September 13, 2010
Cable carriers have come a long way since the introduction of the first carrier in the 1950s. No longer made solely of steel, modern-day carriers span greater distances and protect cables, hoses, and machinery in many industries, including metal fabricating and green energy.
No one can deny that automation has greatly improved many different areas of our lives over the last two centuries. Streamlined processes and mass production have made our daily needs affordable and easily sated. Modern-day conveniences are readily available at our fingertips. Indeed, we expect them to be.
Manufacturing has been forced to take heed of this culture of expectation, especially in the face of emerging Internet technologies. Nowadays any dissenting voice can find an online platform from which to share: word-of-mouth gone global and automation flipped online. Quality must be higher and delivery times slashed; everything funnels down to improving the end user’s experience. Machine functionality is integral to all this. Each and every machine component must be able to withstand ever-increasing demands and incur as little downtime as possible.
A cable carrier is an indispensable component on any automated machine with moving cables and hoses. It prevents conduits from tangling, becoming damaged from debris buildup, and making contact with the machine, and it extends the machine’s service life. Reflecting on the development of cable carriers is a useful way to understand how the rise in automation has influenced component technology over the last half-century.
The first cable carrier was introduced in the 1950s. It was made from steel, because this was an inexpensive, readily available material that had been mass-produced since the invention of the Bessemer process a century before. Cable carriers made from steel offered high tensile strength and resistance to high temperatures.
At the end of World War I new forms of plastic emerged. In 1971 the first cable carrier injection molded from polypropylene (PP) - a material discovered in 1954 and mass-produced since 1957 - was released to market.
Although there was skepticism at first about the use of plastics in engineering, thermoplastic cable carriers are just as prevalent as steel today, as is evident on almost any machine shop floor. This growing acceptance is due largely to the extensive testing that has demonstrated the longevity of these carriers. Field-proven case studies also have convinced engineers of the suitability of plastic for a wide range of applications.
The diversification into different and increasingly demanding application areas has been facilitated by the development of new cable carrier styles, alongside research into various material blends to solve commonly encountered problems.
For example, quick-fill cable carriers with easy-snap or split-open crossbars enable ultrafast conduit installation or retrofitting, saving automated-machine manufacturers and end users both time and money.
Mirroring automation technology’s push toward producing higher volumes and improving work flow, manufacturers have modified their basic cable carriers to produce newer versions capable of withstanding faster speeds, heavier loads, and longer travel distances in a multitude of different – often extremely demanding - environments.
Robust, modular designs offer maximum life in heavy-duty applications, while designs eliminating the traditional pin-bore connection have proven ideal for fast-moving, high-dynamic loads. These carriers are very quiet – some emitting noise values at just 38 dB(A) - and have low vibration, thereby substantially reducing noise on the factory floor.
Inventions such as guide troughs enable cable carriers to be channeled safely over increasingly longer distances. More recent material developments include a high-performance polymer blend that allows for a 25 percent increase in unsupported span (Figure 1) — up to 23 feet.
Travel distances in excess of 2,000 ft. that once were thought to be impossible with traditional sliding cable carriers now can be achieved easily. This is due to advances in side-link designs and the addition of wheels that allow cable carriers to roll instead of glide on themselves.
Many green-energy technologies rely on cable carriers. UV-resistant carriers are critical to solar-power systems in extremely hot desert environments, as are seawater-resistant materials used underwater on tidal turbines.
The metal fabricating industry was afforded a way of keeping hot metal shards and debris away from cables and hoses some years ago with the invention of an enclosed-style cable carrier. Since this carrier’s introduction, product modifications have led to newer versions, such as one that is molded from an extremely temperature-resistant polymer capable of withstanding hot metal chips at 1,652 degrees F.
More recent unveilings in the last two years have included an almost completely airtight tube with a smooth, contoured shape and no holes or cracks that prevents hot metal debris from accessing conduits (Figure 2). Only 0.09 ounces of metal chips were reportedly measured inside this design after 251,900 cycles in tests.
Last year a horizontal guiding system was introduced to keep a cable carrier’s upper and lower runs apart over long travels. The design means metal chips fall through instead of becoming trapped between the two runs as they glide on top of one another (Figure 3). A more traditional solution would have allowed large metal chips to settle in the inner radius between the upper and lower runs, which could have caused damage and wear.
Other developments have moved away from the traditional cable carrier trajectory to multiaxis cable carriers for six-axis robots (Figure 4). These can move through all three dimensions and are designed to glide around the outside of a robot without catching. The point is to preserve optimal cable performance by preventing cables from bending beyond their minimum bend radius. With the successful integration of multiaxis cable carriers into key automotive plants and elsewhere, fiber rods assemblies, heat protection jackets, dresspacks, and other accessories have been introduced to supplement the original design.
The future of automation technology is difficult to predict, but if technology continues to advance, older technology, such as slip rings and electrified conductor bars, could be replaced by newer innovations, such as wireless induction technology. This evolution makes sense for very long, fast travels and applications in particularly dirty or wet environments. Several areas on the factory floor could be supplied with power, at once and travel direction would be virtually limitless.
Other new technologies are currently being developed for rotational movements of more than 3,000 degrees, as well as continuous rotations for conveyor and pick-and-place operations.