The "why" and "how" of the
world of custom-built cables
Irene Barber is president of elocab
Tailor-Made Cables, the Canadian branch of elocab
Sonderkabel, a leading European manufacturer of
To most of us, buying custom-made no longer has
the appeal it had for our forefathers. They didn't think twice about
having a suit or a pair of boots made to order. Today, buying "off
the rack" is most often the first option people look at.
In the cable world, using custom-made is, in many
cases, the better business decision; often the only sensible choice, in
extreme operating conditions. Increasingly, custom-made cables are seen
as the optimum solution for the tough and challenging jobs, where cabling
is exposed to moisture, pressure, constant movement, corrosive agents,
extreme cold, heat or electromagnetic interference.
Imagine bending the printer cable from your
computer in the same place, say, ten million times. Would it still work
flawlessly after one million or more bending cycles? Custom-made power
and control cables for robots at assembly lines have to be able to
withstand that kind of repetitive flexing - and still deliver the power
and the correct "commands" without failing.
This isn't to say custom-made is about to
displace standard. Generally, standard cables will do just fine.
Tailor-made cables are, and always will be, niche products. However,
there are so many more niches for them today.
What is a tailor-made cable?
Whereas standard cable is manufactured in bulk
and sold from catalogues or by order numbers, each custom-made cable is a
unique product. It is designed, manufactured and tested to match each
customer's specifications. Standard cables are generic; custom-made
cables are created for specific applications or situations. It might be
just one cable of many on a machine - the one cable that has to be
especially thin, or resistant to very high heat, or have a high-flex
capability, like cables for welding, paint-spray or handling robots.
Every custom cable begins with an in-depth analysis
of the specific application needs. That usually means detailed
consultation with the customer or even on-site reviews. At elocab, each custom cable is designed from scratch
using the latest CAD technology. In average, our design engineers create
a total of eight new cable constructions daily, for diverse applications.
Custom cables are not just for big jobs or big
customers. At elocab, we design and build
tailor-made cables in quantities as small as 100 meters, with
analysis-to-delivery lead-time of no more than three to six weeks - a
quick turnaround to enable responding to more and ever-newer
Companies and institutions are increasingly
opting for custom-designed cables for a simple reason: Each custom
application gives the buyer an advantage or set of advantages that, over
time, more than recoups the upfront cost of buying a designer product.
Tailor-made cables end up paying for themselves through increased
efficiency, reduced downtime and substantially longer service life than
conventional cables. They can help optimize the performance of
state-of-the-art production facilities or diagnostic equipment.
A company's operating costs and maintenance
expenses are lowered because the cables are designed for greater
longevity and reliability. In the just-in-time world, a production halt
due to cable failure means lost output, idle workers, and an accumulation
of inventory and unfinished product. For these reasons, custom cables
have become the rule in automated manufacturing environments. In Europe's
automotive industry, for example, 80 percent of all welding robots rely
on tailor-made, high-flex cables designed and built by elocab's parent company in Germany.
Custom cables are viewed as essential in extreme
operating conditions demanding the highest levels of reliability, such as
in Europe's high-speed trains or in submarines and submersibles, and even
on satellites in outer space.
A "tool box" of individual designs
Designing and building a tailor-made cable
requires the "art" of translating the full range of existing
design and material options into a superior tailor-made cable. Along with
their accumulated knowledge of designing more than 6,000 individual types
of customer-specific cables, our engineers have access to an extensive
"tool box". It provides them with a wide range of materials for
the jacketing, design options for the internal architecture and the
sub-assembly of conductors, special shielding designs, and many other
For example, special strain-relief elements can
be integrated into the jacket for greater stability of a cable. Or, low
friction, sliding wrapping tapes can be used to effectively prevent
"snagging" of the various components of a cable, a feature
crucial in cables required to withstand mechanical stress, i.e. fast
take-up and pay-off reeling operations.
