Canadian Finishing & Coatings Manufacturing Magazine May/June 2022 - 24

INDUSTRIAL FINISHING: OVENS
or dry and release the initial solvents. Flash-off time helps prevent bubbling or
blistering caused by insufficient evaporation time. It also helps reduce rework
by providing proper evaporation before a part enters a curing oven or a second
coating process.
Col-Met specializes in batch ovens. These, the company says, maximize use of
shop space, yet still accommodate a variety of production runs.
" Designed for versatility and variability, batch ovens are well suited for
production applications that vary in shape, size and volume, " the company
states. " Angle iron frames are used in all models, along with 16-gauge aluminized
steel with four-inch insulated panels. "
A slotted channel design reduces heat transfer, and explosion relief doors
with FM-approved latches are featured. The heater box is factory assembled
and tested, and units offer a maximum temperature of 500 degrees F. Factory
shop assembled ovens are available up to 8 x 8 x 20 feet long. " Custom oven
designs can be provided to meet any requirements, " Col-Met adds. " A stack is
not included but can be purchased as an option. "
There is a Smart Touch PLC Control Panel with a six-inch touchscreen,
useful for batch modes and troubleshooting capabilities.
A specialty system from Nordson is the ISC Bottom Cure System. This works
with either solvent-borne or waterborne coatings to cure protective coatings
applied to can bottoms.
The unit heats rapidly at 40 degrees C per
second, curing coatings at high line speeds in a
minimum amount of space. Production speeds
can be up to 900 cpm with a multiple coil tray.
There is simple air cooling for the coils, and
the unit's compact size means it can be used
with existing conveyors. The company states it
uses 80 percent less energy than a gas oven of
comparable capacity.
Heraeus Noblelight offers both electric and
gas catalytic infrared technology platforms for
coating and finishing.
" Production bottlenecks often occur as a
result of tougher production demands, where
the existing drying system can no longer keep
pace, " the company points out. " This can often
be solved by an infrared booster section, which
is positioned in front of the existing drying
system.
An IR booster section rapidly brings the
product up to temperature allowing line speeds
to be increased accordingly. For some products,
this can reportedly result in savings of up to 50
percent of the time required to dry or cure the
coating.
" The use of IR booster ovens is flexible, "
the company adds. " They can be placed before,
or between existing ovens. They save time by
faster heating, and save space through shorter
drying distances.They also save energy through
fast reaction times. "
A Heraeus Noblelight specialty is its Gas
Catalytic IR Pre Gel oven. This sits just in
front of a conventional convection oven, and is
designed to allow newly applied powder to gel
and start the flowing process of the powder as
it starts its chemical change under heat. It is not
designed to completely cure the powder, as this
process is completed in the convection oven.
Pre Gel ovens can be used when products
have thick cross-sections, adding an extra boost
before the convection oven. Further, if there is
a need to increase line speed but the current
convection oven is not long enough, a Pre Gel
oven will ensure increased line speed whilst
utilizing the same overall length of oven.
The creativity that has gone into improving
energy efficiency in ovens and curing systems is
one of the more encouraging stories to emerge
from the paint and powder coatings sector
in recent years. Any oven will still require
significant energy to work properly, but the
faster reaction times and greater efficiency of
today's systems can help any substantial paint
operation to remain profitable.
24
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Canadian Finishing & Coatings Manufacturing Magazine May/June 2022

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