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The mixture of an additive and a subtractive gave birth to this form of prototyping. The figure shown above gives an illustrative example of a laminated object manufacturing model. Layers of materials are added one by one and a laser is used to trace the shape of the model at that cross section. As the layer is cut, unnecessary parts on the side are removed. A cylindrical feeder bound with all the material is used as a material supply role. A special type of tape is applied onto the platform so that the material can get attached. The sheet is then fed in, the other side of which is given into a take up role after being processed by the laser. The laminating roller is rolled across the surface which helps in activating the adhesive and also to apply simultaneous downward pressure. A carbon dioxide laser is used to cut an outline of the cross sectional shape of the model. A border is then cut around the desired part which enables the part to stay intact as each new layer is created. The laser then proceeds to create hatch marks or cubes surrounding the pattern within the border. This is done so that the cubes can act as supporting structure to the parts and there is no movement during the building process. [4] This process is repeated till the part is built. When the build is completed the part is then removed from the platform 1.1.4 Fused Deposition Modeling Fused deposition modeling (FDM) is an extrusion based additive form of rapid manufacturing technology mainly used for modeling, prototyping applications till recently when more development in this sector has enabled parts being used as products and parts for day to day applications. This technology was developed by S.Scott Crump late 80‟s and commercialized in the 90‟s as a concept modeling device. The FDM technology marketed is commercially by Stratasys which also owns the trademark for this technology. As FDM is the main topic of research of this thesis, it will be discussed in full detail in the following sections. 20
1.1.5 Laser Engineered Net Shaping Laser Engineered Net shaping is one of the first type of rapid prototyping systems to use metals in the deposition system. [5] The parts made from this type of system are full strength metals ranging from steel, titanium, aluminum, vanadium etc. This process was developed by Sandia national laboratories and cooperation from various other industry members. Similar to most of the rapid prototyping process, LENS also used a layer by layer approach to build a part. The CAD model of the part is used to obtain a STL file which is used as an input to the machine which builds the parts from the bottom layer onwards. A high powered laser is used to fuse the metal powder when it is fed from feeder tubes into its focal point. This powder is then turned into a layer when deposited in the required shape. A Sample LENS process is shown in Fig 1.6 below. Fig 1.6 A Sample LENS process The deposition device then moves up the distance equal to the height of one layer to proceed to deposit the next layer. This process is repeated till the complete part is built. There are various other forms of rapid prototyping methods with similar techniques and methods of deposition which are being developed to cater to the manufacturing needs. Out of the various forms, FDM is the one which is the most successful and important technology available to the market. Because of this status of Fused Deposition Modeling it is always being propagated for further research and investigation. More developments, improvements and advancements in this field will be covered in detail in the following sections. 21
Page 1 and 2: An Investigation into curved layer
Page 3 and 4: Contents Abstract..................
Page 5 and 6: 3.5.2 Fabepoxy.....................
Page 7 and 8: methodology to print simple curved
Page 9 and 10: List of Figures 1.1 The Rapid proto
Page 11 and 12: 4.3 Parts being tested with Hounsfi
Page 13 and 14: List of Abbreviations 3D: Three dim
Page 15 and 16: Fig 1.1 The Rapid prototyping Cycle
Page 17 and 18: 1.1.1 Stereolithography Stereolitho
Page 19: The object to be made is first mode
Page 23 and 24: 1.2 Fused Deposition Modeling A det
Page 25 and 26: Fig 1.8 Deposition Head Different t
Page 27 and 28: 900mc is capable of producing parts
Page 29 and 30: noted that the parts built in this
Page 31 and 32: structure. Honeycomb scaffold archi
Page 33 and 34: optimal direction to build a part t
Page 35 and 36: processing treatment was analyzed w
Page 37 and 38: The actual influence of the curved
Page 39 and 40: Separating the Main part with its s
Page 41 and 42: limited to simple models. It could
Page 43 and 44: Fig 2.2 Faces, Edges and Vertices o
Page 45 and 46: 2.1.5 Constructive Solid Geometry C
Page 47 and 48: A STL file is a triangular represen
Page 49 and 50: Fig 2.8 A sample Binary STL File Sl
Page 51 and 52: Different processes may either vary
Page 53 and 54: At the very outset of generating th
Page 55 and 56: and correction of each point to sat
Page 57 and 58: apid prototyping machine are remove
Page 59 and 60: Fig 2.13 Main Part Fig 2.14 Support
Page 61 and 62: As this text file is to be used wit
Page 63 and 64: mounted to the axes carriage. Timin
Page 65 and 66: Fig 3.1 The deposition head At the
Page 67 and 68: 3.2.3 Assembling Electronics and ca
Page 69 and 70: microcontroller is now disconnected
Page 71 and 72:
The relationship between test point
Page 73 and 74:
on the mechanical properties and po
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3.5.1 Silicone with other materials
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Fab@home machine. Since our require
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are printed using the two suitable
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The support structure‟s dimension
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machine Fig 3.13 Flat and curved la
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4.1 Experimental conditions Chapter
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have many factors from contention a
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4.3 Taguchi methods There are two t
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Such steps usually identify the nee
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Nominal is best Larger is better S
Page 95 and 96:
Control of material flow - The lead
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Fig 4.3 Parts being tested with Hou
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values in all cases are almost doub
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level. The other parameters were in
Page 103 and 104:
The finite element method has had a
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performance of finished FDM parts [
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ehaviour with failure occurring at
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Fig. 2 (a) is the thin curved part
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Table 5.1 Property data: Fabepoxy M
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optimum number. The final finite el
Page 115 and 116:
Fig. 5.11 Load and boundary conditi
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overall deflection pattern of two s
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Fig. 5.13 Variation of compressive
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Fig. 5.15 shows the overall deforma
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The effectiveness of the deposition
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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