JEC COMPOSITES MAGAZINE - Issue #99 - September 2015 - 54

manufacturing

controller, which regulates the output
of the torque device, which may be a
brake, clutch or drive, to maintain the
desired tension level. If any changes
in tension are detected, the controller
can instantly alter the torque device to
maintain the set tension.
This ensures that throughout the entire
process, tension is consistent, uniform
and precise. And all of this happens
automatically. We like to use the term
"set it and forget it" to describe how
a high-quality tension control system
should operate.
A type of closed-loop control system
that most people are familiar with is
the cruise control system of a vehicle.
In your vehicle, you set your speed,
like you would set your tension, and
then as the vehicle gets feedback on the
constantly changing elevations of the
road, it controls the speed to maintain
what was set, just as a tension controller
would regulate torque to maintain the
set tension.
In both closed-loop and open-loop systems, tension is managed by the torque
applied to the centre of the roll from a
brake, clutch, or drive. Tension controllers automatically regulate this torque,
making any necessary corrections or
adjustments throughout the process and
allowing for continuous production.
Operators simply input the parameters
of the production run (such as speed,
tension, etc.), press start/run and allow
the controller to automatically manage
production.
As mentioned, one of the key elements
to improved productivity and profitability can be traced to the lack of effective
tension control. Often, due to their
manufacturing process or poor tension
control, manufacturers are not able to
run their material rolls all the way down
to the core, affecting both productivity
and profitability.
This more or less is leaving money on
the core, only to end up as scrap. Other

Fig. 7: Multiple tension control zones within a single process

sources of scrap and lost productivity
come from web breaks and inconsistent
end products. Quality tension control
helps to eliminate these scrap producers by creating a uniform and consistent
process.
Automated, consistent and continuous
production, reduced scrap, increased
end product quality and increased
productivity can be achieved through
high-quality tension control.
Currently, the composites industry relies primarily on new equipment to provide tension control systems. However,
the purchase of new equipment is not
always feasible for manufacturers.
Montalvo specializes in incorporating
the latest tension control technology
and innovations into existing applications, which often require minimal
adjustment to account for the new tension control equipment being added to
the machine.

Composites tension control
Some of the largest challenges for
tension control in the composites
industry, especially early on, have been
price, design, and the realization by
the composites industry that web tension control is important. Many early
control systems were designed for very
large and heavy applications in other
industries, while the requirement for
the composites industry has been and is
quite often, small, and inexpensive. And

54 jec composites magazine / No99 September 2015

Fig. 8: Multi creel unwind

by inexpensive, meaning that in the past
it would be very expensive to purchase
a closed-loop system for each tow in a
process containing hundreds of tows.
By miniaturizing or adapting new technology, it is now possible to automatically control the tension of all the webs
cost effectively. Montalvo is constantly
developing new technologies that are
not only composites industry-specific,
but application-specific.
The process diagrams depicted below
are not modelled after any particular
process, but are drawn to depict the
variety of options available to control
the tension in a process.

Multi-tow tension control
The application shown in Figure 7 depicts several tension zones, and requires
several types of tension control.
Starting at the beginning of the process
(right side of image), several tows are

Table of Contents for the Digital Edition of JEC COMPOSITES MAGAZINE - Issue #99 - September 2015