Application Note

2 Fluke Corporation Fluke 568 Infrared Thermometer keeps industrial processes on a roll
The go-to guy
His official title at Helios Coat-
ings, Inc. is Manager of Facility
and Process Engineering. Infor-
mally, Dave Summers of Canton,
Ohio is known as “the go-to
guy.” He’s been involved with
technology since he built an FM
radio while in third grade. He
installed a digital dashboard in
his 1951 Mercury back in 1980.
At Helios, his challenge is to
maintain precise control over
the proprietary process his com-
pany uses to finish car wheels
and hubcaps. The core of the
company’s business is refinish-
ing wheels, but auto makers are
eyeing the process for OEM work
because of its low environmental
impact and durability.
“We use green technology to
do chrome-like finishes on alu-
minum rims,” said Summers. said.
A veteran of the powder coating
industry, Summers knows how
important temperature control
can be when baking finishes
onto temperature-sensitive parts
like plastic hubcaps. Parts have
to be cleaned, primed, finish
coated using a vacuum metal
deposition process, and finally
clear coated for protection.
“During the process we use
an infrared heater to cure the
coatings,” he said. “Temperature
is critical as some of the center
caps that are coated will warp
easily. Attempts with a stationary
sensor have failed miserably.” A
try at curing one set of high-end
rims failed when the plastic caps
curled up.
“In our lab environment, the
Fluke 568 absolutely kicks ass,”
Summers said. “I really enjoyed
having the opportunity to play
with it and that’s what I call it—
playing with it—because I abso-
lutely had a blast with it.”
The rims and caps go through
an infrared curing process, then
through a high-tech ultraviolet
system.
“The whole idea is not to heat
your aluminum above 200 °C
(400 °F)—you’ll lose the temper
in the wheel,” Summers said.
“There’s an art to doing it with-
out destroying the aluminum
itself, so we’re real careful about
temperatures. We don’t just
throw them in a baking oven. It’s
all in timing, distance and inten-
sity of the radiation.”
The angle of the rise of the curve is the important part of the process. The smaller the angle of rise,
the less chance of any bubbles forming in the finish. If this condition happens, the underlying area
will do what is known in this industry as “out-gassing.” “When we are using the IR heater we want
a slow rise in surface temperature, “says Summers,” so the coating does not surface cure before the
underlying areas have a chance to cure. In the case of this test rim, we were looking at getting the
surface of the rim to 200 °F (93 °C) from ambient temperature to prepare the rim for a UV bake. The
UV heaters have a fan cooling system which could disturb the coating surface, so a prebake with the
IR is necessary to gel the coating on the rim.”
Monitoring that precise heat-
ing process was one place where
the Fluke 568 paid off for Sum-
mers. The lab’s experimental
infrared curing setup includes
a built-in thermometer, but
Summers discovered that hand-
holding the Fluke 568 at approx-
imately 18 in (45 cm) from the
slowly-rotating parts delivered
far more accurate readings.