Design by Composition for Layered Manufacturing*

[+] Author and Article Information
Mike Binnard, Mark R. Cutkosky

Center for Design Research, Stanford University, Stanford, CA 94305

J. Mech. Des 122(1), 91-101 (Jan 01, 1999) (11 pages) doi:10.1115/1.533549 History: Revised January 01, 1999; Received July 01, 1999
Copyright © 2000 by ASME
Your Session has timed out. Please sign back in to continue.



Grahic Jump Location
When the designer combines two primitives (left), the merging algorithms combine the manufacturing plans (right) to produce a plan for the new design. In this example, the plans are represented by cross sectional views of regions of part material encapsulated in support material that will subsequently be etched or melted away. The composition algorithms preserve ordering constraints among the various regions.
Grahic Jump Location
Shading used in illustrations
Grahic Jump Location
The SDM process cycle. Material is alternately deposited and shaped by different processes. This methodology permits selecting a deposition process that gives good material quality and a shaping process that has good tolerances and surface finish.
Grahic Jump Location
As an alternative to the decomposition of previously generated CAD models, design by composition simplifies process planning and permits immediate analysis of evolving designs.
Grahic Jump Location
Cross-sections of a primitive and its compact set. The compact set (b) for the primitive (a) contains two part material compacts and three support material compacts. The external surfaces of the compact set are either the top or bottom of the workspace, W, or parallel to the growth axis.
Grahic Jump Location
Compact-set merging algorithm. The first part of the algorithm creates the intersection compacts. The function f() is specified by the truth tables shown in Fig. 7. The second part puts nonintersecting compacts into the result set.
Grahic Jump Location
Truth tables for compact set merging operations. The tables specify the material type (part or support) for a compact, c=f(a,b), which is formed by the intersection of two source compacts, a and b.
Grahic Jump Location
An example merging operation. Two primitives, A and B, are combined with a union operation. The amount of overlap between them is determined by their position in the CAD workspace.
Grahic Jump Location
A simple design by composition example. The designer wants to combine the two primitives in (a) to form the shape in (b).
Grahic Jump Location
The two compact sets that will be combined
Grahic Jump Location
Step 1 of the merging operation. The two compacts in (a) are intersected, producing the intersection compact in (b). The intersection is subtracted from the two source compact sets (c), and is added to the result set, C, in (d).
Grahic Jump Location
Steps 2 and 9 of the merging operation. In step 2, the remaining piece of compact a1 is intersected with compact b2. In step 9, the remainder of compact a3 is intersected with b3.
Grahic Jump Location
Source and result CPGs for the example in Fig. 9. The algorithms described in Section 5.1 create the precedence links in the result CPG based on the two source CPGs.
Grahic Jump Location
The compact graph in (a) can be simplified in different ways; two of the possibilities are shown in (b) and (c).
Grahic Jump Location
CPG simplification algorithm. This algorithm uses a utility function calculation to rank all possible simplification alternatives.
Grahic Jump Location
CAD model of embedded components for a robot leg and sequence of merged compacts for creating the leg. The top layer of support material is a product of the merge algorithm in Section 4 and is not required for manufacturing.
Grahic Jump Location
Close-up view of leg (a) just after inserting pneumatic components (step 5 in Fig. 16) and view of finished part (b).
Grahic Jump Location
Integrating design by composition and decomposition. The bold arrows represent transmission of compact graphs.




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