"We are seeing an increasing demand for high-performance tools for machining aluminium, particularly in the aerospace industry," says Wolfgang Vötsch, Senior Product Manager for milling at Walter AG in Tübingen. "New aluminium-lithium alloys are gaining in popularity, and these materials quickly overwhelm conventional tools."
Aircraft components made of aluminium alloys have machining volumes of up to 90 percent, as pockets of varying sizes and depths need to be milled out of the material depending on the size of the component. The components must be machined using the "High Speed Cutting" method (HSC) at cutting speeds of up to 3300 m/minute to ensure cost-effective and high-quality manufacturing.
If the cutting data is too low, this leads to build-up on the cutting edge and therefore rapid wear and frequent tool changes, resulting in high costs due to longer machine running times. Machining operators who specialise in aluminium therefore have good reason to demand outstanding cutting data and tool life from their tools, to say nothing of the fact that high-speed machining in particular requires the highest levels of process reliability.
The tool developers at Walter had these exact requirements in mind when developing the new M2131 ramping mill. They equipped the 90° milling cutter with a new class of indexable inserts that represents the current pinnacle of machining technology for aluminium wrought alloys. The grade designation of these indexable inserts is "WNN15". This refers to an entirely new PVD variant, manufactured using the "HiPIMS method". HiPIMS stands for "High Power Impulse Magnetron Sputtering", which is a technology based on conventional cathode sputtering using magnetrons. The special feature of this physical coating process is that it produces an extremely thick and smooth PVD coating. The advantage of this is that it provides a huge reduction in friction, thereby reducing the tendency to form built up edges. It also provides extremely high resistance to flank face wear and high cutting edge stability. As a result, it provides the best conditions for ensuring the maximum metal removal rate. "Field tests have confirmed the technological advantages of the new indexable inserts in comparison to standard types. Our application engineers have achieved increases in tool life of up to 200 percent with ease. In one case, we even succeeded in reaching an increase of almost 400 percent!" reports Wolfgang Vötsch happily.
To ensure that HSC machining is reliable, Walter manufactures the tool body of the M2131 with the highest possible concentricity. The indexable inserts are provided with integrated protection against centrifugal force. The milling cutter is also pre-balanced. To complete this range of features designed specifically for meeting the exacting requirements of aluminium applications, the tool has internal coolant channels that are suitable both for emulsion and for minimum quantity lubrication. Wolfgang Vötsch concludes: "The aerospace industry is one of our most important key sectors. We have been supplying it with high-performance tools for years. In some cases, we have also developed these tools in collaboration with machine manufacturers. This was the case with the new M2131 as well."
The M2131 ramping cutter from Walter AG is designed to precisely meet the demands of HSC machining of aluminium materials as well as the latest aluminium-lithium alloys. It has two sizes of indexable inserts, enabling it to reach cutting depths of 15 or 20 mm, which are ideal for ramping and pocket milling. The tool, with internal coolant, is available with a variety of interfaces, including HSK, which is available with an enlarged support face as an option, ScrewFit, parallel shank or bore. Walter produces tool bodies with diameters of 20 to 80 mm or 1" to 3".
Indexable insert with the new "WNN15" HiPIMS coating: The M2131 ramping mill is equipped with ZDGT1504.../ZDGT2005 – indexable inserts with corner radii of 0.4-4 mm or 0.8-6.4 mm. Their geometry is optimised for pocket milling. The special feature of this cutting material grade is that WNN15 is a PVD coating applied using the HiPIMS process.
The surface is very smooth and has very low friction, which minimises build-up on the cutting edge during aluminium machining, leading in turn to very high tool life.
