JP2003117773A - Nc data forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an NC data forming device capable of forming optimum NC data optimum for necessary machining precision interpreted from tolerance information for greatly reducing man-hours. SOLUTION: In this NC data forming device having a numeric data forming means used for a numerical control machine tool, graphic primitives and dimensional primitives are read from CAD data on the basis of the previously formed CAD data of a workpiece, and from the read dimensional primitives, a tolerance notation is read. A machining shape is read from the read graphic primitives, the read machining shape and the dimensional tolerance are associated with each other, and then, a machining procedure, a tool, and a machining condition are decided.

Description

Description: BACKGROUND OF THE INVENTION [0001] 1. Field of the Invention [0002] The present invention relates to an NC data generating apparatus having an automatic numerical data programming function. 2. Description of the Related Art Conventionally, when one part is processed using a numerically controlled machine tool (hereinafter referred to as an NC machine tool), for example, a machining center, a drawing of the part is CAD-processed.
2. Description of the Related Art A technique of creating NC data for operating an NC machine tool from a created drawing by a system using an automatic programming function of the NC machine tool is widely used. [0003] However, the created C
If the NC data is created with the AD figure as it is, a dimensional tolerance is not reflected at all, and a program for machining with a series of procedures, tools and machining conditions is output. In this case, the quality becomes excessive or the required dimensional accuracy cannot be maintained. In order to avoid this, a skilled programmer needs to adapt the machining procedure, tools and machining conditions to dimensional accuracy, which requires a great deal of man-hours. [0004] The present invention has been made in view of the above problems, and the object thereof is to significantly reduce the number of man-hours by creating NC data optimal for required processing accuracy interpreted from tolerance information. An object of the present invention is to provide an NC data creation device. [0005] In order to achieve the above object, the present invention comprises numerical data generating means for use in a numerically controlled machine tool based on CAD data created in advance of a workpiece. The NC data creation device reads graphic elements and dimensional elements from CAD data, reads dimensional tolerance notation from the read dimensional elements, reads a processed shape from the read graphic elements, and associates the read processed shape with the dimensional tolerance. , A machining procedure, a tool, and machining conditions are determined. Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 shows an NC data creating apparatus 1 according to the present invention.
FIG. 1 is a block diagram showing a schematic configuration of an NC data creation apparatus 10 in which an NC machine tool 20 and a CAD / CAM engineering workstation (EWS) are connected via a communication interface 9 as communication means. Mutual data communication is possible. [0008] The NC data generating apparatus 10 is configured to control the N
A CPU 1 for generating NC data from CAD data, which is the basis of C data generation, calculating a tool trajectory having a machining procedure and machining conditions according to required accuracy described later, a keyboard for inputting data, parameters, and the like. An RO that stores programs for an input unit 2, a display unit 3 such as a CRT for displaying data and parameters, an output unit 4 such as a printer, fixed parameter and NC data generation, and a tool path calculation unit.
M6, a RAM 7 used as a temporary storage and a working area for variable parameters, a storage device 8 such as a hard disk drive or a floppy (registered trademark) disk, and a communication interface 9, which are communicably connected by an internal communication bus 5. Have been. The NC data creating apparatus 10 converts the CAD graphic elements of the workpiece stored in the storage device 8 into C
Input to PU1. The NC data creation device 10 has a CPU
A process / machining condition and a tool trajectory for optimal machining according to the machining accuracy are calculated based on the graphic element and the tolerance data of the workpiece input to 1. FIG. 2 shows a process for generating a process and processing conditions and a tool trajectory for continuous processing according to the processing accuracy based on the graphic element of the workpiece and the tolerance data described above.
