All-Electric Enters the Domain of Process Pipework

Unison Tube LLC (Asheville, NC) reported that parent company Unison Ltd. (Scarborough, UK) has installed and commissioned the world’s largest and most powerful all-electric pipe bending machine at the Norwegian offshore and maritime services company Westcon Yard AS (Ølensvåg, Norway). Capable of generating a colossal 660,000 Nm of continuous, servo-controlled torque, this custom-designed machine is used for precision bending of thick-walled carbon steel pipes up to 10 in (273 mm) diameter.

Westcon specializes in building and repairing ships for the offshore and fishing sectors, and in servicing, maintaining and repairing semi-submersible and jack-up rigs used by the offshore oil and gas industries. They operate four shipyards in Norway, with their headquarters and pipe production operations forming part of a modern and well-equipped yard near Ølensvåg that enjoys a unique sheltered position on the Ølensfjord with deepwater access to the North Sea. The yard’s facilities include two floating docks, deepwater quays for three drilling rigs and a number of high payload cranes.

This is the second all-electric pipe bender that Unison has supplied to Westcon’s pipe production facilities in Ølensvåg. The first, a 90 mm single-stack model from the Breeze range of equipment, was installed and enabled the company to bring fabrication of all pipe sizes up to 60.3 mm diameter in-house. It has also helped Westcon to simplify and accelerate their production process dramatically by allowing parts to be fabricated from single-piece piping stock, instead of from multiple cut-to-length straight sections and pre-formed bend parts bought-in from external suppliers.

The yard has similarly high expectations for their new 10 in machine, intending to produce virtually all the pipe sizes that they need entirely in-house for their outfitting, service and repair operations, without having to use pre-fabricated bend sections. This application of all-electric bending technology to pipes up to 10 in diameter is without precedent. Although these bending machines are used by a number of the world’s leading ship and submarine builders to produce large pipe and tube assemblies, this piece of equipment is by far the most powerful that Unison has ever designed and built. It highlights the inherent scalability of their machine architecture and underlying motion control technology: their range of all-electric bending machines now extends all the way from 16 mm (5/8 in) to 273 mm (10 in).

The order for both pipe bending machines, which also called for Unison to supply CAD support software, was placed through P Meidell AS (Oslo, Norway), a specialist machine tool company that acts as their representative in Norway. In recent years, Westcon has invested heavily in their pipe fabrication operations for ship and rig outfitting, with the intention of becoming a world leader in this industry. The Ølensvåg site now has a large 3,650 sq m purpose-built engineering workshop with more than 1,500 sq m allocated to pipe production. The new facilities include a fully automated materials handling system – based on 9 m high pipe storage racks and robotic feeders – together with an automatic pipe cutting machine and the two CNC controlled all-electric tube benders.

Most of the pipes that the yard produces are one-off items for new systems, rerouting and maintenance purposes. They are typically manufactured from carbon steel, with each pipe spool normally being up to 6 m long. These pipes usually form part of fresh or sea water systems, hydraulic systems, diesel fuel distribution networks or other special systems. They often involve very tight radius bends, to as little as 1.5 times outside diameter, and need to be constructed to millimeter accuracy.

Previously, the yard fabricated all pipes in sectional form, using multiple cut-to-length straight sections and bought-in preformed bend parts. The individual sections, bends and end connection flanges were then welded together to create the final assembly, with each weld requiring cleaning, inspection and non-destructive X-ray testing. This was an expensive and time-consuming process that was also heavily reliant on outside suppliers meeting tight delivery schedules. Rapid turnaround time is critical for repair organizations like Westcon, where the out-of-service costs of ships and rigs can be astronomical.

Following delivery of their first bending machine, Westcon has produced all pipes up to 60.3 mm diameter in-house from straight piping stock. This has eliminated the need to buy-in preformed bend parts for these pipe sizes, and substantially reduced the number of cutting, welding and testing operations needed for each assembly. The pipes are currently cut slightly over-length before bending to allow for any changes introduced by the process. After bending, they are re-measured, cut to final length and welded to the necessary flanges. The yard intends to further improve this process by cutting the pipes to length prior to bending as their expertise develops.

“We have been using these machines extensively for a few months and are still on a learning curve,” explains Tommy Nilsen, the head of prefabrication at Westcon’s Ølensvåg facility. “Despite this, we are already achieving superb bend accuracy and repeatability with good throughput, and we are confident of increasing this even further when we change the process sequence. In fact, based on our experience so far, now that the larger bending machine is in place, we expect to substantially reduce production times for all pipe sizes. It’s like going from past to present in one stride! We are now effectively a year ahead of the rest of the world in terms of our pipe fabrication capabilities.”

These all-electric pipe bending machines feature servomotor-driven motion axes and fully automated, software-controlled setup. Simplicity of operation and the fact that Unison was prepared to develop custom pipe bending systems were two of the key reasons behind Westcon’s original order. Both the 90 mm and the 273 mm machines are fitted with an innovative laser springback system that automatically measures and adjusts bend angles to compensate for the tendency of tubular parts to spring back slightly after being bent. These machines both feature quick-change tooling that is a major advantage for applications that involve bespoke, one-off manufacturing.

The machines’ unique mechanical design, combined with the precision axis control capabilities of their Unibend software – especially with respect to carriage and pressure die boost – makes it easier to achieve very accurate and repeatable results, with minimal changes to the wall thickness or ovality of the pipe that is being bent. These attributes are ideal for manufacturers of marine, offshore and subsea equipment that invariably need to work to tight tolerances and strict process guidelines.

The material storage/retrieval system, pipe cutting and bending machines at the Ølensvåg facility are fully networked. The engineering department creates the necessary machine control programs from customer-supplied drawings or CAD files, or from data derived directly from a physical pipe using a laser-based coordinate measuring machine (CMM). To help simplify the process, Unison supplied Westcon with powerful VTube software from Advanced Tubular Technologies, Inc. (Waterford, MI) that generates production-ready programs for tube and pipe benders direct from CAD data, and also translates CMM data for reverse engineering purposes.

“Our all-electric tube and pipe bending technology is starting to make major inroads into territory that was once regarded as the sole preserve of hydraulic benders,” noted Alan Pickering of Unison, underlining the significance of this Westcon application. “This has huge implications, and not just for marine vessel and offshore rig outfitting and repair organizations, though these are currently driving the take-up of our larger bending machines. Industries such as nuclear and fossil-fuel power generation, oil and gas refining, and chemical processing also make extensive use of large diameter precision-bent pipes. Accurate and repeatable bending – especially if it involves expensive corrosion resistant alloys – are as important to these industries as any other. Last year, the largest machine that we produced was capable of bending 9 in diameter tubes and pipes. This year it’s 10 in. We are now entering the domain of process pipework, which is an entirely new market.”

“Norway, Finland, Sweden and Denmark all have major shipbuilding interests, which nowadays have to compete with lower labor cost manufacturers in Asia,” added Bjørn Garvik, a sales manager at the Bergen office of P. Meidell AS, the sales support partner in Norway, discussing how the machine tool market in Nordic countries offers significant growth potential. “Automation like our all-electric tube and pipe bending machines can help fabricators to meet the challenge of these competitive trading conditions by significantly improving the efficiency of their production operations.”

Unison Tube LLC, 28 Schenck Parkway, Suite 200, Asheville, NC 28803, USA. Tel: (828) 771-0850; unisontube.com.