The overall process makes the difference

Umformtechnik Radebeul (UFT) is a specialist in forged aluminium. A particular strength of the company is thin-walled drop forgings with intricate geometry, which are in demand when high-quality products require more stability than cast aluminium can offer.

In total, the factory in Radebeul has existed for 120 years, during which ownership and business fields have changed repeatedly. The more recent history begins in 1957 with the construction of a drop forge, from which today’s Umformtechnik Radebeul GmbH emerged. In 2001, the production structure was changed to aluminium forgings. The company, which in the meantime operated in parts as “Aluminiumtechnik Radebeul GmbH”, took on its current form in 2006 with the areas of toolmaking, prototype production, parts machining and assembly.

In 2017, the Radebeul-based manufacturer was taken over by UKM Fahrzeugteile GmbH from Reinsberg. The companies’ business areas complement each other. The UKM Group is a supplier to the automotive industry with a focus on the high-precision machining of metal components. UFT manufactures complex aluminium forgings for many different applications. At around 60 per cent, parts for motorbikes account for the largest share.
 

For motorbikes of major manufacturers, UFT produces, among other things, triple clamps, foot brake and foot shift levers, side supports, and footrest plates. In addition to the sometimes delicate shapes and complicated geometries, the demanding surface design is a challenge during machining. On top of two-wheeler parts, joints and connectors for awnings, ski bindings as well as hose couplings and other parts for fire engines are also produced in Radebeul. The company was also able to win over customers from the aerospace industry. 

Typical order quantities are somewhere between 10,000 and 100,000 parts. However, small series and prototypes of high quality are a particular strength of the factory in Radebeul. UFT is characterised by short delivery times.

On a tour of the manufacturing halls, the extraordinary manufacturing depth is striking. The company’s own tool shop manufactures forging tools, press brake tools, milling jigs as well as measuring and testing devices for UFT’s forges. Prototypes are machined from blanks. A hardening shop is also located in the building, as is a mechanical manufacturing facility where the parts are given their final appearance and are also partly assembled. Only the surface treatment is carried out by partner companies in the immediate vicinity.
 

At UFT, 15 of the total 170 employees work in toolmaking. “They are all trained cutting machine operators”, says Steffen Albrecht, Head of Tool Production at UFT, explaining the efficiency of this area. Occasionally, tools are also produced for external customers, but the majority are intended for internal use. UFT has around 500 finished forging tools in stock at any given time, and with every new part more are being added. For the spare parts market of some customers, the tools have to be kept in stock for up to 15 years.

The toolmakers mill the forging tools out of blocks of tool steel. Felix Wendler, Product Specialist Die & Mould at MAPAL, used his many years of personal contact with the manufacturers to encourage them to try out new tools for their machining. Because at UFT, they were quite satisfied with the existing cutting tools.

This did not immediately change, even when a ball nose milling cutter from MAPAL was tested. “The milling cutter from MAPAL was no worse, but also no better than the one we already had”, states Albrecht. Even an improved version of the milling cutter from MAPAL could not persuade the toolmakers to jump ships. “That was certainly also due to the fact that we are already working at a very high level”, explains Albrecht.
 

Doch MAPAL sollte noch eine richtige Chance zur Bewährung bekommen. Zwar kommt es auch bei der UFT laut Steffen Albrecht sehr selten vor, dass zwei gleiche Teile zu fertigen sind, doch als es um Schmiedewerkzeuge zur Produktion von Fußrasten für einen großen Motorradhersteller ging, sollten dafür gleich zwei Gesenke hergestellt werden. Bei sehr brisanten Werkzeugen verwendet die Produktion Wechseleinsätze, um den Prozess ohne große Störungen laufen lassen zu können. Von den Fußrasten stellt die UFT 20.000 Stück pro Jahr her. Ein Gesenk schafft etwa 10.000 Teile, ehe es ausgewechselt werden muss. 

