| FAQ - FREQUENT
ASKED QUESTION
1.
What is "cavitation"?
2. What is "degassing", and why should it be done?
3. How do I get the best ultrasonic cleaning?
4. Can ultrasonic cleaning damage my parts?
5. What are "direct" and "indirect" cleaning?
6. Why is a special solution required for cleaning?
7. What cleaning solution should I use?
8. What cleaning solution shouldn't I use?
9. When should solutions be changed?
10. Why must I keep solution at the tank's level indicator?
11. What is the length of cleaning time?
12. What is the purpose of the unit heater?
13. How do I know if the unit is cavitating properly?
14. How do I perform the "glass slide" test?
15. How do I perform the "foil" test?
16. Why must trays or beakers be used?
17. What is the optimum cleaning temperature?
18. Is rinsing required after cleaning cycles?
19. Why shouldn't I leave my cleaner on constantly?
1.
What is "cavitation"?
A. "Cavitation" is the rapid formation and
collapse of millions of tiny bubbles (or cavities) in a
liquid. Cavitation is produced by the alternating high and
low pressure waves generated by high frequency (ultrasonic)
sound. During the low pressure phase, these bubbles grow
from microscopic size until, during the high pressure phase,
they are compressed and implode.
2.
What is "degassing", and why should
it be done?
A. "Degassing" is the initial removal of gases
present in the solution. Useful cavitation occurs after
gasses have been removed from the cleaning solution, leaving
a vacuum in the formed bubble. When the high pressure wave
hits the bubble wall, the bubble collapses; it is the energy
released by this collapse that will assist a detergent in
breaking the bonds between parts and their soils.
3. How do I get the best ultrasonic cleaning?
A.
There are many considerations important to ultrasonic cleaning.
Optimizing these variables will produce the best cleaning.
The most important decisions to be made are choosing the
proper cleaning solution, cleaning at the right temperature
for the correct amount of time, and choosing the right size
and type of ultrasonic cleaner.
4. Can ultrasonic cleaning damage my parts?
A. With certain cautions, ultrasonic cleaning is considered
safe for most parts. While the effects of thousands of implosions
per second is very powerful, the cleaning process is safe
since the energy is localized at the microscopic level.
The most important cautionary consideration is the choice
of cleaning solution. Potentially adverse effects of the
detergent on the material being cleaned will be enhanced
by the ultrasonics. Ultrasonic cleaning is not recommended
for the following gemstones: opal, pearl, emerald, tanzanite,
malachite, turquoise, lapis and coral.
5.
What is "direct" and "indirect"
cleaning?
A.
Direct cleaning occurs when the parts are cleaned in a cleaning
solution which fills the cleaner, usually inside a perforated
tray or mesh basket. The limitation of direct cleaning is
that a solution must be chosen that will not damage the
ultrasonic cleaner. Indirect cleaning involves placing the
parts to be cleaned in an inner non-perforated tray or beaker
that often contains a solution that the user may not want
directly filling the ultrasonic tank. When choosing indirect
cleaning, make sure that the water level inside the tank
itself is maintained to the fill line (about 1" from
the tank top) at all times.
6.
Why is a special solution required for cleaning?
A.
Soils adhere to the parts... if they didn't, the soil would
just fall off the parts! The purpose of the solution is
to break the bonds between parts and their soils. Water
alone has no cleaning properties. The primary purpose of
the ultrasonic activity (cavitation) is to assist the solution
in doing its job. An ultrasonic cleaning solution contains
various ingredients designed to optimize the ultrasonic
cleaning process. For example, increased cavitation levels
result from reduced fluid surface tension. An ultrasonic
solution will contain a good wetting agent or surfactant.
7.
What cleaning solution should I use?
A.
Modern ultrasonic cleaning solutions are compounded from
a variety of detergents, wetting agents and other reactive
components. A large variety of excellent formulations are
available, designed for specific applications. Proper selection
is crucial for acceptable cleaning activity and to preclude
undesirable reactivity with the part being cleaned. Cleanosonic
can help you to identify either the optimal 'stock' cleaning
formula, or likely candidates to test and evaluate.
8.
What cleaning solution shouldn't I use?
A.
Flammables or solutions with low flash points should never
be used. The energy released by cavitation is converted
to heat and kinetic energy, generating high temperature
gradients in the solution, and can create hazardous conditions
with flammable liquids. Acids, bleach and bleach by-products
should generally be avoided, but may be used with indirect
cleaning in a proper indirect cleaning container, such as
a glass beaker, and appropriate care. Acid and bleach will
damage stainless steel tanks, and/or create hazardous conditions.
