For companies involved in the oil and gas market and producing workpieces like fluid ends, gate valves, drill bits and pump housings, achieving significant reductions in overall processing times is increasingly important as the industry faces a diminishing need for fossil fuels.

Lee Scott, sales director for Birmingham-based Starrag UK Ltd (www.starrag.com), said: “For instance, by using single-set-up working on a Heckert 800 Athletic horizontal machining centre fitted with a DBF head — DBF stands for turning-drilling-milling in German — one company has slashed machining times on control valves from 20hr to just 4.5hr; this equates to a 95% reduction in overall processing time and a 77% cut in cycle time.

“The DBF 800, which has a six-pallet linear storage system and a 320-tool capacity, features a 45kW 1,700Nm torque spindle with a maximum speed of 3,500rev/min.

“For this valve-machining application, the customer uses the DBF head to undertake a non-stop routine of face milling using a 125mm-diameter cutter at a feed rate of 5,000mm/min, end milling using a 50mm-diameter tool, and solid drilling with a 70mm-diameter tool.

This is followed by turning with 89mm-diameter tooling and a 300mm-diameter external turning tool; and because machining is completed in one set-up, there are no inaccuracies due to re-clamping.”

Mr Scott adds: “With long-range manufacturing forecasts predicting a reduction in global demand — and price — for fossil fuels, due to the increase in electric vehicles and the increased use of renewable energy, companies involved in machining oil and gas components must be at their most competitive now, if they are to retain current contracts let alone secure new deals as we approach 2019/20.

“In the same way that Starrag earlier focused on the aerospace sector by developing sector-specific machines and routines, the company is now offering similar benefits to the oil and gas sector with the development of the DBF 630 and 800 models.”

One head, three ops

Now in its third generation, the DBF head allows single-set-up milling, turning and drilling. It comprises a faceplate with integrated work spindle and CNC radial facing slide.

For turning on a fixed workpiece, the rotating turning tool, which has an axial run-out of just 5-6µm, can be radially adjusted by ±35mm. In addition to external, internal and face turning, the head also permits conical and contour turning courtesy of the radial facing slide’s NC axis.

For milling and drilling operations, the spindle is used in its central position.

The DBF 630 has a work envelope of 1,070 x 870 x 1,200mm, a feed range up to 60,000mm/min and an HSK-A 100 tool-holder (optionally SK 50) in the 45kW work/DBF spindle.

The DBF 800 has similar feeds, tool-holder and spindle ratings but a larger work envelope of 1,320 x 1,070 x 1,300mm.

Both DBF machines also feature a five-axis trunnion (along with a turning option), to allow access to all features — including compound angle holes — in a single set-up.

Mr Scott says: “The capabilities of these machines are fully realised when they are applied in automated systems incorporating advanced software routines that allow them to achieve utilisation levels as high as 95% with minimal operator involvement.

“In the production of fluid ends, which have a life of 2,000-3,000hr, a Heckert HMC with DBF head is machining these parts from 4-tonne blocks of solid stainless steel in just 38hr; without the use of a DBF head, the machining time was 50hr.

“For this application, the use of a Capto 8 head/drilling spindle played a key role, offering the high levels of rigidity required for drilling to depths of almost 1m with no adverse run-out deviation.”

In conclusion, Mr Scott says: “With oil giant BP suggesting there will be 100 million electric vehicles by 2035, coupled with an increased uptake of renewable energies and therefore the eventual reduced demand for oil and gas components, it is clear that savings can already be made to ensure profitable futures for everyone currently involved in machining oil and gas components.”

Future developments

Roland Wozny, Starrag UK’s product sales manager, says the use of Dӧrries vertical turning machines and Scharmann four-axis Ecoforce horizontal machining centres in manufacturing systems where the welding of Inconel cladding is integrated into the production process “is a development that is on the horizon.

“Inconel cladding is used to ‘protect’ parts that may spend 15-20 years in water, and the application of this material will see — for instance — Ecoforce machining centres being used to pre-machine components that are then sent for welding, washing and cleaning before being returned to the Ecoforce for finish-machining.

“Such integrated systems will see manufacturing times reduced from weeks to days.”