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In this ‘Oil Patch’ They Speak with a Burr and Not a Drawl


Scotland has a robust contract manufacturing community that serves the oil & gas industry in the North Sea--and beyond 


Edited by Yearbook Editor James D. Sawyer from information provided by Hurco Companies Inc.

Mention the term Oil Patch to someone on the west side of the Atlantic and you can bet a barrel of West Texas crude that the Lone Star State jumps to mind. Mention the same term to someone on the opposite side of the water—particularly someone from the UK—and they probably are reminded of the North Sea, where drilling platforms abound. What also can be found in abundance—especially in Scotland—are contract manufacturers that serve the energy industry.

Few contract machinists in Scotland have a modern, vertical machining center to match the 2200 × 1700 × 750-mm capacity of the Hurco twin-column, bridge-type DCX22. That is precisely why Managing Director Bert Bradford of Ayrshire Precision (Coylton, Ayr, Scotland) purchased the machine. Since acquiring the DCX22 two years ago, the company has secured new work in each of its main industry sectors—oil & gas, nuclear and mining.

The first new job was the refurbishment of explosion-proof steel covers for transformers used in coal mines. They are cooled by water flowing through a hollow jacket, the inner surfaces of which need to be roughened to create Ayrshire Precision machine operator maneuvers a workpiece into place in company’s new VMC.turbulence and increase heat transfer to the water. These and other plates, up to 4-m long, are machined for the mining sector on the 50-taper DCX22. The larger workpieces require two clampings on the 2100 × 1600-mm table.

Tanks for Storing Nuclear Waste

Ayrshire Precision also won a contract to contribute to a project to make 40-m-long distillation tanks for nuclear waste storage. These tanks require many large, high-tensile steel panels to be machined, and 25 such vessels are planned in the UK to cool and make safe spent radioactive material. The project requires Ayrshire to not only mill the panels but also to drill large numbers of holes to accept temperature probes.

More recently, 500-mm diameter flanges for the oil industry have been machined cost-effectively on the DCX22, thanks in part to the ability to set up four at a time on the table. Each flange requires milling and drilling of 16 holes. Centers have to be within ±25 µm, while the tolerance held on a sealing groove must be 18 μm total.

All four parts are completed at one time to minimize tool changes and maximize production efficiency. Moving from one part to the next is achieved rapidly and automatically using the “work offset” feature of WinMax, the conversational programming software in the proprietary Hurco control system. The same feature can be used for multiple-part machining, even when setting up dissimilar jobs for untended machining.

To maximize flexibility, Bradford bought a universal angle head for use on the DCX22, which is proving especially useful for machining internal slots and angled holes. A separate WinMax module was written by Hurco to accommodate this extra facility.

“We use the menu-driven, conversational programming nearly all the time, as it is so quick and easy at generating cutting cycles for our jobs, which in most cases are relatively simple,” said Bradford. “Occasionally we will program off-line on our Edgecam system for more complex work. The DCX is our first Hurco machine, but our lead programmer, David Torbet, had no trouble picking up WinMax and our other machine operators can use it as well.”

Deep-Water Mooring Systems

Value rather than size was the consideration when QED Sales (Huntly, Aberdeenshire, Scotland) was contemplating new milling centers. “We based our selection of the Hurco DCX32 and the VMX64 on their value for money and reliability,” said QED Managing Director Stuart Murray, who has 25 years’ experience in the oil industry. “We have a 1986-built MD3 machining center from the same supplier on the shop floor that is still in daily use. Its twin-screen UltiMax CNC system goes back to the cathode ray tube era, unlike Hurco’s modern flat-screen controls. However, we have been very impressed with the conversational system’s user-friendliness for programming and producing one-offs and small batches, which is the norm here. There is nothing wrong with the old machine mechanically and we still produce tight-tolerance work on it.”

Inter-M-Swivel , the multipurpose deeper-water, longer-term mooring swivel that QED Sales helps produce for InterMoor.QED Sales recently installed the largest Hurco machining center, the double column, bridge-type, 3-m DCX32 to help fulfill a new contract for producing large plate H-links. With a field life of more than 30 years, the large plate H-links form part of a 5-t steel assembly used to connect polyester rope to large chains used in deep-water mooring systems. QED has manufactured more than 100 similar products for the off-shore industry for use in the North Sea, off West Africa and in the Gulf of Mexico.

