CADCAM & controls
New controls on large machine tools drive dramatic cycle time reductions for globallyconnected
pump manufacturer, and are key enablers in bringing work back in house.
Priming the pumps
AN ambitious machining improvement project at SPP
Pumps has reduced cycle times by over 50%. The project
included installing a new CNC horizontal borer specified
with the Heidenhain iTNC 530, and retrofitting an iTNC
530 to a refurbished CNC vertical spindle gantry mill. The
Gloucestershire firm has also saved around £100k of subcontract
cost over the past year, because split casings for
larger variants of centrifugal pump can now be machined
in-house. Gary Hurcombe, Operations Manager, says this
has cut lead times from three weeks to one week for what
had been the longest lead time item in a pump ‘kit of parts’.
Having manufactured and supplied pumps and
associated equipment since 1875, SPP is now a global
business employing around 300 people, and is a world
leader in designing and producing centrifugal pumps and
fluid handling systems. Applications include oil and gas,
water supply, fire protection/fire fighting, heating and
ventilation/air conditioning, as well as dewatering, drainage
and irrigation. SPP has served the oil and gas industry since
1970, when SPP pumps on the Argyll platform delivered
the first North Sea oil to come ashore. It is also the world’s
leading specialist manufacturer of fire protection pump
packages. Its £300k machining improvement project
reflects progress since November 2003, when it became part
of Kirloskar Brothers, the flagship company of the $2.2
billion Kirloskar Group of Pune, India.
Focus on innovation led to a decision in 2007 to
reconfigure a split casing machining process into roughing
(on a refurbished Mecof gantry mill) and finishing (on a
new Dugard Eagle HBM-4 horizontal borer with 60-station
tool magazine). Initially, it was necessary for roughing and
finishing operations to be completed on the HBM-4 while
refurbishment of the older machine was taking place. Now,
with the two machines up and running, SPP has been able
to refine the machining process - balancing cycle times and
significantly improving throughput.
‘Over the years we have acquired various pump companies
along with their machine tools, so we already had several
different types of CNC system before we decided to add to
the list by specifying the Heidenhain,’ says Hurcombe. ‘The
fact is that when we were first researching our options,
everyone we spoke to said that if we were going to continue
with shopfloor programming the Heidenhain control is
the most user-friendly. This has proved to be the case
because machinists Dave Sayer and Dave Houghton really
like the flexibility and ease-of-use of these new controls.’
The latest development of Heidenhain’s iTNC 530, which
can control up to 13 axes and a spindle, follows on from
other productivity-enhancing additions such as the latest
version of the SmarT.NC programming language, Adaptive
Feedrate Control (AFC) and Dynamic Collision Monitoring
(DCM). Taken together, these innovations underline
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SPP Pumps present some
heavy duty challenges
to borers and gantry
mills
Heidenhain’s commitment to continuous development
with the emphasis on user-friendliness and operational
reliability.
Retrofitting of the iTNC 530 to the Mecof gantry mill
was undertaken by Simon Hopkins of SDH Controls &
Services (an approved Heidenhain TNC retrofitter), who
also fitted a Heidenhain TS 220 touch probe. This probe has
an accuracy of ±5 micron using a standard stylus and a
repeatability of ±1 micron at a probing velocity of 1m/min.
Heidenhain Applications Engineer Martin Lyons then
provided the TS probe training, a crucial requirement as
probing of key features on the raw castings determines the
optimum set-up for the machining of datum faces, with
tighter alignment tolerances being achieved, and also
determines the amount of material to be removed from
wear ring bores prior to finish machining of the assembled
halves of the split casing on the new CNC horizontal borer.
Split casings are manufactured in various materials,
including cast iron, duplex stainless steel and aluminium
bronze, with the same patterns used throughout. This
means that the shrinkage rates vary as, too, does the amount
of material that needs to be removed from the wear ring
bores, the objective being to leave around 1mm of material
prior to finish machining. ‘Martin Lyons, in co-operation
with Seco Tools who supply around 80% of our tooling,
wrote a parametric program that enables us to remove the
optimum amount of material from the wear ring bores of
all sizes of pump casing using a ball nose cutter,’ says Gary
Hurcombe. ‘This new method has eliminated the extreme
boring bar overhangs required when machining on the old
manual horizontal borer, and will also reduce wear and tear
on the new CNC horizontal borer.’
www.heidenhain.co.uk
66 MWP may 2009
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