All of which wreaks havoc on your customer-service
rating. In many cases, room for improvement in productivity –
and perhaps the end of those unhappy customers and insurance adjusters
– lies in the paint department.
Most shops today have invested in top-notch refinishing systems,
the chemistry of which leaves little room for cutting corners.
Two-component primers and topcoats need a certain amount of time
to cure and that’s that. If you’ve invested in a downdraft booth
with convection curing you know that it takes as long to cure
one panel as it does a complete vehicle.
Infrared technology could be the answer to your curing prayers.
Generally, air drying is an overnight process. Curing in a convection
oven in a booth requires about 40-50 minutes. Short-wave infrared,
however, can take as little as 11 minutes, resulting in dramatic
time savings with no compromise on quality. Efficient and cost
effective, infrared can double your paint department output when
it’s used correctly.
Like Energy From the Sun
The sun is the most powerful source of infrared energy – which
heats air rather than objects. Like other visible light rays,
infrared is part of the electromagnetic spectrum and has a stronger
heating effect than other types of radiation.
To get an idea of how infrared curing might improve your shop’s
throughput, you should start by analyzing the number of panels
painted on an average vehicle in your shop. If one to four panels
is your average, there are compelling reasons to investigate portable
infrared units. If the number is five or higher, then you might
be a candidate for a drying arch or a separate drying chamber
attached to your booth with track mounted infrared heaters.
Portable Infrared Heaters:
Portable units are designed to handle spot repairs and full-panel
curing. They usually have two or three curing heads, which can
often be moved in relation to each other to achieve the optimum
distance between them and the panel – even if the panel has a
curved surface. Portable units are generally used outside the
spraybooth for primer and topcoats. Rather than compete with the
booth oven, they often compliment it when you’re only dealing
with one or two panels. Why crank up a 1-million BTU furnace to
cure a small job? If you instead use portable infrared heaters,
the potential energy savings can be enormous.
Curing Arches:
Infrared arches, or traveling ovens, are designed for use within
a spraybooth or drying oven. They are usually computer-controlled
units that can be programmed to heat the entire vehicle or individual
panels on a vehicle. Arches are most effective when a high percentage
of your work is made up of small repairs.
Track-mounted Systems:
Track-mounted systems can be installed in a chamber attached to
your booth or in your prep area for curing primers. They don’t
take up any precious floor space and the electrical service is
permanently attached to the track – eliminating the time it takes
to roll a unit through a busy shop only to find that the cord
won’t reach the outlet. Remember, your painters prime function
is to get vehicles painted and back to the body department. No
painter is being as productive as possible when he’s moving cars
to get a piece of equipment through the shop.
Safety Concerns
In any shop, safety is a major consideration. OSHA and the EPA
require that all spray painting be done in an enclosed and properly
ventilated area. Safety regulations also state that such an area
should be classified as hazardous due to the risk of fire and
explosion and that all electrical equipment should be suitable
for use in flammable areas. With such regulations, careful thought
must be given to the type of infrared curing applied.
It is clearly safe to paint a vehicle in the booth, let it dry
to dust-free, move it out into the shop and complete the curing
with infrared. This way, the spraying and curing operations are
kept safely apart. However, this may not be practical in your
shop. It may instead be more practical to install a track system
in your booth that fits into it’s own enclosure and is connected
to a safe purge and interlock system.
Typically, a safety control system is be comprised of an interlock
to shut off compressed-air supplies when the infrared system is
in use to prevent spraying; a switched isolator to prevent the
use of the infrared system when the booth is in spray or conventional
bake mode; a timer to insure that the booth has been fully ventilated
and purged of solvent vapors; and a parking area to prevent paint
overspray from settling on the lamps. There is also an interlock
to prevent spraying unless the curing system is in the parking
area.
Using Infrared Properly
Most shop owners and technicians are probably asking, "If
it saves that much time and money then what’s the hitch?"
When infrared curing equipment is used properly, there are really
no complications. It will, however, take some tinkering to get
the proper time and distance from the panel being cured.
Most of the short-wave infrared units use tungsten-filament quartz
lamps that reach a 4,000-degree surface temperature. Needless
to say, you can do some serious damage if you aren’t thinking.
Plastic parts, flexible parts, and lamp assemblies on vehicles
need to be protected. Most infrared equipment manufacturers recommend
that you single or double mask parts that you don’t want heated.
Infrared is a surface technology and the tape or paper will absorb
about 50 percent of the energy.
Short-wave units usually have a two-step switching system. The
unit starts out at a half-power setting to drive solvents out
and then switches to full power for the remainder of the cure.
This helps to eliminate solvent popping. You can cure flexible
parts by setting the unit to run at half power for the majority
of the time with a short burst of full power at the end of the
cure.
Your painters should continue to apply paint in the same manner
as always. In other words, they should follow the paint manufacturers
guidelines for flash times between coats and lay down the same
amount of material as they did before using infrared curing technology.
Because of the nature of the curing process it is important not
to allow the paint surface to seal over before starting the cure.
Note: If you are currently using accelerators in your paint
system, they’re not recommended with short-wave infrared systems.
The short-wave technology is designed to penetrate the paint and
cure from the bottom up. Accelerators are designed to make the
surface of the paint tack free. Solvent popping is the likely
result in this scenario.
The Cost of Infrared
If you currently use your downdraft spraybooth to cure everything
when your average paint job requires the refinishing of only a
few panels, your potential for savings is great. Infrared will
get the vehicles through the paint shop quicker and cheaper. An
average 10-minute infrared cure at today’s electrical rates costs
about 15 cents. Your spraybooth – with its fans and furnace running
– averages about $4 per hour. Curing those small jobs outside
of the booth will also allow you to paint more vehicles every
day.
Though you will most definitely see a cost savings once infrared
equipment has been integrated into your paint shop, quality infrared
drying equipment is not an inexpensive investment. Portable units
are in the $2,000 to $5,000 range. Track-mounted systems start
at about $12,000, but their pricing depends on the length of tracks
and the number of curing heads installed. Arch systems usually
start at about $40,000. Your distributor should be able to assist
you in doing a return on investment worksheet that will point
out potential savings for your particular business.
A Future Cure
The changes in paint systems continue to be fueled by environmental
concerns. High-solids and waterborne paints tend to dry slower
than some of the older technologies. No matter what paint technologies
are used, pressure from customers and insurance companies points
directly to the need for productivity enhancements.
If specific products or devices, such as infrared curing units,
can make your current facility and staff more productive, you
should consider how to make it work for you. Add to that the energy
and cost savings your shop will incur and, chances are, using
infrared will make your shop’s future brighter.
Writer Michael Regan is president of The J.J.R. Company in Cleveland,
Ohio.
