Thin-Wall Calculation for Layered Manufacturing

[+] Author and Article Information
Sara McMains

Mechanical Engineering Department, University of California, Berkeley, Berkeley, CA 94720-1740 ASME Member

Jordan Smith

Carlo Séquin

Computer Science Division, University of California, Berkeley, Berkeley, CA 94720-1776

J. Comput. Inf. Sci. Eng 3(3), 210-218 (Sep 16, 2003) (9 pages) doi:10.1115/1.1604812 History: Received March 01, 2003; Accepted June 01, 2003; Online September 16, 2003
Copyright © 2003 by ASME
Your Session has timed out. Please sign back in to continue.


Beaman, J. J. et al., 1997, Solid Freeform Fabrication: A New Direction in Manufacturing, Kluwer Academic Publishers, Dordrecht.
3D Systems, Inc., 1988, Stereolithography Interface Specification, Company literature.
STRATASYS, INC ., 1999, QuickSlice 6.2, Eden Prairie, MN.
Yu, K. M., and Li, C. L., 1995, “Speeding up Rapid Prototyping by Offset,” Proceedings of the Institution of Mechanical Engineers, Part B, 209 (B1), pp. 1–8.
Rossignac, J. R., 1985, “Blending and Offsetting Solid Models,” PhD thesis, University of Rochester.
Li,  C. L., Yu,  K. M., and Lam,  T. W., 1998, “Implementation and Evaluation of Thin-Shell Rapid Prototype,” Comput Ind., 35(2), pp. 185–193.
Lam,  T. W., Yu,  K. M., Cheung,  K. M., and Li,  C. L., 1998, “Octree Reinforced Thin Shell Object Rapid Prototyping by Fused Deposition Modelling,” International Journal of Advanced Manufacturing Technology, 14 (9), pp. 631–636.
Allen, S., and Dutta, D., 1997, “Wall Thickness Control in Layered Manufacturing,” in Proceedings of the Thirteenth Annual Symposium on Computational Geometry, ACM, pp. 240–247.
Allen,  S., and Dutta,  D., 1998, “Wall Thickness Control in Layered Manufacturing for Surfaces With Closed Slices,” Computational Geometry: Theory and Applications, 10 (4), pp. 223–238.
Requicha, A. A. G., 1980, “Representations for Rigid Solids: Theory, Methods, and Systems,” ACM Comput. Surv., pp. 437–464.
de Berg, M., van Kreveld, M., Overmars, M., and Schwarzkopf, O., 1997, Computational Geometry: Algorithms and Applications, Springer, Berlin.
M. Held, 1991, On the Computational Geometry of Pocket Milling, Lecture Notes in Computer Science. Springer-Verlag, Berlin.
Veeramani,  D., and Gau,  Y.-S., 1997, “Selection of an Optimal Set of Cutting-Tool Sizes for 2 1/2 D Pocket Machining,” Comput.-Aided Des., 29(12), pp. 869–877.
Kim,  D.-S., 1998, “Polygon Offsetting Using a Voronoi Diagram and Two Stacks,” Comput.-Aided Des., 30(14), pp. 1069–1076.
Shamos, M. I., and Hoey, D., 1975, “Closest Point Problems,” Proceedings 16th Annual IEEE Symposium on Foundation of Computer Science.
Lee,  D. T., and Schachter,  B. J., 1980, “Two Algorithms for Constructing a Delaunay Triangulation,” International Journal of Computer & Information Sciences, 9 (3), pp. 219–242.
Guibas,  L., and Stolfi,  J., 1985, “Primitives for the Manipulation of General Subdivisions and the Computation of Voronoi Diagrams,” ACM Trans. Graphics, 4(2), pp. 74–123.
Kim,  D.-S., Hwang,  P. K., and Park,  B.-J., 1995, “Representing the Voronoi Diagram of a Simple Polygon Using Rational Quadratic Bezier Curves,” Comput.-Aided Des., 27(8), pp. 605–614.
Shewchuk,  J. R., 1997, “Adaptive Precision Floating-Point Arithmetic and Fast Robust Geometric Predicates,” Discrete Comput. Geom., 18(3), pp. 305–363.
McMains, S., Séquin, C., and Smith, J., 1998, “SIF: A Solid Interchange Format for Rapid Prototyping,” in Proceedings of the 31st CIRP International Seminar on Manufacturing Systems, CIRP, pp. 40–45.
McMains, S., 1999, The SIF_SFF Page. http://www.cs.berkeley.edu/∼ug/sif_2_0/SIF_SFF.shtml.
McMains, S., and Séquin, C., 1999. “A Coherent Sweep Plane Slicer for Layered Manufacturing,” in Fifth Symposium on Solid Modeling and Applications, ACM, pp. 285–295.
Wang, J., 1999, L-SIF Version 1.0. http://www.cs.berkeley.edu/∼ug/LSIF/LSIF.html.
Woo, M., Neider, J., Davis, T., and Shreiner, D., 1999, OpenGL(R) Programming Guide: The Official Guide to Learning OpenGL, Version 1.2, third ed. Addison-Wesley, Reading, Massachusetts.
Wang, J., 2001, “Layer-Based Boolean Operation for Solid Free-Form Fabrication,” Master’s thesis, University of California, Berkeley.
Heisserman, J., and Woodbury, R., 1992. “Unary Shape Operations,” in Geometric Modeling for Product Realization. North-Holland, Amsterdam, pp. 63–80.
McMains, S., Smith, J., and Séquin, C., 2002. “The Evolution of a Layered Manufacturing Interchange Format,” in ASME Design Engineering Technical Conferences 2002, 28th Design Automation Conference, ASME, Paper No. DETC2002/DAC-34136.


