New technologies offer
heavy-duty metal removal, reduced setup steps and flexibility
Despite falling oil prices, the investment valve in the oil and gas
industry remains on—for now—as manufacturers continue their race to provide
large, precision parts for fracking, subsea drilling and other related
activities. But as anybody in the energy sector knows: this is the land of
boom or bust. So when the going is good, the industry can’t source pumps, drill
bits and drilling equipment, tubular stock, and valves fast enough. When it’s
not, well, that’s when it may be time to take stock of advanced machining
technologies, which may offer flexibility to diversify manufacturing operations
for another sector.
For now, the continued growth of hydraulic fracturing remains a force
throughout the sector. Fracking has also brought horizontal drilling with its
increased demand for drilling tools into play. Larger oil parts require larger
machines, faster metal removal, and, in the near future, may get an assist from
the latest hybrid subtractive/additive manufacturing technology.
The challenge for job shops and OEMs alike is how to machine larger
workpieces faster with reduced or single setups and with quicker changeovers
for families of parts. And if they can buy machines and equipment that have
broader use outside of oil and gas, that’s a bonus, too.
Here’s what you might expect to see.
Fracking Pumps: Workpieces as Large as
Diesel Engine Blocks
According to Vince Trampus, vice president, Heller Machine Tools (Troy,
MI), pumps for the fracking industry start out as big blocks of metal that are
very similar to heavy-duty 11 to 16-L diesel engine blocks for the trucking,
construction and agriculture industries. Heller’s H series horizontal machining
centers—and before, that its MCH series HMCs—were developed with the rigidity
and power to machine cast iron and CGI diesel engine blocks making Heller the
leading supplier of machining centers to these industries. “Frack pumps begin
as solid blocks of alloy steel that weigh anywhere from 5000 to 8000 lb
[2268–3629 kg] and require removal of over 2000 lb [907 kg] of metal during the
machining process,” said Trampus.
“The question of how quickly that metal can be removed is answered by the
design of the H series HMCs, which are extremely robust with a gear-driven
headstock that delivers full power at low rpms. We have four gear changes to
get up to an 8:1 ratio from the motor to the spindle resulting in 60 kW [@2292
N•m of torque] at the tool below 500 rpms,” said Trampus.
“Fracking pump housings [typically made from 4340 alloy steel with a
hardness of 300 Brinnell] can be machined in less than 20 hours using our H
Series HMCs compared with the 40–60 hours [or longer] in current machining
processes on multiple machines,” said Trampus.
“Unique to the industry, Heller’s feed out system [U axis] on the H series
allows the use of feed out tools required to generate the finish tapered bores.
The U axis is an NC-controlled axis that enables feed out tools to be loaded
automatically into the spindle from the magazine vs. the current process of
manually loading tools onto the quill spindle of a boring mill. These machine
features make Heller’s H series a perfect fit for machining many types of
energy business parts.”
Additive Manufacturing Poised for the
Oilfield
The next big thing in the oilfield, according to Dana Scott, general
manager at Mazak’s Southwest Technology Center, could very well be hybrid
multitasking machine tools. Such technology combines both additive and
subtractive processes into one machining center. “Right now components that go
downhole behind the drill bit have wear pads on them, either made from titanium
or Inconel. The current process is for the OEM to send the components out to
have these wear pads or wear rings welded on them.”
However, said Scott, a hybrid multitasking machine such as Mazak’s new
Integrex i-400AM would allow shops to impart the titanium or Inconel pads
directly onto the existing components using the additive technology, then
finish them with conventional subtractive machining. “This would eliminate the
welding process and allow the component to quickly go right to assembly,” he
said.
“As with the wear pad components, the demand for fracking tools 3½–6½”
[89–165-mm] diameter in varying lengths has also grown dramatically,” said
Scott. Unique to fracking are perforating guns and frack guns that fracture
shale formations to release oil or gas. “Perforating guns, which are 20′ [6-m]
long and about 4½” [114 mm] in diameter, are used in multiples to blow through
the well casing into the rock formation, while frack guns, in multiple 3′
[0.90-m]-long sections, use ultra-high-pressure liquid and silicon to fracture
formations,” said Scott.
