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Chapter 6 Conclusion The main objective of the project is to establish the effectiveness of the curved layer FDM process through experimental and numerical investigations. A practical set-up and suitable mathematical models were necessary to be procured for the purpose of developing a test platform for FDM. The Fab@home machine is adopted for the purpose of the test platform, and essential mathematical models for CLFDM are reviewed from literature. A working software-hardware system is developed from existing models for the practical implementation of the CLFDM process. Several material options were tried for being used in the investigations leading to the establishment of the significance of CLFDM. However, there was little success with most material combinations due to the multidimensional requirements of the material for FDM. Final experimental and numerical investigations were carried out using fabepoxy as the candidate material. Statistical design of experiments using Taguchi L8 orthogonal array was used and the influences of geometrical and process parameters were investigated. Numerical models were generated using the finite element methods in Abaqus, for modelling the mechanical behaviour of curved and flat layer FDM. The following are the main conclusions: Commercially available Silicone is a suitable material for FDM using a syringe type deposition head. Reinforcement of silicone with powder and other forms of composite ingredients does not yield satisfactory results in terms of producing FDM parts for mechanical testing. Fab@home as a FDM test bed is reasonable, but poses several problems while printing parts of consistent quality for experimental evaluation. Curved layer FDM gives better part characteristics, but the actual influence is dependent on the nature of the material and experimental conditions. The speed of deposition appears to have a negligible effect overall, considering the nature of the material used for FDM. 122
The effectiveness of the deposition style is confounded with the geometry of the part. Finite element simulations clearly depict a marked difference in the deformation characteristics of parts produced by flat and curved layer FDM. Flat layer parts fail at inter layer links, which are the sources of weakest points. Once the weak links give apart, the part distorts due to a shear sliding of flat layers relative to one another. Curve layer part on the other hand withstands compressive loads until the final stages. The final failure is due to the formation of a crack at the bottom layers of the curved part at its peak, and the propagation of the same across part, towards the upper free end. This fracture and mode of the CLFDM part resembles the brittle fracture mode, as was also observed with a few curved layer FDM samples. 123
Page 1 and 2:
An Investigation into curved layer
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Contents Abstract..................
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3.5.2 Fabepoxy.....................
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methodology to print simple curved
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List of Figures 1.1 The Rapid proto
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4.3 Parts being tested with Hounsfi
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List of Abbreviations 3D: Three dim
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Fig 1.1 The Rapid prototyping Cycle
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1.1.1 Stereolithography Stereolitho
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The object to be made is first mode
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1.1.5 Laser Engineered Net Shaping
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1.2 Fused Deposition Modeling A det
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Fig 1.8 Deposition Head Different t
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900mc is capable of producing parts
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noted that the parts built in this
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structure. Honeycomb scaffold archi
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optimal direction to build a part t
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processing treatment was analyzed w
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The actual influence of the curved
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Separating the Main part with its s
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limited to simple models. It could
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Fig 2.2 Faces, Edges and Vertices o
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2.1.5 Constructive Solid Geometry C
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A STL file is a triangular represen
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Fig 2.8 A sample Binary STL File Sl
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Different processes may either vary
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At the very outset of generating th
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and correction of each point to sat
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apid prototyping machine are remove
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Fig 2.13 Main Part Fig 2.14 Support
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As this text file is to be used wit
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mounted to the axes carriage. Timin
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Fig 3.1 The deposition head At the
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3.2.3 Assembling Electronics and ca
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microcontroller is now disconnected
Page 71 and 72: The relationship between test point
Page 73 and 74: on the mechanical properties and po
Page 75 and 76: 3.5.1 Silicone with other materials
Page 77 and 78: Fab@home machine. Since our require
Page 79 and 80: are printed using the two suitable
Page 81 and 82: The support structure‟s dimension
Page 83 and 84: machine Fig 3.13 Flat and curved la
Page 85 and 86: 4.1 Experimental conditions Chapter
Page 87 and 88: have many factors from contention a
Page 89 and 90: 4.3 Taguchi methods There are two t
Page 91 and 92: Such steps usually identify the nee
Page 93 and 94: Nominal is best Larger is better S
Page 95 and 96: Control of material flow - The lead
Page 97 and 98: Fig 4.3 Parts being tested with Hou
Page 99 and 100: values in all cases are almost doub
Page 101 and 102: level. The other parameters were in
Page 103 and 104: The finite element method has had a
Page 105 and 106: performance of finished FDM parts [
Page 107 and 108: ehaviour with failure occurring at
Page 109 and 110: Fig. 2 (a) is the thin curved part
Page 111 and 112: Table 5.1 Property data: Fabepoxy M
Page 113 and 114: optimum number. The final finite el
Page 115 and 116: Fig. 5.11 Load and boundary conditi
Page 117 and 118: overall deflection pattern of two s
Page 119 and 120: Fig. 5.13 Variation of compressive
Page 121: Fig. 5.15 shows the overall deforma
Page 125 and 126: [11] M. Greul, T. Pintat, M. Greuli
Page 127 and 128: [32] Philip J. Ross, 1988, “Taguc
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