The Volvo name has always been synonymous with high-quality performance
vehicles. But what some people don’t know is that the Volvo Group’s
product offerings extends well beyond its automotive industry roots
and now reaches into aerospace, commercial trucking and construction
equipment to name a few. For instance, the company’s Motor Grader
division, part of Volvo Construction Equipment, is one of the largest
and oldest (130 years) producers of motor graders worldwide. As
with its sister divisions, quality, safety and environmental care
are the three core values that form the foundation of the Construction
Equipment Group.
Making the Grade(r)
The task of ensuring quality and performance falls to the
700 employees at Volvo Motor Grader’s Ontario, Canada assembly plant.
Because the motor graders must be able to withstand the demands
of everyday use in a variety of climates, a quality finish is imperative.
In the facility’s paint shop, Volvo employs a multi-step finishing
process designed to meet the company’s quality standards while still
conforming to its strict environmental policies.
As parts enter the paint shop, they are washed and sent through
a dry-off oven. After being dried, they are subjected to a “wet-on-wet”
coating process in which the parts are first painted with a primer
coat. Before the primer dries, the topcoat is applied. As Volvo
uses a true paint-before-assembly process, masking plays a critical
role. A single part may contain dozens of machined areas or threaded
surfaces that need to be protected from the paint. After the topcoat
has been applied, the parts are sent through an IR oven, where temperatures
reach 200°F.
Uncovering the Issues
A strong environmental ethic is part of Volvo’s corporate
philosophy, so the ongoing disposal of thousands of single-use masks
conflicted with their values.
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Volvo Construction Equipment
has been manufacturing motor graders since 1875.
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“We were discarding literally barrels of plastic plugs per year,”
said Mike Gilbert, manufacturing services supervisor at Volvo Motor
Graders. “We knew that every one of those plastic plugs ended up
in a landfill. We didn’t like that, as it is contrary to our ISO
14001 Environmental ideals.”
Another concern revolved around Volvo’s use of heavy, 20-pound
steel masks to protect the machined hub surfaces of their large,
built-to-order motor graders. Cumbersome to fit and remove, each
steel mask had to be shipped off-site for “burning”—a process which
literally burned the built-up paint off the steel masks.
Using the Internet, Gilbert began exploring potential solutions
for his masking dilemma. He discovered Shercon, Inc, a California-based
custom molded rubber products manufacturer and made contact with
the company. A short time later, he replaced his disposable plastic
caps and plugs with Shercon’s off-the-shelf “high-temperature” molded
caps and plugs.
“The caps are holding up great” said Gilbert. “Our IR oven heats
our just-painted parts to more than 200°F, and we needed long-lasting,
easy-to-install masks that would excel in that kind of application.
The new parts are doing just that.”
“The longevity is at least 40:1 compared to plastic plugs,” said
Gilbert. “And while we’re happy with the environmental results,
we also see reusable plugs as providing an overall cost savings.”
A New Challenge
After replacing their one-use caps and plugs with Shercon
caps and plugs, Gilbert inquired about possible alternatives to
the 20-pound steel masks used to protect the six hub surfaces on
every motor grader from paint.
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Shercon’s custom mask
installs quickly, protecting the sizable hub surface area from
their finishing process while meeting Volvo's environmental
standards.
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“Each steel mask had to be shipped over 60 miles to get the paint
buildup burned off,” explains Gilbert, who also pointed out that
the heavy steel masks were difficult to remove off the just-painted
assemblies.
Because the heavy steel masks had to be shipped out for cleaning,
Gilbert needed to maintain multiple sets of masks to be sure he
always had enough for the motor graders that moved down the assembly
line each day.
In addition, the high temperatures involved in the paint removal
process sometimes caused the steel masks to warp, which limited
their life and forced an added inspection step to ensure the warped
masks were not used.
Gilbert explored a variety of replacement masking products, but
many of them were unable to withstand Volvo’s demanding wash/prime/paint/bake
finishing cycle or were simply too time consuming to install.
Meeting Every Need
Designing a custom replacement for Volvo’s steel masks fell
to Ruben Dominguez, a production engineer at Shercon. “Designing
a mask to protect a large hub surface and the 10 threaded holes
surrounding it wasn’t simple—the outside diameter of the mask ended
up at 13.5 inches, which is a big mask.”
Shercon produced prototypes from Gilbert’s mechanical drawings
and shipped them to Gilbert for testing. After these prototypes
were tested on Volvo’s assembly line, Gilbert requested a few changes,
hoping to improve clearances around some of the plugs and easing
worker access for insertion and removal. The masks went into production
a week after Shercon received feedback from Gilbert. Later, one
more minor modification was made to improve mask fit.
The resulting mask was complex, yet effective—the result of some
deft engineering touches by Dominguez. For instance, Dominguez wanted
to reduce the amount of material used in mask fabrication (to reduce
mask costs) while keeping mask strength at a maximum (for the sake
of longevity). As a result, he engineered the masks using extensive
ribs and gussets.
“This helped reduce cost, yet maintained mask performance and longevity,”
said Dominguez. His sentiments were echoed by Gilbert, who anticipates
getting years out of the masks.
“Because we wanted to completely seal a large opening from the
wash/prime/paint process, I also designed the mask with a bit of
undercut, which promoted a much stronger seal across the large open
area,” says Dominguez, who incorporated plugs for the 10 threaded
holes surrounding the hub right into the mask, so workers installed
one mask instead of eleven.
Shercon’s custom solutions have performed beyond Gilbert’s expectations,
whose line workers have fully embraced the benefits of the considerably
lighter and more flexible masks.
The new masks don’t require Volvo to ship the used masks to an
outside paint removal vendor. In fact, according to Gilbert, workers
can easily remove paint buildup from the masks. Volvo’s non-toxic
paint simply comes off the flexible mask and can be disposed of
in the everyday garbage. The masks are simply dropped in a box until
they are needed again.
While costs savings weren’t the primary goal of Volvo’s mask upgrade
program, Gilbert figures his costs will ultimately prove to be lower,
with full payback in about two years.
