TEST AND MEASUREMENT | TORQUE CALIBRATION
He explains that initially the
focus was to accommodate torque
wrenches requiring forces up to 50kg
applied to the handle, but during the
18-month design project discovered
ones that required a mammoth 110kg
force. “We needed to beef up the
machine dramatically, the original
drives could not cope and there was
too much friction on the bearings. To
overcome these issues, we worked
with igus adding in a gearbox, larger
linear crosstrack and modifying the
bearings.”
The result is the AWS Universal
Torque Wrench Calibration Machine
(UTWCM), which provides an
efficient and cost-effective means
of calibrating and testing manually
operated torque wrenches to
international or company specific
standards and specifications. It
is designed to calibrate and test
wrenches up to 2,500 Nm and
equivalents. The benefit of using the
machine is that it removes the need
for operators to manually apply, at
the right speeds, high forces when
calibrating large torque wrenches.
Instead, the machine applies the force
using AWS proprietary firmware,
a stepper motor and linear guide
system.
Available with either semi- or
fully-automated operation, the
UTWCM applies the force to the tool
via a linear carriage stepper motor
and a proprietary microcontroller.
This set-up assists in minimising
the parasitic forces applied to the
torque wrench handle. The machine
can be used with the latest AWS
Kepler software, Kepler 4, to speed
up completion of the calibration
and certification process to comply
with ISO 6789:2017, ISO 6789:2003
or type approval requirements for
manufacturers.
“This calibration software was
developed 15 years ago and has been
used by a number of large and small
manufacturers and laboratories. Early
users were Danish, so we named it
Kepler in tribute to the 17th-century
German astronomer, mathematician
and astrologer, Johannes Kepler,”
says Sangster. “The software runs
on a standalone PC to ensure it is not
compromised and data cannot be
corrupted and can be backed-up
using the user’s in-house IT server
system.”
The fully-automated
“Parasitic forces
acting on the wrench
during calibration are
reduced by design feature
and easy to adjust force
balancer systems
to counterbalance
the weight of a torque
UTWCM uses AWS
Intelligent Inline
Torque Transducers
(IITTs) and the AWS
Professional Transducer
Display (PTD) to
provide feedback to
the microcontroller,
automatically detecting a
first peak signal for setting
type wrenches, stopping the
machine and returning to zero,
greatly speeding up the calibration
process and reducing operator
input. With indicating wrenches, the
operator stops the machine when the
torque wrench displays the target
torque. An optional Transducer
Switch Box keeps AWS IITTs powered
up continually, allowing quick
changeover between transducers.
The semi-automatic version relies on
the operator to instruct the machine
as to when 80% of the target torque
has been reached, so that the
machine slows to the correct rate, and
to stop the machine when the target
torque is reached.
The built-in microcontroller
controls the accuracy of the load
applied and operation speeds of
which there are four settings for
different ranges of tools. This ensures
the adherence to the minimum
target torque approach times,
complying to the ISO standard, for
the capacity of wrench being
calibrated. Multiple safety
features ensure that the
machine, transducers and
torque wrench are not
overloaded in operation
or over driven due to a
wrench fault.
Parasitic forces acting on
the wrench during calibration
are reduced by design feature
and easy to adjust force balancer
systems to counterbalance the
weight of a torque wrench handle.
Multiple or single transducer cassette
variations for different transducer
manufacturers are available or built
to suit customer requirements. “To
accommodate wrenches with fixed
heads, the transducer mounts in our
carriages can be rotated 360° in steps
of 30°,” adds Sangster.
Since the launch of UTWCM,
the company has sold all that it has
built so far, with new orders coming
in quickly. Calibration accredited
laboratories and large OEMs in
various sectors, including aerospace
and defence, subsea, transportation,
power generation, production plants
and processes, around the world are
discovering the value of using a truly
universal machine. The benefits of the
UTWCM being automated, reliable,
maintenance-free, quick and easy to
use, energy efficient and quiet are
proving highly desirable. !
wrench handle.”
28 WWW.EUREKAMAGAZINE.CO.UK | JANUARY 2020
/WWW.EUREKAMAGAZINE.CO.UK