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A novel approach for increasing the traceability of 3D printed medical products

Current Directions in Biomedical Engineering 2020年第3期6卷

作者： Matvieieva, Nataliia Neupetsch, Constanze Oettel, Markus Makdani, Varun Drossel, Welf- Guntram Fraunhofer Institute for Machine Tools and Forming Technology Iwu Nöthnitzer Straße 44 Dresden Germany

According to the European Medical Device Directive (MDR (EU) 2017/745), medical products of all risk classes are obliged to be labelled with Unique Device Identification Codes (UDI). In order to meet the requirements of the MDR, a novel method of identification for additively manufactured metallic products was developed at the fraunhofer Institute for machine tools and forming technology (IWU). The method provides a product traceability within its production process and during the whole product lifespan, and also functions as a counterfeit protection. This paper shows the integration of a unique identification during an additive manufacturing process for a titanium part. The readout of the integrated identification was executed using ultrasonic and eddy current methods, as well as micro computed tomography. Obtained results are discussed in the paper. © 2020 by Walter de Gruyter Berlin/Boston 2020.

关键词： Laser beams

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High performance machining of continuous metal fibers with cascaded multi-stage profile tools

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Procedia CIRP 2021年 101卷 334-337页

作者： Uwe Teicher Tristan Lange Steffen Ihlenfeldt Fraunhofer Institute for Machine Tools and Forming Technology IWU Dresden 01187 Germany Technische Universität Dresden Institute of Manufacturing Technology Dresden 01062 Germany Technische Universität Dresden Institute of Mechatronic Engineering Dresden 01062 Germany

Metallic fibers are essential for applications in the chemical industry, the automotive industry for brake pads and, more recently, for the air conditioning modules. The most productive process to date for producing continuous fiber lines with fiber cross-sections between 50 and 150 µm is the application of cascaded multi-stage profile tools for cutting from semi-finished wire products. One challenge is the development of a technology for highly ductile materials made of aluminium, which are used as fiber materials in the area of refrigeration adsorbers. Preliminary studies have shown that high cutting speeds are necessary for machining. For this reason, a highly manually operated machine system was advanced to meet the requirements of high cutting speeds and to integrated a process monitoring system. For the first time, experimental investigations were able to show the interrelationships between set technology values and the effective machining forces for this process. Further investigations were done using the example of aluminium alloys 5019 for an analysis of a control system for wire breakage detection on the basis of force sensors.

关键词： machining aluminium metal fiber optimization

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Development and Validation of Bone Models using Structural Dynamic Measurement Methods

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Current Directions in Biomedical Engineering 2019年第1期5卷 343-345页

作者： Neupetsch, Constanze Hensel, Eric Werner, Michael Meißner, Sven Troge, Jan Drossel, Welf-Guntram Rotsch, Christian Chemnitz University of Technology Professorship for Adaptronics and Lightweight Design in Production Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology IWU Chemnitz/Dresden Germany

Vibration measurement and signal analysis methods are common to evaluate the functionality and characteristics of technical components in different industrial and scientific areas. Modal analysis for example is a standard method to characterize the dynamic behavior of a structure and enables the development of validated bone models. The state of the art of analyzing bone structures does not include the modal damping, although it has a significant influence on the dynamic characteristics. Within the presented investigations, the modal analyses have been performed contactless with respect to excitation and response acquisition, which implies that there are no influences of shakers or sensor couplings. Therefore, an automatic impulse hammer and a 3D Scanning Laser Doppler Vibrometer were used for excitation and response detection. Various supports of the test specimens, surface pretreatments, excitation points and excitation impulses were examined to optimize the measurement setup and process. Experimental modal analysis data were analyzed by curve fitting methods to determine the modal parameters. To evaluate different structures and effects of damping, 3D printed artificial bones and animal in vitro bones were used to perform the measurements. To produce the cortical layer of the artificial bone models, volume models were generated based on medical image data and printed by polyamide-based selective laser sintering. The cancellous bone was represented by different foam fillings for the artificial bones. Thereby, the variation of the porosity was achieved by using different mixing ratios of polyurethane foam and hardener. Furthermore, the modal damping parameters were determined from the measurement of animal bones. The measurement time was optimized during the practical implementation of the parameter determination to minimize the influence of drying and decomposition processes on the measurement results. © 2019 by Walter de Gruyter Berlin/Boston.

关键词： Structural dynamics

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High performance machining of continuous metal fibers with cascaded multi-stage profile tools 9

High performance machining of continuous metal fibers with c...

