More precise cut edges, less cutting force and therefore a longer tool life: cutting folded sheets with ultrasound technology makes all this a tangible reality. A joint cooperation project conducted by Fraunhofer IPA and bielomatik GmbH came to this preliminary result. A follow-up project is to verify the suitability of the innovation for industrial applications. Scientists are still on the look-out for companies interested in participating.
Processes for cutting stacked sheets of paper are incredibly advanced in technological terms. Having said that, quality defects are still occurring when cutting bound layers of paper with a cover. Particularly when the cutting edge first plunges into the bound layer very large forces are exerted for a short period on the cutting edge and the paper.
Consequently, if the paper pushes the cutting edge sideways or forwards during cutting, the layers of paper at the bottom are shorter or longer than those at the top. The result is an undercut or an overcut. Conversely, the paper may be deformed by the cutting edge before it penetrates. The sheets on the top are bent downwards and jump forwards after cutting. They are then longer, producing a “mushroom cut”.
In practice, these cutting errors frequently overlap. The use of ultrasonic technologies offers a promising solution with regard to cutting processes for multiple layers of paper. Blades subject to ultrasonic vibrations cut with less force, which is why they are considerably leaner and therefore cause less displacement. In a cooperative project within the framework of the “AiF Arbeitsgemeinschaft industrieller Forschungsvereinigungen ›Otto von Guericke‹ e.V.” Fraunhofer IPA together with bielomatik GmbH from Neuffen has used ultrasonic technology to develop the basis for a continuous cutting process.
Use of ultrasonically-supported cutting
”A detailed analysis of the existing systems for the ultrasonically-supported cutting of various other materials validated the innovation in relation to the paper industry“, says Frank Eicher from the Image and Signal Processing department at Fraunhofer IPA. Existing applications using ultrasonic vibrations are largely used in the area of machining, and here too the main aim is to minimize friction forces and signs of wear and tear. Similar cutting processes can be found primarily in the food industry, albeit only to prevent food residues sticking to the blade. Cutting forces do not play a key role.
Eicher explains: “The underlying principle when cutting with ultrasonically stimulated tools is based on the generation of high-frequency electrical alternating voltages and their conversion to mechanical vibrations through what are known as energy converters that work according to the reciprocal piezoelectric principle.”
Ultrasonic systems for processing are operated in resonant frequency, which requires a very precise balance between the ultrasound generator and the connected vibration system. This consists of an acoustic transducer, also called a converter, and the cutting tool, which is set into resonance vibration by inducing the ultrasound. The highest demands are placed in particular on the vibrational behavior of this so-called cutting sonotrode. With state-ofthe-art control technology tools can nowadays be stimulated with ultrasonic vibrations to vibrate in a controlled and beneficial manner at their resonant frequency.
Initial experimental system
An experimental system was conceived and the vibration system designed for the application was then integrated into it. Slight skewing of the layers of paper stimulated what is known as a shear cut. The project partners also designed the configuration of the system in such a way that cutting was possible with or without ultrasonic support. This simplified the direct comparison of the cutting forces. “By using ultrasound the process forces were reduced by up to 50% during the cutting process, which led to a reduction of the material stress in the cutting area,” Eicher commented.
This means that the strain on the cutting blade or sonotrode is reduced and the product life is extended. In addition, the lower process forces decisively reduce the effort required to secure the item to be cut. This all has a positive impact on the cutting quality and the operating costs. In a next step, the experimental design is to be optimized to create a purely ultrasonic cutting system in order to fully exploit the full ultrasonic potential.
This is precisely what the engineer would like to focus on in the course of another funded project in cooperation with interested companies. Frank Eicher is optimistic when it comes to the potential of the ultrasonic process: “The use of ultrasound to increase edge quality and tool life for cutting of layers of paper is a unique selling point. It can take a company to technology leader in cut edge quality.”
Frank Eicher | Phone +49 711 970-3543 | firstname.lastname@example.org | Fraunhofer Institute for Manufacturing Engineering and Automation IPA
Press and Public Relations
Jörg-Dieter Walz | Phone +49 711 970-1667 | email@example.com | Fraunhofer Institute for Manufacturing Engineering and Automation IPA | Nobelstrasse 12 | 70569 Stuttgart
Jörg Walz | Fraunhofer-Institut für Produktionstechnik und Automatisierung IPA
How protons move through a fuel cell
22.06.2017 | Empa - Eidgenössische Materialprüfungs- und Forschungsanstalt
Fraunhofer IZFP acquires lucrative EU project for increasing nuclear power plant safety
21.06.2017 | Fraunhofer-Institut für Zerstörungsfreie Prüfverfahren IZFP
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
Germany counts high-precision manufacturing processes among its advantages as a location. It’s not just the aerospace and automotive industries that require almost waste-free, high-precision manufacturing to provide an efficient way of testing the shape and orientation tolerances of products. Since current inline measurement technology not yet provides the required accuracy, the Fraunhofer Institute for Laser Technology ILT is collaborating with four renowned industry partners in the INSPIRE project to develop inline sensors with a new accuracy class. Funded by the German Federal Ministry of Education and Research (BMBF), the project is scheduled to run until the end of 2019.
New Manufacturing Technologies for New Products
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
22.06.2017 | Medical Engineering
22.06.2017 | Life Sciences
22.06.2017 | Life Sciences