Manufacturing Machinery World July 2017

ABRASIVES, HONING & FINISHING
rk international machine tools
adds grinding versatility
to its range
RK International Machine Tools has announced
the arrival of the Robbi Omicron IGU highprecision
CNC internal grinder to its range.
This versatile and accurate machine features a
four position spindle turret that can be
configured in a multitude of set-ups to include
internal and external grinding wheels, with an
additional position for a tailstock to allow
centring of the workpiece.
In addition to the versatility provided by the
spindle turret, the Omicron IGU benefits from
Robbi’s exceptional build quality. The Italybased
machine tool builder mixes the highest
technology and design with competitive pricing
and the Omicron IGU features a solid granite
machine base to provide thermal stability,
rigidity is aided by the use of roller linear
guides that as well as improving rigidity also
reducing stick-slip for increased speed and
acceleration. To maintain the high precision
grinding accuracies, absolute linear encoders
are used on the X and Z axes for maximum
positional and repeatability performance.
With a footprint of 2600 mm by 1600 mm the
Omicron IGU is a fairly compact machine but
presents impressive capabilities, with axis
travels of 450 x 650 mm in X and Z axes, with a
maximum workpiece diameter of 650 mm and
200 mm maximum diameter for both internal
and external grinding. The spindle turret has a
repeatability accuracy of 2 arc seconds with a
total swivelling range of -5 deg to + 275 deg
with a resolution of 0.001 deg.
The CNC control is provided by Robbi’s
tried and trusted solution in collaboration with
Siemens. The 840D sl control system, that in
addition to an array of standard internal and
external grinding programs the intuitive
interface allows more complex programs to be
created without any ISO G-code knowledge,
with a summary of the program highlighted on
screen to avoid any potential errors. The control
also features three options for shoulder
grinding, which can be achieved manually,
automatically, or with the addition of gap
control, the latter aiding cycle time reductions.
Wheel dressing is also carried out automatically
either outside the grinding cycle, automatically
as part of the cycle, automatically at specified
intervals or on demand.
Commenting on the arrival of the Omicron
IGU, Dick Aldrich, RK International Machine
Tools’ Director, says: “We have a long working
relationship with Robbi, with many
installations across the UK. The addition of the
Omicron IGU brings diversity to the range and
opens up further opportunities to advance our
position as a leading provider of high quality,
high technology grinding solutions.”
tel: 01322 447611
email: simonrood@rk-int.com
Web: www.rk-int.com
aluminium mirror finish no
longer a challenge
Kemet International launched their new Kemox
SF slurry only 3 months ago and it has already
been found to be a perfect solution for aluminium
mirror polishing, prior to super finishing, by
Professor David Walker, Professor of Ultra
Precision Surfaces at Huddersfield University.
Their application involved polishing a
480mmø aluminium mirror for the LOCUS
project. This being a proposed space mission to
observe the Earth’s atmosphere at grazing
incidence, giving long path-lengths, to measure
pollutant chemical species. It is based on an offaxis
Cassegrain telescope design, for cryogenic
operation in the TeraHz (microwave) and nearinfrared
regions.
The mirror was first CNC milled to generate
an off axis parabolic surface, and then pre lapped
to generate a uniform grey surface. A variety of
polishing slurries were tested, but these couldn’t
produce a uniform polished surface, and some
crystallised too quickly, clogging up the
dispenser system.
Kemet recognised these issues and supplied
their Kemox SF slurry as a solution. This not only
produced a uniform polished surface, but also
reduced the polishing time and alleviated the
slurry clogging issue.
Finally the mirror was super finished using
Kemet’s COL-K NC non-crystallising colloidal
slurry producing a texture of 6nm.
From first contact with Kemet to producing a
finished mirror took only 2 weeks. If you think
you could benefit from Kemet’s 80 years in
precision surface finishing, give them a call.
tel: 01622 755287
email: sales@kemet.co.uk
Web: www.kemet.co.uk
mapal
introduces
hydraulic
chucks for
tool grinding
MAPAL has now developed its first line of
hydraulic chucks specifically for tool grinding
machines. The new HydroChuck Grind-A and
the HydroChuck Grind-M have been launched
to provide users of grinding machines the
advantages of MAPAL’s hydraulic expansion
technology.
The new hydraulic chucks ensure
remarkably high-precision clamping and
repeatability during grinding. The impressive
line of hydraulic chucks are manufactured for
the shank tolerance h6 band and this new
MAPAL line also demonstrates exceptionally
low wear characteristics that makes the
HydroChuck Grind-A and the HydroChuck
Grind-M extremely cost-effective for end users.
In addition to the high radial run-out
accuracy, the automatic workpiece clamping of
the HydroChuck Grind-A is characterised in
particular by its energy-efficient function. The
workpiece is clamped by means of an
innovative cup spring pack. This ensures the
hydraulics of the machine are only required for
releasing the workpiece. The hydraulic chuck
can be rapidly set and adjusted in just a few
minutes to micron precision using two dial
gauges.
Any 'wobble' can be compensated and this
results in maximum workpiece precision. In
addition, a uniform material removal and high
surface finish quality is guaranteed. In
designing this new HydroChuck line, MAPAL
has paid particular attention to minimising
access restrictions to the tool and achieving the
best possible grinding wheel run-out. The new
chuck significantly reduces the wear upon the
grinding wheel whilst delivering a constant
quality and form/dimensional accuracy of the
workpiece.
The HydroChuck Grind-A is available for
the clamping of tool shank diameters of 20mm
whereas the HydroChuck Grind-M has been
developed for 12, 20 and 32mm tool diameters.
To make the HydroChuck Grind-A and the
HydroChuck Grind-M completely flexible,
reducing sleeves are available to accommodate
common tool shank sizes.
tel: 01788 574700
email: sales@uk.mapal.com
Web: www.mapal.com
14 Machinery World, July 2017