Change of coating at Dathan Verzahnungswerkzeuge: The regrinding specialist now protects its customers' skiving wheels, hobs and shaping wheels with Balinit Alcrona Evo, according to the supplier Oerlikon Balzers. The all-round coating is now available in its third generation. This is also the case at the family-run company Dathan, which recently celebrated its 100th anniversary in England and has a great deal of expertise in gear skiving in Germany.
Gear skiving benefits from advances in CNC technology
This machining process has been experiencing a renaissance for some time now thanks to advances in CNC technology. Known as skiving, it is shaking up established gear cutting processes: While hobbing is mainly used for external gears and broaching for internal gears, skiving can be used for both. Due to its flexibility, the continuous hobbing process is suitable for the diverse machining of gearing parts, even with interfering contours. Thanks to its high cost-effectiveness and productivity, this production technology is the preferred choice for more and more users and manufacturers, especially for small and medium batch sizes.
"When the trend started almost 20 years ago, Dathan was one of the first tool suppliers," explains Jonathan Zimmermann, Managing Director and partner of Dathan Verzahnungswerkzeuge in Neukirchen-Vluyn. He himself contributed a great deal of gear skiving expertise from application technology when he took over the management of the German subsidiary of Dathan Tool and Gauge Ltd. which was launched in 2019. The parent company from Holmfirth near Manchester, England, was founded in 1924 and serves international customers from industries such as aerospace, robotics, automotive, agriculture, power generation, construction, oil and gas with mostly customized gear cutting tools.
Performance leap in gear skiving
According to Oerlikon Balzers, it is the preferred coating partner for resharpening gear skiving wheels, shaper gears and hobs - the core competence at the German site. The AlCrN-based coating material for the cutting tools is applied by arc evaporation. The manufacturer specifies a coating hardness HIT of approximately 44 Gpa (±4), measured by nano-indentation according to ISO 14577, whereby the value depends on the respective application as well as the ambient and test conditions. The residual stress is -3.5 Gpa (±1), measured using X-ray diffraction or the bending method (Stoney equation). The calculated thermal load was deducted. According to the manufacturer, the maximum application temperature is around 1100 °C, although this also depends on the pressure.
Zimmermann experienced significant progress when switching from the AlCrN coating Balinit Alcrona Pro, which has now been replaced, to the new generation Alcrona Evo. Both coatings were used in comparative tests on gear skiving wheels for a German Dathan customer. The process conditions, feed rates and tool life for the machining of camshaft sprockets there remained unchanged. The result showed that the shift change alone resulted in a 20 to 30 % reduction in wear mark width and a correspondingly longer service life. This is due to the fact that the regrinding volume is reduced and the tool can be reconditioned more often - including lower new tool costs.
Balinit Alcrona Evo also shows off its increased coating hardness and toughness compared to its predecessor, as well as its improved homogeneity and edge stability, according to the Oerlikon Balzers press release. "We also work together with Oerlikon Balzers when rounding the cutting edges of the cutting wheels for our customers, as the coating should be distributed as homogeneously as possible over the cutting edges," adds the Dathan Germany CEO. He recommends the coatings particularly for use at high cutting speeds with high heat generation.
From 12,000 to 16,000 sprockets at peak times
The new generation of coatings also demonstrated its properties at a manufacturer of sprockets for the two-wheeler industry. Eight hobs with both coatings were tested in succession, and in the end this Dathan customer was also convinced. Balinit Alcrona Evo enabled a leap from 12,000 to a peak quantity of 16,000 sprockets, resulting in an increase in tool life of 20 to over 30 %. "Such trials are not least a good opportunity for everyone involved to bring processes up to date," says Zimmermann.
According to Oerlikon Balzers, this confirms that the Balinit Alcrona universal coating, which was introduced over 20 years ago, still demonstrates the qualities of an all-rounder in its third generation and can even improve its performance. "The coating scores points not only in gear cutting, but also on shank tools or in punching and forming, with different tool substrates, cutting speeds and component sizes. Customers are rolling it out and the feedback is consistently positive," explains Klaus Springer, Customer Consultant at Oerlikon Balzers. And Zimmermann is also pleased that the coating is already available in all Balzers customer centers in over 30 countries in Europe, North and South America and Asia: "Since Dathan is internationally positioned, we value reliable partners who can deliver worldwide - whether from Germany or China."