At first glance, Maysteel's manufacturing facility in Menomonee
Falls, Wisconsin, looks like a typical stamping and metal
fabrication operation. But a closer look at its manufacturing
process, and its finishing line in particular, reveals an operation
that is anything but typical.
Maysteel's Precision Enclosures Group manufactures furniture, and
electrical and telecommunications enclosures for a blue-chip roster
of clients—including IBM, Cisco, Allen Bradley, Rowe and Haworth.
The parts that Maysteel manufactures range from small fan plate
enclosures to large computer server cabinets and even larger vending
machine bodies.
Competition can get pretty intense for outsource manufacturing,
so Maysteel works hard to keep its big-name customers satisfied by
keeping its costs inline and its quality high. Consistent quality
gives the company an edge, but the ability to turn on a dime for its
customers really sets Maysteel apart.
"Through our prototype center, we have the ability to quickly
design and develop new products so we can respond right away to our
customers' production needs," said George Bush, manufacturing
engineer, Paint/Assembly. "Our biggest strength is our ability to
meet the ever-changing needs of our customers."
Until last year, Maysteel relied on a labor-intensive liquid
coating operation for its finishing line. However, the manufacturer
wanted to improve product quality while increasing production
capacity. With more than 60 standard colors used on its finishing
line, that also meant Maysteel needed efficient, quick-color change
capabilities.
"We absolutely had to have quick color change because of the
diversity of products we coat and our lean manufacturing production
schedules," said Mr. Bush. Seeking a powder-coating solution to this
requirement, Maysteel set two ambitious goals—spray-to-waste color
changes in six minutes and reclaim-to-reclaim in 15 minutes.
Maysteel selected the ColorMax® system from Nordson,
which appeared to offer the fast, easy color changes. To prove it,
Maysteel spent a week at the Nordson customer testing lab, running
and re-running dozens of its parts.
The
New Finishing Line
Convinced the booth would work,
Maysteel wasted no time in making the switch to powder. The company
built a new environmental room and installed the powder spray system
for automated coating, and two Nordson® Versa-Coat® walk-in booths
for pre- and post-reinforcement. In less than 24 hours, Maysteel's
coating operation went from wet to total powder and was back to full
production levels in only three days.
|
Maysteel's Precision Enclosures Group
manufactures furniture, and electrical and telecommunications
enclosures for clients such as IBM, Cisco, Allen Bradley, Rowe
and Haworth. |
Maysteel coats a variety of substrates for its customers, such as
cold-rolled and electrogalvanized steel, G-30 material and aluminum.
To properly treat such a range of materials, products enter the
powder coating operation by way of an eight-stage pretreatment
process built by ITS. Parts then move into a 325F dry-off oven
before moving into the environmentally controlled coating room.
Because of the complex configurations of a number of products
coated, Maysteel typically uses a combination of the three spray
booths during the coating process. Parts enter a walk-in spray
booth, where one operator manually applies powder to the Faraday
cage areas where automatic guns cannot reach. A part identification
system then identifies the parts and selects parameters for gun
triggering and gun positioning before moving into the spray booth.
There, 16 automatic Nordson® Sure Coat® spray guns apply powder
anywhere from two to five mils, depending on customer
specifications. The system has two 16-gun feed centers with the
capability to feed from a 50-lb box or 75-lb fluidized hopper.
Parts are then conveyed to another walk-in booth where two
operators manually apply powder for post-touch up of inside corners
of boxes, if needed. Maysteel also uses the pre- and
post-reinforcement manual booths to coat smaller one- or two-piece
color runs.
According to Mr. Bush, the three-booth system is ideal for
Maysteel's lean production schedules. "Altogether, the system gives
us the most flexibility to meet each customer's unique needs."
Powder coating materials are supplied by Sherwin-Williams, IVC
Industrial Coatings, HB Fuller, Morton, DuPont and Interpon.
Following the coating process, parts move to a curing oven for 25
minutes, typically baking at 365F before being conveyed to an
assembly area. The finishing line runs at a constant 14 fpm, with a
complete trip from the hanging area to assembly area lasting two
hours.
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Parts pass through the
ColorMaxTM System, where powder is applied,
anywhere from two to five mils, depending on customer
specifications. |
The
Multicolored Pluses of Powder
"We've increased line
densities, even doubling them in some cases, through automation and
quick, cost-effective color changes," said Mr. Bush.