In 2010, InterMoor developed the Inter-M-Swivel, a multipurpose, deeper-water, longer-term mooring swivel that can join chains of the same or dissimilar sizes while allowing complete rotational freedom under tension. Approximately 50 have been sold in the Gulf of Mexico, Alaska and the North Sea. QED won a contract to manufacture parts for the device and needed the Hurco VMX64 with its 1625 × 864 × 762-mm capacity to accommodate them. A fourth axis was supplied to enable milling operations on these and other components that were previously turned on CNC lathes.

Both the DCX32 and VMX64 have been purchased with 50-taper spindles to cope with QED’s tough machining requirements. Drawing tolerances are generally ±0.025 mm, which the Hurcos easily achieve. Established in 1995, QED has gained a global reputation for providing a complete subcontract service to the oil & gas industry and more recently the renewable energy sector, including design, machining and fabrication at the top end of the capacity range. It also manufactures its own products, such as WAG Mill for grinding within cuttings’ slurrification systems, and the SRS swarf removal system for extracting metal swarf, large pieces of cement, pieces of casing and other debris from the circulating fluid used during casing milling operations.

Wating to Keep Doing Things Well

With a BP quality award hanging on the office wall alongside a platinum award from Cameron Subsea Systems confirming 24 consecutive months of products with zero defects, Quadscot Precision Engineers (Glasgow) has proof that it has a history of serving the offshore oil & gas sector well.

Until recently, the company relied on three-axis vertical machining centers (VMCs) including a Hurco VMX1 installed in 2008 and a 12-year-old VMX42 with Nikken fourth axis for its prismatic machining requirements. In order to bring their milling capacity more into line with their 1.5 m × 500 mm diameter turning capability, two more VMCs were purchased in 2010.

One of the new machining centers was Quadscot’s first five-axis model: the Hurco VMX60SR, with a 1525 × 660 × 610-mm working volume, a horizontal rotary C-axis table and a ±92° degree B-axis head that allows the 36-kW, 40-taper spindle to be positioned within a program anywhere between vertical and horizontal. Renishaw tool and part probing have been fitted to speed setups.

Not only does the VMX60SR meet the size requirement stipulated by Production Director Jim Smith, but it also allows multisided parts and those of complex geometry to be produced more accurately and cost effectively. “Some components that previously needed three separate setups for milling operations,” Smith said, “can be produced in one hit on the VMX60SR. The faster cycles and reduced handling result in production cost savings of around 30% for some bigger parts. Therefore, our customers benefit from more competitive prices and faster turnaround. Additionally, tolerances of ±25 μm are easier to hold when not repeatedly refixturing heavy components in different axes and the cost of fixtures is also reduced.

The other new Hurco machining center is a VMX50-50 taper four-axis model with a 22-kW, 8000-rpm, 353 N•m CAT50 spindle, large axis travels of 1270 × 660 × 610 mm, and was supplied with 3D mold software within the Hurco WinMax programming suite running in the proprietary twin-screen control system.

Smith’s partner, Sales Director Billy Hepburn, said, “A lot of our customers use high-performance materials such as Super Duplex, Inconel and Toughmet, which are challenging to a machine. Having the 50-50t allows us to be more cost-effective when machining tough and exotic metals. The accuracy is there too—we frequently mill parts using four-axis simultaneous movements to 25 μm tolerance.”

The 44-employee subcontractor was established 22 years ago by a team of skilled engineers and toolmakers with a wealth of experience in precision CNC subcontract machining. Production of subsea Christmas tree parts, down-hole tools and wellhead equipment are particular specialties. A highly focused approach to customer service has been fundamental to the development of the company, along with careful selection and purchase of CNC milling and turning machines. Today, Quadscot operates from an 8500-ft² (791-m²) factory a few miles southeast of Glasgow.

The company is a long-time user of Hurco equipment. Indeed, the first VMC it bought back in 1990 was one of the supplier’s KM3P knee mills with Ultimax II twin-screen CNC. Even in those days, the control and programming software was well ahead of its time, allowing Quadscot’s machine operators to program parts easily without needing to know or even learn G-codes. Any programming mistakes were picked up from the graphic screen before putting tool to metal.

“We have stayed with Hurco equipment over the years,” Smith said, “largely because of the flexibility of the control system, which has always been much faster than others on the market. That is important to us, as all of our programming is done on the shop floor. We looked at a number of five-axis machines before buying the VMX60SR and even considered a horizontal-spindle, twin-pallet machining center at one point. However, we opted again for the Hurcos due to the combination of the user-friendly control and rigidity of construction, plus the versatility and robustness of the B-axis head design in the case of the five-axis machine.”

This article was first published in the 2013 edition Energy Manufacturing Yearbook.

Published Date : 12/18/2013

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