The key technologies driven by mechatronics for sensor, actuator and electronic components as well as for assemblies and processes are driving a growth market. Technology-leading companies founded the Mechatronics Alliance Saxony (AllMeSa) to implement integrated high-performance manufacturing technologies in systems and products worldwide. It presented itself at an Alliance Day at the end of February.
Mechatronic parts, components and modules are of crucial importance for the digitalization of industrial processes, products and workflows. Mechatronics can be found in almost 100% of mechanical engineering products. High performance can only be achieved through mechatronics. Technologies for mechatronic components and assemblies as well as manufacturing processes are therefore becoming key technologies. The AllMeSa growth core in the BMBF's 'Innovative regional growth cores' funding program, which is part of the 2019-2022 evaluations of the company-region funding programs, focuses its activities on this problem. The developments of this technology platform are based on new manufacturing technologies and innovative production organization processes. In addition, assembly and testing technologies as well as industrial-grade manufacturing processes for high-performance mechatronic components and systems are being developed and demonstrated in prototype applications. A competence center has been established for the sustainable and disruptive further development of the resulting technologies, which will enable the consortium of six industrial partners and three research institutions to continuously develop the know-how, apply it to other topics of economic relevance and offer innovative products and services there as well.
At the digital Alliance Day, the partners reported on their work and presented new concepts. The high number of 120 participants in this digital workshop, to which the members of the Saxon Working Group for Electronics Technology SAET were also invited, showed the great interest of the specialist colleagues in the topics presented.
New unimagined possibilities through hydrogels
Hydrogels offer unimagined new possibilities for the production of reversible sensor/actuator microsystems due to their miniaturization potential resulting from their high energy density and their switching properties through multi-sensitivity, particularly in the field of microfluidics. Their properties are adjustable, they are biocompatible and can be coupled to soft matter, emphasized Prof. Gerald Gerlach from the Institute of Solid State Electronics at TU Dresden. In mechatronic assemblies, stimulus-responsive hydrogels can be used as sensors for piezoresistive or plasmonic chemical sensors, e.g. for pH sensors with pressure or temperature compensation. They can be used as actuators or sensor-actuator systems for force-compensated sensors or for sensor switches - Bistable Zero-Power Sensor Switch (BIZEPS). Prof. Gerlach explained the basic physical relationships in detail. Filters with adjustable pore sizes are also possible with hydrogels, for example light-sensitive rain nets for bicycle helmets. One of the first commercial products was the implantable glucose sensor Eversense XL with continuous measurement from Ascensia Diabetes Care. Diabetics will appreciate this application.
Innovation cluster of flexible organic electronics
Dr. Dominik Gronarz is Managing Director of Organic Electronics Saxony e. V. OES, Europe's leading cluster for flexible, printed and organic electronics, for Organic Light-Emitting Diodes (OLED), Organic Photovoltaics (OPV), Organic Transistors (OTFT), printed batteries, printed electronic circuits or flexible hybrid electronics. It has 51 members representing 34 companies. Together with the leading Saxon industry and technology clusters Biosaxony, Silicon Saxony, the network of automotive suppliers AMZ, aerospace LRT, mechanical engineering VE.MAS and railroad technology BTS, the SenSa network for sensor activities with flexible organic electronics in Saxony was founded as part of the European SmartEES funding. Dr. Gronarz explained that this sensor technology innovation cluster is intended to promote digital networking between the sensor technology players active in Saxony. He described the large number of existing applications that the Saxon cluster members have produced. They range from flexible displays and printed sensors to antennas and batteries. Dr. Gronarz described the activities together with the Japanese YU-FIC cluster to realize and improve the roll-to-roll production of flexible OLEDs on ultra-thin glass foils, the development of smart systems based on OLED/OPV, systems based on OLED-OPV for printed sensor technology on packaging (a Coke bottle printed with the sensor technology was shown) or multidimensional PCBs made of flexible printed electronics by thermoforming. Dr. Gronarz referred to other international OES workshops on flexible electronics, sensors, textiles and automotive applications that will be taking place in the near future.
