Geometric algorithms for automated design of multi-piece permanent molds

Priyadarshi, Alok; Gupta, Satyandra K.

doi:10.1016/s0010-4485(03)00107-6

Cited by 73 publications

(40 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In mold design, each movable mold piece associates a parting direction from which the mold should be opened without interaction with other pieces and the object in the mold itself. Therefore, the parting direction for a mold piece has to be one of the visible directions of the corresponding surface region formed by a particular mold piece [Ravi and Srinivasan 1990;Priyadarshi and Gupta 2004]. Woo [1994] first developed the concept of the spherical visibility map and linked the visibility problem to various manufacturing processes.…”

Section: A Set Of Triangular Facets For Each Facet Find the Set Of mentioning

confidence: 99%

Computing an exact spherical visibility map for meshed polyhedra

Liu

Ramani

2007

Proceedings of the 2007 ACM Symposium on Solid and Physical Modeling

View full text Add to dashboard Cite

This paper considers computation of the exact visibility range (or the spherical visibility map) for a closed polyhedron whose boundary is represented as a triangle mesh. For each facet on the mesh, we calculate the set of view directions from which all the points on the facet can be seen from the exterior. The projection of those visible directions onto the unit sphere forms the visibility map for the facet. We show that the exact visibility map is a spherical arrangement of closed 0-cells, 1-cells, and 2-cells embedded on the surface of the unit sphere. Based on a provable method for calculating the potential occlusion regions of a facet, a vector visibility algorithm is developed for computing the exact solution of the spherical visibility map for a facet. Examples are given to illustrate our algorithm.

show abstract

Section: A Set Of Triangular Facets For Each Facet Find the Set Of mentioning

confidence: 99%

Computing an exact spherical visibility map for meshed polyhedra

Liu

Ramani

2007

Proceedings of the 2007 ACM Symposium on Solid and Physical Modeling

View full text Add to dashboard Cite

show abstract

“…Manually designing multi-piece molds can take a significant time, and require many iterations before a feasible mold can be realized. Therefore, a multi-piece mold design algorithm was developed to automate several important mold-design steps: (1) finding parting directions, (2) locating parting lines, (3) creating parting surfaces, and (4) constructing mold pieces [24]. This algorithm constructs mold pieces based on global accessibility analysis results of the part and therefore guarantees the disassembly of the mold pieces.…”

Section: Iib1 Mold Designmentioning

confidence: 99%

Replamineform Inspired Bone Structures (RIBS) using multi-piece molds and advanced ceramic gelcasting technology

Gyger¹,

Kulkarni²,

Bruck³

et al. 2007

Materials Science and Engineering: C

View full text Add to dashboard Cite

A new technology was developed for quickly, simply, and affordably creating Replamineform Inspired Bone Structures (RIBS) that combines multi-piece mold manufacturing for creating complex macroscale geometries with advanced ceramic gelcasting technology for controlling microporosity. A conventional gelcast alumina formulation was modified by adding 0-10 wt. % of fugitive carbon particles (graphitic and activated) to obtain porous microstructures during sintering. The carbon-filled gelcast alumina formulation was used to create replicas of bone structures by filling a multi-piece mold automatically generated from a 3-D image of a real bone. Both types of carbon produced total porosity levels of up to 35% that increased with carbon content in a manner that indicated residual porosity from the burned out carbon was not being consumed during sintering. However, activated carbon specimens exhibited linearly increasing percentage of closed porosity with increasing carbon content, while graphitic samples exhibited more interconnected porosity with pore channels in the range of 200 µm. The influence of porosity on mechanical properties was studied by compression tests. The tests indicated that 35% total porosity in bone replicas can decrease strength 88%, decrease stiffness 80%, and reduce total deformation 40% in comparison to bone replicas with 13% total porosity fabricated without carbon. The reduction in stiffness was consistent with a model developed from microscale finite element analysis of overlapping solid spheres that produce microstructures similar to those observed in these specimens. Furthermore, the increased porosity of the material permits axial cracks to grow and bifurcate more easily at substantially reduced deformation and load levels.

show abstract

“…This can be framed as an optimization problem whose objective is to minimize the number of index positions required to fully machine the roll. This is a visualization problem akin to those seen in 5-axis machining and injection molding [16], [17], [18], [19]. The conventional way to solve this is to calculate the optimal view locations by applying geometric algorithms.…”

Section: Efficient Machiningmentioning

confidence: 99%