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2.1.3 Boundary Representation Boundary representation is also known as either B-Rep or BREP. It is a method wherein limits are used for representing shapes. A collection of connected surface elements is used to construct a solid. Topology and Geometry are two main compositions of a Boundary Representation. Topology -- records the connectivity of the faces, edges and vertices by means of pointers in the data structure. Geometry -- describes the exact shape and position of each of the edges, faces and vertices. * The geometry of a vertex is just its position in space as given by its (x,y,z) coordinates. * Edges may be straight lines, circular arcs, etc. * A face is represented by some description of its surface (algebraic or parametric forms used). Vertices, faces and edges are the main topological items in a boundary representation. A face is a bounded portion of a surface; an edge is a bounded piece of a curve and a vertex lies at a point. Fig 2.2 shows faces, edges and vertices. Other elements are the shell, the loop and loop-edge links which are used to create the edge circuits. The edges are like the edges of a table, bounding a surface portion. Compared to the constructive solid geometry (CSG) representation, which uses only primitive objects and Boolean 42
Fig 2.2 Faces, Edges and Vertices operations to combine them, boundary representation is more flexible and has a much richer operation set. This makes boundary representation a more appropriate choice for CAD systems. 2.1.4 Sweeping Sweeping is a method of producing solid models for manufacturing. Depending upon the size, shape and complexity any of the methods – Revolve, Extrusion and Sweeping with guide lines can be used for sweeping. Revolve is a feature were models are generated by revolving around the centre axis. The main limitation of this type being that this method is best suitable for models which are symmetric over the centre axis. Fig 2.3 shows an example of the revolve feature. Fig 2.3 “Apple” made with the revolve feature. 43
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: limited to simple models. It could
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
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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