TURNING NEWS IN THE ROUND
Better
bigger cuts Based on a shopfl oor poll, Renold
Twin-pallet HMC installed at transmission specialist; crusher machine
OEM invests in horizontal borer; large turn-mill machine arrives at
turbine/pump manufacturer. Steed Webzell provides the details
The replacement of an ageing, singletable,
horizontal-spindle machining
centre (HMC) with a new, German-built
Burkhardt + Weber (BW) twin-pallet model,
supplied by UK agent Kingsbury (https://
is.gd/exevoc), has boosted the machining of
industrial gearbox casings at Renold Gears,
Rochdale. Casings are produced mainly from
iron castings and fabrications, but also from
steel and aluminium.
The resulting savings in oor-to- oor
times of between one-half and two-thirds are
due to increased metal removal rates during
cutter engagement, reduced non-cutting
times through faster axis movements, fewer
operations due to better xturing methods,
and faster component changeover via of ine
set-up on the second pallet. Furthermore,
with the twin-pallet con guration, if there is
an issue during component machining, it can
be brought out of the working area for
inspection, allowing production of the next
part to commence. Such troubleshooting
would have resulted in a lot of unproductive
time on the previous machine.
Renold’s gearboxes can measure more
than 2 m in height and weigh up to
3 tonnes. Around 20% of products are
standard, the remainder being customerspeci
c designs that are manufactured in
quantities of between one and 30 per
month.
SHOPFLOOR VOTES FOR CHANGE
When the company’s shop oor employees
were asked which machine they would most
like to replace, the large HMC was almost
unanimously chosen. The machine’s
unreliability was, by then, resulting in
sometimes having to outsource machining to
meet production deadlines. After several
twin-pallet HMC options had been
Gears chose to replace a large,
unreliable HMC, opting to replace it
with this Burkhardt + Weber unit
considered, a B+W MCX 1400 with a 3,200
by 2,200 by 2,000 mm working volume and
B-axis NC table was purchased.
A senior manufacturing engineer at
Renold Gears says: “During trials, the B+W
machine proved capable of more than
halving the cycle times on the old HMC, and
was more productive than the other 4-axis
machines with pallet changer that we
considered. We gave two test parts to each
potential supplier, a gearbox casing for a
heat exchanger and another for an escalator
drive. On average, they were machined
around 15% quicker on the MCX 1400.”
The 180-pocket tool magazine
(extendable to 330) is especially helpful, as
a large number of cutters is needed to cope
with Renold’s wide range of gearbox casing
sizes and materials, and a majority of these
tools can be permanently resident in the
magazine.
Drawing tolerances are tight for such
large components, down to 20 micron for
some machined features like gear centres
and shaft bores, some of which are
produced by interpolation milling. The
reliability and repeatability with which this
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