handling and care due to their extremely small size. Plastic or rubber coated tweezers or a vacuum pick-up tool may
be used to securely hold a micro-component by its edge. If specialty trays (usually custom designed Teflon trays) are available, non-coated parts can also be cleaned using an ultrasonic bath with a mild detergent solution, followed
by subsequent rinses with de-ionized water and alcohol, and then dried in an oven at 135 degrees F. |
