High rotational speeds, more exact machining: Celeroton's system often are used in micromachining applications. An interview with one of our project partners.
Hello Dr. Kuster. Inspire supports the technology transfer between research and industry. What are the main tasks out of inspire and what is your personal area of activities?
As an ETH transfer institute inspire supports the innovation in the area of product development and production engineering, including manufacturing equipment. The involved professorships cover a broad competence spectrum and, together with inspire itself, are a powerful partner for new research and development projects of the industry. Based on an order from or in collaboration with industry, the professorship for machine tools and production engineering, led by Prof. Konrad Wegener, develops innovative and productive manufacturing solutions involving materials, tools, machines and measurement methods. Precision, reliability and custom-made solutions have been the strength of the Swiss Industry, which have to be continuously improved to fulfill the increasing expectations. In this processes, we support our project partners with developing entirely new solutions or improving existing processes.
In our research group manufacturing processes we for example develop new methods for the dressing of super abrasives with very hard bonding. We achieve this with the help of electrical discharge machining or lasers.
Micromachining technologies have been taking great steps in development over the last few years. Which trends do you predict for the future evolution?
The manufacturing of micro structures is mainly known in the electronics industry and also in sensor technology. With photolithography, masks and etching smallest structures are applied to usually flat surfaces. Often, this is used for mass production. The choice of materials is limited mainly to silicon and glass. However, small structures also become more important in other applications, such as medical technology or cameras in our smartphones, therefore also here appropriate manufacturing methods are required. Currently, we are undertaking experiments with short pulsed lasers, micro electrical discharge machining or microcutting. For the latter we are looking for a machining and drilling spindle with highest rotational speed and sufficient stiffness for machining small structures or holes with small diameters.
Inspire has also realized a project with Celeroton. What was it about? Can you tell us more about it?
The very fast and small motors and the high skills in electrical drive systems of Celeroton attracted us very much from the beginning. Based on the collaboration with Celeroton we hope for a very fast turning spindle for microcutting. Such a spindle is very important for us since only with the high rotational speed we can reach acceptable cutting speeds which we require due to the small tool diameters of around 1 mm. From conventional chipping we know that the high cutting speeds not only reduce the machining time but also the machining forces. Especially with small tool geometries this is very important for achieving precision.
And how did the tests evolve?
In our pre-evaluation tests we run a slightly modified motor from Celeroton at speeds of 200,000 up to 300,000 rpm, and could confirm our expectations. Such a drive systems allows for a significant reduction of machining time. The tools did withstand the loads, but the observed forces were higher than the motor is designed for. But we strongly believe that thanks to the technology of Celeroton an optimized design of very fast rotating spindle is feasible, which would open us the door to explore the microcutting of very different materials. A further challenge is the required balancing quality of the tools.
It seems that Celeroton’s solution proved of value. What is the long term potential you see for drive systems with high speeds in the micromachining industry?
Especially Switzerland as a country for the manufacturing of watches and medical products, offers a huge potential for these drive systems if you think about the manufacturing of mechanical parts. The combination of highest speeds and small and compact dimensions of the motor is the solution the market is looking for. Micro-optical and micro-mechanical products of different type, mold design and construction for the micro impression and various other applications add it up. I wish Celeroton a lot of innovative capacity and endurance when capturing these markets.
Many thanks for the interview.
Many thanks to Celeroton for the uncomplicated support and the good collaboration.
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Dr. sc. techn. Fredy Kuster
Fredy Kuster works at the institute of machine tools and manufacturing at ETH Zurich in close collaboration with the transfer institute “inspire”. As the group leader in processes he leads researchers as well as PhD students of both institutes. Due to his projects he has a broad contact base in the worldwide machine industry.