Functional machine control simply programmable
Hydrive Engineering GmbH designs manufacturer-independent drive technology and control systems ranging from simple motion control to electrohydraulically controlled axes. The company carries out the development of user-specific solutions, develops control systems, builds test benches and tests the solutions. Dr. Thomas Neubert explained the software solutions for machines used by Hydrive. Machines must be functional, operable and easy to program. By consistently using object-oriented methods under CODESYS, process sequences and product variants are hard-coded. This enables the customer to carry out process optimization and implementation of product variants themselves, without their own programming knowledge, to efficiently implement settings and cycle time reductions or to install new product variants by copying and adapting recipes. The operator's own process know-how can thus grow and be implemented in short cycles. He is less dependent on the system manufacturer if the latter uses proven software modules. System commissioning or complex process optimization is therefore possible without the direct intervention of the software developer. The result is shorter system delivery times. The software framework is available as a library. A video of an assembly process and the presentation of the recipe editor explained the procedure.
"Validation enables confidence to be gained in the simulation and improves numerical models"
Numerical simulation plays an important role in the development process of electronic components and systems as a tool for optimizing robust design at system level, explained Przemyslaw Gromala from Robert Bosch GmbH, Automotive Electronics, in his introductory lecture on the progress made in this field. The accuracy of a numerical simulation is heavily dependent on the input to the FEM model, i.e. geometry data, material properties, boundary and load conditions and error criteria. Validation makes it possible to gain confidence in the simulation and improves numerical models, explained Przemyslaw Gromala using practical examples. To describe the problem, it is necessary to develop a consistent multi-domain and multi-scale simulation methodology to accelerate the design process for electronic control modules based on the system-level approach. In the first level of simulation, the evaluation of qualitative reliability and quantitatively accurate results of design evaluation and validation are required. Pre-selecting the right materials and geometries speeds up the design process. Key objectives in the second level are rapid optimization and design changes, consideration of interactions between domains and scales, agile design and evaluation, rapid adaptation to new requirements and the reuse of data and models. The third and final level aims to reduce time to market, development and product costs and improve quality and key performance indicators.
Substrates - microminiaturizable and sustainable
Daniel Schulze described the objectives of the Micro Systems Technologies Group MST, which includes the companies and miniaturization specialists Dyconex (Switzerland) for high-end PCB, LCP and other packaging substrates, the German company Litronik GmbH for battery packs, the German company Micro Systems Engineering GmbH (LTCC substrates, assembly and semiconductor packaging) and the US company Micro Systems Engineering Inc. for the development and manufacture of electronic modules and SMD production. The presentation described the designs and production variants for high-density wiring carriers, passive components or RF components in many examples. Results from the Interconnect Stress Test IST and design forms for reliability were discussed. The characteristics for traceability were also considered. The trends resulting from thinner materials for substrates, the need for blind vias and packaging were discussed.
As part of the bioESens project, which is linked to the Dresden University of Applied Sciences (HTW) and financed by the European Social Fund (ESF), practical solutions for the use of bio-based plastics in the fields of electrical engineering, electronics and sensor technology were found, which cover the entire value chain from biomaterials, their material modification and processing, application in sensor technologies and functions to questions of production technology, application testing, durability and environmental compatibility, reported Prof. Reinhard Bauer, Faculty of Electrical Engineering at the HTW and Chairman of SAET. Biopolymers, modified PLA and PU were examined in the project, are interesting materials for wiring carriers if they are adapted to different requirement profiles, e.g. for polymer thick-film or printed circuit board technology (Cu foil technology), by means of additives and post-treatment. The researchers at the HTW were able to gain important insights into the development of sustainable concepts in electronics, which need to be further developed in follow-up projects for industrial implementation in products and production technology. The status achieved is a further important step towards the application of biopolymers in electronics. Under certain conditions of use, products that meet the requirements of sustainability will be possible in the near future for selected applications. The author of this article reported on the project in the report from Dresden PLUS Jg.22(2020)08 p. 1108-1114. Following his presentation, Prof. Bauer announced that, although he has retired, he will continue to work as a senior scientist at the HTW and that the design and technology of electronics and mechatronics will remain at the HTW's Faculty of Electrical Engineering. He thanked everyone personally for their many years of cooperation. He will continue to shape the Electronics Technology working group together with Dr. Oppermann (see the current communication in PLUS Jg.23(2021)05 p. 534, 535 ).