“Deep subsea drilling programs typically involve very large parts like
blowout preventers [BOP] that are up to 75′ [23-m] tall, valves and pumps of
all types, and big drill bits—parts that are often processed on Mazak’s
Integrex e-670H Multi-Tasking Machine, for instance,” said Scott. “Two
different types of drill bits are the single head PCD drill bit that is 26″
[660 mm] in diameter and the tri cone bit with tungsten carbide that can drill
holes 6–30″ [152–762 mm] in diameter. PCD drill bits are machined in two
operations on the Integrex e-670H reducing shop time by more than a third and
providing agile production for low-volume product mix compared with four or
five milling and turning operations on conventional machines.”
One machine tool builder is also exploring the potential for a large
premium-priced trunnion-style HMC that has proven itself in machining
difficult-to-machine metals like Inconel and titanium for aerospace
applications. “The HU100-5X series machining centers delivers 2000 ft-lb [2711
N•m] of torque with a 10″ [254-mm] face mill and would be well-suited for
faster metal removal machining forged pump housings. Also drill bits are
getting larger, reaching 40″ [1016-mm] diameter, making them well-suited for
large meter trunnion machining centers,” said Scott Walker, president, Mitsui
Seiki USA Inc. (Franklin Lakes, NJ).
Changeover Versatility in Families of
Frack Pump Wear Parts
The ANW Series twin-spindle CNC lathes from Fuji Machine America (Vernon
Hills, IL) feature the company’s integrated Fuji-engineered robots and
workholding. The ANW Series is used for precision machining of wear parts for
couplings, well service valves and valve seats, pump valves and seats, and
pistons and other parts to 20″ (508-mm) diameter. According to Bill Gore,
regional manager-North America, these parts are typically made from metals like
8620 alloy steel forgings or saw-cut bar and have to meet the operating and
performance requirements associated with abrasive and corrosive environments
found in oil field and fracking operations.
“One of the challenges that our oil-field customers face on a daily basis
is the need to change over within families of parts. The ANW machines are
versatile and able to handle changeover for families of parts, which may
consist of tris, quads, or quints, fracking pumps with three, four, and five
pistons, in different diameters for different sizes of valves and seats,” said
Gore.
“It isn’t unusual for end users to mix and match different brands of
components based on their preferences. They can change internal components to
match the different conditions of fluids, media, and chemicals that they are
required to pump,” said Gore. “For downhole applications, we have developed a
cell for turning the OD and ID of popular 5½ and 7″ [140, 178-mm] semi-premium
couplings. It features an ANW 5000 twin-spindle horizontal machine, with a lot
of Z-axis travel to machine both sides of the part. Internally, there’s extra
travel in the Z stroke to accommodate long-reach boring bars. We leave the bore
semi-finished with enough stock so that they can be threaded on another
machine,” said Gore.
Y-Axis for VTCs, Contouring Head for
Boring Mills, HMCs
Fives Giddings & Lewis LLC (Fond du Lac, WI) has introduced a Y-axis
attachment that adds off-centerline milling, drilling, and tapping capability
to vertical turning centers. The Y-axis attachment combines a C-axis head with
table X and Z-axis motions, allowing for single-setup processing of flanged
parts, pumps, housing and other energy industry parts. “The Y-axis attachment
for vertical turning centers allows us to provide capability to our customers
that would normally be done on a secondary operation on a horizontal machining
center or a boring mill,” said Pete Beyer, director of product strategy and development.
“For large-part machining, it’s always desirable to be able to machine the part
complete on one machine or in the least number of setups,” said Beyer.
