SilverLine: good tools made even better

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%, 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, with reduced cutting forces and the cutter generating less heat and noise, while allowing cutting data to be increased between 20 and 40% (material dependant) while tool life increases by as much as 50%.

Enter the dragon

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 excellent 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,” Mr Fitts adds. “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 bestselling product lines,” says Tony Pennington, managing director, Ceratizit UK & Ireland.

“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,”

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 subcontract 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, we maintain a raw materials warehouse filled with material of various different sizes and grades along with machining capacity to completely machine parts from 10 to 800mm in diameter and up to 2,000mm in length. We can supply our customers with everything that they require from a single source," she adds.

"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 through our employees.”

Out in the field

As a family-owned business with few employees, Ms Knöpfle and her two brothers, Andreas and Christian, who are responsible for technology and production, rely on their supplier base to provide technical support and reduce the workload on internal staff; keeping 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 onsite 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 those," says Christian Knöpfle.

The results showed a tangible difference of between 20 and 40% higher cutting speeds. At the same time, the service life increased by 30 to 40%. "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’re very happy with the results,” Mr Knöpfle enthuses.

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 and service life,” Mr Knöpfle recalls.

"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 in the market but only wish to use a small selection of tools. SilverLine is now our clear favourite."

Ceratizit UK & Ireland www.ceratizit.com