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Micro machining once again breaks new ground in tolerances with Zecha

The manufacture of graphite electrodes has established itself as an important process in tool and mold making. Nevertheless, it is also a great challenge for every machinist. Modern CNC machines enable particularly intricate shapes and structures to be manufactured at µ accuracy. However, to a large extent, it is the milling cutters that determine the quality of the finished graphite electrodes. This is why Zecha Hartmetall-Werkzeugfabrikation GmbH has over a dozen high-performance precision tool series providing a high degree of geometric and concentric accuracy.             

Many tools and mould manufacturers rely on graphite electrodes in their manufacturing processes as this material, a modification of carbon, is extremely corrosion and heat resistant as well as highly abrasive. Machining of graphite generates very low vibrations, making it extremely easy to produce intricate shapes and contours without any burring. Manual reworking or burn-off - material loss caused by oxidation - are, thanks to the right mill cutter, a thing of the past.

Robust diamond coating

"The high speed processing of graphite not only requires modern CNC machines, but also, and essentially, high quality tools," stresses Arndt Fielen, Sales Manager at Zecha Hartmetall-Werkzeugfabrikation GmbH. Zecha offers just such efficient milling tool series for an exact manufacture of intricate 3D contours.

In order to make the mill cutters even more resistant to wear, the tool manufacturer based in Königsbach-Stein not only selects a suitable coating but also draws on the experience of a renowned coating company. Arndt Fielen: "Its competence in the field of hard material coating and the CVD diamond coat exclusively developed for Zecha means that our milling tools also display significantly higher life cycles as well as concentric accuracy."  Its hardness of 10,000 HV makes diamond one of the world's hardest materials and thus absolutely essential as a coating material for the machining of graphite as well as other materials as it consistently guarantees optimum tool quality.

Long-life versatility

Boasting diameters from 0.1 mm the solid carbide tools in the graphite mill cutter range can mix it with the best of them: The terms "Quality Line", "Premium Line" and "High-End Line" stand for reliable VHM radius and torus end mill cutters that perfectly equip the graphite machinist. All three mill cutter ranges are recommended for roughing, pre-finishing and finishing for precise machining. The geometries developed by Zecha enable tight tolerances in shape, concentricity and diameter. Especially noteworthy are the SEAGULL® mill cutters with shortened flute lengths and low cutting pressure: They are virtually vibration free and reliable within 5 µm.

The Premium Line ball and torus mill cutters are available in two and four flute versions and in diameters ranging from 0.2 to 12 mm and 0.4 to 16 mm respectively. "These tools are very processed capable especially in roughing operations," says Arndt Fielen. "The salient features of this product line are the exceptionally high life cycle and the narrow tolerances." The Premium mill cutters, such as, for example, Series 572, can machine at an accuracy of 10 µm both in shape and concentricity. In addition, there are the low cutting forces, likewise essential for graphite machining: They prevent faulty contours and insufficient surface quality.

The Zecha Quality Line represents superb value for money: Large-scale manufacture has optimized the cost of these quality tools. Series 565 or 575, for example, are particularly suitable for standard applications. Furnished with the tried-and-tested diamond coating, the ball mill cutters are available in diameters ranging from 0.2 to 10 mm and the torus cutter from 0.2 to 12 mm. The carefully conceived geometry is an innovation; the two-flute cutters achieve concentric accuracies of 5 µm and geometric accuracies of +/- 7 µm. The precise machining results convince every user involved in the HSC machining of graphite electrodes.

High precision graphite cutters

Zecha's High-End Line is the high-performance cutter for large-scale manufacture. Its very strong, robust diamond coating means that this line produces superb surface quality and extremely narrow tolerances. A geometric accuracy of about 5 µm and a concentric accuracy of 3 µm means that this versatile tool is up there with the best of them.

Moreover, the ball and torus cutters which are available in diameters ranging from 0.1 to 10 mm and 12 mm respectively, such as the Series 560 or 570, boast very long life cycles as well as short mill processing times. Arndt Fielen is well aware of the tools' strengths: "The highest manufacturing precision is not just a case of wishful thinking - the two and four flute graphite cutters are processed capable and display their abilities in 3D machining even at maximum speeds."

Vibration-free SEAGULL® cutters

The range of applications offered by the standard length cutters is augmented by the robust SEAGULL® cutters in the Quality and High-End lines. They are ideally suited for the milling of fine-grain graphite, for example, in the processing of freeform surfaces and ribbed geometries as well as for finishing.

The key difference from the conventional torus and ball cutters is the effective flute length: The patented short flute and the special geometry allows the cutting pressure to be minimised, with the result that the cutters demonstrate the highest level of performance in electrode manufacture Arndt Fielen: "Optimum results can be seen precisely in hard brittle materials like graphite: You can even reliably mill very thin and intricate shapes within 5 µm. In contrast, conventional cutters frequently machine at cutting pressures that are too high, leading to faulty contours or insufficient surface quality. This does not happen with our SEAGULL® cutters! “

The ball mill cutters are each available in total lengths of 40 - 120 mm and in diameters ranging from 0.3 to 10 mm. Somewhat larger are the torus cutters in diameters from 1.0 to 12 mm with a total length of between 60 and 120 mm. The series is suitable above all for thin and deep contours. "By deciding on the low-vibration SEAGULL® cutters, the user is opting for a high performance and reliable machining talent - precise and with extremely high life cycles," explains Arndt Fielen.

Ideal partner for highly complex machining

The cutters offer a perfect balance with their combination of optimum tungsten carbide types, robust coating, precise finishing and special geometry tailored to graphite processing. "Our tools enable the HSC milling of highly complex graphite electrodes to be effected with low vibrations and with top results," confirms Arndt Fielen. "It is an ideal partner that saves time-consuming reworking and is quite simply the most economical solution out there."

You can reach to:
Dagger Master Tool Industries Ltd.
Office no 53, 4th floor C wing,
KK Commercial Market, Bibwewadi Road,


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