The Winning Drill


Walter’s high-performance drill gives client competitive edge

THE DC170 SUPREME HIGH-PERFORMANCE drill from Walter AG helped Feldmann-MAB GmbH gain a distinct advantage over competitors, when they applied for a manufacturing contract for rocker arm shafts for a new generation of engines. The ‘Ikon of Drilling’, as Walter calls it, landed the contract thanks to its advanced technology and the improvements provided in cost efficiency.
“Prior to this new project, we always drilled using standard tools. But this time, these were completely new parts for an entirely new engine. We had to drill lengthways through differently sized rocker arm shafts made of very tough steel,” explains Udo Achterholt, MD of Feldmann-MAB. This needed to be accurate and quick in equal measure. “Without external help, we might not have been able to get it right because the positions and position tolerances are incredibly strict.” To make things even more difficult, not even the tiniest amount of burr may remain in the drilled hole and the cross holes. The shafts are therefore thermally de-burred as well.
For the rocker arm shaft project, Walter introduced the DC170 Supreme. Walter Deutschland field service employee Udo Schuster says this is a typical situation for them: “Customers are often not sure how they can carry out machining in an optimum manner. We generally assist them with one or more Walter products that are suitable for this precise type of machining.”
Achterholt adds, “We always go directly to Walter with a new part and the demands made on us, and we get to work formulating proposals.” The decisive factor for him is that “the process must be correct in order to manufacture in a way that is cost-effective.”
About the rocker arm shafts, he says, “They are completely finished when they leave the machine; all we then have to do is subject them to de-burring and vibratory finishing.”
Oliver Fischer, head of process engineering, points out, “We use Walter tools for all operations on shafts: Tiger tec Silver indexable inserts for turning, the Proto•max high-performance milling cutter for milling and the X•treme high-performance drill for the rest of the drilled holes.” However, the most difficult challenge by far was drilling the long internal hole through high-strength steel heat-treated to 1300 N/mm². Achterholt explains that “this kind of steel is particularly tough, making it difficult to machine. Nevertheless, the drilled hole must never run off-centre.” The DC170 Supreme is at home with this material. The drill offers three advantages: accuracy, service life and speed. As Fischer explains, “The DC170 Supreme allows us to achieve much higher cutting data than with our standard drills. The DC170 Supreme goes into the material like it is butter and we don’t ever have to peck in between.” Achterholt believes that this drilled hole was also a key factor in Feldmann-MAB ultimately being awarded the contract for the shafts.


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May 2019
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