US 5,351,196 A · Method and apparatus for solids based machining

Abstract

The present invention relates to processes for the automatic generation of numerical control (NC) tool paths in a CAD/CAM environment. The present invention operates on mechanical parts described as solid models. The process employs well-defined solid models of the part to be machined and the raw stock from which it will be machined. The volumetric difference between the stock and the part defines the material (delta volumes) that must be cut away during the actual machining process. Delta volumes are solid models, and users (or an expert system) can subdivide delta volumes into smaller volumes that are consistent with a manufacturing process plan. A delta volume and a user-defined strategy for machining the delta volume are then input to NC algorithms. The algorithms generate NC tool paths that remove as much delta volume material as possible. Tool volumes are automatically generated from NC tool paths to represent the volume traversed by the cutting tool. By subtracting the tool volume from the delta volume, the material that remains to be machined modeled and stored as new delta volumes. The subtraction of the tool volume from the stock defines a new stock model that represents the incremental change in stock when the NC tool path is processed at the machine tool. The process is repeated until all delta volumes have been machined and the part has been manufactured.

Claims64

Dependent claims

A process for manufacturing a part comprising the steps of:

(1) obtaining a computer model of the part using a solid modeler;
(2) obtaining a computer model of a stock piece using the solid modeler;
(3) obtaining a process plan for manufacturing the part;
(4) associating manufacturing attributes with the model of the part;
(5) determining at least one delta volume to be removed from the stock piece by subtracting the model of the part from the model of the stock and migrating the manufacturing attributes from the model of the part to a corresponding face of the at least one delta volume;
(6) obtaining a model of a manufacturing setup;
(7) obtaining a machining strategy;
(8) computing tool paths for numerically controlled manufacturing equipment having a cutting tool from the at least one delta volume in accordance with the machining strategy and the model of the manufacturing setup;
(9) computing at least one tool volume representing the total volume of space swept out by the cutting tool;
(10) subtracting the at least one tool volume from the at least one delta volume to obtain a new delta volume;
(11) subtracting the at least one tool volume from the model of the stock piece, thus modeling the machining of the tool paths and verifying that the tool paths have not intruded into the model of the part and thus that the cutting tool will not gouge the part;
(12) repeating steps (7) through (11) until the removal of the at least one delta volume has been modeled;
and
(13) manufacturing the part according to the process plan by transferring the tool paths to the numerically controlled manufacturing equipment, wherein steps (1) through (7) may generally be carried out in any order provided that step (1) must precede step (4), steps (1) and (2) must precede step (5), and steps (1) through (7) must precede step (8).

11 more elements

A method for manufacturing a part by modeling sequential tooling operations to be performed on a piece of stock to produce the part, comprising:

(1) obtaining a machining strategy;
(2) obtaining a solid model of the piece of stock;
(3) obtaining a solid model of the part;
(4) obtaining a two-dimensional profile of an avoidance volume;
(5) locating the model of the part within the model of the stock;
(6) obtaining initial planar cross-sections at an initial depth of the model of the piece of stock and of the model of the part located therein;
(7) performing a first two-dimensional Boolean operation to subtract the initial cross-section of the model of the part from the initial cross-section of the model of the stock to obtain a cross-section of the piece of stock to be removed;
(8) performing a second two-dimensional Boolean operation to subtract the profile of the avoidance volume from the cross-section of the piece of stock to be removed
(9) using the machining strategy and the initial cross-section of the piece of stock to be removed to compute an initial tool path for a machine tool;
(10) determining an initial tool volume from the initial tool path at the initial depth;
(11) not allowing the tool path to intrude into the cross-section of the model of the part or the avoidance profile;
(12) repeating steps (7) through (11) using next planar cross-sections of the model of the part and of the model of the piece of stock obtained at a next depth;
(13) repeating step (12) until the piece of stock to be removed is less than a predetermined volume;
and
(14) sequentially applying the initial tool path and each next tool path to control at least one machine tool to machine the part from the piece of stock.

12 more elements

Dependencies are inferred from the claim text.

Method and apparatus for solids based machining

Life of this patent

Method and apparatus for solids based machining

Life of this patent

Abstract

Claims64