Linking Additive Manufacturing and Sensor Integration: A Direct Path towards Structural Electronics?

Additive manufacturing (AM) of polymers, metals and ceramics has received tremendous attention since maturing from a prototyping to a full-fledged manufacturing technology for geometrically complex objects. [...

Laser beam melting of technical springs: Additional functionality and powder quality control

Springs are applied in diverse shapes and sizes for a wide range of technical devices, machines and applications. Usually, they interact with many other components as part of an assembly to fulfil a joint function. Generally, springs are produced by coiling a drawn wire into multiple-turn windings around as haft or mandrel. Demands for miniaturisation and reduction of assembling operations require new spring designs that cannot be realised by coiling. The paper summarizes new design opportunities that Additive Manufacturing offers for complex-shaped springs. Additional functionalities for technical springs are highlighted. The focus is on the challenge of the addition and removal of support structures required for Laser Beam Melting (LBM) as well as powder quality control for the utilized material. New spring designs were achieved provided that specific design rules were followed

Influence of Particle Size Distribution in Metal Binder Jetting - Effects on the Properties of Green and Sintered Parts

In binder jetting, parts are build layer-by-layer in a powder bed by locally printing an organic binder. After curing the binder, the green parts are cleaned of the loose powder. A combined furnace process removes the binder and fuses the particles together. The microstructure of a sintered part depends on powder properties, green part density and sintering parameters. The influence of the particle size distribution (PSD) on the sintering behaviour is widely known. With decreasing particle size, the sintering activity increases. This enables a reduction of the sintering temperature and reduces the distortion potential. Finer powders have higher capillary forces and tend to agglomerate, which affects packing density and flowability. This paper takes a closer look at the influence of PSD and layer thickness on density and dimensional accuracy of the green parts. The effects on shrinkage behaviour and sintering density of binder-jetted parts are also shown

A Series of Workshops and presentations provided by the Fraunhofer Additive Manufacturing Alliance: Presentation held at Additive Manufacturing for Aerospace & Space, 21st - 22nd February 2018, München

Facilitated by the Fraunhofer Alliance for Additive Manufacturing, which is the largest consortium for applied research in the field of Additive Manufacturing in Europe – the workshop provides the opportunity to learn about the newest research in this field and the possible implementation of state of the art processes for your products. An overview will be given on how to design complex products for AM with a focus on metals and polymers and with respect to different applications related to Aerospace and Space. It will be discussed how AM can be integrated in the product development with other manufacturing technologies. A significant factor for the quality of AM products is the processing and quality of the raw material, which is metal or polymer powder for most AM processes. You will learn about influencing factors for powder quality and the implementation of an efficient powder process for AM. The information given will enable participants to evaluate potentials for their own AM processes and products and it is hoped to enable them to find approaches for the implementation of new or enhanced methods, tools and processes for their companies and organizations. What you will learn:• Overview of research state in design methods for AM and how to design complex geometries(e.g. bionic design, lattices) with already available design tools• How to implement design guidelines and additional functionality (e.g. electronics) in AM for metals and polymers in CAE product development and AM processes• Understanding of the importance of powder quality and processing and how to implement an efficient powder process for AM• New potentials in using surface-treated polymers for space applications About the Fraunhofer Additive Manufacturing Alliance:Fraunhofer is Europe’s largest application-oriented research organization. Its research activities are conducted by 69 institutes and research units at locations throughout Germany. The Fraunhofer Gesellschaft employs a staff of 24,500, who work with an annual research budget totaling 2.1 billion euros. Of this sum, 1.9 billion euros is generated through contract research. More than 70 percent of the Fraunhofer-Gesellschaft’s contract research revenue is derived from contracts with industry and from publicly financed research projects. International collaborations with excellent research partners and innovative companies around the world ensure direct access to regions of the greatest importance to present and future scientific progress and economic development. The Fraunhofer Additive Manufacturing Alliance integrates seventeen Fraunhofer institutes across Germany, which depending on their main focus, deal with subjects concerning additive manufacturing and represent the entire process chain. This includes the development, application and implementation of additive production processes as well as associated materials

