TUBE NEWS 2016 May 2016 - Page 43

Fig 2: 27 cubic metre flexible enclosure used to prevent oxidation of parts during robot controlled WAAM operations. and various nickel alloys. Since then the focus has shifted to airframes. Although laser and powder methods are useful for certain applications such as rapid prototyping or for small highly complex parts, this technology is limited by its speed and the size of component it can accurately manufacture. In contrast, the processes being developed at Cranfieldare designed for high deposition rates. To put this difference into context, the centre is currently targeting a deposition rate of 10kg an hour for titanium, compared with a typical 0.1kg using laser + powder methods, which can also potentially carry the risk of the material not being fully consolidated if fusion has not occurred between grains. Additive arc + wire systems are also capable of producing parts several metres in size and simplify the process of producing single piece linear intersections. One of the main projects at Cranfield’s Welding Engineering Research Centre takes the technology one step further. The programme began in 2007 with funding from both the University’s Innovative Manufacturing Research Centre and 15 industry partners. The idea is to simplify the process of complete product within a single one-hit additive manufacturing system incorporating a fully integrated robot. Additive layer manufacturing offers several advantages for certain structural airframe components such as a vast reduction in material wastage, especially when producing many heterogeneous parts, and the ability to produce a great variety of part designs for prototype work quickly. There is also the key benefit that it allows the consideration of unconventional designs that otherwise would not be practical because of manufacturing or cost constraints due to, for example, complex or unusual geometries, bringing with it many different opportunities and challenges. Overcoming the problem of oxygen contamination during WAAM Many alloys may be used during the WAAM process simply by using the welding torch inert gas shr Y\X[ۋ]\YHX]\X[\H]X[ܙHۙHXX[ۈ]\YX[Y[[\[XY\[ۈۙH[\XHY][ۋ][][H[\\H\X[\H[]]H[[X[Y][ۘ[[\X[ۋ]H[XۈX[H\X[ۂ\\\Y[H\][ۜ\H\YY][HX][K]\[\\\[^[]B[\]]H\[[˂^XH[\HXB\H]HY[ۜY\XHY[\[[\H][Y[[HHۘ\\š[XYݙ\XY\Yˈ[[ۂ\[ۈX\]Y\܈^[\H\œX\XYYH]H\Yۈ\[\XYX[B܈H[[[\KH\[H\Y[]HܙY۝[][[\H[\\܂X[HYX\[\^]YHܝ[]Y\›ٙ\YHY[Y[[Y\[[Y\ˈ\B[ݘ]]HXٙ\YYۚYX[]X[ۜ›ݙ\X][H[ݙH[\]]\ ‚PVH M