Tooling that shapes tomorrow

With innovation at its heart, milling cutter specialists, Hofmann & Vratny is producing tooling today that will help shape the aerospace manufacturing world of tomorrow.

Hofmann & Vratny (H&V) is a leading manufacturer of solid carbide milling cutters based near Munich, Bavaria. The company's success is based on innovation, a culture of togetherness, open interaction and many years of successful and trusting cooperation with its business partners. H&V focuses on permanent innovation and continuous development of its products, which is also reflected in its comprehensive product portfolio. 

Depending on the application, H&V produces cutters for machining steel, cast iron, titanium, Inconel, aluminium, hardened steel, abrasive material, inox and stainless steel. The new EXN1 series was developed to enable potentially easily machinable materials to be safely processed and meet the specific requirements of non-ferrous material cutting.

In addition to extensive tests in the company’s own R&D department, the performance of the series has been successfully confirmed in wide-ranging field tests. The successful launch of the series is reflected not least by the feedback from enthusiastic customers from a wide range of industries such as food and automotive industry. 

The enthusiasm was particularly great in the aerospace industry because, in addition to the standard cutters of the EXN1 series, special solutions are also developed particularly for this industry. When cutting materials for the aerospace industry, the demand for surface precision and dimensional accuracy in extremely narrow tolerance fields is of high importance. In addition, there are constantly new materials and innovative machining processes for which the right tools are required. H&V has permanently adapted its special milling cutters to the new demands in the aerospace industry so that they can be subjected to the highest loads while delivering the best machining results.

In the development of the new expert series, the focus was on increasing the tool life, the surface quality on the produced workpiece and highest process reliability. The milling cutters possess a special cutting-edge preparation with a defined edge rounding. This ensures homogeneous cutting edges throughout, even distribution of cutting forces and reduced wear. 

The manufacturing tolerances for radius and concentricity have been optimised to a maximum of 0.003mm to 0.005mm and ensure the best possible level of accuracy. The new high-performance geometry with refined grinding pattern and tuned micro-cutting edge ensures a sharp cut and excellent chip removal. 

The milling cutters are completed by using a fine-grain substrate specially designed for machining non-ferrous materials. The portfolio includes 35 article groups (645 individual articles), consisting of end mills, roughing mills, finishing mills, trochoidal mills, single flute mills, torus mills, full radius mills and micro milling cutters with diameters ranging from 0.1mm to 20mm.

“We have conclusively proved that using EXN1 reduces production time by more than 50% per component,” says H&V’s managing director, Marius Heinemann-Grüder. “Everything we do is driven by trust and a constant hunger for change. That’s what makes us stand out as a company. We do everything we can to surpass our own quality standards every day and to make worldwide innovation happen. That is our ambition as a team.”

The test phase has shown that it’s possible to massively reduce production times by switching to the H&V EXN1 series. With the use of the new Performmaker (endmill), one customer reduced production time per component by more than 50%. This was achieved by larger infeeds and higher feeds. Likewise, the use of the new Mirrormaker (finishing cutter) improved the surface quality on the machined parts to a roughness of less than 1µm. Previously, the customer used standard aluminium cutters from a competitor with zirconium nitride (ZrN) coating.

In order to optimise the surface quality when using the milling cutters, as well as to prevent built-up edges, an innovative coating of tetragonal carbon was also designed. This novel coating process increased the sp3 bonds to over 85%, reduced the coating thickness to less than one micron and lowered the coating hardness to approximately 4500HV. In addition, the coating is characterised by a very high smoothness, as it forms almost no droplets and ensures a minimal coefficient of friction (approx. 0.05 dry on steel). Almost all non-ferrous materials can be machined quickly and reliably with these milling cutters. 

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