Starting with the commercialization of stereolithography in the mid-1980s and the development of new additive manufacturing processes in the 1990s, additive manufacturing quickly became an interdisciplinary research field in academia and slowly gained foothold in industry.
Additive manufacturing is a technology which allows fabrication of products with complex geometries which are not accomplishable by traditional formative and subtractive manufacturing processes. Starting from a digital design on a computer, parts are printed by sequential solidification of layers of material. Today we have different methods to deposit material in a layer-by-layer fashion at our disposal. Techniques range from deposition of melted material, selective fusing of powder, inkjet-printing and extrusion printing to Vat-photopolymerisation and lamination of sheets and cover materials of varying types such as metals, polymers and composites, ceramics and materials of biological origin.
Initially limited to rapid prototyping, additive manufacturing made its way in industrial manufacturing. The advantages are evident: As a tool-less fabrication method, additive manufacturing and 3D printing guarantees freedom in geometric complexity and design. This allows creation of objects with unique material and structural properties and increased functionality. Clever design allows printing parts in a single step while in subtractive manufacturing several individually produced parts must be welded or glued together to achieve the same complexity. This not only reduces cost and minimises resource consumption but also reduces the risk of failure and damage. Compared to traditional manufacturing methods, one of the strengths of additive manufacturing lies in the low volume production and mass personalisation of products at potentially reasonable costs. This is not only a step forward in the development and production of medical devices such as customized prosthetics or implants but likewise important for manufacturing customized parts on the high-tech end for aerospace and automotive industry. Reduction in cost for hardware and software as well as solutions for feedstock material supply and post processing contribute to an increased uptake of additive manufacturing in industrial production.
However, a significant amount of manufacturers indicate that reproducibility and the quality of the products are a barrier to adopt additive manufacturing. The success of additive manufacturing therefore critically depends on understanding the manufacturing process entirely and on understanding how processing parameters affect the performance and function of a product. For industry applications this means that the development of quality management systems and developing standards for the manufacturing process and process reliability, the quality of the feedstock material used and the quality of the final product are important. One of the bottlenecks towards a reliable printing technique is the lack of ability to account for defects or to accurately predict or describe properties of materials. Ideally, in-process decisions can help to adjust the final product but this needs computational capabilities to describe and predict properties, as well as powerful low cost process monitoring systems.[3,4]
Besides establishing a greater reliability, materials development still lacks behind and inferior material properties currently set limitations to additive manufacturing. Limitations on scale and speed of production need to be tackled by focusing research on rapid production and expanding the range of materials which are suitable for additive manufacturing.
At Nature Communications we created a collection highlighting the importance of the field and showcasing the latest research in printing methods and resolution, application in biological, electronic and robotic devices, modulating materials properties and insights into the 3D-printing process. All the papers are free to access and we hope you enjoy reading them.
 Tofail, S. A. M. Koumoulos, E. P. Bandyopadhyay, A. Bose, S. O’Donoghue, L. Charitidis, C. Additive manufacturing: scientific and technological challenges, market uptake and opportunities. Mater. Today (2018) 21, 1, 22-36
 AM-motion Roadmap https://www.am-motion.eu/am-motion-roadmap.html accessed on 17.08.2020
 Julia Greer answers questions about additive manufacturing. Nat Commun. (2020) 11 3993 DOI: 10.1038/s41467-020-17723-2
 Peter Lee answers questions about additive manufacturing. Nat Commun. (2020) 11 3995 DOI: 10.1038/s41467-020-17732-1
 Andrew Boydston answers questions about additive manufacturing. Nat Commun. (2020) 11 3992 DOI: 10.1038/s41467-020-17722-3
 Robert Langer and Mark Tibbitt answer questions about additive manufacturing. Nat Commun. (2020) 11 3994 DOI: 10.1038/s41467-020-17724-1
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