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On the Separation of a Polyhedron from Its Single-Part Mold [article]

Prosenjit Bose, Dan Halperin, Shahar Shamai
2017 arXiv   pre-print
We study the case in which the mold is made of a single part and the object to be produced is a three-dimensional polyhedron.  ...  We give an algorithm that decides whether a given polyhedron with n facets is castable with a single-part mold, and if so indicates how to orient the polyhedron in the mold and a direction in which the  ...  Theorem 3 The polyhedron P is castable with a single-part mold if and only if the arrangement A(C) contains a point of depth 1.  ... 
arXiv:1708.04203v1 fatcat:fx7mb3uptneerpoyzseuwhgufa

Page 5114 of Mathematical Reviews Vol. , Issue 2000g [page]

2000 Mathematical Reviews  
Summary: “A parting line for a polyhedron is a closed curve on its surface which identifies the two halves of the polyhedron for which mold-boxes must be made.  ...  A parting line is undercut-free if the two halves that it generates do not contain facets that obstruct the de-molding of the polyhedron.  ... 

Manufacturing processes [chapter]

Ravi Janardan, Tony Woo
2004 Handbook of Discrete and Computational Geometry, Second Edition  
GLOSSARY Mold: A cavity in the shape of the part to be manufactured into which molten metal is poured. It consists of two mating parts called mold halves.  ...  A key step here is the design of the mold from a digital model of the part, since this affects both the speed of the process and the quality of the finished part.  ...  [Bra86]: A good general reference on a variety of design and manufacturing processes, including casting, molding, forging, stamping, machining, etc.  ... 
doi:10.1201/9781420035315.ch55 fatcat:77gyrwh5nfabpirmyvamjtjav4

Sufficiently Fat Polyhedra are not 2-castable [article]

David Bremner, Alexander Golynski
2002 arXiv   pre-print
We consider a generalization of the sand casting process where the object is manufactured by gluing together two identical faces of parts cast with a single piece mold.  ...  In this note we consider the problem of manufacturing a convex polyhedral object via casting.  ...  Let P be a polyhedron that lies in H, while one of its faces F lies on the boundary of H. The set M = H \ P is called a mold for P .  ... 
arXiv:cs/0203025v1 fatcat:cdynyv75l5b33oygpehwx2zcxy

Computing a flattest, undercut-free parting line for a convex polyhedron, with application to mold design

Jayanth Majhi, Prosenjit Gupta, Ravi Janardan
1999 Computational geometry  
A parting line for a polyhedron is a closed curve on its surface, which identifies the two halves of the polyhedron for which mold-boxes must be made.  ...  A parting line is undercut-free if the two halves that it generates do not contain facets that obstruct the de-molding of the polyhedron.  ...  Acknowledgements We thank the Geometry Center at the University of Minnesota for providing access to computational and videotaping facilities during the implementation phase of this project.  ... 
doi:10.1016/s0925-7721(99)00023-1 fatcat:hyk6twozirejlfl4ijp43fjtse

Computing a flattest, undercut-free parting line for a convex polyhedron, with application to mold design [chapter]

Jayanth Majhi, Prosenjit Gupta, Ravi Janardan
1996 Lecture Notes in Computer Science  
A parting line for a polyhedron is a closed curve on its surface, which identi es the two halves of the polyhedron for which mold-boxes must be made.  ...  A parting line is undercut-free if the two halves that it generates do not contain facets that obstruct the de-molding of the polyhedron.  ...  Acknowledgements We thank the Geometry Center at the University of Minnesota for providing access to computational and videotaping facilities during the implementation phase of this project.  ... 
doi:10.1007/bfb0014489 fatcat:cgqqmev5ifgtzgflhuav4fvltm

Geometric algorithms for automated design of rotary-platen multi-shot molds

Xuejun Li, Satyandra K. Gupta
2004 Computer-Aided Design  
Then, starting from the last mold stage, we generate the mold pieces for every mold stage.  ...  For every basic type, we find a molding sequence based on the precedence constraints resulting due to accessibility and disassembly requirements.  ...  Opinions expressed in this paper are those of authors and do not necessarily reflect opinion of the sponsors.  ... 
doi:10.1016/j.cad.2003.11.003 fatcat:2f3yryvykjattjw7bjqwafh2sa

Algorithms for generating multi-stage molding plans for articulated assemblies

Alok K. Priyadarshi, Satyandra K. Gupta
2009 Robotics and Computer-Integrated Manufacturing  
As a part of the planning problem, we determine the molding sequence and intermediate assembly configurations.  ...  During the multi-stage molding process, assembly operations are performed along with the molding operations. Hence, it gives rise to a new type of planning problem.  ...  Opinions expressed in this paper are those of authors and do not necessarily reflect opinion of the sponsors.  ... 
doi:10.1016/j.rcim.2007.10.002 fatcat:5cgzdlg36fbjdfa6jadqucswiu

