Upon entering the production halls of VMK, one immediately senses: Here, traditional craftsmanship meets state-of-the-art precision technology. Since its founding in 1976 by Dieter Kaiser, the company has evolved from a small family business into a sought-after specialist for gearing – particularly for worm gear drives. Today, the second generation, led by Rico Kaiser, runs the company, and the third generation is already in the starting blocks. With more than 50 employees, VMK produces components such as housings made of cast and steel or coupling components for rail vehicles, covering nearly the entire value chain in gearing: from turning and milling to grinding processes such as worm and gear grinding, internal and external cylindrical grinding, flat grinding, and bevel gear cutting, as well as complex combination machining. 'We want to deliver not only high-quality components but also continuously improve our manufacturing,' emphasizes managing director Rico Kaiser. 'This can only be achieved with modern machines, powerful tools, and partners who can also provide us with new impulses from outside.'
Challenge of new component
In 2024, a new component made of unalloyed structural steel (St52-3; 1.0570) entered production. It was to be manufactured on a 5-axis milling machine of the type Okuma MU4000V-L, which was also integrated into the machine park in 2024. The machine opens up additional possibilities for VMK: in addition to the turning function, it also allows for power skiving. This enables internal and external gearing to be produced directly on the same machine. Thus, several machining steps can be combined in one pass, significantly increasing both accuracy and efficiency in manufacturing.
The new component brought VMK the realization that the previously used milling tools were reaching their limits during roughing. 'The machining took too long, and the process reliability left much to be desired.'
The indexable cutting inserts broke in the middle of the cut, and even if the workpiece was not damaged, every stoppage meant not only lost time but also additional costs. Furthermore, the machining was accompanied by a significant noise level,” describes Rico Kaiser, managing director at VMK, the initial situation.
For a company, this is a serious challenge, as every machine must run reliably and efficiently. 'With our machine park, every minute of production time must be utilized. Downtimes cost time, money, and nerves,' emphasizes Kaiser. It was therefore natural to involve the long-standing partner Tungaloy-NTK Germany, with whom VMK has been successfully collaborating since 2010.
Optimization with a familiar partner
Marc Deckwart, consulting and sales at Tungaloy-NTK Germany, has known the company VMK and its processes for many years and maintains a friendly relationship with many employees. Together with Richard Lachmann (project manager for milling at VMK), who is considered the 'brain behind the processes', he analyzed the machining in detail. The goal was clear: a solution that provides longer tool life, shorter machining times, and higher process reliability – and additionally reduces the noise level.
Particularly during roughing, VMK faces special challenges. This work step is crucial for the production of gears, as a lot of material often needs to be removed in a short time before fine precision machining can take place. The clamping conditions are often far from optimal. Many workpieces are only fixed at a few points to allow for machining from as many sides as possible in one setup. 'For conventional milling cutters, this is a challenge, as deep cuts and high cutting pressure can cause vibrations and delays,' explains Marc Deckwart.
'Our high-feed milling cutters excel precisely here: thanks to lower depth of cut and high feed speed, they can be well adapted to the respective setup. The cutting pressure remains low, the components are preserved – and yet VMK achieves high material removal rates. Additionally, the tools run significantly quieter, which noticeably increases working comfort in manufacturing.'
Dream team for efficient rough machining
The tool choice ultimately fell on DoFeedTri and AddDoFeed from Tungaloy. Both high-feed milling systems bring speed, safety, and cost-effectiveness to roughing in manufacturing. The DoFeedTri is the specialist for maximum performance. Its indexable cutting insert offers six cutting edges, drastically reducing costs per edge and significantly increasing cost-effectiveness. At the same time, the triangular geometry ensures a stable hold in the insert seat – even with long overhangs or dynamic ramp movements. The reduced entry angle significantly lowers cutting pressure, chatter marks are avoided, and the machine runs noticeably quieter. In short: The DoFeedTri delivers high feeds, impressive material removal rates, and great process reliability.
The AddDoFeed is the ideal complement and comes into play when space is tight. With its compact and relatively thick indexable cutting inserts, it effortlessly masters small diameters and confined machining situations.
The robust design ensures that the tool runs stably even under difficult conditions – and that with four cutting edges per insert, which further increases tool life and productivity.
Even in the first test runs, the tools convinced. The cutting behavior was clean, the operation smooth, vibrations no longer occurred, and the feed speeds were significantly higher than before. After a brief fine-tuning of the parameters, the tool ran like a clock. 'We were immediately impressed by how stable and quiet the DoFeedTri operates – and that with significantly higher feed rates,' recalls Rico Kaiser.
Clear results in the comparison test
The decisive proof of the performance capability of the Tungaloy tools finally came in the direct comparison test. Under identical conditions, the previously used competitive tool and the DoFeedTri faced off – and the result was clear. The high-feed milling cutters enabled significantly higher cutting parameters with a spindle speed of 3,937 min⁻¹, which corresponds to an increase of almost 300 percent, and a feed of 8,951 mm/min – about 800 percent higher.
At the same time, the number of required cuts decreased from 103 to 57, a reduction of nearly 45 percent. In practice, this meant significantly shorter processing times and a considerably increased productivity.
The tool life also increased significantly. The output per cutting edge could be increased sixfold – from five to thirty pieces. At the same time, the wear pattern changed fundamentally. While the competitor's tool failed due to chipping, increasing the risk of scrap and machine downtimes, the DoFeedTri exhibited uniform flank wear. This stable, well-calculable wear allows for planned tool changes, higher machine availability, and overall significantly better process reliability.
More efficiency and safety in everyday manufacturing
Today, DoFeedTri and AddDoFeed are indispensable in the production of VMK. They are used in almost all roughing operations, whether on solid cast housings or complex coupling parts. Processing times are significantly shorter, tool lives considerably longer, tool changes less frequent, and process reliability noticeably higher. 'With Tungaloy-NTK, we have a partner that does not just supply tools but also thinks along and provides new impulses. This allows us to continually optimize our production and produce more efficiently, stably, and economically. This collaboration gives us the necessary edge in competition,' summarizes Rico Kaiser.
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