AllMeSa joint projects: Pressure cell transducers and glass sensors
Pressure cell transducers can be produced using stainless steel thin-film technology, MEMS silicon technology or thick-film ceramic technology. In one sub-project, a bonding process for connecting the membrane to the steel cylinder is being investigated and a product demonstrator from i2S is being set up for this purpose. Benjamin Reichelt from XENON Automatisierungstechnik GmbH explained that the material system and process are being developed on the basis of reactive multilayer systems as well as the transfer to the plant technology. Gert Springer from Intelligente Sensorsysteme Dresden GmbH i2S described the concept, structure and process sequence for manufacturing the 2 x 2 mm2 demonstrator, his pressure transmitter with a laser-structured stainless steel pressure cell.
Dr. Karsten Sager from i2s described the development of a new joining process for the pressure transmitter with MEMS pressure cell, the reactive joining of the silicon measuring element and the ceramic. This requires metallization and a reactive paste. Lukas Stepien presented the parallel paste development by the Fraunhofer IWS. Initial investigations revealed that, in contrast to previous bonding technology, joining with reactive pastes is not yet possible. Although joining using reactive film is possible, it does not meet the project's cost target.
At the Institute for Innovative Technologies, Technology Transfer and Continuing Education e. V. ITW Chemnitz e. V., the contacting and testing technologies used in the project are being investigated. Up to now, metallization and soldering have been necessary for soldering glass or ceramics, explained Prof. Bernd Hommel. However, as the reactive pastes developed have not yet proved suitable for the joining processes, alternative investigations into glass fusion joining (MEMS Glass Attach - MAG) were carried out. This also means that the time-consuming metallization and soldering work step can be dispensed with.
In AllMeSa sub-project 3.1, a new type of pressure cell structuring by means of laser processing (structuring of the membrane) is being pursued. SITEC Industrietechnologie GmbH carried out technology studies on this. Dominique Schubert reported on this. Benjamin Reichelt also presented the development of automated manufacturing processes for the production of laser-structured stainless steel pressure cells at XENON. Technological analyses were carried out by Philip Knoch from the Institute of Packaging Technology at TU Dresden. The conceptual design and system structure, the possibilities of characterization by metallography, the measurement setup for testing and the electrical characterization of the laser trenches were examined. The influence of the insulation layers on the stainless steel and the reliability are to be determined using Ansys 2020 simulation. A cloud-based MES system is being developed at Kontron AIS GmbH, reported Thomas Dreyer.
Glass sensors - flexible and resistant
Uwe Beier from Adenso Industrial Services GmbH spoke about the production of glass sensors for use in a fuel cell/electrolysis stack. Chemically resistant glass sensors for high-temperature applications consist of a base layer made of ultra-thin glass, the functional layer with sensor characteristics, a hermetically sealed sealing layer and the top layer, which in turn is made of non-thin glass. The concept envisages manufacturing the glass sensors using productive roll-to-roll technology. Dr. Robin Schulze from SITEC Industrietechnologie GmbH described the technology evaluation work and presented the system concepts. One possible application for such sensor foils in fuel cells was described by Dr. Ludwig Reichel from sunfire GmbH. He explained the design of an optimized fuel cell/electrolysis stack with integrated glass sensors. The technology platform is the stack, which is a multilayer consisting of multiple stacked repeating units. These contain the active cell and a seal on a bipolar plate. He described the requirements for the bipolar plate and the adaptation of the joining process and component geometry. Sunfire's aim in the project is to integrate a glass sensor system into the stack that is unchangeable and mechanically stable over its service life.
