MPW Industrial Services experts discuss labor-intensive dry

ROFIN-BAASEL’S
MPS Laser Workstation
SCHUNK’S
PGN-Plus Permanent Gripper
JENOPTIK’S
Opticline Shaft Measurement
November/December 2015 • TodaysMotorVehicles.com
MPW Industrial Services
experts discuss labor-intensive
dry-scrub paint removal systems
and wet-scrub options that require
less manpower but generate more waste.
BMW spent $1 billion upgrading
its Spartanburg, South Carolina, plant
last year. Part of that investment was
for an Eisenmann SE dry-scrub system for
removing overspray from its paint booths.
MPW Industrial Services experts discuss labor-intensive
dry-scrub paint removal systems and wet-scrub options
that require less manpower but generate more waste.
BY GREG ARMSTRONG AND SHANE DEFAZIO
coatings
D
ealing with paint overspray and waste removal
can be a costly, time-consuming effort, something
that most automotive original equipment manufacturers (OEMs) and their top tier suppliers turn
over to facility managers such as MPW Industrial
Services.
The wet-scrub, water-based technique for
paint booth cleaning systems has long been the
standard, but MPW engineers have seen an
increasing number of companies turn to dryscrub systems that have been embraced mostly by
European manufacturers. More U.S. manufacturers are beginning to test the waters in dry-scrub
systems as well.
By our estimation, OEMs still favor wet scrub
systems 90% to 10% or more. It’s 75% to 25%
in plants we manage. Based upon observations
from these plants, however, we predict it will shift
closer to 60% to 40% in the next 10 years.
Because we’re on the floors and in the shops
for manufacturers such as Volkswagen, BMW,
Ford, and Honda, we’ve adapted to managing
and maintaining both platforms, so the following comparison might be helpful for automakers
considering whether to stand pat or shift to a
different system.
Traditional wet-scrub systems
It’s important to recognize that paint shop management is not a core component of the automotive manufacturing process. However, it’s essential
in the finished product, and the work is highly
specialized.
Automotive spray booths often use wet-scrub
systems that feature a chemically treated water
curtain to capture contaminants from paint
overspray. In this process, air is drawn through a
continuous curtain of moving water and suspended paint particles are scrubbed out and flushed
into a collection pan.
The paint shop management for a wet-scrub
system might include water blasting, cleaning
supply pipes, filters and exhaust systems, and
ensuring waste sludge travels into the pit through
the sluiceway, which is an artificial water channel
for carrying off overflow.
Chemical, sludge, and other waste must also
MPW INDUSTRIAL
SERVICES
MPW Industrial Services has been assisting in
paint shop management, maintenance, cleaning,
and overall quality control since 1979, when
it began working in Honda’s Marysville, Ohio,
motorcycle plant. With $40 million in annual
revenue, the company works with 14 automakers in 15 original equipment manufacturer (OEM)
plants across North America to set up, manage,
and maintain automotive paint booths and the
systems on assembly lines that carry vehicle
shells through the painting process.
be disposed of at a frequent and often expensive
rate within the traditional wet-scrub process.
Vacuum trucks suck up all the overspray, paint
waste, water, and sludge into a vacuum box.
Discarded substances are dewatered so the manufacturer is not paying for water waste, reducing
sludge disposal costs.
The OEM typically has a company that takes
care of the rest of the waste. Otherwise, MPW
handles everything from when fresh air comes
into the paint shop space to when it leaves the
exhaust system.
Newer technology dry-scrub systems
In contrast, dry-scrub systems recirculate spray
booth air by directing it into scrubber chambers
where a plastic filter protected by a pre-coat of
calcium carbonate captures the wet paint particles.
The resulting dry waste material, similar to
limestone or marble, is collected and removed,
and often recycled into cement.
Newer technology dry-scrub systems can be
more efficient, environmentally friendly, and cost
effective compared to
water blasting wet-scrub sludge into a pit.
