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34 August 2016 M A T E R I A L S Manufacturing of small components using 3D printing techniques, namely selective laser melting (SLM), is well known in aeronautical engineering, especially with the use of powdered titanium. The significance of this lies not only in improvements in manufacturing, but in achieving reductions in the weight of finished parts used in aircraft, with the concomitant result is reduced fuel consumption and lowering of the costs of flying. Using SLM processes to develop a single unit fuel nozzle that previously comprised 20 separate parts, General Electrics (GE) has achieved significant results with the part being much lighter, more reliable and - five times stronger. The production of this fuel nozzle has ‘taken off’ and is now in production and installed in the Airbus A320 and Boeing 737. Motivated by this achievement GE is venturing into other industries where 3D printing might benefit engineering processes such as the production of a range of valves that could enhance the transporting of natural gas, oil and other fluids. Recently a hydraulic valve housing for an aircraft wing was designed and produced at the University of Chemnitz in Germany, built in an SLM Solutions laser system using titanium alloy. As with the fuel nozzle, the benefits of 3D printing to valve block construction, lies in design optimization of intricate and complex features like internal holes and flow channels. In 2014 VTT Technical Research Centre in Finland, produced a reliable hydraulic valve block 66% lighter than the original part, demonstrating the commercial viability of 3D printing to this component. These are just two examples where manufacturing is capitalising on the opportunities presented with 3D printing. Customisation affords the medical and dental industries a major benefit in meeting patient requirements afforded with the ability to design intricate and complex parts tailored to everyone. Customised 3D printed medical implants have received wide publicity in the popular media in Australia such as the 3D printed titanium vertebral cage developed in Melbourne between RMIT University and Anatomics which gave relief to a back pain sufferer, and the titanium heel joint, that increased the walking ability of another Australian patient suffering a rare form of cancer. The dental industry may not have gained such news shattering notoriety as medical implants, but significant opportunities are already being exploited simply because not one human being’s dental requirements is exactly the same as another and 3D printing enables customisation. Already attested, that 3D printing not only offers reduced costs but an increase in the speed and accuracy of the production of crowns, bridges and orthodontic appliances. The success of customised medical and dental 3D printed solutions rely on already available scanning and imaging technology - CT, MRI and ultrasound. Combined with CAD/CAM software, biomedical engineers design the specific ‘part’, and structure the path or procedure the laser system will follow. Combining all of these technologies has one US journal referring to it as ‘digital healthcare’. Whatever the label, it is on trend with the world wide push towards improved health and wellbeing, and the uptake is nothing short of revolutionary. As a senior clinical maxillofacial prosthetics from Kings College Hospital in London, recently confirmed, 3D printers are now “a must” in hospitals treating serious head, neck and jaw injuries. The benefits lie in surgeons being able to create implants from scans taken of the patient well in advance of reconstructive surgery. The 3D parts can be used to ‘rehearse the surgery’ for the team to gain familiarity with both part and procedure. Practiced well before the actual surgery occurs ensures the most appropriate procedure is used. This ‘ready made’ part along with practice, combine to achieve faster and more precise operations, which can only be said, provides tremendous benefits to both surgical team and patient. As in medical applications, the successful use of 3D printing in dentistry relies on oral CT scans to gain patient information as the basis of a digital design. A biomedical engineer then develops the CAD/CAM design and production process that controls the 3D printing. The capability of a design controlled layer-by-layer process, removes many of the constraints in traditional manufacturing such as casting, fabrication and milling that don’t always address the fine detail or complexities required ADDITIVE MANUFACTURING RIPE FOR SMALL PARTS PRODUCTION Advances in additive manufacturing, known more popularly as 3D printing, demonstrates real gains in laser technology, opening up new business opportunities by freeing design and manufacture from the restrictions of traditional processes, enabling ease of design alteration and more importantly, customisation. Other advantages occur such as more economical use of metal resources but the impact of changes to product design opens doors previously not available.


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