Posters on display

Parallel robot platform for 3D freeform manufacturing -  Rainer J. Beck, Heriot Watt Univ.  Nick Weston, Renishaw plc., Jonathan D. Shephard, Duncan P. Hand, Heriot Watt Univ.

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Parallel robot platform for 3D freeform manufacturing

Author(s): Rainer J. Beck, Heriot Watt Univ. (United Kingdom); Nick Weston, Renishaw plc. (United Kingdom); Jonathan D. Shephard, Duncan P. Hand, Heriot Watt Univ. (United Kingdom)

Modern manufacturing in traditional European strongholds has experienced a migration of mass production towards low cost economies. To enhance the global competitiveness for the UK manufacturing industry an important strategy is to concentrate on the manufacture of high value customised parts that provide significant added value. Hence, there is an urgent need to develop processes which support the manufacture of such specialised parts. Freeform fabrication is one of the most flexible manufacturing platforms and enables highly flexible design and manufacturing processes. Many limits of traditional manufacturability are removed and a fluid evolution from concept to product is provided. Difficult but important geometries and even tailored material properties can be realised by this technology. Our goal is to develop a novel 3D freeform fabrication laser based manufacturing platform and our initial results on this will be presented. The philosophy is to provide a flexible platform that combines (i) the ability to construct and add material to freeform shapes with (ii) metrology of the created part, and (iii) the ability to remove material: in order to achieve a high level of form fit and low tolerances in excess of that achievable in freeform manufacture alone. This involves the integration of fibre-delivered laser sources into a parallel robot device to produce a flexible system capable of several concurrent engineering processes. This will enable new product development and fabrication steps for novel customised parts such as medical prostheses or the repair of damaged high value components like turbine blades whilst also providing process monitoring and on-machine component inspection.

 

 

 

High repetition rate picosecond laser interaction with Ti alloy – Ahmad Syamaizar Ahmad Sabli, The Univ. of Manchester

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High repetition rate picosecond laser interaction with Ti alloy

Author(s): Ahmad Syamaizar Ahmad Sabli, The Univ. of Manchester (United Kingdom)

The interaction of high repetition rate (500 kHz to 10 MHz) high power picosecond Nd:YVO4 at 1064 nm wavelength with Ti6Al4V is reported. A special phenomenon on the position of the focal position relative to the workpiece has been identified. The work shows that the maximum material removal rate and ablation penetration depth is not at the focal position, but at 15-20 mm above the focal plane. A discussion is given to explain this unusual phenomenon not known before in laser materials processing.

 

 

Microstructure and properties of IN718 in samples manufactured using selective laser melting fabrication – Miren Aristizabal Segarra, The Univ. of Birmingham , Raja Khan, TWI Ltd.,  Moataz M. Attallah, The Univ. of Birmingham, Javier Cortes, Iñigo Iturriza, Ctr. de Estudios e Investigaciones Técnicas de Gipuzkoa, Khamis Essa, Michael H. Loretto, The Univ. of Birmingham

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Microstructure and properties of IN718 in samples manufactured using selective laser melting fabrication

Author(s): Miren Aristizabal Segarra, The Univ. of Birmingham (United Kingdom); Raja Khan, TWI Ltd. (United Kingdom); Moataz M. Attallah, The Univ. of Birmingham (United Kingdom); Javier Cortes, Iñigo Iturriza, Ctr. de Estudios e Investigaciones Técnicas de Gipuzkoa (Spain); Khamis Essa, Michael H. Loretto, The Univ. of Birmingham (United Kingdom)

Samples of IN718 have been manufactured from gas-atomised powder using a range of conditions in a laser powder bed facility. The influence of build conditions has been studied using optical microscopy and scanning electron microscopy to define the porosity level, surface roughness and changes in the microstructure. In addition, the microstructure of samples containing the bond line between a volume manufactured using powder bed and IN718 powder, which were hot isostatically pressed together in a can, has been analysed. It has been found that the increase of laser powder and the reduction of scan spacing minimise the pore content, and that to minimise the surface roughness the scan speed should be reduced and laser power increased. The microstructure observed in samples built using different scan strategy (island or simple) will be discussed in terms of the influence of different laser process variables on the formation of Laves, carbides and δ phase.