This will be described with reference to FIGS. FIG. 2 is a flowchart showing the outline of the NC data generation processing according to the embodiment of the present invention, in which graphic elements and tolerance data are extracted from the CAD data stored in the storage device 8 (step S1). Then, of the extracted graphic elements, those which form a closed area as a figure (hereinafter, referred to as a closed area) are extracted, and the processing range is interpreted based on the closed area (step S2). The required processing accuracy is interpreted based on the tolerance within the interpreted processing range. In the case of the drawing as shown in FIG. 4, the dimensional tolerance is ±
0.01, and the required machining accuracy is 0.1 in the tolerance range.
02 is interpreted (step S3). If there is an unprocessed closed area, the process returns to step 2 to check the required machining accuracy of all closed areas (step S4). Next, it is checked whether or not the graphic element in the closed area processed up to step 3 is in contact with the graphic element in another closed area (step S5). If there are graphic elements that are in contact with each other, compare the required machining accuracy interpreted in the closed area with the touching elements, and adjust the two closed shapes to match the one that requires higher accuracy. The required processing accuracy of the area is the same. In FIG. 5, the dimensional tolerance of the B1 shape is ± 0.1.
(B), the shape of B2 is in contact with B1, the relationship of B2 and D1 is also in contact, and the figures from B1 to D1 are in contact with each other. They are connected. The dimensional tolerance of the D1 portion in this contact relationship is ±
It is 0.01. Therefore, the dimensional tolerance of the portion B1 described above is ±
Although the required processing accuracy is 0.1 at 0.2, the required processing accuracy is set to 0.02 in accordance with D1 (step S6). A search is performed to determine whether there is a closed region in which a graphic element in contact with a graphic element of another closed region has not been checked.
It is checked whether or not there is a graphic element having a relationship in contact with another closed area in all closed areas (step S7). As described above, a processing procedure and a processing condition corresponding to a preset required precision are selected for each closed area from the required processing accuracy and the closed area shape recognized for all the closed areas. FIG. 3 shows an example in which a processing procedure and processing conditions according to the required processing accuracy are set in advance. Required machining accuracy is 0.0
If 2, the processing procedure and the processing condition such as a are selected, and if the required processing precision is 0.04, the required processing precision of b is 0.1.
If it is, the processing procedure and the processing condition of c are selected, and if the required processing accuracy is 0.2, the processing procedure and processing conditions of d are selected (step S8). Then, the tool trajectories in all the regions are calculated from the machining procedure and the machining conditions selected in step 8 described above, and the processing is terminated (step 9). As is apparent from the above description, according to the present invention, there is provided a numerical data generating means for use in a numerically controlled machine tool based on CAD data created in advance of a workpiece. The NC data creation device reads graphic elements and dimensional elements from CAD data, reads dimensional tolerance notation from the read dimensional elements, reads a processed shape from the read graphic elements, and associates the read processed shape with the dimensional tolerance. Since the machining procedure, tool, and machining conditions are determined, it is possible to create NC data that is optimal for the required machining accuracy interpreted from the tolerance information, and it is possible to significantly reduce the number of steps.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a schematic configuration of an NC data creation device according to the present invention. FIG. 2 is a flowchart illustrating an outline of NC data generation processing. FIG. 3 is a diagram showing an example of a processing procedure and processing conditions according to a preset required accuracy. FIG. 4 is a diagram showing one embodiment of a drawing from which the present invention is applied. FIG. 5 is an example of a drawing with several types of dimensional tolerances to illustrate the invention. [Description of Signs] 1 CPU 2 Input unit 3 Display unit 4 Output unit 5 Bus 6 ROM 7 RAM 8 Storage device 9 Communication interface 10 NC data creation device 20 NC machine tool

Claims (1)

Claims: 1. An NC data generating apparatus provided with numerical data generating means for use in a numerically controlled machine tool based on CAD data generated in advance of a workpiece, comprising: Reading the dimension tolerance notation from the read dimension element, reading the processed shape from the read graphic element, associating the read processed shape with the dimensional tolerance, and determining the processing procedure, tools and processing conditions. An NC data creation device characterized by the above-mentioned.