By William Helinski
Many press brake owners find themselves in a predicament about what to do with their old press brakes. They’re caught between
selling and moving the old machine and installing
a new one. Replacing it can cost hundreds of thousands of dollars and may be accompanied by some
serious logistical headaches.
A cost-effective approach is to increase the productivity of an existing, properly functioning press
brake by retrofitting it with features that can help
reduce setup time, scrap, and operator fatigue.
Knowing which types of retrofits are available
and which are most suitable for your machine may
help you decide whether it is worth investing in an
upgrade or replacement. Taking these five steps will
help you decide your next course of action.
1. Evaluate the Machine’s Hydraulic,
Mechanical, and Electrical Condition
The most important considerations are:
Ram Accuracy. Is the ram accurate, consistent,
and level on both sides? Depending on your current
bending methods, your press brake may be accurate enough for your applications. Are you coining,
bottom bending, or air bending? If your bending
method is producing accurate results, it may be
tough to justify replacing the press brake. You may
find that a cost-effective retrofit option will increase
your machine’s productivity at a lower price than
Pedestal Control. Does your pedestal control
or foot pedal function properly? Some press brake
OEMs might consider these components to be ob-
solete, or the programmable logic boards may be
nearly impossible to find. Researching the availabil-
ity of these components is a proactive way to assess
the risk versus reward aspect of investing in a press
brake retrofit. Many control retrofits require these
components to be functioning properly, while oth-
ers may be executed with replacement boards that
mimic the OEM’s logic boards.
Backgauge Control. Do you currently have a
faulty backgauge control on the press brake that
desperately needs replacement? One way to increase productivity of your press brake is to reuse
the existing mechanical structure of the backgauge,
while replacing the control that runs it (see Lead image). Many backgauge controls on older machines
are hitting their end-of-life phase.
Press Brake Control. Does all of the press brake
functionality come through the programmable control head? Is this control necessary for the press
brake to run, or can you run the machine manually
without the control? If the signals from the press
brake control are necessary for the brake to run,
retrofit options are more sophisticated and more expensive. However, if the machine can still run manually without an integrated control, a lot of basic retrofit interfaces typically can work for your machine.
2. Know What You’re Working With
Mechanical Press Brake. If your machine is a
mechanical-style press brake with a flywheel and
clutch, a stand-alone CNC backgauge system can be
added to the machine, but ram programmability will
not be an option (see Figure 1). Mechanical press
brakes are great for accuracy because the machine’s
tonnage comes from its rotation through the bottom
dead center (BDC). In essence, the machine can produce very high tonnage at the bottom of the stroke.
However, the downside is that there is no true
way to gain programmability of the ram. Therefore,
sequencing through multiple bend angles is not
possible, like it is on a traditional hydraulic press
brake. Mechanical press brakes are typically used in
Hydraulic Press Brake. A great example of a ret-rofittable hydraulic press brake is the traditional
rocker-style press brake that became popular in the
1980s and 1990s. These machines use mechanical
linkages to amplify the force and maintain high ac-curacies. Typically, they have a ram repeatability of
± 0.002 inch. Because they use transducers, hydraulics, and limit switches to regulate the ram force and
position, third-party retrofit companies usually can
interface their controls and offer a programmable
position and speed.
Other examples of hydraulic brakes are depth
stop style, pure twin cylinder hydraulics, torque
tube style, upstroking, and hydramechanical.
Proportional Valves/Synchro Style (Y1, Y2).
These hydraulic press brakes have excellent accuracy and repeatability. They are perfect for air bending with precision-ground tooling.
However, because of the “brains” required to
communicate with the proportional or servo valves,
these machines come standard with a sophisticated
control (typically high-end, PC-based). They con-
stantly regulate the hydraulics on each side of the
machine to maintain accuracy and a level ram.
The retrofit controls used to interface with the ma-
chines are usually PC-based also, and they come with
numerous features and functionality to help get the
most productivity out of the precision press brake.
Precision-ground tooling for air bending is most
commonly used. Retrofit controls for these machines usually offer a full tool library and perhaps
graphical simulation to assist the press brake operator. Retrofitting these controls often can be expensive because of the increased control functionality
and the need for a deeper integration with the press
One way to increase productivity of your press brake
is to reuse the existing mechanical structure of the
backgauge, while replacing the control that runs it.
Ascertaining the condition of your backgauge’s mechanical structure and drive mechanisms is important
in assessing whether you need a complete backgauge
system or just a backgauge control.
A stand-alone CNC backgauge system can be added to
almost any machine.
to modernizing your old press brake
A right-fit retrofit may save big