Customized Smartness: A survey on links between additive manufacturing and sensor integration

In many areas, Additive Manufacturing (AM) has made the decisive steps from prototyping to true manufacturing technology. AM processes excel based on aspects like outstanding geometrical flexibility and lack of tooling, which allows significant lead time reductions both in initial product design and in case of design adaptations. However, in production today, most of these advantages are realized based on homogeneous materials. Attempts at advancing the state of the art address the topic of material combinations and functionally graded materials. The challenges faced by such approaches differ in their level of severity, and are influenced in this respect by the actual AM process chosen. Beyond composites with spatially varying properties, the next level of complexity is the integration of geometrically defined 3D structures within the volume of a part, and specifically functional structures at that. Endeavours of the latter kind are currently receiving increased attention under headlines like “Structural Electronics” or “3D Electronics Printing”. Here, the surface or volume integrated structure typically is a sensor or electronic system. Beyond this system, the AM process then either provides a complex 3D substrate and thus addresses the packaging issue and/or replaces a conventional PCB, or it generates an engineering component directly and closely integrates it with electronic and sensor systems. So far, the backbone of most solutions realized have been hybrid production systems that integrate different manufacturing processes in a single piece of equipment. The present work provides a brief introduction to the various AM techniques and discusses a disambiguation based on their general capability of producing functional structures on a volume integration level. A classification of such structures is suggested that accounts for their level of complexity in relation to the typical, layer-wise manufacturing scheme adopted in AM. Examples stemming from a global research landscape are discussed in the context of this classification. In this, two special foci are selected reflecting related activities at the Fraunhofer Institute for Manufacturing Technology and Advanced Materials (Fraunhofer IFAM): One of these is a combination of manufacturing processes, with functional printing and other direct write techniques linked to AM processes in a dedicated manufacturing cell. The other addresses integration of pre-fabricated electronic components like RFID systems into metal components produced by means of selective laser melting (SLM).The study closes with an overview of future research trends towards producing components with integrated electronics. In doing so, special emphasis is given to AM techniques that allow for in-process switching of materials and thus have the potential of realizing complex systems not by combination of processes, but within the boundaries of a single process. Also addressed are potential application scenarios that profit specifically from the combination of AM and sensor integration

OHB initiatives in development of additive manufacturing technology for opto-mechanical and mechatronic space systems

Additive Manufacturing (AM) technology has shown impressive new opportunities and convincing results over the last years, mainly in terrestrial applications. Today, it has proven to represent a completely new approach to shape complex mechanical parts, with enormous potential for optimization of dedicated parameters. Numerous possibilities shine up for the aerospace industry, among others, and let engineers dream of mechanical parts which only some years ago looked like science fiction. OHB System has been involved in the development of Additive Manufacturing since more than five years via several ESA studies, DLR-funded projects and by significant internal R&D activities. These projects and studies have convinced us of the potential of AM for future satellite platforms, instruments and payloads. A new dimension of freedom in generating shapes and geometries is opened, offering more flexibility for optimizing the parts and components according to functional and performance requirements. On the other hand, the efforts of qualifying an AM part to flight worthiness are significantly higher than for conventional manufacturing technologies, taking into account all the required aspects of material and production process control, inspection and testing. A concise trade-off has to be performed for each potential use case to find out whether these high efforts and resulting costs are justified by the benefits of the new technology in terms of e.g. light weighting, ease of integration and performance improvement. The paper will introduce the OHB AM roadmap, which has been developed jointly by OHB experts from both sites in Bremen and Oberpfaffenhofen, following in-depth analysis of the potential impact of the technology on space systems. It will furthermore provide an overview of applications where AM is expected to offer extraordinary opportunities. Among these 'high-potential' applications are the two following topics: • opto-mechanical assemblies (isostatic structures, optical mounts) and • mechatronic systems (compliant mechanisms or integrated smart structures). The paper will report on the objectives and work logic of ongoing studies in these specific topics and provide intermediate results