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9th CIRP Conference on High Performance Cutting, HPC 2020

作者： Teicher, Uwe Lange, Tristan Ihlenfeldt, Steffen Fraunhofer Institute for Machine Tools and Forming Technology IWU Dresden01187 Germany Technische Universität Dresden Institute of Manufacturing Technology Dresden01062 Germany Technische Universität Dresden Institute of Mechatronic Engineering Dresden01062 Germany

ISBN: (纸本)9781713835431

Metallic fibers are essential for applications in the chemical industry, the automotive industry for brake pads and, more recently, for the air conditioning modules. The most productive process to date for producing continuous fiber lines with fiber cross-sections between 50 and 150 µm is the application of cascaded multi-stage profile tools for cutting from semi-finished wire products. One challenge is the development of a technology for highly ductile materials made of aluminium, which are used as fiber materials in the area of refrigeration adsorbers. Preliminary studies have shown that high cutting speeds are necessary for machining. For this reason, a highly manually operated machine system was advanced to meet the requirements of high cutting speeds and to integrate a process monitoring system. For the first time, experimental investigations were able to show the interrelationships between set technology values and the effective machining forces for this process. Further investigations were done using the example of aluminium alloys 5019 for an analysis of a control system for wire breakage detection on the basis of force sensors. © 2020 The Authors. Published by Elsevier B.V.

关键词： Automotive industry

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Modular instrument for the minimally invasive surgery with SMA actuation and control

Modular instrument for the minimally invasive surgery with S...

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International Conference on Shape Memory and Superelastic Technologies 2019, SMST 2019

作者： Braun, Dennis Weik, David Eisner, Sophia Werner, Michael Fraunhofer Institute for Machine Tools and Forming Technology IWU Department of Medical Engineering Dresden Germany

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Evolutionary optimization of deep-drawing processes on servo screw presses with freely programmable force and motion functions

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Procedia CIRP 2021年 104卷 1482-1487页

作者： Sebastian Kriechenbauer Peter Müller Reinhard Mauermann Welf-Guntram Drossel Fraunhofer Institute for Machine Tools and Forming Technology IWU Nöthnitzer Straße 44 01187 Dresden Germany Technische Universität Chemnitz Institut für Werkzeugmaschinen und Produktionsprozesse Professur Adaptronik und Funktionsleichtbau 09107 Chemnitz Germany

Servo screw presses with freely programmable force and motion functions lead to innovative forming technologies for deep drawing of sheet metals. The advanced application potential of the machine type is mainly based on the accuracy and flexibility. Due to the increase of process parameters in deep-drawing processes with variable force and motion functions, the standards for method planning (consideration of machine properties, parameterization of the movement functions) in comparison to conventional deep-drawing processes increase. The high number of parameters motivates the aim: A systematic design of deep-drawing processes with free force and motion functions on servo presses based on computational science methods. In the context of this publication, the determination of optimal parameters (force and motion functions) for a deep-drawing process with superimposed vibrations on servo screw presses will be investigated. With the help of evolutionary optimization approaches a process-design for a deep-drawing process with superposition of low-frequency oscillations will be carry out. The results of the evolutionary optimization approaches are validated by experiments with cross die part.

关键词： deep-drawing evolutionary process optimization servo screw press machine learning cushion-ram-pulsation variable stroke

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Does the wall sound different? Variable acoustics in rehearsal rooms using small resonator structures in an acoustic panel 50

Does the wall sound different? Variable acoustics in rehears...

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50th International Congress and Exposition of Noise Control Engineering, INTER-NOISE 2021

作者： Knöfel, Björn van Brummelen, Paula Behrens, Tobias Schirmer, Hartmut Fraunhofer Institute for Machine Tools and Forming Technology IWU Nöthnitzer Straße 44 Dresden01187 Germany Weißensee Kunsthochschule Berlin Bühringstraße 20 Berlin13086 Germany ADA-Acoustics and Media Consultants GmbH Arkonastr. 45-49 Berlin13189 Germany SCHIRMER GmbH Beratende Ingenieure Radeburger Straße 124 Dresden01109 Germany

