全体的なプロセスが違いを生む

Umformtechnik Radebeul (UFT) 社はアルミ鍛造のスペシャリストです。同社が特に得意とするのは、複雑な形状を持つ薄型のドロップ鍛造品で、高品質の製品が鋳造アルミニウムでは提供できない安定性を必要とする場合に需要があります。

ラーデボイルの工場は120年の歴史を持ち、その間、所有者や事業分野は何度も変遷してきました。1957年に落し鍛造品の製造が始まり、そこから今日のUmformtechnik Radebeul GmbH社が誕生しました。2001年には、生産体制をアルミニウム鍛造品に変更しました。Aluminiumtechnik Radebeul GmbH社として部分的に運営していた同社は、2006年に金型製造、試作品製造、部品加工、組立の分野で現在の形態になりました。

2017年、ラーデボイルに本拠を置くこのメーカーは、ラインスベルクのUKM Fahrzeugteile GmbHに買収されました。両社の事業分野は互いに補完し合っているといえます。UKMグループは、金属部品の高精度機械加工を中心とする自動車産業のサプライヤーです。UFTは、さまざまな用途向けの複雑なアルミ鍛造品を製造しています。約60％を占める二輪車用部品が最大のシェアを誇っています。

UFTは主要メーカーのバイク向けに、トリプルクランプ、フットブレーキ、フットシフトレバー、サイドサポート、フットレストプレートなどを製造しています。デリケートな形状や複雑な形状の場合もあるほか、機械加工では厳しい表面設計が課題となります。ラーデボイルでは二輪車部品に加え、日よけのジョイントやコネクター、スキーのビンディング、消防車のホースカップリングやその他の部品も生産しています。同社は、航空宇宙産業の顧客も獲得してきました。

一般的な注文数量は1万から10万個の間です。しかし、少量生産や高品質のプロトタイプは、ラーデボイルの工場が特に得意とするところです。UFTは短納期を特徴としています。

製造ホールを見学すると、その製造の奥深さに驚かされます。自社の工具工場では、鍛造用工具、プレスブレーキ用工具、フライス用治具、UFTの鍛造用測定・検査装置などを製造しています。試作品はブランクから機械加工されます。焼入れ工場も建物内にあり、部品に最終的な外観を整え、部分的に組み立てる機械製造施設もあります。表面処理のみ、近隣の協力会社が行っています。

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.
 

However, MAPAL was still to be given a real chance to prove itself. According to Albrecht, it is very rare for UFT to produce two identical parts, but when it came to forging tools for the manufacture of footrests for a large motorbike manufacturer, two dies had to be produced at the same time. In the case of very sensitive orders, production uses exchangeable inserts to be able to run the process without major disruptions. UFT produces 20,000 footrests per year. A die can handle about 10,000 parts before it needs to be replaced.

This provided the perfect opportunity to test the tools of two manufacturers against each other under identical conditions – with the same connections and on the same machine, a Hermle C40. In addition, it was a demanding part with complex machining. When the die is machined, less than half of the material remains at the end. To produce all the contours, relatively small tools sometimes plunge deep into the material.
 

“We decided to let MAPAL machine a part completely from start to finish in order to determine what the tool manufacturer is actually capable of”, says Albrecht. “In terms of testing conditions, it couldn’t have been better.” Wendler took advantage of the freedom granted and worked out a machining strategy. In order to match geometries and avoid problems with tolerances and tool restrictions, he oriented himself to the tools previously used and selected 18 suitable tools from the MAPAL portfolio to compete against them. 

MAPAL sent its high-feed milling cutter NeoMill-4-HiFeed-90 into the race against the proven classic round-insert milling cutter. The result amazed the manufacturers in Radebeul: The machining time could be reduced by 28 percent. “It was a big wake-up call when we realised that we could save so much working time and, consequently, money on a single part”, admits Albrecht.

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.