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Silverline – innovation extends its advantage

Posted in Technical Members News on 18th Mar 2020

Making changes to what is your most popular product can pose significant risk, but in the case of
CERATIZIT Group’s SilverLine solid carbide milling cutters, taking those calculated risks has paid significant
dividends for customers with improved performance from the totally updated range.
SilverLine has been part of the WNT (one of CERATIZIT Group’s competence brands) product range for
over 10 years, so it was time to look again at this key product and update it not only with the latest in cutting
tool technology, but also expand its application range with new cutters being added to the already extensive
portfolio. While cautious not to make change for change’s sake, the development team was tasked with
improving the three key elements that give a solid carbide tool high performance, namely the carbide
substrate, coating and geometry. The changes made to all three elements in SilverLine work in harmony to
deliver significant improvements in metal removal rates and tool life.
The new substrate along with changes to cutter geometry have enabled the creation of a completely new
core to the SilverLine cutters. Increasing flute numbers allowed for a larger core diameter to be created, this
in turn generates much greater cutter rigidity and reduces cutter deflection with tensile strength increased by
50 per cent, thereby increasing overall process security. This along with associated changes to the chip
gullet and the addition of through tool coolant also improved chip flow, reduced cutting forces and the cutter
generates less heat and noise, while allowing cutting data to be increased between 20 and 40 per cent
(material dependant) while tool life increases by as much as 50 per cent. Maximising this new performance
is the use of the latest Dragonskin coating, this latest development of CERATIZIT’s multilayer coating is
silver in colour and is compatible with most materials including stainless steel or steel, flame-cut, uncoated
or scaled billets. The high temperature resistance of the coating makes it suitable for either wet or dry
machining applications, with exceptional service life in either application area. “In short SilverLine cutters are
now stronger, last longer and are faster than their predecessors,” says Adrian Fitts, Business Development
Manager, CERATIZIT UK & Ireland. “Cutters are now available with 3, 4, 5, 6, and 8 flutes dependent on

application and diameter and with the burgeoning aerospace sector in mind we have added many more
options when it comes to corner radii and cutter diameters.”
As with all successful product development processes the customer was central to many aspects of the
changes to Silverline, not least the extension of the range to encompass not only greater choices in
diameter and corner radii, but also cutter styles including ripper and Torus cutters. “We listened to
customers who were asking for heavier-duty roughing cutters and, thanks to the increased core size and
rigidity we can now offer a ripper version of SilverLine,” says Adrian Fitts. “As customers wanted to run
faster this created a problem, higher cutting data equated to greater chip volume and evacuating those chips
became an issue. Now, with the strengthened core, through tool coolant and Dragonskin coating, combined
with a ripper-style geometry to create smaller chips, we can push tools harder as evacuation is no longer the
issue it once was. For more specific high-speed applications when milling we’ve also added HA-style shanks
to the standard range of SilverLine cutters. This plain shank is ideal for use in heat shrink and hydraulic
chucks, allowing increased spindle speeds to be used.”
“SilverLine is a tremendous success story for CERATIZIT, especially here in the UK where it is one of our
premium products and one of our best-selling product lines. Therefore, when the decision was made to
update it, we had to be certain that we would be making changes that would both maintain and extend its
reputation for delivering high performance metal removal across a range of applications. The success we
are seeing with the new SilverLine confirms that the hard work that went into these developments has
produced a superior product that will continue to deliver productivity gains for our customers,” says Tony
Pennington, Managing Director, CERATIZIT UK & Ireland.
A product video and further information will also be found from the above date at cutting.tools/silverline.

Customer case study:
Ensuring that this latest version of Silverline exceeded customer expectations was vital to its success, the
popularity of the original cutters meant that any loss in performance would have a significant impact on
sales. To prove that SilverLine was a ‘good tool made even better’ extensive field trials were undertaken in
Germany, the test results speak for themselves as this example at longstanding SilverLine user Heinz
Knöpfle GmbH highlights. Over its history Heinz Knöpfle GmbH has changed from a manufacturer of low-
volume parts for the special-purpose machinery it built into a high volume machine shop providing sub-
contract capacity for customers in industries such as medical, scientific, aerospace and general engineering.
“We provide a rapid service in line with the needs of our customers and always to the same high quality
standard," says Managing Director Susanne Knöpfle. To accomplish this, the company maintains a raw
materials warehouse filled with material of various different sizes and grades along with machining capacity
to completely machine parts from 10 to 800 mm in diameter and up to 2,000 mm in length. “We can supply

our customers with everything that they require from a single source," explains Susanne Knöpfle. "We
identified a demand for this level of versatility, for example tools ranging from simple to complex in nature.
To accommodate this, we have a diverse range of machinery at our disposal, backed by many years of
experience in our employees.”
As a family-owned business with few employees Susanne and her two brothers, Andreas and Christian, who
are responsible for technology and production, have a great reliance on their supplier base who can provide
technical support and reduce the workload on internal staff and keep the 18 Mazak CNC machines running
efficiently. Ceratizit Group is the dominant force among its cutting tool suppliers providing a wide range of
support from its four competence brands (CERATIZIT, WNT, KOMET and KLENK). As an existing user of
SilverLine and with such a diverse range of materials and applications running, Heinz Knöpfle GmbH was an
ideal field test partner, as few customers use SilverLine in such a versatile manner. With agreement in place
the new SilverLine tools were tested on-site for six months across virtually all 18 of Heinz Knöpfle GmbH’s
CNC machines. “As a big fan of the original SilverLine tools, we had very high expectations and the amazing
results that we have achieved with the upgrade have far exceeded our expectations," says Christian
Knöpfle. The results showed a tangible difference of between 20 and 40 percent higher cutting speeds. At
the same time, the service life increased by 30 to 40 percent. "We noticed straight away that the new
SilverLine tools are quieter, thus reducing the burden on the machine. The values obtained over the months
then fully confirmed this. We have a new favourite tool," says a very happy machining expert.
During the tests SilverLine was initially used on a challenging application machining a stainless steel
polygon shaft, which Knöpfle produces in various sizes for a water management company. SilverLine
impressed in every respect: "These milling cutters left the competition in the dust when it came to
performance data, service life, etc.," recalls Christian Knöpfle. "However, the SilverLine not only impressed
on VA materials, but it is also suitable for any application – even simpler steels. We use the tool at extremely
high cutting speeds and therefore achieve excellent chip evacuation, with a service life and level of process
security that other milling cutters never reach. This is ideal for users like us, who are well-positioned on the
market but only wish to use a small selection of tools, SilverLine is now our clear favourite.