ISBN: (纸本)9781732598652

As the name already states, multipurpose rooms are often used from various people for different intentions like meetings or musical practicing. One example are musical rehearsal rooms, where the acoustic specifications have to meet the requirements of musicians playing different instrument groups. To meet the desire for variable acoustics in a rehearsal room, musicians often like to adjust the room to there personal preferences, what is mostly done by adjusting the frequency dependent room decay curve (T60). Hence, a variable acoustic panel has been developed which consists of several small adjustable resonator structures. In a closed state, the structure acts like a resonator. Although Helmholtz resonators are mostly used at low frequencies, the acoustic panel can address acoustic resonance absorption in the mid-frequency range between 500 Hz and 1.500 Hz. The paper highlights especially the dimensioning of the resonators and its measurements in an impedance tube, a reverberation cabin and a reverberation room. Finally, the prototype of the acoustic panel has been analysed in different rehearsal rooms where musicians examine the panel and T60 differences between the open and closed state of the panel were measured. © INTER-NOISE 2021 .All right reserved.

关键词： Reverberation

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Combined laser hardening and laser surface texturing forming tool 1.2379

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Procedia CIRP 2020年 94卷 914-918页

作者： Endalkachew Mekonnen Aragaw Eric Gärtner Andreas Schubert Institute for Machine Tools and Production Processes Chemnitz University of Technology Reichenhainer Str. 70 09107 Germany Fraunhofer Inistitute for Machine tools and Forming Technology IWU Reichenhainer Str. 88 09126 Germany

This paper deals with the tribological performance of forming tool steel 1.2379. Laser hardening and Laser surface texturing are proposed as processes to improve this tribological performance. Hardening influences the surface hardness and wear resistance. While considering the parameter and the specific material, the correlation between heating power and material property is first modelled using FEM of the heat transfer. Based on the modelling result, the realization is performed by nanosecond laser and analyzed by SEM and by comparing the micro –hardness comparison with a reference value. Then textures are integrated into the hardened surface by picosecond laser ablation while focusing on its suitability for smooth dimples and on the examination by pin-on-disk tests for the effect of incorporating textures on the friction performance. Lower friction coefficients between tool and workpiece improve tool durability and product quality as well.

关键词： Laser Hardening (LH) Laser Surface Texturing (LST) Tribology forming tool 1.2379

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Influence of the stiffness of burnishing tools on process force and surface quality of EN AW-2007 and C45 workpieces

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Procedia Manufacturing 2020年 43卷 635-641页

作者： Rico Stöckmann Marco Posdzich Philipp Klimant Matthias Putz Chemnitz University of Technology Institute for Machine Tools and Production Processes (IWP) Reichenhainer Str. 70 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools and Forming Technology (IWU) Reichenhainer Str. 88 09126 Chemnitz Germany

Burnishing is a highly efficient surface finishing process, which is also more sustainable compared to grinding. Such processed surfaces are characterized by a low roughness and an increased hardness. In recent years, the interest in the process grew due to the steady adoption on flat and free-form surfaces. Especially the latter may benefit from a soft burnishing tool, due to the nearly constant burnishing force and therefore a less strong interaction with geometric imperfections of the free-form surface. In this paper, the influence of the burnishing tool stiffness on the surface features indent, bulge and roughness are shown. Several low and one high stiffness burnishing tool were investigated. As evaluation data, the burnishing force and the finished surface were measured. As shown in this paper, soft tools result in a constant force and can improve surface quality.

关键词： Manufacturing process Surface modification Burnishing

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An investigation of abrasive waterjet machining of cubic boron nitride (CBN) with a softer abrasive material

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Procedia CIRP 2020年 95卷 6-11页

作者： F. Morczinek M. Putz Institute for Machine Tools and Production Processes (IWP) Chemnitz University of Technology Reichenhainer Str. 70 09126 Chemnitz Germany Fraunhofer Institute for Machine Tools an Forming Technology IWU Reichenhainer Str. 88 09126 Chemnitz Germany

For an effective machining of high-performance materials, high-strength cutting materials, e.g. cubic boron nitride (CBN), with high resistance to any kind of wear are used. However, these materials must also be able to be machined in order to produce geometric elements such as chip breakers or chip grooves. According to the current state of the art, grinding and laser beam technology are used for this purpose. In this paper, an attempt was made to use the erosive removal mechanism of abrasive water jet technology to cut a harder material with a softer abrasive. Within the framework of a full factorial test plan, the removal rate, the macroscopic kerf geometry on CBN were investigated by means of abrasive water jet machining. It could be proven that it is possible to remove a harder material with a softer abrasive by means of abrasive water jet technology.

关键词： Abrasion Cubic Boron Nitrid (CBN) Hardness Machining Material removal Removal rate Waterjet machining

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