MANUFACTURING TECHNOLOGY As Bill Eccles says, “self-loosening tests are important in
allowing the comparative performance of locking mechanisms used on fasteners to be determined”.
The Junker Test The Junker Vibration Test (DIN 65151) is the standard
transverse vibration test. It involves inducing transverse movement into a joint while simultaneously measuring the fastener preload. This creates the most severe conditions possible to bring
on self-loosening and test a product’s likelihood of giving way to the problem.
Complying with DIN testing? Testing your products on a Junker Test machine is the only
way to comply with DIN 65151 and to test for self-loosening characteristics in general. Which is where Vibrationmaster comes in. Up until now, it reckons, there has been an extremely limited
choice of machines available and, in any case, these have not actually met the demands of DIN 65151. Located at Ribe in Denmark, Vibrationmaster currently
employs fifteen people and is already making waves in vibration testing, because, as company CEO Morten Schiff explains: “Vibrationmaster Junker Test Benches really do comply with the DIN standard and even go beyond it. They’re also around 30% cheaper than the competition with more advanced technology and, of course, additional benefits.”
“ Vibrationmaster Junker Test Benches really do comply with the DIN standard and even go beyond it. They’re also around 30% cheaper than the competition with more advanced technology and, of course, additional benefits.”
Vibrationmaster Junker Test Benches Morten Schiff describes Vibrationmaster, which was formed
in 2010, as “a company born out of inspiration and a powerful desire to offer peace of mind and add value by lifting mechanical
vibration testing standards to new levels”. Vibrationmaster’s Junker Test Benches are currently the only machines capable of testing from 5mm (0.2 inch) to 24mm (1 inch) in all fastener classes including Class 12.9. The company currently offers three Junker Test Benches: the
portable 100, compact 400 and the 600. Of the three machines, Morten Schiff says the Junker 600 is perhaps of most interest to Fastener + Fixing readers and boasts some eye-catching features: • 100% accurate amplitude – the Closed Loop System continuously measures the actual amplitude and adjusts it to what the user specified during operation.
• No need to change load cells or calibration – one load cell tests all fastener sizes from 5mm to 24mm.
• Severe quality testing of bolt and nut material – using rapid 0mm to 4mm peak-to-peak adjustable amplitude during operation.
Vibrationmaster and the Bill Eccles connection At the heart of Vibrationmaster’s innovative technology is the
revolutionary Variator, invented by the brilliant Danish engineer Jesper Boesen Nielsen in 1988. After he’d invented the Variator and was excitedly searching
around for potential applications, Jesper got in touch with Bill Eccles. Bill explains what happened next: “
After Jesper told me what the Variator was capable of, we
saw that it could be applied to vibration testing and to creating a truly effective Junker T
est machine because there was a gap in
the market for this type of machine. But, although I would definitely say anyone needing to test
their fasteners for self-loosening to DIN standards or for their own peace of mind should find out more about Vibrationmaster’ Junker T
est benches, my own recent research suggests that
development of the machine is needed so it can impart axial as well transverse loading to allow the truly effective testing of certain locking mechanisms. Knowing what I do about Vibrationmaster, I’m sure the company is looking at how to make this a reality
“It certainly is,” concludes Morten Schiff. Vibrationmaster is grateful to Dr Bill Eccles of Bolt Science,
especially for permission to refer to his article ‘The Loosening Of Prevailing Torque Nuts’, published in Fastener + Fixing Issue 60 November 2009. Visit boltscience.com for extensive information on bolted joints as well as how to contact Bill Eccles.
110 Fastener + Fixing Magazine • Issue 68 March 2011 s