“Selective Cement Activation” (SCA) allows the fabrication of freely formed objects with a high degree of geometric complexity. In order to utilize SCA for applications in construction, a full understanding of the manufacturing process is necessary. The presented work focuses on the process step of layer creation and the influence of process parameters on the resulting packing density of the particle-bed. The results show that each process parameter has a significant influence on the packing density of the particle-bed. In general, slower processing speeds lead to higher densities. Increasing the compaction height increases the packing density, although competing effects in the particle flow can cause the density to decrease. Concerning the particle composition, it was found that a particle mixture with a wider particle size distribution requires lower compaction heights to achieve high packing densities. Such mixtures are also influenced to a lesser degree by changes in the process speeds.

Additive manufacturing processes that are using wood particles as feedstock material either require large amounts of binder or have relatively poor mechanical properties.This paper details the novel Individual Layer Fabrication (ILF) process and the respective machinery which allow for the additive manufacturing of objects with a low binder content and high strength values.With flexural properties exceeding those of conventional particle boards, an application of objects produced via ILF in the construction industry is possible.

The global challenges of our time are climate change, population growth and the reduction of resource consumption. For the building industry, this means building more in the coming decades while at the same time using fewer resources and producing fewer emissions. The building industry, which is traditionally organised by craftsmen, is not prepared either technologically or in terms of personnel to meet these challenges economically and ecologically. This is where the Collaborative Research Centre TRR 277 Additive Manufacturing in Construction (AMC) of the both Universities of TU Braunschweig and TU Munich comes in with its basic research. The AMC considers additive manufacturing to be a key digital technology for the construction industry, because it combines the advantages of automated and customised manufacturing. In additive manufacturing, components are built up layer by layer without using a separate formwork. This creates fundamentally new requirements for materials, process technologies as well as design and construction and can only be researched in highly interdisciplinary teams of scientists from the fields of civil and mechanical engineering. The basis for cross-material research into different additive manufacturing technologies for application in construction is the research infrastructure in the field of digital building fabrication that has been systematically built up over many years. At its two locations, TU Braunschweig and TU Munich, the AMC can rely on the most innovative research facilities. These include both DFG-funded large-scale research equipment such as the Digital Building Fabrication Laboratory (DBFL) and the RoboCoop(3D), as well as a large number of self-financed innovative research devices at both locations. The AMC research infrastructure is constantly being expanded and extended in the ongoing research project. This article presents the existing research infrastructure as well as the research infrastructure currently being acquired and planned.

Die globalen Herausforderungen unserer Zeit sind der Klimawandel, das Bevölkerungswachstum und die Reduzierung des Ressourcenverbrauchs. Für das Bauwesen bedeutet dies, in den kommenden Jahrzehnten mehr zu bauen und gleichzeitig den Ressourcenverbrauch zu verringern und weniger Emissionen auszustoßen. Die handwerklich organisierte Bauindustrie ist weder technologisch noch personell darauf vorbereitet, diese Herausforderungen ökonomisch und ökologisch zu bewältigen. Hier setzt der Sonderforschungsbereich TRR 277 Additive Manufacturing in Construction (AMC) der beiden Universitäten TU Braunschweig und TU München mit seiner Grundlagenforschung an. Der AMC betrachtet die additive Fertigung als eine digitale Schlüsseltechnologie für das Bauwesen, denn diese vereint die Vorteile von automatisierter und individualisierter Fertigung. Bei der additiven Fertigung werden die Bauteile ohne Formenbau schichtweise aufgebaut. Dies schafft grundlegend neue Anforderungen an Werkstoffe, Verfahrenstechniken sowie an Design und Konstruktion und kann nur in hochgradig interdisziplinären Teams von Wissenschaftler:innen aus den Bereichen des Bauwesens und des Maschinenbaus erforscht werden. Die Basis für die werkstoffübergreifende Erforschung unterschiedlicher additiver Fertigungstechnologien für die Anwendung im Bauwesen stellt die über viele Jahre systematisch aufgebaute Forschungsinfrastruktur im Bereich der digitalen Baufabrikation dar. An seinen beiden Standorten, der TU Braunschweig und der TU München, kann der AMC auf innovativste Forschungseinrichtungen zurückgreifen. Darunter befinden sich sowohl DFG‐geförderte Forschungsgroßgeräte wie das Digital Building Fabrication Laboratory (DBFL) und das RoboCoop 3D als auch eine Vielzahl eigenfinanzierter innovativer Forschungsgeräte an beiden Standorten. Die AMC‐Forschungsinfrastruktur wird im Laufe des Forschungsprojekts stetig ausgebaut und erweitert. Der vorliegende Beitrag stellt die bestehende sowie die in Anschaffung und Planung befindliche Forschungsinfrastruktur vor.

The renewable resource, wood, is becoming increasingly popular as a feedstock material for additive manufacturing (AM). It can help make those processes more affordable and reduce their environmental impact. Individual layer fabrication (ILF) is a novel AM process conceived for structural applications. In ILF, parts are formed by laminating thin, individually contoured panels of wood composites which are fabricated additively by binder jetting. The individual fabrication of single panels allows the application of mechanical pressure in manufacturing those board-like elements, leading to a reduction of binder contend and an increase of mechanical strength. In this paper, the ILF process is described in detail, geometric and processing limitations are identified, and the mechanical properties of the intermediate product (panels) are presented. It is shown that the thickness of panels significantly influences the geometric accuracy. Wood composite panels from spruce chips and pMDI adhesive showed flexural strengths between 24.00 and 52.45 MPa with adhesive contents between 6.98 and 17.00 wt %. Thus, the panels meet the mechanical requirements for usage in the European construction industry. Additionally, they have significantly lower binder contents than previously investigated additively manufactured wood composites.