要約書
A method of generating a computer-based three-dimensional representation of an object resulting from cutting tool operations that remove portions of material from an initial tool solid(固体?)is disclosed.
A method of ... is disclosed(開示).
Using data containing dimensions of the cutting tool and data concerning the tool paths (e.g., points defining the tool paths), the method involves creating a model of the initial tool solid, creating a model of the tool solid removed along each tool path, and subtracting each tool solid model removed from the initial tool solid model. The data concerning the tool paths can be derived from numerically controlled (NC) machine fabrication instructions.
クレーム
1. A method of generating a computer-based three-dimensional representation of an object from data containing dimensions of a cutting tool and a plurality of(複数の)points defining one or more tool paths of that(その、前記)cutting tool, the object resulting from the operation of the cutting tool along the tool paths within an initial tool solid, which operation(関係代名詞による修飾)results in removal of one or more tool path solids from the initial tool solid, the method comprising the steps of: creating a mathematical model of the initial tool solid from data containing dimensions of a cutting tool(既述だが不定冠詞)and a plurality of points(既述だが不定冠詞)defining one or more tool paths such that the initial tool solid model encompasses the tool paths; creating a mathematical model of the tool path solid removed along each tool path by defining a modeling tolerance and representing the tool path as the mathematical model if the difference between the points defining the tool path and the points of the mathematical model is less than or equal to(以下)the modeling tolerance; and subtracting each tool path solid model from the initial tool solid model;
thereby producing the computer-based three-dimensional representation of the object.
2. The method of claim 1 wherein the step of creating the model of at least one of the tool path solids comprises representing the tool path as one or more geometric figures, thereby creating a representation of the tool path.
3. The method of claim 2 wherein the geometric figures are selected from the group comprising(から成る群)straight line segments, arcs, spline curves, and planar segments.
明細書
FIELD OF THE INVENTION
The present invention relates to computer-aided design (CAD) processes(複数)and, more particularly(より詳細には), to a method for creating a three-dimensional CAD solid model of a component from the numerically controlled (NC) fabrication(製作)instructions(命令)for the component that were previously used to fabricate the component by NC machining procedures.
BACKGROUND OF THE INVENTION
Many engineering designs of machined components in current use(現在使用されている)were initially developed. prior to or without the aid of CAD systems and, consequently(従って、その結果), electronic representations of such designs do not exist. Accordingly, updating or making modifications to such component designs using current CAD processes requires first creating a computer-based digital representation of the component. Although methods have been developed for creation of computer-based representations from component drawings, photographs, and/or shop(仕事場、現場)measurements, these methods are tedious(面倒), expensive, and often produce inaccurate results.
In cases where(の場合)a component has been fabricated using NC machining processes, the NC instruction file or "book" contains fabrication instructions for NC machines to follow to produce all or part of that(その)component from a piece of raw stock material(素材), such as a metal billet. The stock material is often referred to in the CAD environment as a "tool solid." Broadly, the NC file describes the paths along which the fabrication machine operates one or more rotating cutting tools upon the tool solid to create the machined component.
Other processes have been used to generate engineering data from NC files; however, the output from these processes has been in the form of(の形、形式)point clouds and Stereo Lithography (STL) files, which are not fully compatible with(適合)modern CAD systems. As known in the art, a point cloud comprises(有する、成る)a plurality of coordinates for individual points that represent locations on the surface of an object. A point cloud can be generated through scanning or digitizing(デジタル化、二値化). An STL format model represents the surface of an object by a plurality of triangles, each triangle defined by the coordinates of its three vertices and a single normal vector directed away from the object's surface. Thus, these methods require extensive processing of the output files before the results can be utilized on a CAD system. Accordingly, it would be desirable to have a reliable, inexpensive, and accurate method of creating a CAD solid model of a component from the machine fabrication instruction file used for its fabrication.