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endfacet facet normal 0.577 0.577 0.577 outer loop vertex 1.0 0.0 0.0 vertex 0.0 1.0 0.0 vertex 0.0 0.0 1.0 endloop endfacet endsolid The facet record has the form: * The normal vector, 3 floating values of 4 bytes each; * vertex 1 coordinates, 3 floating values of 4 bytes each; * vertex 2 coordinates, 3 floating values of 4 bytes each; * vertex 3 coordinates, 3 floating values of 4 bytes each; 2.2.1 Binary STL File A binary version of STL exists because ASCII STL files can become very large. The header of a binary STL file is generally 80 characters which should never begin with 'solid' because that will lead most software to assume that this is an ASCII STL file. A 4 byte unsigned integer follows the header indicating the number of triangular facets in the file. Following that is data describing each triangle in turn. The file simply ends after the last triangle. Fig 2.8 shows a sample binary STL file. Each triangle is described by twelve 32-bit-floating point numbers: three for the normal and then three for the X/Y/Z coordinate of each vertex - just as with the ASCII version of STL. After the twelve floats there is a two byte unsigned 'short' integer that is the 'attribute byte count' - in the standard format, this should be zero. 48
Fig 2.8 A sample Binary STL File Slicing models is now possible by a number of methods irrespective they were made in B-Rep, STL or CSG, but STL gives the easiest method so far. It also gives a far accurate, reliable result first time, every time. Due to the nature of the STL having no topographic data, there may be some or little problems with these files from time to time. Other errors like Gaps, degenerated facet, non manifold topology, overlapping occur in polygonal approximation models which are made by many commercial tessellation programs by various Cad vendors. Also, all the rapid prototyping machines available in the market not readily accept STL files. Some of them may require processing to be accepted. STL however is by far the most commonly accepted file for different rapid prototyping machinery in the world. 2.2.2 Flat layered Slicing A new form of manufacturing emerged in the „80s with technologies starting to build parts layer by layer. This technology helped decrease the total time it would take for a product to be designed and built. Stereolithography apparatus, shown in Fig 2.9 is a good example for layered manufacturing. 49
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 and 20: The object to be made is first mode
Page 21 and 22: 1.1.5 Laser Engineered Net Shaping
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: A STL file is a triangular represen
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
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 and 122:
Fig. 5.15 shows the overall deforma
Page 123 and 124:
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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