University of Birmingham 3D Printing
University of Birmingham 3D Printing: Potential to Revolutionise
Additive Manufacturing (AM) or 3D Printing is now referred to as Game Changing Technology and appears to be creating a whole new manufacturing genre. Its impact is so significant that Barack Obama President of the United States of America, in his 2013 State of the Union Speech, described it as having the potential to revolutionise the way we make things. It is estimated that this business approached £1.2 bn in 2011, including the AM systems sales, and its associated materials and services. The Technology Strategy Board (TSB) estimates that by 2020 the net worth of this field will approach £4.5 bn, and as such it is important to understand the range of technologies and applications that can arise from AM.
The concept of AM is simple. A computer geometrical (CAD) model is used to generate a numerically-controlled path to add a material layer-by-layer, building a structure bottom-upwards. For metals, the process generally comes in a number of variants, one of which is what is commonly referred to as a powder bed method, whereby thin layers of powders (~20-100 microns) of the material to be ‘printed’ are spread using a recoater blade from a powder reservoir to a neighbouring substrate. A heat source (e.g. laser or electron beam) is used to selectively melt or sinter the powders on the substrate, only in the regions that correspond to the 2D section of the component being built. By repeating this process, the entire structure can be grown, and then extracted from the powder bed, with the surrounding un-sintered powder being recycled. The other more common variant is direct laser deposition, where a laser, electric arc, or electron beam is used to melt a wire or powders being sprayed through a nozzle to melt and deposit in ‘free-form’. The process can be used for repair applications, or hybrid additive manufacturing where structural features (e.g. bosses or lugs) can be deposited on structures to simplify the manufacturing process and to avoid whenever possible excessive machining operations. The Following picture shows the complex geometry manufactured using AM in University of Birmingham.