"Marathon” tools with a license for precision

Consistently high quality and maximum flexibility aren’t only key features in mould making. Maintaining maximum efficiency means you have to use high performance, high-end tools. Because once you have these, you are ready to take the next step: low manpower, automated production. Unthinkable?

ZECHA Hartmetall-Werkzeugfabrikation GmbH is banging the drum for mixed machining with an intelligent tool selection.Mould making companies’ ability to compete depends completely on their automation. In addition to machining, this especially includes the clever connection and coordination of all manufacturing technologies needed for component production. These included erosion, laser machining, as well as component cleaning and measurement. An essential aspect is the milling of usually very demanding materials – the perfect area of application for ZECHA Hartmetall-Werkzeugfabrikation GmbH’s high precision micro tools.

It’s all in the mix

At first glance, some things just don’t seem to go together: who would ever think of machining graphite and copper on the same machine? “Most people immediately dismiss it” according to Andreas Weck, Application Engineer at ZECHA Hartmetall-Werkzeugfabrikation GmbH. “But the solution is mixed machining! This is the machining of different material that aren’t usually machined with the same cooling lubricant, in this case combining graphite and copper electrode machining – two strategies that couldn’t be more different.”

This is because graphite is usually dry milled on specially configured milling machines with particularly powerful extraction systems and the corresponding ventilation. Copper, on the other hand, is impossible to dry machine and therefore requires a differently configured milling machine with emulsion or oil, ideally with internal shaft cooling at the same time. So surely a combination is out of the question.

Not necessarily, because in the meantime we have very good filter systems for liquid cooling lubricants, making it an interesting option to wet-mill copper and graphite electrodes on the same machine. This results in users achieving maximum flexibility as well as better utilisation of the machines integrated into the automated system. In combination with ZECHA’s highly precise and reliable milling tools, this enable optimally calculated and safe production workflows and milling processes.

Laser sharp and high precision IGUANA cutters are a good fit for all non-ferrous metals 

One tool series has already become the perfect partner in mould making in a very short time: the unique IGUANA cutter series. These solid carbide tools with up to three cutting edges have a sealed diamond coating resharpened by laser.  Dennis Thiermann, Application Engineer at ZECHA, explains: “The coating process inevitably leads to a cutting edge radius of the same order of magnitude as the coating thickness, which can be considerably more than 0.01mm. This is reworked by means of a laser either on the rake and flank surfaces or only on the flank surface. This gives us a consistently sharp cutting edge radius of up to 1 µm. At the same time, coating defects, so-called clusters, are smoothed out.

Because of their sharp cutting edges, IGUANA tools have become the standard when machining many different materials, such as aluminium, copper, all types of brass as well as simple and fibre-reinforced plastics. These tools are even used in the machining platinum. In the meantime, there are now 5 sub-series. In addition to the original IGUANA range layered on both sides, there are also tools with edge protection, helix, shank cooling as well as helix and shank cooling. IGUANA tools are available as ball, torus and end mills, the series with shank cooling as torus and end mills. Drills are also available. The new 935 series completes all of your copper electrode mould making needs by being available in the usual free lengths and corner radii.

A top performance thanks to the lowest tolerances

In many cases, IGUANA technology has already been able to increase process reliability. “Above all, since the tool life and dimensional accuracy can maintain an excellent level over extremely long periods, users benefit straight away. In contrast to PCD tools, which are usually only available with one cutting edge in small diameters, IGUANA cutters have up to 3 cutting edges,” says Mr. Thiermann.

The lowest possible production tolerances, such as an impressive 2 µm concentricity and form accuracy of +/- 5 µm, optimise quality, especially when finishing fine surfaces. This often eliminates time-consuming remachining which in turn reduces process costs. Moreover, there is an upward trend in overall economic efficiency thanks to longer tool life and therefore few tool changes. 

Further strong tool partners

Despite the IGAUAN’s strengths in mould making, there are still a few partners in the ZECHA product range capable of increasing your possibilities. These include the graphite cutters and the steel cutters from the PEACOCK range (incl. CBN) and the new QUEEN BEE tools.

PEACOCK tools are the multi-talents for hard and powder-metallurgical steels up to 70 HRC, such as cold and hot work steels, PM steels, special alloys or tungsten copper with more than 50% tungsten content. ZECHA offers an extensive range with mould-optimised total and free lengths. The F-series enable a very high metal removal rate and the whole tool series produces excellent surface qualities. 

The QUEEN BEE 589 series ball and torus cutters promise process-reliable machining of steels up to 58 HRC, nickel based alloys, titanium and special materials up to 1,800 N/mm2. The cost-optimised specifically for mould making adapted tools are available from 0.8 to 12mm in diameter. Solid tool properties, coupled with the latest coating technology, increase tool life and minimise tool changes. Furthermore, you get very smooth surfaces and less material adhesion.

Maximum precision and cutting quality

Both tool concepts, PEACOCK and QUEEN BEE, combine the performance potential of the latest solid carbide grades with finely tuned tool geometry and state-of-the-art PVD coating. The carbide offers a high level of hardness and toughness at the same time, making it very stable. Thanks to their optimised micro-geometry, these tools achieve low cutting forces and a smooth cut. The coatings possess an impressively smooth and homogeneous surface, temperature resistance, strength and damping, as well as the best possible coating adhesion.

Thanks to the lowest manufacturing tolerances, a concentricity of 3 µm and a shape accuracy of +/- 5 µm, these series are particularly interesting for finishing fine surfaces. Andreas Weck: “Both are perfectly suited for wet and dry milling. This makes them the perfect choice for mixed machining, automation and demanding applications with long running times. Thanks to their high mechanical load capacity, they can withstand any marathon machining session – unmanned, overnight or even the entire weekend.” “

For hard cases: CBN 

Occasionally in mould making, hard and powder metallurgical steel of up to 70 HRC simply can’t be avoided. This requires a particularly tough cutting material to withstand the intense temperatures in the machining process. Cubic crystalline boron nitride (CBN) is the ideal counterpart for such tough jobs, as it combines a high hardness and fracture resistance, even in interrupted cuts, with high thermal and chemical resistance. “In a way, it’s a trick to heat up the material for machining, making it softer which leads to longer tool life.,” explains Mr Thiermann. 

At the same time, CBN has a very high density and resistance to cracking and diffusion. It enables a homogeneous and even cut, which also contributes to very good surface finishes. Overall, CBN cutting materials offer high reliability, tool life and accuracy when machining steels of up to 70 HRC 

High performance tool life champions

If you don’t want to worry about precision, tool life and quality in your machining processes when mould making, it’s best to use tried and tested milling tools. In order to get the most in terms of efficiency, mixed machining and automation solutions show us where the road can lead in the future. “And,” as Mr Weck states, “with our extensive tool portfolio, our tool users are well prepared for current and future challenges!”

Image 1: Laser sharp and proven in mould making: the IGUANA series from ZECHA Hartmetall-Werkzeugfabrikation GmbH is the diamond coated  solids carbide milling series with extremely sharp cutting edges and endurance.

Image 2: the excellent surface qualities achieved often save time consuming reworking of the workpiece. The copper electrode example shows that IGUANA achieves a form accuracy of 5 µm with a running time of 9 hours and surfaces in gloss quality (Ra 0.1 µm).

Image 3: Thanks to their high mechanical load-bearing capacity, they successfully achieve long-term use in demanding applications – unmanned, overnight or even the entire weekend.

For further information:

ZECHA Hartmetall-Werkzeugfabrikation GmbH
Benzstraße 2
75203 Königsbach-Stein
Tel: +49 7232 3022-0
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