Wire versus synthetic rope products
By Hannah Sundermeyer24 November 2020
When it comes to the relationship between lifting products and rigging a crane, a rope on a crane is selected to provide the best performance to the load and cycle requirements the crane is designed for, according to Christian Schorr-Golsong, director product marketing, WireCo WorldGroup.
“This typically leads to compacted ropes with a high metallic area,” said Schorr-Golsong. “Those ropes have the needed high breaking strength and are also perfect for the mostly required multi-layer spooling. Each time the rope has to go over a sheave it gets bended and straightened. For this some flexibility is needed.”
The right rope
With an abundance of rigging products on the market, one of the important decisions that riggers are faced with is choosing between wire or synthetic rope.
“Steel ropes stand for a well-proven, rugged solution with high radial stiffness and optimal spooling behavior,” added Schorr-Golsong. “There is not such a temperature restriction as for synthetics (at least for the ones using Dyneema) and the sensitivity to cuts or damages is much lower. I wouldn’t name it a safer solution but over the long time of use in the industry there is general knowledge in the market how to handle, inspect and discard a steel wire rope. For synthetic, such a perception must first be generated. But this is for all new technologies and shouldn’t block technological progress.”
The popularity of synthetic rope as an alternative to wire rope continues to grow as technological advances continue. However, many companies still steadily produce steel/wire rope due to its respected track record and reliability. Both are seen utilized on mobile and crawler cranes, and for a variety of applications such as construction, rigging and lifting. Check out the latest product rope and lifting solutions from some of the industry’s leading manufacturers and distributors.
An optimal balance
Synthetic hoist ropes for crane applications have already been successfully in use at WireCo for many years, for example, in ship cranes and various lifting devices. Their use in mobile cranes, however, represents a special challenge as the rope must be able to provide an optimal balance between breaking load and weight. Both the limited axle load of road-approved vehicular cranes as well as the limitation on transport weight for crawler cranes has led to a steadily increasing breaking load combined with a constant rope diameter. Replacing these high-performance steel ropes with ones made of synthetic materials requires special fiber materials with a tensile strength similar to that of steel. Ropes made of such special fibers are already available and WireCo already offers the rotation-free hoist rope LankoLift S.
The bright yellow rope, made by Lankhorst Ropes, consists of 12 braided outer strands made of the high-tech material Dyneema. The properties of these special fibers result in a breaking strength equal to a steel rope of the same thickness. The construction of the rope core is designed to achieve the required resistance to transverse pressures, the company said. Laboratory tests have produced excellent results for breaking strength and projected service life based on the reversed bending cycles completed during testing. An additional noteworthy feature is the special coating treatment applied to the fibers to reduce interior friction and increase UV resistance. The rope’s low weight and flexibility enable an easier handling of the product during installation and hook block changes. They are also suitable for higher payloads, especially with higher lifting heights and longer jib lengths. The low maintenance requirements are a further advantage as synthetic ropes of this type are corrosion-proof and require no further lubrication.
When trying to meet the technical lift specifications of larger and more challenging lifts, synthetic rope lifting solutions surpass traditional steel wire sling solutions through strength, weight, handling and storage efficiencies, according to Cortland.
Cortland’s Plasma UHMWPE synthetic fiber rope slings are lighter than wire rope, offer greater flexibility both in design and use and are less labor intensive to move.
Cortland’s patented Plasma UHMWPE (Ultra High Molecular Weight Polyethylene) synthetic fiber rope slings are lighter than wire rope, offer greater flexibility both in design and use and are less labor intensive to move. Plasma rope slings have been successfully replacing steel wire rope in lifting applications for more than 25 years. Cortland Plasma rope slings are manufactured in the USA and tag certified to meet all ASME B30.9 lifting standards (other certification standards met upon request).
One of the biggest developments in the rope sector in recent times comes from a co-operative relationship between Austria-based rope manufacturer Teufelberger and Liebherr. Together they developed Solite fiber rope which went was unveiled at Bauma 2019 along with Liebherr’s new Solite-equipped EC-B ‘Fibre’ flat top tower cranes (240 EC-B 10 Fibre/240 EC-B 12 Fibre/ 370 EC-B 12 Fibre).
Synthetic fiber rope on a Liebherr tower crane drum.
Both companies believe Solite will prove to be a game-changer, especially for the tower crane sector, by enabling the current boundaries of possibility, particularly with tower crane applications, to be pushed. The companies also say Solite has multiple benefits for mobile crane and crawler crane applications.
According to Teufelberger, the safety and operational advantages Solite offers include an up to 80 percent lower rope weight, the crane components do not wear, and the rope does not need to be lubricated. The rope’s point of discard is easy to determine, it adds, as it is indicated via the rope’s red core. When this can be seen the rope must be discarded, even though it still maintains 100 per cent of its breaking load at this point.
Teufelberger also says Solite’s life cycle is much longer than wire rope. Björn Ernst, R&D manager for Solite at Teufelberger says, “Solite can, compared to a steel cable, reach up to ten times the service time in multi-layer windings.”
Yale Cordage’s newest product, Sierra 78, was created with bio-based ultra-high molecular weight polyethylene Dyneema SK78 fiber. This marks one of the first partnerships with DSM Protective Materials to create a ‘green’ synthetic rope product manufactured in the USA.
Sierra 78 is a 12-strand single braid of bio-based Dyneema fiber that will be utilized by companies across industries such as electrical utility, industrial, mining and arboriculture. In addition to sustainable manufacturing with the lowest carbon footprint, this product offers three times the service life due to improved fatigue performance, four times the creep life and four times better abrasion resistance. The innovation behind this product’s sustainability factor is in the utilization of the mass balance approach, which reduces reliance on fossil fuel-based resources.
By applying a mass balancing approach, bio-based Dyneema fiber delivers the same consistent durability and performance with a reduced environmental impact.
Strength and flexibility
The Mazzella 7-Part wire rope sling is constructed from one continuous piece of wire rope which results in a sling solution that is ultra-flexible and ergonomic for the end-user. A 7X19 construction contains seven strands with nineteen wires per strand. A mechanical (flemished) splice provides added strength compared to a hand splice and the eye and eye configuration allows it to be used in vertical, choker and basket hitches.
For large lifts, the Mazzella 7-Part wire is a more manageable sling at a cost savings versus standard wire rope slings, the company said. The Mazzella 7-Part wire rope sling can be made in equal capacities as any single-part wire rope sling. It ranges from 1/8-inch to 2-3/4 inches component rope with vertical capacities anywhere from 1.2 tons to over 400 tons.