For example, where Maysteel previously hung six 12-inch cabinet
drawer fronts on the finishing line, nine are now being hung. Where
one cabinet hung before on a four-foot center, now two are hung.
Parts are hung and coated in sets, so when they come off the line,
they are kitted and can go right into build cells in assembly. With
this increased production capacity, manual intervention has
decreased significantly.
A number of quick color-change features of the system means
Maysteel easily met its immediate goal to use more colors more
efficiently, and coat more products more quickly. That's been
critical to meet lean manufacturing production schedules with
maximum operating efficiencies. It's also meant daily production
schedules can be met even with an average of 20 to 25 or more color
changes in an eight-hour shift.
Dramatic improvements in efficiency on the finishing line haven't
been the only benefits of switching to powder. Powder coatings are
proving to be more durable, which hasn't gone unnoticed by
customers.
"We've always focused on quality, but our customers have been
impressed with the consistent mil coating and coverage, and overall
quality we're providing with powder. With some products, we're
seeing five times more corrosion resistance," said Mr. Bush.
The move from liquid to powder has also taken Maysteel out of the
hazardous waste handling business, which has meant decreased
disposal costs, saving an estimated $5,000 per month. It's also
meant less paperwork for environmental reporting and less labor
needed for related data gathering.
Quick-Color Change: What Makes it so
Fast? |
The Nordson ColorMax powder spray system is designed for
color changes that take between 15-25 minutes. Here are a few
of the features of the ColorMax system that allow it to
operate so efficiently.
• The ColorMax system canopy, constructed of double skin
PVC panels, resists powder attraction and therefore minimizes
the amount of powder that would otherwise attract to the
canopy walls. The spray booth also utilizes an air
distribution system called AeroDeck which plays a key role in
decreasing color-change time by directing powder toward the
cyclone through the uses of high air velocities and periodic
pulse cleaning. Doors on manual openings and exit openings to
the booth ensure higher air velocities during the color change
sequence. Combined with high air face velocities (over 0.7
m/sec), this ensures improved powder containment in the air
stream, minimizing build-up on both the booth floor and the
booth walls. Less powder to clean translates into faster color
change times.
• Time spent cleaning the feed center and changing colors
typically accounts for the majority of the overall color
change time. The ColorMax system minimizes the amount of time
spent on this stage via the use of a cyclone recovery system
and a powder transfer system. The powder transfer system
removes powder from the cyclones and returns it to the feed
system., The high cleaning efficiency of the automatic
transfer system in combination with the easy accessibility of
the cyclone, transfer system, and feed center again makes for
less powder to clean and therefore quicker color change
times.
• The manual guns in the two additional manual booths are
supplied with powder from three vibratory box feeders. When it
comes time for the operator to switch colors, he simply
disconnects the hose from his gun, blows it out, connects the
hose for the new color, and flips a pneumatic switch to the
new box feeder without ever having to exit the booth. The
entire process takes less than 30
seconds. |
Quality Control is Key
With its
high-profile consumer customers, quality control throughout its
operation gets close attention at Maysteel. Quality in its finishing
area begins with a finely tuned operation, with every detail for
each product outlined on extensive process control sheets. The
sheets cover everything from hanging to pretreating and coating to
assembly. Such meticulous detail ensures consistent, repeatable
quality across the finishing line.
The sheets tell hangers exactly how to hang parts, how many of
each part to hang, and which parts to group together for easy
assembly at the end of the line. The sheets also tell hangers what
breaks to leave on the line to allow for color changes. During the
coating process, system operators refer to the sheets for each booth
to know what gun settings and modes to use and what areas of the
part to coat in the manual booths.
Quality control also extends to an extensive preventive
maintenance schedule. Two employees spend an entire shift each night
going through a two-page list that covers such areas as cleaning the
powder spray booths, ultrasonically cleaning gun tips and rotating
all venturi pumps. More in-depth maintenance is performed on a
bi-weekly and monthly basis, all of which means the finishing line
can run at peak performance every day.
Growing the Business Now, Later
The
move to powder coating has been everything Maysteel's Precision
Enclosures Group wanted—and more. Efficient, quick color changes.
Greater production capacity. Better quality. It's also helping bring
in more work from existing customers. And, Maysteel has created
extra capacity needed to continue growing its business.
"Our powder coating operation gives us the flexibility we need to
meet the production requirements of our customers—whether that means
they need one filing cabinet in 15 different colors or 1,000 in one
color," said Mr. Bush. "Looking at all the benefits, we now have a
substantial and sustainable competitive
advantage."