small-diameter tube fed down the
mandrel rod and terminated close to
the shank. An air line pushes the fluid
through the mandrel (see Figure 1). The
frequency of the pump, which determines how much fluid is delivered, is
controlled by a frequency generator and
an electric solenoid valve. Because the
system is modular, it is easy to add additional pumps for wiper die lubrication,
and the user can program these pumps
to cycle independently of the others, regardless of how many pumps are needed.
Unist’s expertise goes beyond designing and manufacturing the application
equipment. It also uses its application
knowledge to configure its systems to
meet the needs of the application.
“We like to look at all parameters of
the application before we quote the system,” said Michael Francisco of Unist.
“Not all applications are the same, and
since we are delivering such minute
amounts of fluid, it is crucial that we get
it where it needs to be.”
In some cases, the lubricant is applied
to three bender tools.
“When bending aluminum, it’s ap-
plied externally,” Winn said. “A mist
on the tube’s outside diameter prevents
galling on the wiper die. It’s also applied
through the mandrel, and for machines
that have a built-in cutoff system, the lu-
bricant is applied to the shear.”
According to Wiedemann, the micro-
lubrication concept makes a bigger dif-
ference as the bend protocol becomes
more complex. For a five-bend part, the
system applies the lubricant in five spe-
cific places rather than relying on the
mandrel rod to distribute lubricant along
the tube’s entire length, he said.
After the system is set up and dialed
in, the machine operator can use the
settings as a reference when taking on a
new bending job.
“They start with a general idea of how
much lubricant they need, then add or
subtract until they get it right,” Wiedemann said. This is an ideal situation because it means that the fabricator doesn’t
have to wait for a service technician to
visit the company and make adjustments
to the system when it takes on a new job.
Using Less Lubricant Now
and in the Future
Horn hasn’t abandoned the conventional process, but for many of its customers,
the low-quantity alternative is beneficial
for several reasons. It uses less, it wastes
far less, and it saves the time and effort
formerly spent in removing the lubricant
residue from tubes, machines, and floors.
Although using a small quantity and
a misting applicator is still a niche, this
process is progressing into the mainstream. It has been successful on tubes
up to 3 inches in diameter, but this isn’t
“Recently it has been used on 5- and
6-in. tube,” Wiedemann said. “We’re developing new formulations and finding
success on more difficult bends, such as
a 1D bend on 6-in. stainless steel,” he
said, referring to a bend radius equal to
the tube’s outside diameter.
“The key is the boundary between the
tube and the tooling,” he said. “The perception is that you need a thick, viscous
lubricant to prevent metal-to-metal contact. Viscosity is one element, but not the
only one. Chemistry is another. When
using a light oil, chemistry plays a bigger
role than viscosity.”
Mark Cooper is director of international
sales for Unist Inc., 4134 36th St. S.E.,
Grand Rapids, MI 49512, 800-253-5462,
Horn Machine Tools Inc., 40455
Brickyard Drive, Madera, CA 93636,
Metalloid Corp., 1160 White St., Sturgis,
MI 49091, 800-686-3201, www.
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