When milling carbon fiber reinforced plastics, especially the aerospace industry demands maximum quality of the machined surfaces and highest process reliability. The companies Hufschmied Zerspanungssysteme GmbH and CemeCon are now setting new standards for this important future industry in close collaboration. A jointly developed premium tool combines geometry, substrate, and diamond coating into an optimal solution.
The machining of carbon fiber reinforced plastics, or CFK, which are particularly advantageous for lightweight construction, is one of the greatest challenges in the machining industry. In aircraft construction, even more demanding variants of the composite material are used. At the same time, there is an absolute focus on maximum component quality, which completely forbids compromises and demands the highest performance from the milling tools used. The high-strength fibers must be cleanly separated despite their different orientations within the matrix. Otherwise, fiber overhangs or delaminations occur, which require at least a labor-intensive manual reworking.
Especially the manufacturing of large aircraft parts, such as shells or segments for the aircraft fuselage, presents aircraft manufacturers and suppliers with a very specific problem: The wall thicknesses often range from a few millimeters to several centimeters. Enormous transverse forces act on the milling tool at the transitions. In the worst case, it can break, and fracture pieces can enter the interior of the component - production interruptions or even the loss of entire components would be the costly consequences. The use of copper mesh as lightning protection presents another challenge in machining. The goal is a post-processing-free component edge - without copper overhangs.
The development partners Hufschmied and CemeCon have jointly faced exactly these challenges. The Bavarian tool manufacturer and the coating specialist collaboratively designed a new milling tool that significantly increases process reliability in CFK milling and whose service life could be extended by more than 50 percent compared to similar tools.
Structured Path to the New Premium Tool
"Our customers from the aerospace industry emphasize it repeatedly in discussions: When machining components made of composite materials, process reliability has the highest priority, as even the smallest component deviations can become very expensive. This has awakened our ambition to convince users in this area with a significantly improved solution," says Fabian Lindinger, Head of Application Technology at Hufschmied. The foundation for the groundbreaking HEXACUT 058 milling cutter specifically for aircraft components made of CFK was laid.
On the way there, the existing tool geometry was first re-evaluated and revised at Hufschmied's development center near Augsburg. The new tool should not only ensure optimal process reliability but also meet another requirement: The cutting quality must remain guaranteed over as long a service life as possible.
Perfect Coordination of Tool Parameters
In the further process, it became clear how a strong partnership in terms of innovation technology can make a difference: Because essential for an ideal overall result was, of course, the adapted coating, which was tailored to the tool geometry developed by Hufschmied and the novel substrate. For this purpose, the coating experts from CemeCon specified a diamond coating material for the new tool, which already achieved absolutely outstanding quality in the tests. "It was extremely fascinating to observe how the optimal pairing of carbide substrate and coating material gradually crystallized," recalls Javier Fuentes. The Head of Development for Coatings and Cutting Tools at Hufschmied emphasizes: "In productive teamwork, we were finally able to achieve a homogeneous wear pattern, with which we can achieve a clear, smooth milling edge at a consistently high level throughout the entire tool life. And coating flaking or even tool breakage simply did not occur in the product tests anymore."
Marco Furrer, Sales Manager at CemeCon, explains: "For the new Hufschmied tool, we specifically adapted the proven CemeCon coating material CCDiaAeroSpeed. This allowed us to achieve extraordinary adhesion on the carbide selected by Hufschmied despite a high coating thickness. The convincing result: The new HEXACUT 058 from Hufschmied enables users to maintain consistently high cutting quality, maximum process reliability, also due to significantly less vibration, and a significantly higher service life.
Strong Partners Operate at Eye Level
The entire project process has greatly benefited from the professional collaboration of those involved, as the partnership between Hufschmied and CemeCon has long gone far beyond a mere supplier-customer relationship. In close collaboration, important details such as edge preparations, cutting radii, or coating thickness and architecture were developed. "With combined expertise, we were able to optimize all parameters until we achieved a solution that was consistent in all respects," explains Michael Woda, Manager Development Diamond at CemeCon.
Even in the series production of the HEXACUT 058, the companies continue to work together. The premium milling cutters of the new type are coated at CemeCon's headquarters in Würselen, in the world's largest diamond coating center, and undergo comprehensive quality control. Independently of this, Hufschmied checks relevant criteria, such as the homogeneous coating thickness distribution, once again - for the end customers, this means an additional increase in process reliability.
"This project, just like our other long-standing collaborations with CemeCon, makes an important contribution to establishing Hufschmied worldwide as a synonym for first-class machining solutions," says Managing Director Christel Hufschmied, pleased with the development success. "The new diamond tool and the joint path with CemeCon to its industrial maturity sustainably advance us in achieving our goals."
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