JPH01123302A - Method for generating nc processing information - Google Patents

Abstract

PURPOSE:To generate NC processing information at a high speed by removing an interfering part to interfere a tool and a curved surface, and making once shape data as the target processing shape of a material to be worked approximate to the polyhedron composed of fine patches. CONSTITUTION:It is not necessary to execute the converging calculation concerning a curved surface in order to remove an interfering part to interfere a tool and a curved surface by the interfering part removing processing. Since shape data DTI as the target processing shape of the material to be worked are made once approximate to a polyhedron data DT2 composed of a bi-primary patch by an off-setting polyhedron processing, the data generation of off-setting polyhedron data DT3 or below is facilitated. As these results, even when the processing shape, which is the target of the work piece, becomes a complicated curved shape, the calculation time to calculate NC processing information (moving channel data DT4 of tool center) can be shortened and the NC processing information can be generated at a high speed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for creating NC machining information for creating information for NC machining the shape of a three-dimensional curved surface of a press mold or the like.

[Prior Art] Conventionally, as a method for creating such NC machining information, the shape of a target three-dimensional curved surface is created in advance in a computer, and the created shape data is processed as shown in FIG. 11. As shown in FIG. Then, there is a method that creates NC machining information by using the locus L2 of the offset point P1 as the moving path of the center of the tool. Note that the point P2 that transfers from the surface S1 to the surface S2 is determined by performing convergence calculation on the related surfaces S1 and S2, and moving the tool A1 at the optimal position for both surfaces S1 and S2.
were asked to make contact.

[Problems to be Solved by the Invention] However, the above-mentioned conventional technology has the following problems, and further improvements have been desired. That is, (1) When the target shape of the workpiece becomes complex, the above-mentioned convergence calculation will be used frequently, and for this reason,
A large amount of calculation time was required to calculate the movement path of the center of the tool.

(2) When the target shape of the workpiece becomes complex, as shown in FIG. 12(a), there may be a large number of surfaces interfering with the tool A1. In such a case, No matter how much convergence calculation is performed, the calculation result may not be obtained. Also, as shown in Fig. 12(b), if there is a fillet F1 with a large diameter at the intersection of the surfaces, The angle with the surface becomes nearly flat, and even if you perform convergence calculations, it will not converge,
Calculation results may not be obtained. As a result, the accuracy of the created NC machining information decreases, and interference between the tool and the workpiece occurs, and therefore, it is necessary for the user to correct the machining information in a subsequent process.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method for creating NC machining information that can create NC machining information at high speed and with high accuracy.

[Means for solving the problems] In order to achieve the above object, the present invention adopts the configuration shown below as a means for solving the problems. That is, as shown in the flowchart of FIG. 1, the method for creating NC machining information of the present invention involves storing in advance the target machining shape of the workpiece as shape data consisting of a plurality of three-dimensional curved surfaces; In the method for creating NC machining information, the NC machining information indicating a moving path of the center of a tool with respect to the workpiece is created based on the stored shape data, A step (Pl) of dividing each three-dimensional curved surface into a large number of minute patches to create polyhedral data, and offsetting the created polyhedral data by the radius of the tool, and creating a gap generated by the offset into a minute patch. a step (P2) of creating offset polyhedron data by filling in and correcting it with (P3); and a step (P4) of calculating an intersection line with a predetermined shape body in the offset polyhedron data from which the interfering portion has been removed, and calculating a movement path of the tool center. The gist is:

[Function] The method for creating NC machining information of the present invention configured as described above stores the target machining shape of the workpiece in advance as shape data consisting of a three-dimensional curved surface, and stores the target machining shape in advance. Process P to create polyhedral data from the stored shape data
i) Step P2) to create offset polyhedron data from the polyhedral data; Step P3) to remove the interference part of the offset polyhedron data; The movement path of the center of the tool with respect to the workpiece is calculated (
Step P4). Therefore, even the shape of a complex three-dimensional curved surface can be approximated to a polyhedron consisting of minute patches, making it easy to create data smaller than offset polyhedral data.Moreover, by removing interference parts of offset polyhedral data, There is no need to perform convergence calculations. In addition, N
In C machining, the tool can only be advanced in steps, so as described above, approximating the three-dimensional curved surface to a polyhedron made of minute patches does not impede the improvement of machining accuracy.

Here, the minute patches divided in step P1 are:
This corresponds to a so-called bilinear patch, and when it is a bilinear patch, the calculation time in steps P2 to P4 can be extremely short.

[Example] Next, a preferred embodiment of the present invention will be described in detail.

FIG. 2 is a block diagram showing an apparatus that employs a method for creating curved surface NC processing information as an embodiment of the present invention.

As shown in FIG. 2, this device is composed of a three-dimensional graphics creation device 1 and an NC processing information creation device 3.

