tooling
coating, which has 2000 layers and measures less than
0.003mm. This film-like thickness enables high shear
geometries to form part of the insert design to reduce
cutting force and permit higher feed rates on lower
powered machines. The ZX coating at 4000Hv is almost
as hard as CBN and extremely resistant to wear and heat.
Increase this hardness value by 40% and out pops newly
developed Super ZX with a hardness value of 5300Hv.
Super ZX uses alternating TiAlN and AlN layers with
added chromium. Sumitomo says, compared with
common TiN coatings, Super ZX offers substantial
increases in tool life coupled with the potential to
reduce annual insert spend by as much as 50%.
Sliposity, resistance to heat, wear, oxidation and
plastic deformation are all qualities high on the list of
coating development, and all are demonstrated in
another new coating from Sumitomo called Super FF.
This comprises TiCN (titanium carbonitride) and
Al2O3 to give high resistance to chip adhesion because
of its anti-welding capability, not to mention superior
resistance to edge wear when compared with
conventional CVD coatings. Sumitomo says Super FF is
well suited to machining grey and nodular cast iron,
and is offering customers a 50% introductory discount
until the end of March 2008.
From high speed to interrupted cuts, and from fine
finishing to heavy roughing and general purpose
turning, Sumitomo’s ACE coat is the world’s first
carbide insert to contain zirconium in the substrate.
Subject to a programme of continuous development,
this thick TiCN layer has improved wear, peeling and
chipping properties, while the top layer comprising
fine particles of alumina offers good heat resistance.
At Seco, experts are not alone in stating that coating
is one of the principal differentiators in the cutting
tool marketplace. In its quest to make an impact on the
Sandvik Coromant’s
new generations of
inserts and grades
typically use a combination
of more than one coating,
PVD or CVD-applied
LMT Fette IQ Plus taps
feature an intelligent
coating that adapts to
cutting conditions
80 MWP march 2008
ability to improve the machining of a broad range of
materials Seco has explored all the possibilities right
down to atomic level. The result of this project is a
special CVD process called Duratomic. With extreme
levels of both toughness and wear resistance
(producing inserts exhibiting over 30 GPa hardness),
Seco says that the Duratomic process will become the
framework for (insert) coating development for years
to come, and will have a dramatic effect on the
industry, raising the productivity bar for everyone
involved in metalworking. Duratomic’s secret lies in
the nucleation stage, which builds the coating
structure and orientates the atoms in the directions
required to produce the crystal planes most suited to
the application.
Like Duratomic, another breakthrough to grab the
headlines in recent months occurred at LMT courtesy
of its abrasion and heat resistant Nanolock coating for
indexable cutting inserts (see January 2008 issue, page
46). However, because of this, many may have missed a
simultaneous LMT coating development for taps: users
of IQ Plus taps for blind and through holes should
now be able to plan for extended production life of
between 30 and 50% over conventional TiCN coated
taps due to a new ‘intelligent’ coating that in effect,
adapts to cutting conditions to provide a more
predictable process.
The multi-layer nano-structured coatings have a
highly wear resistant base layer adhered to the substrate
of the insert with a softer, but tougher IQ Plus sputter
coating fused into its surface. Under cutting conditions
and following a few passes in contact with the material
being processed, the IQ Plus coating is subjected to
micron-compression. This has the effect of ‘running in’
or smoothing the outer coated surface that reduces the
co-efficient of friction which in turn reduces the
torque requirement for the process. Both the soft and
hard layer then interact to provide a more consistent
performance demonstrating lower wear factors on the
tool and so increasing production life. In trials on 42
CrMo4 steel, an M10 x 1.5 IQ Plus tap was run at
25m/min to a depth of 24mm using a soluble coolant.
When compared with the usable life of a standard
TiCN coated tap of 1,800 holes, this was improved by
44% to 2,600 holes using IQ Plus.
There is of course no shortage of new grades
featuring new coatings making their way to market.
Kennametal, for example has just introduced its
supernitride PVD coating for standard indexable
milling inserts. It provides enhanced adhesion allowing
thicker PVD coatings and therefore extended tool life.
Coating technology may appear complex to many
production engineers but behind the chemical
formulae lay genuine competitive advantages. Why not
trial a few differently-coated inserts on your latest
application? You might be pleasantly surprised at the
outcome.
www.taegutec.co.kr
www.guhring.co.uk
www.coromant.sandvik.com
www.oerlikon.com
www.sumitomo-hardmetal.co.uk
www.secotools.com
www.LMT-tools.com
www.kennametal.com
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