9.
When should solutions be changed?
A.
Cleaning solutions should be replenished when a noticeable
decrease in cleaning action occurs, or when the solution
is visibly dirty or spent. A fresh batch of solution at
each cleaning session is usually not required.
10.
Why must I keep solution at the tank's
level indicator?
A.
The solution level should always be maintained at the
level indicator in the tank, with trays or beakers installed.
The ultrasonic cleaning system is a 'tuned' system. Improper
solution levels will change the characteristics of the
environment, can affect the system frequency, decrease
effectiveness, and potentially damage the cleaner. Maintaining
the proper solution level provides optimum circulation
of solution around parts, and protects heaters and transducers
from overheating or stress.
11.What is the length of cleaning time?
A.
Cleaning time will vary, depending on such things as soil,
solution, temperature and the degree of cleanliness desired.
Highly visible removal of soils should start almost immediately
after the ultrasonic cleaning action begins. Cleaning
time adjustment is the easiest (and most often misapplied)
factor used to compensate for process variables. Although
new application cycle duration can be approximated by
an experienced operator, it usually must be validated
by actual use with the chosen solution and the actual
soiled parts.
12.
What is the purpose of the unit heater?
A.
The primary purpose of the unit heater is to maintain
a solution temperature between cleaning cycles. The tremendous
energy released by cavitation will generate the heat for
cleaning.
13.
How do I know if the unit is cavitating
properly?
A.
Most poor cleaning usually results from improper control
of one or more process variable(s); such as choosing the
wrong detergent solution, insufficient heat, or not allowing
enough time for the particular soil to be removed. If
you suspect that your ultrasonic cleaner is not cavitating
properly, there are two simple tests you can perform:
the "glass slide" test and the "foil"
test.
14.
How do I perform the "glass slide"
test?
A.
Wet the frosted portion of a glass slide with tap water
and draw an "X" with a No. 2 pencil from corner
to corner of the frosted area. Making sure that the tank
is filled to the fill line, immerse the frosted end of
the slide into fresh cleaning solution. Turn on the ultrasonics.
The lead "X" will begin to be removed almost
immediately, and all lead should be removed within ten
seconds.
15.
How do I perform the "foil" test?
A.
Cut three small pieces of aluminum foil about 4" x
8" each. Fold each piece over a rod that you will use
to suspend the foil in the tank. A clothes hanger works
well. Your cleaner should be filled with an ultrasonic cleaning
solution, degassed, and brought up to normal operating temperature.
Suspend the first "square" in the center of the
tank and the other two a couple of inches from each end
of the tank. Make sure that the tank is filled to the fill
line, and turn on the ultrasonics for about ten minutes.
Remove the foil and inspect: All three pieces of aluminum
foil should be perforated and wrinkled to about the same
degree.
16.
Why must trays or beakers be used?
A.
Items being cleaned should never be placed directly on the
tank bottom. Transducers (which produce the ultrasound)
are bonded to the bottom of the tank. Items resting directly
on the tank bottom can damage the transducers and/or reduce
cavitation. Additionally, a tray or beaker will position
the item within the optimal cleaning zone of the tank. The
tray or beaker will also hold the load together and allow
for easy, no-touch removal, draining and transport of the
items to the next step in the cleaning process.
17.
What is the optimum cleaning temperature?
A.
Heat usually enhances and speeds up the cleaning process,
and most detergent solutions are designed to work best at
an elevated temperature. The best way to find the optimum
temperature, which will give you the fastest, cleanest and
safest results, is to run tests. Usually, the best results
are within the 50¡C to 65¡C range.
18.
Is rinsing required after cleaning cycles?
A.
Rinsing is recommended to remove any chemical residue, which
could be harmful to the part. Parts can be rinsed right
in your ultrasonic cleaner, using a clean water bath, or
in a separate tub containing tap, distilled or deionized
water.
19.
Why shouldn't I leave my cleaner on constantly?
A.
Low solution levels can seriously damage your cleaner. Running
your unit continuously runs the strong risk of lowered levels
as the solution evaporates, especially when heated. Getting
into the habit of shutting off the ultrasonics when not
in use, and monitoring the solution level when in use, will
yield many years of trouble free service from your ultrasonic
cleaner.
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