A knowledge-navigation system for dimensional metrology

Journal of Research of the National Institute of Standards and Technology, March-April, 2002 by Howard T. Moncarz

2.6 Machining Errors

This concept covers errors that affect the part measurement results. Sources of machining errors include out-of-calibration machine tools, tool wear, and the environment (e.g., extreme temperatures). Ultimately, machining errors show up as deviations from the design dimensions of a part, based on the measured differences between the completed part and the nominal specification. The part would be incorrect if the differences caused an out-of-tolerance condition. The deviations will often show a distribution pattern that is characteristic of the type of process, the error source, and the type of surface being machined, e.g., a vertical end mill that was out of calibration could create lobing errors when machining out a hole. A taxonomy could be created that could connect particular manufacturing error sources to the error patterns created. Conversely, particular error results could be connected back to suspected error sources in the manufacturing process. Thus, a representation, as simple as a taxonomy, could be associated with an empirical database of the information described here.

3. Scenario

The idea envisioned is that the user would explore objects (concept representations), study the associated information, interact with the objects to gain intuitive insights, and observe the relationships among different objects. The exploration strategy outlined enables the user to construct an intuitive framework for a particular knowledge base in the user's mind to support better understanding and retention of it.

This section provides the author's conception for how this kind of system can be used to explore and study the knowledge base described in this paper. The treatment is brief and provides a flavor of the capabilities rather than a detailed description of them. In the scenario, two types of windows are referenced. The first is the concept window, referred to simply as a window, for display of concept representations. The second is the information window for display of information files or file fragments that are linked to the concepts' sub-objects and accessed upon selection of them.

For example, Fig. 6 shows a window with four frames. As mentioned earlier, a frame is referred to as a window in this paper. The two "windows" on the left are concept windows. The part concept is shown in the top-left window and the inspection-process concept is shown in the bottom-left window. The two windows on the right are information windows and contain file data that were sent to the respective windows as a result of the user clicking on features in the part concept. Also note that the middle concept plane of information types in the inspection-process concept has been rendered invisible to view the interoperability standards against the backdrop of the task decomposition.

The scenario below will first describe the exploration of the GD&T knowledge base; then it will describe the exploration of interoperability standards for the inspection process. Concepts selected by the user are shown in boldface in the discussion. Each concept can be set to MOVE mode in which case the user can manipulate the position and orientation of the concept representation, or it can be set to INFO mode in which case the user can access information by selecting a sub-object.