Page 9 - Industrial Technology February 2020
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       Torque wrench calibration

                                                                     LINEAR MOTION

       LINEAR MOTION SYSTEMS AND ENERGY CHAINS PROVE KEY IN THE                           process to comply with ISO 6789:2017, ISO 6789:2003
                                                                                          or type approval requirements for manufacturers.
                                                                                            The  fully-automated  UTWCM  uses  AWS  Intelligent
                                                                                          Inline  Torque  Transducers  (IITTs)  and  the  AWS
                hen  developing  a  new  torque  wrench  discovered ones that required a mammoth 110kg force.  Professional Transducer Display (PTD) to provide feedback
                calibration  machine,  Advanced  Witness  “We  needed  to  beef  up  the  machine  dramatically;  the  to the microcontroller, automatically detecting a first peak
                Systems  (AWS)  turned  to  Igus  for  its  low  original  drives  could  not  cope  and  there  was  too  much  signal  for  setting  type  wrenches,  stopping  the  machine
       Wfriction  plain  bearing,  drylin  linear  drives  friction  on  the  bearings.  To  overcome  these  issues,  we  and returning to zero, greatly speeding up the calibration
       and  cable  management  systems.  The  design  project,  worked  with  Igus  adding  in  a  gearbox,  larger  linear  process  and  reducing  operator  input.  With  indicating
       which took only 18 months to complete, enables AWS to  crosstrack and modifying the bearings.”  wrenches,  the  operator  stops  the  machine  when  the
       offer  calibration  accredited  laboratories  and  large  OEMs  The  result  is  the  AWS  Universal  Torque  Wrench  torque  wrench  displays  the  target  torque.  An  optional
       the  most  advanced  and  truly  universal  torque  wrench  Calibration  Machine  (UTWCM),  which  provides  an  transducer  switch  box  keeps  AWS  IITTs  powered  up
       calibration machine in the world.        efficient  and  cost-effective  means  of  calibrating  and  continually,  allowing  quick  changeover  between
         Based  in  Banbury,  Oxfordshire,  AWS  is  a  leading  testing  manually  operated  torque  wrenches  to  transducers.  The  semi-automatic  version  relies  on  the
       designer  of  torque  transducers,  instrumentation  control  international  or  company  specific  standards  and  operator to instruct the machine as to when 80% of the
       systems, calibration apparatus and certification software  specifications.  It  is  designed  to  calibrate  and  test  target  torque  has  been  reached,  so  that  the  machine
       programs. Its pedigree traces back more than 40 years to  wrenches up to 2,500Nm and equivalents. The benefit of  slows to the correct rate, and to stop the machine when
       managing director Ron Sangster who has been involved in  using  the  machine  is  that  it  removes  the  need  for  the target torque is reached.
       developing national and international torque standards as  operators  to  manually  apply,  at  the  right  speeds,  high  The  built-in  microcontroller  controls  the  accuracy  of
       well  as  national  standard  calibration  machines.  While  forces  when  calibrating  large  torque  wrenches.  Instead,  the load applied and operation speeds of which there are
       consulting  for  the  National  Physical  Laboratory  he  the  machine  applies  the  force  using  AWS  proprietary  four settings for different ranges of tools. This ensures the
       designed  the  Master  2kNm  torque  calibration  machine,  firmware, a stepper motor and linear guide system.  adherence to the minimum target torque approach times,
       which has been proven to be one of the most accurate                               complying to the ISO standard, for the capacity of wrench
       torque calibration machines in the world.  Minimising parasitic forces             being calibrated. Multiple safety features ensure that the
         “Torque  wrench  calibration  machines  are  generally  Available with either semi- or fully-automated operation,  machine,  transducers  and  torque  wrench  are  not
       intended  for  a  specific  manufacturers’  products,”  says  the  UTWCM  applies  the  force  to  the  tool  via  a  linear  overloaded in operation or over driven due to a wrench
       Sangster. “For laboratories and OEMs this can be a real  carriage stepper motor and a proprietary microcontroller.  fault. Since the launch of UTWCM a few months ago, the
       nuisance,  requiring  several  different  machines  to  cover  This  set-up  assists  in  minimising  the  parasitic  forces  company  has  sold  all  that  it  has  built  so  far  with  new
       each  torque  wrench  manufacturer  – which  can  be  applied to the torque wrench handle. The machine can be  orders coming in quickly. “We were given great technical
       expensive and takes up a lot of bench space.”  used with the latest AWS Kepler software, Kepler 4, to  support  from  Igus  throughout  the  design  project
         Sangster’s  aim  therefore  was  to  develop  a  truly  speed  up  completion  of  the  calibration  and  certification  journey,” Sangster concludes.
       universal  machine,  able  to  meet  the  ISO6789:2017
       manual  torque  tool  standard,  that  would  be  able  to
       guarantee  the  absolute  and  consistent  accuracy  of  any
       torque wrench, be it a tool for use with bone screws used
       in prosthetic surgery, a click torque wrench for tightening
       a car’s wheel nuts or a torque wrench used for aviation,
       construction  and  heavy  machinery  assembly.  He  also
       wanted the machine to operate quietly and require as little
       maintenance  as  possible.  “Technicians  appreciate  using
       quiet equipment in their labs; unwanted background noise
       can be annoying,” he explains. “They also do not want to
       have to regularly maintain their equipment – long life and
       high reliability are therefore other key criteria.”
         On searching the market for low maintenance and low
       friction bushings and bearings, linear drive systems and
       cable management systems, designers at AWS contacted
       Igus. “We received a high level of technical support from
       Igus,  as  well  as  many  samples  from  the  Igus  iglidur
       bearing,  drylin  E  linear  drives  and  e-chain  ranges,  to
       realise the initial design concept for the machine,” adds
       Sangster. Initially the focus was to accommodate torque
       wrenches  requiring  forces  up  to  50kg  applied  to  the
       handle, but during the 18-month design project Sangster
                                          MORE INFORMATION: • • Tel: 01604 677240

       February 2020 •INDUSTRIAL TECHNOLOGY                                                                                     9
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