The three-dimensional graphics creation device 1 is composed of a so-called microcomputer and its peripheral devices, including a keyboard 5 for manually inputting characters and various instructions, a function switch 7 for manually inputting various commands, and a graphic input device for manually inputting figures. (tablet) 9, a display device (CRT display) 11 that displays figures and characters, a control dial 13 that uses a dial to adjust the display direction of figures displayed on the CRT display, and a control dial 13 that is connected to these devices and displays three-dimensional figure data. It is composed of an electronic control unit 15 for graphics that controls input and editing, and the like. The electronic control device 15 is a well-known CPU 15a.

It is configured as an arithmetic logic circuit mainly including ROM 15b, RAM 15c, etc., and includes an input/output circuit 15d for manually outputting data from the aforementioned peripheral devices, and a communication boat 15e for transmitting created three-dimensional graphic data to the outside. The human power/editing control processing of the three-dimensional figure data executed by the electronic control device 15 creates the target machining shape of the workpiece (hereinafter, the three-dimensional figure data is referred to as shape data). Well-known method (detailed explanation will be omitted).

) is executed. In addition, the created shape data is
It is transmitted to the NC machining information creation device 3 via the communication line 15e by a well-known communication control process (detailed explanation will be omitted).

The NC processing information creation device 3 is composed of a so-called microcomputer, and is similar to the electronic control device 1 for graphics.
An electronic control device 2 for creating NC machining information that receives the shape data sent from 5 and calculates a machining path for the ball end mill as a tool for machining the workpiece.
1, and a disk device 23 as an external storage device that stores the calculated route. Electronic control device 2
1 is a well-known CPU 21a, ROM2 lb, RA
A data output circuit configured as an arithmetic logic circuit mainly including M21c and the like, and outputs data to the communication boat 21d that receives shape data sent from the graphics electronic control unit 15 and the aforementioned disk device 23. 21e etc. Note that the shape data 1 received via the communication board 21d is temporarily stored in a predetermined area of the disk device 23 via the data output circuit 21e.

Next, the process of creating NC machining information executed by the electronic control unit 21 will be explained using the flowcharts shown in FIGS. 3 to 7.

This NC machining information creation process is performed by the CPU 21a in the ROM.
21b, when the process is started, first in step 100, polyhedron data creation processing is executed to create polyhedron data. .

In detail, the polyhedron data creation process is executed according to the flowchart shown in FIG.
When the subroutine is called and processing starts, first, the shape data DTI stored in the disk device 23 is
is called, and each curved surface data constituting the shape data DTI is approximated into a bilinear patch according to the properties of the curved surface (curvature, etc.) and mesh-divided (Step 1
10). Next, the outer curve of each mesh-divided surface data is divided into polygonal lines, which are collections of straight lines, within a tolerance range (step 120).
), the polygonal line on the inner and outer periphery (hereinafter referred to as an edge) is judged as to whether it is a convex line, a concave ridge line, or an uneven ridge line, and the judgment result is used as edge data. grant (step 130). In this way, from the shape data DTI as shown in FIG. 8(a), for example, FIG.
) is created as polyhedral data DT2.

After that, this routine ends once, and the process starts again in the third step.
Return to diagram.

In the following step 200, offset polyhedron data creation processing is executed to create offset polyhedron data. In detail, the offset polyhedron data creation process is executed according to the flowchart shown in FIG. offset by the tool radius (step 210). Next, of the interference parts caused by the offset, the parts that interfere within one plane are removed (step 220). For example, in the case of a surface having a recess with a radius less than or equal to the offset value as shown in FIG. 9, the cylindrical portion 31 corresponds to the interference portion, and the data of this portion is deleted. A gap is generated in the convex edge portion of the shape data DT'l due to the offset in step 220, but in the subsequent step, this gap is filled with a cylindrical surface to correct the offset polyhedral data, and the concave edge portion is filled with a cylindrical surface. , data indicating that the surfaces intersect and interfere is added in preparation for later processing (step 230). Also, a gap is generated at the vertex of the shape data DT1 due to the offset in step 220, but in the following step, the offset polyhedron data is corrected by filling this gap with a spherical surface (step 240). That is, the polyhedral data DT2 as shown in FIG. 8(b) is
In step 210, as shown in FIG. 8(C), the offset is made, and in step 220, the gap between the convex ridges is filled with the cylindrical surface 33, as shown in FIG.
Offset polyhedron data DT3 is created. In addition, in step 240, as shown in FIG. 10, if there is a gap between the three curved surface data 35, 37, and 39, the gap at the apex is corrected using the spherical surface 41. after that,
This routine once ends, and the process returns to FIG. 3 again.

In the following step 300, offset polyhedron data DT
Interference part removal processing for removing the interference part No. 3 is executed. Specifically, the interference part removal process is executed according to the flowchart shown in FIG. Based on the indicated data, the intersection line is calculated between surfaces related to the data (step 310). Subsequently, the side (interfering portion) that protrudes from the intersection line is removed (step 320).