 

 

Nanofabrication with laser interference ablation method – Haider Butt, Qiancheng Zhao, The Univ. of Birmingham

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Laser cutting excellence

Author(s): Erwin Tomsin, Nitto Europe NV (United Kingdom)

 Nitto Europe has launched a new generation of Fiberguard series. Fiberguard is a surface protection tape that protects stainless steel surfaces during both CO2 and Fiber laser cutting processes. Fiberguard combines a white printed PE carrier with a release layer and modified rubber-based adhesive. It has been specifically designed to ensure that no pre-cutting is required, thereby saving users vital production time. The special formulation of the adhesive system means that the film remains in place and that therefore no bubbleforming occurs during the laser cutting process. As a fully white film is used there is no carbon deposit, eliminating the cleaning process following laser cutting and additional quality control. Nitto offers two versions: Fiberguard Blue has the highest adhesion level in the market and is therefore recommended on rougher surfaces and thicker steel plates. It is a problem solver for very difficult and complex shapes where the risk for blowing up during laser cutting remains minimal. Fiberguard Light has a lower adhesion level and is therefore the perfect solution for thinner steel, as it guarantees easy removability afterwards. Fiberguard is different because it not only meets the practical needs of our customers, but also has been designed with the entire supply chain in mind. The benefits of Fiberguard, such as no pre-cutting required, no bubble forming and no carbon residue after the laser cutting process have been specifically designed to ensure a reduction in cleaning operations, additional quality control and fewer production shut-downs, thus saving users time and cost.

Nano-hardness and microstructure of selective laser melted AlSi10Mg scan tracks – Nesma T. Aboulkhair, Chris Tuck, Ian Ashcroft, Nicola Everitt, The Univ. of Nottingham

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A study on single tracks of selective laser melted AlSi10Mg

Author (s): Nesma T. Aboulkhair, Chris Tuck, Ian Ashcroft, Nicola Everitt

Selective laser melting (SLM) is a relatively new technique with which to process a range of materials. Aluminum alloys are low-density potential candidates for the process; but are more difficult to process than materials typically used in SLM such as Titanium alloys, Stainless steels, and Nickel based alloys. Although the majority of studies are considering the development of structural objects or studying the means for porosity reduction and the mechanical characterization of the parts, the importance of studying single tracks formed during the process of SLM should not be overlooked since they are the building blocks of the process. This study considers single tracks created from AlSi10Mg. The geometrical features of the melt pools were defined. Energy dispersive X-ray mapping was implemented to compare the chemical composition distribution in the selective laser melted material and the as-cast material. Nanoindentation alongside energy dispersive spectroscopy was used to establish an understanding of the hardness profile across melt pools of single tracks and its interrelation to the chemical composition. In addition, some defects developed in single tracks were investigated to determine their contribution to defects in multi-layer processing.

 

Study of fundamental laser material interaction parameters in powder melting – Wasiu Ayoola, Stewart Williams, Wojciech Suder, Cranfield University

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Study of fundamental laser material interaction parameters in powder melting

Author(s): W.A. Ayoola, S.W. Williams and W.J. Suder, Cranfield University (UK)

Powder bed additive manufacturing, from the process point of view, is similar to conduction laser welding. In laser welding depth of penetration (PD) and weld width (WW) are bead parameters that laser users wish to control. Using system parameters approach makes the process dependent on a particular laser system. The complexity arises from the fact that the same combination of laser power and travel speed will result in different weld geometries if different beam diameters are used. Previous studies on keyhole welding at Welding Engineering and Laser Processing Centre (WELPC), Cranfield University, have shown that power density and specific point energy control PD and interaction time controls WW. In the current study, the interaction parameters that control condition laser welding and fusion characteristics of powder melting in additive manufacturing are investigated.