Walter tools at work in the toughest of machining conditions

By Niraj M Wanikar, Chief Editor, CNCTimes.com, 2015-11-26 15:04:41

Uwe Krumm Burbach GmbH (UKB) is considered Europe's leading partner for edging tools and shear blades. But when the contract manufacturing department had to machine components two metres long made of high-tensile-steel, the company found its existing tools were reaching their limits. Only intensive consultation and the tools provided by Walter AG lead to a breakthrough for the project.
All the tools available at UKB failed when machining a component made of the high-grade steel X36CrMo17 (1.2316), which is often used in the plastics and foodstuffs processing industries. The hardened and tempered profile steel is particularly tough and wear-resistant;an operating strength of up to 1100 N/mm² caused the tools to wear out in a matter of minutes. However, almost a half of the components, measuring approximately two metres in length and half a metre in diameter, have to be machined.
Production Manager, Mr Peter Diehl contacted Walter field service employee Mr Andreas Greiner and Walter Application Engineer, Mr Achim Hoepfner. In the preliminary discussions, they clarified the actual task and created an initial concept. "In the preliminary stage, as application engineers, we first exchange ideas on this type of project in order to be able to present a rough concept during the first visit. Together, we consider what tool and which indexable inserts could be suitable," explains Mr Hoepfner. After two and a half days of hard work at the customer's site, a solution was found and the joint project could begin.

Tool life and metal removal rate multiplied
Andreas Greiner and Achim Hoepfner replaced a copy mill with a Walter round insert cutter fitted with ROHX1204MO indexable inserts. The cutter body, indexable inserts and relative cutting data, significantly changed from the previous machining parameters, achieved surprising results. Andreas Greiner: "We were able to increase the tool life by more than six times. The metal removal rate per minute was almost quadrupled."
The results when milling a slot were even more drastic: A conventional solid carbide cutter was replaced by a high-performance Walter Proto?max™ ST solid carbide cutter. Andreas Greiner: "We have increased the metal removal rate by more than sixteen times from just 1.72 cm³/min to 28 cm³/min." That naturally resulted in a significant reduction in working time. Working time dropped from five hours to just 50 minutes per component for this step in the process. In addition, Mr Greiner and Mr Hoepfner recommended the Walter F2238 porcupine cutter for further milling operations. This cutter helped to shorten machining time further, while improving quality at the same time.
Experience is required when working with this material," explains Andreas Greiner. "If machined incorrectly, the material will become so work hardened that it is unmanageable for replacement tools." He also refers to the important factor of speed, using an ideal tooling concept: "If the machines are working at full capacity, solutions are then required that save the customer time and achieve cost optimisation through lower machine tool cost rates."
Tool harmony is crucial
These figures and values are impressive, but for Achim Hoepfner they're just one side of the coin. For him, it's the "harmony" that's particularly important. By that, he means not just a harmonious relationship with the customer, but primarily, the way in which tools are effectively matched together. Mr Hoepfner explains: "In terms of the overall process and efficiency, one individual tool having a long tool life is no use at all. The tool life of one tool must fit in with the longevity of the other tools. Otherwise, I'd have to be constantly changing yet another tool, which costs both time and money."
It can therefore undoubtedly make sense not to fully exhaust the usability of a tool. This can increase the tool life in such a way that it corresponds to the tool life of the other tools. "The aim of harmonisation is to change as many tools at the same time, in order to minimise downtimes." Since application engineers are usually only familiar with the tools made by their own company, and know how these react to changes in parameters, Hoepfner recommends that a component should only be machined using the tools of a single manufacturer so that they can be ideally matched together.
Torben Braun is responsible for tool procurement at UKB. As far as he's concerned, service plays an important role alongside product features: "Collaboration must be straightforward and honest in order for such a project to succeed." Production Manager Peter Diehl adds: "For example, we were struck by the way in which Walter employees were able to identify machining parameters very precisely from the start. This allowed us to find an ideal solution very quickly."
The first project with Walter went so well that UKB has no intention of going without benefiting from this expertise in future: "We have other tasks, such as Hardox machining. That is also an extremely tough, difficult-to-machine material, for which we want to use a thread milling cutter from Walter." And Walter is already scheduled to participate in the next projects where special tools are involved.
Uwe Krumm, Managing Partner of UKB, adds: "I have seen how the Walter employees have dedicated themselves to their work with us here, and I can only say I take my hat off to them."

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