However, dry-scrub systems are more labor
intensive. The two paint shop envi­ronments are
similar, but the difference rests with the manpower necessary to
coatings
HONDA TURNS
TO DRY SCRUBBING
Honda of America Manufacturing Inc. will invest $210 million throughout the
next two years to overhaul the paint shop at its Marysville, Ohio, Auto Plant (MAP).
That upgrade will include the largest dry-scrub overspray removal system in North
America. Honda estimates that the new system will:
• Eliminate more than 255 tons of sludge per year
• Reduce CO2 emissions by 18%, 12,000 metric tons
• Cut water use by 2 million gallons per year
“Honda is committed to delivering products that have outstanding quality and
low environmental impact,” says Tom Shoupe, executive vice president and COO
of Honda of America Mfg. “Our Ohio operations are once again raising the bar for
quality and environmentally responsible manufacturing operations.”
Other Honda paint shop improvements include:
Short process and new primer coat – A 4-coat, 2-bake process replaces
a 4-coat, 3-bake method, eliminating one primer-coat curing oven. The primer
coat and waterborne base coat will reduce volatile organic compounds (VOC)
emissions nearly 66%.
Two-step curing – A more-automated, two-step temperature curing process
supports paint finish appearance improvements.
Increased capacity – Replacing a paint line built in 1985, the facility will be
able to coat 229,000 vehicles per year.
set up and maintain a contaminant-free
environment for dry-scrub systems.
Manpower differences
In a traditional wet-scrub system, one
person can apply a protective grease
coating on surfaces before water blasting
the overspray, paint sludge, and waste
below grates where the vehicles are
painted. It’s simply a process of grease,
rinse, and repeat.
With a newer dry scrub system,
everything under the grates needs to be
coated, covered, or protected by plastic
to collect the limestone dust residue.
Multiple workers also need to hang
plastic on walls and water pipes, and
more safety issues arise when they need
to move hundreds of heavy 2ft x 3ft
grates that line the pit beneath the car
being painted.
Because it doesn’t produce the
volume of cars the other manufacturing
plants must construct, one luxury brand
uses a unique dry paint booth that
collects the overspray in filters that are
simply replaced when they get full.
A common link
Both wet- and dry-scrub systems rely on
optimally functioning regenerative thermal oxidizer (RTO) systems, which take
exhaust out of facilities. Automotive
paint fumes release high levels of volatile
organic compounds (VOCs) into the
atmosphere. Without an RTO system,
certain automakers can’t paint. An effective paint shop management team cleans
RTOs to extend their lives and ensure
continued high-level performance. An
underperforming RTO system might
result in a manufacturer’s inability to
produce its expected quota of cars during a given timeframe.
Because of air quality standards
outlined in the plant’s permits, RTOs
operating below safety standards could
result in hundreds of thousands of dollars in fines.
Decision-making process
Dry-scrub systems require 25% more
manpower to prep the booth. However,
we also estimate that the 25% increase
in manpower is more than offset by reductions in chemical and waste disposal
costs.
We’ve already seen several domestic
and import automakers making the
switch to dry-scrub systems. Although
the dry-scrub paint booth setup is similar to the wet-scrub paint booth setup,
the coffers underneath the grates collect
the limestone dust waste, removing the
need to transport and dispose of potentially toxic sludge collected in wet-scrub
systems.
Despite the environmental benefits
associated with reduced waste, OEMs
have been reluctant to make the switch
from wet-scrub systems to dry-scrub
systems. The technology is still new,
relatively unproven, and manufacturers previously had issues with disposing
of the limestone that wasn’t recycled,
because some landfills were unsure that
this type of waste was non-hazardous.
Those concerns have since been alleviated, with the bulk of the limestone now
sent to a location in Alabama.
At MPW, we are happy to offer
opinions, but the say on which system
to use is up to the OEM’s environmental
teams.
MPW Industrial Services
www.mpwservices.com
About the authors: Greg Armstrong is business
development and regional operations manager
for facility management support services at
MPW Industrial Services, and can be reached at
[email protected]. Shane DeFazio
is director of operations for facility management support services at MPW Industrial
Services, and can be reached at sdefazio@
mpwservices.com.
Reprinted with permission by Today's Motor Vehicles Magazine, November/December 2015