Guide

4
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How the Bend Sensor
®
Potentiometer Works
Flexpoint’s patented Bend Sensor
®
device consists of a single layer, thin, (0.005” typ.) flexible piece
of material that is coated with a proprietary carbon/polymer based ink. This type of resistive element
is commonly used to make thick film resistors, resistor networks, slide potentiometers and
transducers. Flexpoint’s proprietary inks are primarily printed on thin plastic films.
Flexpoint uses a coating that when printed on a plastic film such as polyimide forms a bond that is
very strong. The ink is very hard and brittle. During processing micro cracks are introduced into the
carbon/polymer coating, When the coated film is bent, the ink’s many micro cracks, which upon
movement open and close to the specific bending of the material. The ink maintains its integrity in
shape and continues to have a very strong bond to the substrate. One of the most unusual
characteristics of this ink occurs when the material is bent over a given radius repeatedly. It returns
to its original value within the same slope or curve of resistance proportional to displacement.
The sensors are easily customized as the coatings can be applied in many patterns to adjust the
resistance and can be screen printed as required by the application. The tremendous reliability,
consistency and repeatability of the Bend Sensor
®
device make it highly desirable to many industries.
Other technologies such as force sensors do not display and deliver the reliability and versatility of
the Bend Sensor
®
potentiometer.
As mentioned the Bend Sensor
®
is a single layer construction. As such dirt, dust and other
particulates that cause issue with multiple layer sensors do not affect the Bend Sensor
®
. The same is
true for many liquids including gasoline, diesel fuel, motor oil, antifreeze, alcohol and water to name
a few.
Since the coating can be placed on several types of substrates, the sensor may be designed to act as
its own spring allowing the sensor to return to its original position.
The proprietary inks are custom manufactured by Flexpoint and can be easily adjusted to the specific
resistance requirements of the customer. Flexpoint can design the method of actuation or bending to
fit the measurement needs. New inks and products are constantly being developed.