CSME Conference Proceedings (May 27-30, 2018)
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Browsing CSME Conference Proceedings (May 27-30, 2018) by Subject "Additive manufacturing"
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Item Open Access Constrained Topology Optimization For Additive Manufacturing Of Structural Components In Ansys®(CSME-SCGM, May-18) Jankovics, Davin; Gohari, Hossein; Barari, AhmadTopology Optimization is currently the main technique to optimize an objects structural design. This method commonly produces parts that have exceedingly complex geometry. Additive manufacturing (AM) is the main manufacturing process to produce these optimized designs due to the flexibility and speed it offers. However, results of topology optimization without considering manufacturing process limits, even AM ones, may result in designs that are expensive and difficult to build. This paper presents a topology optimization filter that minimizes the effect of overhang structures. These structures are very difficult to manufacture using conventional AM techniques. In order to constrain the gradient compliances with respect to densities and converge the results towards a structure with the least amount of overhang structures, sensitivities are modified using the proposed filter. To implement the proposed filter and the base topology optimization methods ESO and SIMP, ANSYS Parametric Design Language (APDL) is employed within the ANSYS® Workbench™ environment. The results of a case study using the different topology optimization methods are investigated. Finally, an implementation of the proposed AM filter is used to solve an MBB-beam problem. The result isItem Open Access Development Of A Dynamic, Reconfigurable Finger-Hand Skeletal Structure(CSME-SCGM, May-18) Patki, Shreya; Urbanic, Dr. R. JillA finger or hand brace may be required to be worn for people who require physical support or ‘controlled motion’ support. Ehlers Danlos Syndrome (EDS) patients have connective tissue disorders, and wear braces to support and limit motion. Manual assembly operators, carpal tunnel sufferers, and the elderly may also benefit from wearing finger or hand braces. Additive manufacturing (AM) solutions provide flexible manufacturing options for customized braces; however, a CAD model must be developed to facilitate a manufacturing solution. The goal of this research is to develop a readily adaptable CAD model for a hand, which would link to a flexible brace model. Rhinoceros® and Grasshopper® modelling tools are employed to develop a solution that can be dynamically manipulated to adjust to a specific hand size, and/or localized finger-hand configurations. The final CAD model (hand or brace) can then be built using an AM process.Item Open Access A Hybrid Manufacturing Approach For Low Volume High Temperature Thermoplastic / Thermoset Material Molds(CSME-SCGM, May-18) Kalami, Hamed; Urbanic, JillThe mold costs for low volume production molds can be expensive due to the mold material, the process planning time, and the fabrication costs. The focus of this research is to develop a methodology to fabricate molds for low volume production, where the production quantities vary between 1 – 200 components. For this application, the cycle time is not an issue. Employing an additive manufacturing solution could reduce the required amount of materials and the processing planning costs, but there are cost, or technology feasibility issues related to constructing a mold directly from a CAD file. Consequently, a hybrid manufacturing approach is taken where an AM process (material extrusion based) is used to create a sacrificial pattern for specialty, low cost, interchangeable inserts manufactured using an epoxy (Aremco 805). An over molding case study is carried out using a high temperature molding material - Technomelt-PA 7846 black. The pattern, insert, coating, and mold fabrication is discussed, as well as the initial results. The initial material cost estimates to fabricate this over molding solution is approximately $140 US. The durability of the RTV coating and the inserts needs to be determined to yield the final solution costs.Item Open Access The Influence of Powder Size and Packing Density on the Temperature Distribution in Selective Laser Melting(CSME-SCGM, May-18) Moraes, Diego Augusto de; Czekanski, AleksanderMetal powder properties in Selective Laser Melting (SLM) is among one of the most important factors when implementing new alloy developments for the equipment. In fact, not all commercially available metal powder alloys are ready to be implemented without a comprehensive set of tests. Besides the powder properties, we have a large number of building and environmental parameters that demands extensively research prior implementation. Although selected alloys are commercially available and documented to be used in SLM, including Ti6Al4V, SS316L and In718, the majority of it still not ready to be utilized in this system. The focus of this study is to use a thermal model in order to predict the thermal distribution of the process regarding different aspects of the powder properties, especially the thermal conductivity, when different powder packing densities and diameters are used. A Stainless Steel 304L will be utilized in this work, since it is not yet available to be commercially used. The main goal is to show the capabilities of the Finite Element Method in the pre-definition of optimal parameters for the process using a new alloy development. Our findings can be used as a pre-evaluation guideline when printing SS304L, since the comparison with similar experimental work in the field showed significant resemblance and outcomes. The temperature distributions show that the packing density has greater sensibility on the final temperature distributions, compared to the powder diameter variance. Two different power inputs are compiled and the temperature outcomes demonstrate that a power input of 100 Watts is recommended to use when printing SS304L, rather than 400 Watts that brings high temperature into the powder bed.Item Open Access On Microstructure And Corrosion Properties Of Selective Laser Melted 316L Stainless Steel(CSME-SCGM, May-18) Kazemipour, Mostafa; Mohammadi, Mohsen; Nasiri, AliIn this study, a laser additive manufacturing method, known as selective laser melting (SLM), was applied to produce cube blocks of 316L stainless steel. The microstructure and corrosion properties of the produced samples were analyzed using scanning electron microscopy, cyclic potentiodynamic polarization testing, and electrochemical impedance spectroscopy. The results were also compared with the properties of a conventional wrought 316L stainless steel sample. The microstructural studies showed that the SLM-manufactured samples have a regular network of melt pools containing austenite grains along with elongated or equiaxed cellular sub-grains. The potentiodynamic polarization results depicted that the SLM fabricated samples had higher positive pitting potential and a wider passivation range than those of the wrought sample, corresponding to their better corrosion resistance. However, the SLM fabricated samples showed a weaker re-passivation property, which possibly is attributed to the presence of pre-existing porosities in the structure of the SLM sample formed during the fabrication process. The EIS data also confirmed a larger capacitive arc for the SLM fabricated samples than its wrought counterpart, indicating a higher charge transfer impedance and a better corrosion resistance.