The best solution for dental technology

03.09.2020

Hufschmied tool wins the dental technology benchmark of the Augsburg University of Applied Sciences

The Faculty of Mechanical and Process Engineering at Augsburg University of Applied Sciences has carried out a scientific comparative test of dental technology tools for zirconia machining. The conclusion: The choice of milling tools has a significant impact on the quality of the results and the efficiency of the machining process. The winner of the benchmark is a tool from Hufschmied Zerspanungssysteme GmbH that has been optimized for this material. Only with the HC720DT-DIP®3S milling tool from Hufschmied the finest structures could be machined effectively. Even in the tool life test it delivered consistently high quality.

The benchmark test of tools for machining zirconium dioxide was carried out by Lena Wieland as part of her bachelor thesis under the supervision of Prof. Dr.‑Ing. Ralf Goller (process technology for polymer and ceramic fibre composites). Ten manufacturers had provided milling tools for the machining of the ZrO2 ceramic, which is indispensable in dental technology. The benchmark followed the Merlon test, which has proven itself in the industry. In this test, dummy crowns with different wall thicknesses are milled from a ZrO2 blank.

The images compare the milling tool from the company Hufschmied (left) and one of the uncoated tools (Zz right) after the entire test series.  Here a clear difference in the condition of the tools can be seen. While the tool on the left shows no flaws in the coating or in the geometry, the right picture clearly shows signs of wear (color-coded). The perfect condition of the benchmark winner from Hufschmied explains the consistently high quadratic performance in all three machining cycles. Image source: Hufschmied Zerspanungssysteme.

Test procedure

The milling of the blanks was repeated with three tools from each manufacturer. The six tools from the manufacturers with the best results then took part in a further series of tests on tool life behaviour. For this purpose, the machining process was carried out two more times with one milling cutter already in use, so that one of the tools machined a total of three blanks. This shows the tool wear and its effect on the quality of the machining. What is striking is that the performance of uncoated tools drops dramatically from the second blank onwards. Only the Hufschmied tool shows the same high performance in all three runs.

"I congratulate Hufschmied on winning the benchmark for zirconium dioxide machining," says Prof. Dr.-Ing. Ralf Goller, Faculty of Mechanical and Process Engineering at Augsburg University of Applied Sciences." It has been confirmed once again: Material science and material engineering always includes process engineering - in this case material-optimized tools.

"The benchmark of the Augsburg University of Applied Sciences shows objectively how successful we were with the development of a special milling tool for cutting zirconium dioxide in the dental technology. Decisive for the outstanding results in terms of machining quality and tool life are the cutting-edge geometry of the HC720DT-DIP®3S, which is specifically adapted to the material, and our patented diamond coating. Here, dental technology follows the experience with industrial processes: Efficient and process-reliable production in dental technology is only possible with high-quality special tools," says Ralph Hufschmied, Managing Director of Hufschmied Zerspanungssysteme GmbH.

With the HC720DTA, these small crowns can be milled without defects. The wall thicknesses can be milled down to 0.1 mm without breaking. Image Source: Hufschmied Zerspanungssysteme

Adaptation to machine is equally important

The test was conducted with the 5-axis milling and grinding centre developed for the dental technology market Sirona inLab MC X5. The second-best result after the Hufschmied tool in the benchmark was achieved by a tool supplied by Dentsply-Sirona. No surprise for the machining specialist Ralph Hufschmied: "In addition to the adaptation of tools to the material to be machined, the consideration of the characteristics of milling machines and machining programs has the greatest effect. A practical consequence of the benchmark: manufacturers of milling machines for dental technology can score points by providing optimized tools. We are happy to offer our know-how in cooperation with them.

For those interested, the company Hufschmied has summarized the procedure and detailed results of the dental benchmark in a whitepaper - including tables of results for the tested tools: Benchmark of tools for machining dental ceramics.pdf

More information available at www.hufschmied-tools.com