“There is demand from the fracking segment for horizontal boring mills and
horizontal machining centers equipped with another one of Fives’ recent
developments, the Integrated Contouring Head [ICH],” said Beyer. “Some
customers are interested in moving turning operations from a turning center to
a boring mill or a horizontal machining center with integrated contouring head.
If the percentage of turning versus milling is small or the part is difficult
to fixture or highly unbalanced, it makes more sense to do turning operations
by spinning the tool on a boring mill than by spinning the part on a lathe,”
said Beyer.
“Machining a forged steel main pump housing, called a fluid end, that
weighed in at 10,000 lb [4536 kg], 3000 lb [1361 kg] of metal were roughed off
in less than 12 hours, holes bored with the live spindle, and turning
operations completed with the ICH,” said Beyer.
Recently Fives Giddings & Lewis added a second extended-range ICH.
Rated at 56 kW, the extended-range integrated contouring head handles up to
980-mm ID and 780-mm OD. Its U-axis slide stroke of 440 mm can produce small or
large-diameter features in a single setup without head changing or operator
intervention. It loads tools via the machine’s ATC, which accommodates tools up
to 609-mm long weighing up to 18 kg.
Twin-Pallet HMCs Machine Precision Parts
Plano Machine & Instrument Inc. (Gainesville, TX) has four Kitamura
HX-630i HMCs that are being used to machine energy industry parts, principally
for the fracking industry, as well specialty parts for precision applications.
“We’re primarily 75-80% energy related,” said Billy D. Dennis, production
manager. “We machine a lot of internal parts for frack pumps and families of
chrome moly parts, including bearing retainers and connecting rods. With the
Kitamuras, which have twin oil-cooled ballscrews and twin pallets, we are able
to get uptime well above 90% spindle utilization and accuracy that is better
than competitive brands,” said Dennis.
“Typical applications include bearing retainers and exit parts that may
require fourth-axis work or offset holes, and internal grooves,” said Dennis.
Parts are made predominantly from chrome moly steels, 4140 steel casting for
housings, as well as 17/4 stainless steel, high nickel alloys, and some ductile
iron castings. We’re just getting set up on a new job, a ductile iron casting,
which is for a large mud pump. We also machine parts for offshore seismic work,
as well as some drilling rig parts.” Specialty applications handled on the
Kitamura HX-630i HMCs include precision machining of a housing part for a
parabolic dish for a tracking device. Another specialty part is used on a
drilling mechanism that is used on a drill rig for digging bridge pilings used
in the construction industry.
Heavy-Duty Machining for Large Energy
Workpieces
Methods Machine Tools Inc. (Sudbury, MA) offers a range of machines including
the new Feeler SBM-2000 universal milling machine, featuring extensive design
and engineering by Methods to meet the oil-field industry requirement for
highly accurate machining of large heavy-duty parts comprised of exotic
materials. The SBM-2000 features an articulated head and integrated fourth
axis, eliminating the need for multiple setups and operations.
“The SBM-2000 allows for a single setup for complicated jobs by providing
multi-angle and side machining capabilities for increased flexibility,
machining efficiency and cutting accuracy. A long 79″ (2000-mm) X axis,
combined with a narrower Y axis and a bed positioned close to the machine
doors, provides easy access, further facilitating flexible, fast setups. The
vertical axis is counter-balanced by a hydraulic cylinder, ensuring exceptional
stability to the milling head and the ram assembly,” said Dale Hedberg, Feeler
product manager at Methods.
The Feeler SBM-2000 features a horizontal milling head with spindle speed
of 4000 rpm and has a 79 × 39″ (2000 × 1000-mm) working area with a maximum
table loading capacity of 11,023 lb (5000 kg). It also offers an X-axis travel
of 79″ (2000 mm), Y-axis travel of 47″ (1200 mm), and a 39″ (1000 mm) Z-axis
travel. A BT50 precision standard horizontal spindle is driven by an AC
servomotor via a two-step transmission gearbox to supply high torque that
provides superb, heavy-duty cutting performance.
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