Page 27 - Industrial Technology March 2020 issue

re-ending Precision

Pneumatic Cylinders

“

WE HAVE SEEN HOSES
REPAIRED WITH A BUNDLE OF
GAFFER TAPE. PEOPLE DON’T
SEEM TO APPRECIATE JUST
HOW MUCH PRESSURE THESE
SYSTEMS ARE UNDER

at the upper end of the tolerance band, it may not fit
properly. I’m not saying that ours are better – they just
match our hoses. Anyone who’s done a re-end has lost
those tolerances. Where are they getting measurement
information from? Whose data are they using?”
And Smart explains: “There is an extreme amount of
force trying to push these components apart. In its own
right it is hard to put into words, but we have showcased
it by setting up an assembly with a mis-manufactured
hose, which is then put under 350 Bar of pressure. In this
instance, it blew within 15 seconds and decimated a 3kg
melon we had put next to it. We had to use a 2,000 frames
per second camera to catch the failure and resulting
impact. The hose end was measured at 600 feet per
second – similar to the muzzle velocity of a rifle.”

The cost of failure
The consensus from Smart, Dickens and the BFPA is that
hydraulic hoses need to be addressed with the same level E.MC provides a wide range of pneumatic
of importance and attention to detail that you would give to cylinders for the automation industry. With
any precision engineered component. In addition to the
bore sizes ranging from 10 mm to 125 mm,
simple cost of replacement, users must consider the cost of
failure, from both a financial and a cost perspective. each element of the cylinder series has
Only by using hoses from suppliers accredited by the
been engineered to produce superior
BFPDA’s Approved Hose Assemblies Scheme, can users
have the confidence that they have purchased an assembly performance and reliability.
that has undergone rigorous measurement and testing;
assemblies that use matched components that are within E.MC Cylinders & Accessories
defined tolerances and are backed by industry wide ISO 6432 standard mini cylinders
guidelines.
“The more we educate people, the better and safer the ISO 15552/VDMA standard cylinders
industry will become,” Smart concludes. “Hoses will get ISO 15552/VDMA standard pro le cylinders
damaged in their everyday use. We need users to consider Compact cylinders
how and where they are used and then develop a proactive
inspection and maintenance plan. This way, early failures ISO 21287 compact cylinders
can be more easily predicted and even have their causes Guided cylinders
designed out. Some protective systems are highly effective
and are more palatable in cost terms versus replacement.”
Dickens adds: “None of us seem to know who is doing
this re-ending. But it is still going on. We will replace entire
assemblies that have failed testing rather than elements of
it, even though it costs us more. This is how committed we
are to the safety of users, as should all of industry. We are
then confident to offer warranties; which leads me onto an
interesting final thought: re-ends do not come with any
form of warranty or guarantee. Would you be prepared
to purchase any other product without these in place?”
MORE INFORMATION: www.bfpa.co.uk
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March 2020 •INDUSTRIAL TECHNOLOGY