How CNC process plans constrain designs of rotational parts: A rigorous approach

Georg Thimm, Graeme A. Britton, Fok Sai Cheong

Research output: Contribution to journalArticlepeer-review


The purpose of this paper is to present the use of a graph theoretic model to link designs with CNC process plans. The approach to develop process plans from design dimension trees is discussed for rotational parts. The procedures to determine datum-hierarchy tree from designs are given for direct, indirect, and pre-forming machining. This procedure is illustrated with a simple example. The approach exploits the structure of datum-hierarchy trees underlying process plans to formulate design heuristics to achieve higher machinability. The designs resulting from applying the heuristics have the fewest number of constraints on process planning and allow parts to be produced with minimal tolerance stack-ups and production costs. By using the proposed framework, it is possible to generate process plans, which are optimal in terms of minimal tolerance stacks, directly from the design specification dimensions.

Original languageEnglish
Pages (from-to)359-366
Number of pages8
JournalComputer-Aided Design and Applications
Issue number1-4
Publication statusPublished - 2004


  • Datum-hierarchy tree
  • Design heuristic
  • Part variation
  • Process planning
  • Tolerance stack

ASJC Scopus subject areas

  • Computational Mechanics
  • Computer Graphics and Computer-Aided Design
  • Computational Mathematics

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