Position tolerancing in reverse engineering: The fixed fastener case

Abstract The present paper addresses the assignment of geometrical position tolerances in reverse engineering. Specification of manufacturing position tolerances for a reconstructed component of an existing mechanical assembly constitutes a complicated task that requires a well-grounded approach. Among features of size, cylindrical features such as holes in conjunction with pegs, pins, or screws are the most frequently used for critical functions, as are the alignment of mating surfaces or the fastening of mating parts. The relationship between mating features is classified either as a fixed or as a floating fastener type. The presented method focuses on the fixed fastener case. It is based on the systematic formulation of dimensional and geometrical relationships and constrains that allow for rational computer-aided processing and evaluation of the measured data from the reference parts, for which appropriately developed algorithmic tools are used. It is shown that the method is reliable, provides for realistic results, and is also time and cost competent as compared with the conventional trial-and-error methods. A case study demonstrates the concept and method.

[1]  Bryan Fischer,et al.  Mechanical Tolerance Stackup and Analysis , 2004 .

[2]  S Park,et al.  Mathematical modelling of geometric tolerance propagation, considering effects of datums , 2001 .

[3]  R. N. Roth,et al.  A New Approach to Statistical Geometrical Tolerance Analysis , 1999 .

[4]  S. Hossein Cheraghi,et al.  An efficient approach for the identification of candidate datum set for a nominally flat primary datum feature , 2003 .

[5]  Utpal Roy,et al.  Representation and interpretation of geometric tolerances for polyhedral objects. II.: Size, orientation and position tolerances , 1999, Comput. Aided Des..

[6]  Tom M. Cavalier,et al.  Numerical approximation approach to the producibility of composite position tolerance specifications for pattern of holes , 2004 .

[7]  M. M. Sfantsikopoulos,et al.  A Knowledge-Based System for Tolerance Allocation in Reverse Engineering , 2000 .

[8]  Weidong Zhu,et al.  Feature-based reverse modeling strategies , 2006, Comput. Aided Des..

[9]  Tamás Várady,et al.  Reverse Engineering , 2002, Handbook of Computer Aided Geometric Design.

[10]  Edward C. De Meter,et al.  An analysis of the effect of datum-establishment methods on the geometric errors of machined features , 2000 .

[11]  Robert B. Fisher,et al.  Object reconstruction by incorporating geometric constraints in reverse engineering , 1999, Comput. Aided Des..

[12]  Ralph R. Martin,et al.  Constrained fitting in reverse engineering , 2002, Comput. Aided Geom. Des..

[13]  Kathryn A. Ingle,et al.  Reverse Engineering , 1996, Springer US.

[14]  M. M. Sfantsikopoulos.  A cost-tolerance analytical approach for design and manufacturing , 1990 .

[15]  Thomas C. Henderson,et al.  Feature-based reverse engineering of mechanical parts , 1999, IEEE Trans. Robotics Autom..

[16]  William Tandler.  The Tools & Rules for Computer Automated Datum Reference Frame Construction , 1998 .