A Step Towards Automated Design of Side Actions in Injection Molding of Complex Parts [chapter]

Ashis Gopal Banerjee, Satyandra K. Gupta
2006 Lecture Notes in Computer Science  
This paper describes algorithms for generating shapes of side actions to minimize a customizable molding cost function.  ...  Side actions contribute to mold cost by resulting in an additional manufacturing and assembly cost as well as by increasing the molding cycle time.  ...  However, the opinions expressed here are those of the authors and do not necessarily reflect that of the sponsor.  ... 
doi:10.1007/11802914_35 fatcat:ghp5q3sfabf2hhmstj4sxkh32q

Characterization of polyhedron monotonicity

J.S. Ha, K.H. Yoo, J.K. Hahn
2006 Computer-Aided Design  
This notion can be more extended for categorizing the boundary shapes of polyhedrons, but it has not been explored enough yet.  ...  We reexamine the three types of polyhedron monotonicity by relating them with 3D manufacturing problems, and present their formulation with geometric problems on the sphere. q  ...  We have defined the pockets and the lids of § by computing its deficiencies from the operations of §K Ã CHð §Þ.  ... 
doi:10.1016/j.cad.2005.06.003 fatcat:nd5j4o6fzne27jadb3o5ctmhmq

Finding Mold-Piece Regions Using Computer Graphics Hardware [chapter]

Alok K. Priyadarshi, Satyandra K. Gupta
2006 Lecture Notes in Computer Science  
An important step in the mold design process that ensures disassembly of mold pieces consists of identifying various regions on the part that will be formed by different mold pieces.  ...  By using a system that can quickly find various mold-piece regions on a part, designers can easily optimize the part and mold design and if needed make appropriate corrections upfront, streamlining the  ...  However, the opinions expressed here are those of the authors and do not necessarily reflect that of the sponsor.  ... 
doi:10.1007/11802914_53 fatcat:tzuy6a5bbfepnemotzuxbegeo4

Geometric and computational aspects of manufacturing processes

Prosenjit Bose, Godfried Toussaint
1994 Computers & graphics  
For a plane ta interseet the closure of all edges of E', it must separate G+ from G-.  ...  For sorne casting processes, it is not necessary that the cast parts be separated by a plane. In these cases, every couvex polyhedron is castable.  ... 
doi:10.1016/0097-8493(94)90061-2 fatcat:4raorpcr2vcgnlmtj2gbx3fx2q

Bounded distance field for assisting interactive layout design of water circuits

Masatomo INUI, Tomohiro IMAI, Nobuyuki UMEZU
2019 Journal of Advanced Mechanical Design, Systems, and Manufacturing  
Manufacturing companies often define various guidelines on the part placement in a mechanical product.  ...  Based on a placement of new objects or a position change of objects, the distance field in the modeling space must be updated.  ...  Fig. 5 Computation of the distance of p from a single object.  ... 
doi:10.1299/jamdsm.2019jamdsm0095 fatcat:qelp4zmcgrfqlka3nu2425qqee

TERRAIN DECOMPOSITION AND LAYERED MANUFACTURING

SÁNDOR P. FEKETE, JOSEPH S. B. MITCHELL
2001 International journal of computational geometry and applications  
Terrain polyhedra have a base facet such that, for each point of the polyhedron, the line segment joining the point to its orthogonal projection on the base facet lies within the polyhedron.  ...  In order to maximize the integrity of a prototype, one wants to minimize the number of individual sub-models that are manufactured and then glued together.  ...  Aspects of Injection Molding, where this work began.  ... 
doi:10.1142/s0218195901000687 fatcat:42n4mkhzergodofmietzrfgvle

Rotary-actuated folding polyhedrons for midwater investigation of delicate marine organisms

Zhi Ern Teoh, Brennan T. Phillips, Kaitlyn P. Becker, Griffin Whittredge, James C. Weaver, Chuck Hoberman, David F. Gruber, Robert J. Wood
2018 Science Robotics  
Requiring only a single rotary actuator to fold, the device is suited for remote operation onboard underwater vehicles and has been field-tested to encapsulate a variety of delicate deep-sea organisms.  ...  The design is based on an axisymmetric dodecahedron net that is folded by an external assembly linkage.  ...  Each gasket was formed by molding the silicone rubber in two-part molds printed on an Objet500 3D printer, in Stratasys TangoBlue resin.  ... 
doi:10.1126/scirobotics.aat5276 pmid:33141728 fatcat:yewg4fsn45bexce732wmyyltdi
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