By Sue Roberts
Akilowatt-hour here, a loonie there ... manufac- turers are constantly looking for ways to drive
down the amount due on monthly energy bills. And
since the equipment on the shop floor is responsible
for the bulk of the power consumption, OEMs are
continually tasked with developing equipment that
produces with lower energy costs.
Press brake manufacturers responded with electric brakes. Hydraulics are replaced with electric
motors that drive the ram; acceleration is increased;
accuracy and repeatability are excellent; and the
energy is consumed only when the brakes are
actually making money. One consideration is that
the tonnage and bed size available from most electric brake manufacturers are limited.
Two technologies bridge the gap between electronic brakes and the high-tonnage hydraulics. One
is hybrid machines with servo-driven or electric-assisted hydraulics. In one hybrid configuration, each
cylinder has a small reservoir of oil and a pump/
motor combination that actuates the fluid during
the bending cycle and turns off when not in use.
They can offer more bending power across longer
beds with a similar energy consumption to the
The other is a technology based on a belt and
pulley system. A series of belts and pulleys located
across the length of the bed work in conjunction
with servomotors to activate the beam. Again,
power is used only while the foot is on the pedal.
How do you choose? Brake manufacturers recommend that you consider your applications, available
floor space, and typical part size.
Make Small, Precise Parts
Bill Bossard, president of Salvagnini America, said,
“Electronic brakes operating from a reverse point
ball screw are extremely accurate and fast. They
are compact, tend to be 4- or 6-ft. machines, and are
very efficient for small, precise parts.
“They save energy with small motors that draw a
lower amperage than the hybrids. The hybrids typically draw a little more power because they have
larger motors to produce the higher tonnage output
to bend larger, thicker, longer, heavier parts.
“The way the hybrids are designed today, the
power is either on or off and they don’t need a
continuous draw like the hydraulics. The actuators
are much more independent, accurate, and self-contained than the ones used a short while ago.
“Compare the energy usage of either technology
to a light switch. Flip the switch and the machine
draws the electric power it needs to move. Flip the
The not-so-hidden efficiencies of
electronic brakes and hybrids
TruBend 5000 EP,
can offer high
tool setup to a
Applications, available floor space, and typical part size should be
considered when choosing between an electric and a hybrid brake.
Photo courtesy of Salvagnini.