Tech Briefs Magazine - August 2024 - MD-16

How a Shear Manufacturer Improved Accuracy
While Reducing Costs
W
ysong USA has been manufacturing
industrial press brakes, hydraulic
shears, and mechanical shears
for sheet metal and plastics for nearly
120 years. Like many companies, their
motto was " if it ain't broke, don't fix it, "
so their product had remained essentially
the same. But during a customer
visit that motto clashed with another
company saying, " the customer is always
right. " This customer had replaced the
dry clutch brake for an oil shear clutch
brake that was more accurate. " The customer
is always right " won, so Wysong
updated their product line and increased
accuracy while reducing costs,
making it a win all around.
Wysong Shears cut sheet metal and
sheet plastic for companies making large
automotive components, tractor hoods,
lawnmower hoods, and more. Often the
presses run 24/7, so accuracy, repeatability,
and durability are essential. As
the business has shifted more toward
cutting plastic sheets, customers have
been seeking increased accuracy.
During a routine customer visit with
Plastics, Wysong
Primex
Production
Engineer Linton Summers noticed that
the Wichita clutch brake originally installed
had been replaced with a Force
Control clutch brake. Summers was impressed
with the increased accuracy and
repeatability as he watched the machine
shear section after section of sheet plastic.
Originally the shear was designed to
run even if the mechanism is slightly out
of position. " When you told it to go, if it
skipped a tooth, it would still go, " said
Summers. This breakdown created a
scrap part and wasted material - both
undesirable outcomes.
Wysong formerly used a Wichita Clutch
brake in their shears. Designed to run at
60 strokes a minute, the shears included a
flywheel to overcome the inertia and an
encoder on the chain drive cam switch.
Depending on the speed, the flywheels
were quite large, up to 40-inches tall.
Because there is inherent fluctuation with
a chain drive, the accuracy was not optimal.
The encoder certainly helped, but
slight inaccuracies over time meant manual
adjustments were required, either by
an operator or by maintenance personnel.
The old-style designs also needed $4700
worth of parts for annual maintenance,
plus three hours to change them out.
Once re-assembled, the shear had to be
manually finessed to ensure it was running
properly before production could resume.
The new Force Control clutch brakes
do not require flywheels, and one Force
Control Posidyne® model 3 clutch brake
replaces a pair of Wichita's, so the cost
savings add up quickly. The old-style design
required a D style motor with high
slip to allow the motor to accelerate the
flywheel up to speed. Eliminating the
flywheel allowed the use of a more common
(and less expensive) B style motor.
When equipped with Force Control
clutch brakes, the shears achieve greater
accuracy and repeatability and are far
more cost-effective to manufacture and
maintain. " The repeatability standpoint
is a night and day difference. On the
Wichita, you've got the brake and then
you've got the clutch that's on a flywheel.
It's all one set of air, " said
Summers, " so there is only so much adjustment
available.
With
the
Force
Control,
we have the manifold with the
air adjustment for the brake and the
clutch. You can run more air on the
brake and less on the clutch, because its
separate. And the Model LC corrects itself
automatically. "
The new Force Control clutch brakes do not require flywheels, and one Force Control Posidyne® model 3
clutch brake replaces a pair of Wichita's, so the cost savings add up quickly. (Image: Force Control Industries)
16
The Force Control Model LC is a form
of closed loop positioning control. It reads
the machine position on each stop and
adjusts, in real time, where to signal the
stop for the next part/cycle. This compensates
for any frictional wear, or thermal
changes that occur over time, and significantly
improves accuracy. Adding the
Model LC eliminated the cam switch and
chain drive from the old design, simplifying
assembly while improving accuracy.
Motion Design, August 2024

Tech Briefs Magazine - August 2024

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