Rick Cardinale, Bird
Bird Electronic, founded in 1942 by
J. Raymond Bird, soon became a leader in radio frequency
instrumentation. Today, Bird also has moved into digital
instrumentation test equipment.
development of digital instrumentation came the increased need for
controls to prevent ESD events. Improving ESD protection has been an
ongoing process since the late 1980s. In 1997, the company
determined that an automated PCB production line would be installed
and that the entire manufacturing area should be protected against
This decision led
to an evaluation of ESD protective flooring. In 1998, 20,000 square
feet of conductive floor tile were installed in the main production
area. To help brighten the area, white tile was selected. The floor
resistance measured less than 1.0 × 106 W.
high-gloss appearance was part of the selection criterion for the
floor. While the electrical properties were unchanging, by 1999, the
floor was starting to dull. It was being maintained like a regular
tile floor. No waxes or finishes were used; however, the tile
manufacturer did recommend using buffing pads.
with the tile manufacturer and the installer, maintenance was
increased to sweeping clean and damp mopping two times per week and
buffing once per month. Monthly floor maintenance was $1,700 per
month, a $20,400 annual expenditure.
In late 1999, the
maintenance schedule was modified to add more buffing since this was
the only way to keep the floor shiny. The floor now was swept and
damp mopped weekly and buffed twice per month. The floor was clean
and shiny, but the cost went up 41% to $2,400 per month, a $28,800
At this same time,
we wanted to evaluate and improve the ESD program. Kimco, our ESD
control supplier, recommended that Desco provide an ESD survey,
which it does at no charge.
During the survey,
floor resistance measurements were taken, and the floor was reliably
measuring less than 1.0 × 106 W. The survey led to a discussion of
our current goals with regard to the ESD tile floor:
- Preserve the
electrical properties of the floor.
- Improve the
visual characteristics to look clean, bright, and shiny.
- Reduce the floor
Desco suggested a
high-end dissipative floor finish, assuring us that a specific ESD
floor finish would improve the gloss, reduce costs, and not damage
the electrical properties of the floor. We were very skeptical,
especially since the tile manufacturer had always told us that
conductive tile should not be waxed.
Because of our
skepticism, we obtained a sample of the floor finish and tested it
on about 9 square feet. The test confirmed that the electrical
properties of the floor had not been compromised and that the area
protected with the dissipative floor finish maintained a shine much
better than unprotected areas.
It was now time for
a test on the entire floor. In early 2000, our floor maintenance
company put down the recommended initial three coats of the floor
finish over a weekend. The floor looked beautiful. But within two
weeks, it started to take on a yellow look.
We contacted Desco,
which responded immediately by sending a regional sales manager to
see the floor and a product manager to review the process with the
maintenance company. The cause: the mops. While dedicated mops were
used, they were brand new cotton mops and not properly rinsed prior
to being used, a common problem.
Also, the initial
application was too thick. The maintenance people thought if one
gallon per 2,000 square feet was good, one gallon per 1,200 square
feet would be better.
The floor was
stripped and the dissipative floor finish reapplied. This time, we
had shiny, mirror-finish floors. Three months later, we still had a
shiny floor that measured between 4 × 105 W in low traffic areas to
7 × 106 W in high traffic areas.
are well within the recommended minimum performance specifications
of the ESD Association’s ANSI/ESD S20.20 and Flooring Standard ESD
STM7.1 for floors and ESD STM97.1 governing floors used for the
primary grounding of mobile people. The resistance from the floor to
people using heel grounders is well under 35 MW. Additionally,
charge generation is well below 100 V in accordance with ESD
After one year of
using the high-end dissipative floor finish, all three of the
initial goals were met and exceeded:
- The electrical
properties were not compromised. Tribocharging on all personnel
also has been reduced to less than 100 V.
- The floors are
clean and shiny. Black scuffmarks are more easily removed, often
with damp mopping.
costs have been reduced, saving more than 40% or about $12,000 per
As a result, all
the hard floors now are covered with Statguard Static-Dissipative
Floor Finish, improving ESD control throughout the entire plant
including R&D and design.
Cardinale is the manufacturing/process engineer at Bird
Electronic and responsible for defining and implementing the
company’s ESD control program. He has spent the last 20 years in the
electronics industry in the fields of programmable controllers,
radiation measurement, data acquisition, and RF test/measurement.
Bird Electronic, 30303 Aurora, Solon, OH 44139, 440-519-2328,
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