EMI-shielding a major concern
A strong demand for tailor-made exists in cables
designed for optimized protection against EMI (electromagnetic
interference). At elocab, approximately every
fourth customer is looking for special protection against strong magnetic
fields and high-frequency interference.
fields creating interference of sensitive signals appear particularly
when power, sensor and control wires are run adjacent to each other. This
applies to tight cable tracks and multi-cable bundles usually found in
modern automation and machinery equipment. Typical sources of
interference are controllers and electronic components. EMI also plays an
important part in hybrid cables, where different components are combined
in a single cable for cost and space savings.
In order to optimize their cables for protection
against electromagnetic interference, design engineers appraise a full
range of alternatives before selecting the best solution. The applied
shielding designs range from the use of foils to served wire or braided
shields. Extremely difficult problems are solved by shielding designs
which may combine the same or different shielding in multiple layers.
The choice of material, the shielding conductor
diameter, the angle of pitch and the number of strands are all factors
which determine the density and the specific frequency resistance of a
shield. High-permeable alloys, such as MU-metal, used as a wrapped foil
shield, can absorb low-frequency magnetic fields.
Classic EMI "problem sectors", such as
machine building, measurement and control systems, as well as the
communications and high-frequency technologies, are among the prime users
of perfectly-shielded, tailor-made cables. A strong demand for shielded
cables is also found in the medical industry, where cables in X-ray
machines and other diagnostic equipment carrying extremely sensitive
video information require reliable protection against any interference.
Hospital patients may book tests on the latest
diagnostic equipment weeks or even months in advance. A cable failure
that debilitates equipment represents lost billable time for the
institution and enormous inconvenience for staff and patients.
Cables on a diet
Putting cables on a diet (reducing their
diameter) is one of the most common challenges to design engineers
involved in building tailor-made solutions. Space is extremely limited in
many machines and automation tools, where cables often must perform in
tight cable tracks or in a confined working environment.
design of small-diameter, high-flex cables with improved electrical
properties offers easy installation as well as weight- and space-saving
options. Ultimately, slimming down a cable translates into a more
flexible and longer-lasting product. Design engineers are able to
substantially reduce the diameter of tailor-made automation cables - by
30 to 40 percent - compared to standard products.
A significant portion of tailor-made automation
cables are specifically designed for applications in cable tracks and on
robots where they are required to flex millions of times at high speeds.
The key to designing a superior product for these flex applications is to
slim down the cable, which either allows for a tighter bending radius or
increases the bend radius-to-cable diameter ratio.
At elocab, we build
high-flex, diameter-reduced cables which can withstand a bending radius
as small as five times the outside diameter, designed for a life-span of
up to 20 million bending cycles or 20,000 operating hours.
The longer life-span is primarily attributed to
unique cable designs. High-flex cables can, for instance, incorporate
high conductor stranding. In tailor-made cables, particularly with a
bigger diameter, the conductors are cabled in bundles of several
components to prevent breakage.
Engineered for optimum performance in cable track
applications, tailor-made high-flex cables deliver rugged, durable
performance in robotic processes, high-speed assembly lines, automation
equipment, machine tool and material handling systems. Cables used in
cable tracks typically flex back and forth on one axis. Tailor-made
cables are capable of performing high-speed flexing at speeds of up to 10
meters per second.
In addition, longevity is provided by special
jacket materials that make the cables resistant to abrasion and other
environmental challenges. The recently launched, UL-approved,
flame-retardant, halogen-free polyurethane (PUR) material featured on elocab cables can withstand temperatures from -50°C
to +90°C and has high tensile and shear strengths. From an environmental
perspective, halogen-free PUR cables can be recycled, landfilled or incinerated
without releasing dioxins or other toxic emissions.
Tailor-made cables not only offer high
performance and reliability that looks good on the balance sheet, but is
also noninvasive to the environment.
Where a perfect fit is a must, custom-made is the