Eine ideale Gelegenheit, um die Werkzeuge zweier Hersteller unter identischen Bedingungen gegeneinander zu testen – mit denselben Aufnahmen und auf derselben Maschine, einer Hermle C40. Zudem handelte es sich um ein anspruchsvolles Bauteil mit einer aufwendigen Bearbeitung. Beim Zerspanen des Gesenks bleibt am Ende weniger als die Hälfte des Materials stehen. Um alle Konturen herzustellen, tauchen relativ kleine Werkzeuge teilweise tief ins Material hinein.
 

„Wir haben beschlossen, MAPAL ein Bauteil komplett von A bis Z bearbeiten zu lassen, um festzustellen, was der Werkzeughersteller tatsächlich kann“, so Albrecht. „Von den Testbedingungen her hätte das besser nicht sein können.“ Wendler nutzte den eingeräumten Freiraum und erarbeitete eine Bearbeitungsstrategie. Um Geometrien abzugleichen und Probleme mit Abmaßen und Störkonturen zu vermeiden, orientierte er sich dabei an den bislang eingesetzten Werkzeugen und wählte 18 passende Werkzeuge aus dem Portfolio von MAPAL aus, die dagegen antreten sollten. Gegen den bewährten klassischen Rundplattenfräser schickte MAPAL seinen Hochvorschubfräser NeoMill-4-HiFeed-90 ins Rennen. 

Das Ergebnis verblüffte die Fertiger in Radebeul: Die Bearbeitungszeit konnte mit den MAPAL Werkzeugen um 28 Prozent reduziert werden. „Uns kam das große Erwachen, als wir feststellten, dass wir bei einem einzigen Bauteil so viel Arbeitszeit und damit Geld einsparen können“, räumt Albrecht ein. 
 

In order to create the best conditions for the subsequent machining steps, Wendler used a 35 mm milling cutter instead of the previous 52 mm cutter. Production Manager Albrecht was very surprised about this: “I was sceptical because with that size difference I didn’t think the small tool could work faster.” But Wendler had his reasons. The 52 mm milling cutter is simply too large for the existing SK40 machines, and the potential of the larger tool cannot be fully exploited. The smaller NeoMill-4-HiFeed-90 high-feed milling cutter he chose, on the other hand, was able to run exactly the cutting data needed. With less cutting width and cutting depth, work was faster in the end.

There was also another factor that contributed to the time savings in the process. The smaller diameter of the milling cutter allows for closer contour machining, leaving less residual material in the corners. This reduces the effort required for further machining. According to Wendler, this is crucial: “Shorter times can hardly be achieved in finishing alone, because the machine is the limiting factor for most users. So I try to create the best conditions already during roughing to gain time overall.”

Thanks to the extremely positive outcome of the project, UFT wants to expand cooperation with MAPAL and tackle further machining work together. “With MAPAL, we have a partner who knows what it is doing. Unfortunately, that’s becoming rarer and rarer”, Albrecht praises. “Having a permanent contact person who can help or give tips if we ever have a problem is a good basis for cooperation.”
 

One milling cutter from MAPAL has become the favourite of machine operators within a short space of time: the OptiMill-3D-HF-Hardened, an extremely powerful solid carbide roughing tool that can be used from soft mild steel to 68 HRC hard powder metallurgical tool steel. “If a tool can actually make the operator beg to be allowed to use it, then we’re really on to something”, Albrecht comments. There are reasons why the tool is so well received: It’s quieter than its predecessor, cuts more smoothly and is therefore more pleasant in terms of volume alone. Operators know up to which tool life they can work with the tool without hesitation before they have to listen more closely during machining.

Another joint project under discussion is the introduction of the UNIBASE-M tool dispensing system, which could be used not only by the UFT tool shop but also by the mechanical finishing department right next door. Tools from MAPAL are also used there, but it is also possible to store third-party tools in the system. The tool stock can be monitored and kept in line with requirements via the digital tool management system c-Com. The adaptive system ensures that as few tools as possible are stored, but that the customer is always fully capable of action – after all, production should run smoothly.