Grahic Jump Location
For a simple rectangular block, all of the interior slices are “hidden” and thus can be built using the fast build style pictured on the left. For contrast, the regular solid-fill build style used on the top and bottom slices is pictured on the right, with densely spaced parallel roads in the interior. In areas where a part surface shows a shallow slope with respect to the build plane, the build style on the left cannot be used.
Grahic Jump Location
Gaps result in a part built with an over-aggressive manual extension of the QuickSlice software’s fast build region
Grahic Jump Location
For this central slice, the area we want to fill densely with the build material (a solid fill) is simply the slice offset region (Region1). The interior region of this layer will be filled with a looser cross-hatched pattern for support.
Grahic Jump Location
We use a solid fill in the slices directly above or below horizontal faces (subset of Region2)
Grahic Jump Location
We also use a solid fill at angled faces anywhere the current slice is not covered by the slice above or not covered by the slice below (subset of Region2)
Grahic Jump Location
Here we are looking at a cross-section of the part. All of the regions that are in the slice offset regions are labeled with Region1 shading. The regions that were in Region2 but not Region1 are labeled with Region2 shading. The “gaps” in the thin wall are circled.
Grahic Jump Location
Looking at the same cross section, we see the additional areas that are solid filled when we add Region3
Grahic Jump Location
For a wall that we want to be two layers thick, we must extend Region2 up an additional layer above down faces and down an additional layer below up faces
Grahic Jump Location
The cross section of the full 2-layer thick wall, showing the addition of the extended Region3+
Grahic Jump Location
An example where it is necessary to clip the extended Region3+ against the boundary of the current slice
Grahic Jump Location
Input contour (thick black), Voronoi diagram (thin gray), and offset contour (thick gray)
Grahic Jump Location
Input contour in z=0 (thick black), Voronoi mountain (thin gray), and offset contour in z=d (thick gray)
Grahic Jump Location
Input contours (thick black) and Voronoi diagram (thin gray)
Grahic Jump Location
Input contours (thick black), Voronoi diagram (thin gray), and three inner and two outer offset contours (thick gray)
Grahic Jump Location
The screw part manufactured using our algorithm. Using the QuickSlice software directly, the build took over twice as long to complete.
Grahic Jump Location
A sample slice through the screw part, using the QuickSlice software’s fast build option. All of the interior roads are densely spaced. (The looser spaced roads on the exterior are for support material.)
Grahic Jump Location
The same slice using our algorithm. The interior roads are loosely filled for a faster build.
Grahic Jump Location
Detail of the cow tail region half way through the build



Some tools below are only available to our subscribers or users with an online account.

Related Content

Customize your page view by dragging and repositioning the boxes below.

Related Journal Articles
Related eBook Content
Topic Collections

Sorry! You do not have access to this content. For assistance or to subscribe, please contact us:

  • TELEPHONE: 1-800-843-2763 (Toll-free in the USA)
  • EMAIL: asmedigitalcollection@asme.org
Sign In