are suitable for less critical clean rooms and the costs vary
widely based on features and capacity.
For customers who require zero-emissions, there are
“vacuum degreasers” that look like front-loading clothes
washers. These use the same solvents but completely reclaim
the solvent during use. These would be very well-suited for
the most stringent cleanroom environments. These typically
cost $250k or more and have longer cleaning cycles.
For the highest-volume customers, there are in-line
vapor degreasers. Each configuration has its drawbacks and
advantages, but all of them out-perform aqueous cleaners.
Q. How are they configured?
Modern vapor degreasers are perfectly compatible with
most cleanroom environments. They are generally installed
in one of three places. The least expensive option is just
outside the cleanroom, with a positive-pressure air system
to move the cleaned parts immediately into the white room.
Another popular configuration is the through-the-wall
style, where the dirty parts are dropped into the machine
outside the cleanroom and clean parts are removed inside
the cleanroom. There also are systems that nicely fit inside
cleanrooms themselves. The tiny quantity of volatile chemistry that may be emitted from the cleaner does not affect
the performance of the cleanroom in any way.
Q. What is the most important consumable in these types
The big decision is the choice of cleaning solvent. There are
many good chemical choices today. Each one has good features and drawbacks, so I can’t say one particular formulation
is the best. But I can tell you this: the solvent selection is driven by the contamination. “Start with the dirt,” we like to say.
Find the cleaning fluid that works best with your contamination, and that will drive the rest of the process decision.
Q. What is the most common hardware mistake made
with vapor degreasing in a cleanroom?
The most painful mistake we see people making is they
buy cheap cleaning machines. You see, there are many good
makers of vapor degreasers. But there are an even larger
number of companies that make junk. Those companies
don’t understand the thermodynamics, materials compatibility or even the vapor cleaning process. So they cut corners on the design and never explain how those short-cuts
will degrade the cleaning process.
Q. What’s involved in maintaining these cleaning systems?
Unlike water-based cleaning systems, solvent-based clean-
ing systems have very simple maintenance requirements,
and are very easy to operate. The customer will need to
maintain a proper solvent level in the machine. Allow excess
moisture to drain from the machine via the drains that are
designed into the degreaser. Lastly, periodically clean the
sumps, clean the heater elements, and change the particu-
late filters. That’s about it for maintenance. There are many
vapor degreasers out there that operate for decades with
very minimal maintenance.
Q. Does vapor degreasing have an “Achilles heel”? What
should we watch out for?
Most customers initially are surprised by the cost of the
cleaning fluid. Water-based saponifiers and surfactants cost
hundreds of dollars per drum; vapor degreasing solvents
are thousands of dollars per drum. It’s a huge difference.
But, in use, the cost-equation swings the opposite way.
People buy far less solvent with a vapor degreaser, because
modern systems recycle the fluid and have very low solvent
losses. In contrast, most aqueous systems are a “use and
lose” design, with slower cycles and much higher energy
costs. So vapor degreasing is almost always the lowest cost,
Q. How can a company determine the cleaning system
that is best for its operation?
The trick is to compute, in the greatest possible detail, the
cost-per-part-cleaned. You need to collect all the cost of
your cleaning operation: the cost of the equipment, the cost
of installing the equipment, the consumables, the labor,
electricity, waste disposal, scrap, everything. Then you
divide those costs by the number of parts to be cleaned.
The system with the lowest cost-per-part-cleaned is
probably the best choice for that application. While the
data collection may be complex, the analysis itself is a fairly
Q. What you are planning for the future?
Three significant trends are at work across most industries:
the continued miniaturizing of components, the need to
protect people and the environment, and the need to minimize production costs while boosting quality. To adapt to
this new world, the only viable, low-risk option that meets all
the critical cleaning requirements is solvent cleaning.
There’s no doubt about it: vapor degreasing is the critical cleaning answer of the future.
Mike Jones is Vice President of MicroCare Corp. in New
Britain, Conn. www.microcare.com