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Next generation of the
Geometrical Product Specifications (GPS) language
The vision for an improved engineering tool
The objective of the improved GPS system is to provide tools for the economic management of variability in products and processes. This will be achived by the use of a more precise method of expressing workpiece functional requirements, complete and well defined specifications, and integrated verification approaches. This improved GPS system will clarify the current practices and be harmonized with the work of other relevant Technical Committees (TC) of the International Organization for Standardization (ISO). This harmonization will, for example, enable better integration with 3D CAD/CAM/CAQ-systems.
The improved GPS system will be based on the experience from the use of current practices and traditions. The legal and technical contents of existing drawings will be left intact, realizing that there is a vast domain of existing specifications, which cannot be changed without the explicit or implicit consent of those responsible.Proper implementation of the improved GPS system will reduce costs by avoiding the manufacture of inadequate workpieces due to incompletely defined specifications.
The intended function of a product can be ensured by controlling the geometry and material properties of the workpiece(s) making up the product. GPS is the language for controlling geometry only and its evolution will be based on computable mathematics and correct, consistent logic using a generic set of rules, that can be applied to all types of specifications.
The challenge for the future is to enrich the GPS language to allow expression of requirements relating to a wide range of workpiece functions.
Uncertainty - An economical tool
The improved GPS system will use "uncertainty" as the "currency" for quantifying:
a) how well the specification expresses the functional requirements;
b) what ambiguities exists in the specification itself;
c) the uncertainty of measurement.
The improved GPS language will be richer, more precise and, therefore, more verbose. However, in most cases, the complexity of drawing indications will not increase due to the consistency of the logic and the "default" concept.
There will be a global default for each type of GPS specification, which is based on simplicity and minimization of total cost. In addition, there will be a number of shorthand indications covering commonly occurring workpiece functions, e.g. fits.
This effort is being spearheaded by ISO/TC 213 "Dimensional and geometrical product specifications and verification".
This vision has been unanimously approved by the 9th plenary session of ISO/TC 213 on 23 June 2000 in Berlin, Germany.
of ISO/TC 213
Danish Standards Association
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