That is, the offset polyhedron data DT3 as shown in FIG. 8(d) is processed in step 31 as shown in FIG. 8(e).
0, the intersection vA43 is given, and in step 330, the interference unit 4
5 (the part indicated by the broken line in the figure) is removed, and the part shown in Figure 8 (
Offset polyhedral data DT3- as shown in f) from which the interference portion 45 has been removed is created. Thereafter, this routine ends once, and the process returns to FIG. 3 again.

In the following step 400, a tool center movement path creation process is executed to calculate the movement path of the center of the tool that processes the workpiece. For details on the tool center movement path creation process, please refer to Section 7.
The process is executed according to the flowchart shown in the figure, and when the subroutine is called in step 400 and the process is started, first, based on the tool path generation pitch specified in advance using the keyboard 5, the tool path generation pitch is Assuming a plurality of planar objects that are spaced apart, an intersection line calculation (cross section calculation) between these planar objects and the offset polyhedron DT3- from which the interference portion has been removed is performed (step 410), and then,
The calculated intersection line is used as the tool-centered movement path data DT.
4 (step 420). That is, Fig. 8 (
As shown in g), a plurality of planar data PLI and PL2 separated by the tool path generation pitch t1 and offset polyhedral data DT3 from which the interference portion has been removed - 1 and K2 are calculated on which intersection line they intersect. and this intersection line ■(1,
K2 becomes tool-centered movement path data DT4. As described above, movement path data of the center of the tool (ball end mill) is created as machining information.

According to the method of creating NC machining information of this embodiment described in detail above, since the interference part where the tool and the curved surface interfere is removed by the interference part removal process shown in FIG. There is no need to perform calculations, and the offset polyhedron processing shown in FIG. Data creation of data DT3 and below is easy. As a result, even if the target machining shape of the workpiece is a complex curved shape, the calculation time for calculating the NC machining information (tool center movement path data DT4) can be shortened, and the NC process can be performed at high speed. Processing information can be created. Furthermore, since there is no need to perform convergence calculation as mentioned above, it is possible to prevent a decrease in machining accuracy due to the inability to obtain the calculation result of convergence calculation, and to obtain highly accurate N.
C processing information can be created.

Although one embodiment of the present invention has been described in detail above, the present invention includes
It goes without saying that the present invention is not limited to the above embodiments and can be implemented in various ways without departing from the gist of the present invention.

As detailed above, according to the method of creating NC machining information of the present invention, since the interference part where the tool and the curved surface interfere is removed, convergence calculation regarding the curved surface is performed. This is not necessary, and since the shape data as the target machining shape of the workpiece is once approximated to a polyhedron made up of minute patches, it is easy to create data smaller than the offset polyhedron data. As a result, even if the target machining shape of the workpiece is a complicated curved shape, the calculation time for calculating the NC machining information can be shortened, and the NC machining information can be created at high speed.

Furthermore, since there is no need to perform convergence calculation as described above, it is possible to prevent a decrease in machining accuracy due to the inability to obtain the calculation result of convergence calculation, and to create highly accurate NC machining information. be able to.

Therefore, the created NC machining information can be directly provided to the NC machining device without having to be modified in a post-process as in the past.

[Brief explanation of the drawing]

FIG. 1 is a flowchart illustrating the basic configuration of the present invention, FIG. 2 is a block diagram showing an apparatus employing a method for creating curved surface NC processing information as an embodiment of the present invention, and FIGS. 3 to 7 8(a) to 8(g) are flowcharts representing the process of creating NC machining information executed by the electronic control unit for creating NC machining information of the device, and FIGS.
An explanatory diagram showing various shape data created by the C processing information creation process in the order of change over time. Figure 9 is an explanatory diagram showing an example of offset processing. Figure 10 is an explanatory diagram showing vertices generated by performing offset processing. FIG. 11 is an explanatory diagram of the prior art, and FIGS. 12(a) and 12(b) are explanatory diagrams of the problems of the prior art. . 1... Three-dimensional graphics creation device 3...
NC machining information creation device 21 ... Electronic control device 21 for creating NC machining information
a-CPU 23... Disk device

Claims (1)

[Claims] A target machining shape of a workpiece is stored in advance as shape data consisting of a plurality of three-dimensional curved surfaces, and NC machining information indicating a movement path of the center of a tool with respect to the workpiece is stored in advance. , N created based on the stored shape data
A method for creating C machining information, comprising: dividing the stored shape data into a large number of minute patches for each three-dimensional curved surface to create polyhedral data; and using the created polyhedral data to the tool. The process of creating offset polyhedron data by offsetting by the radius of a step of removing a protruding part as an interference part; and calculating an intersection line with a predetermined shape body in the offset polyhedron data from which the interference part has been removed, and calculating a movement path of the tool center. A method for creating NC machining information, comprising the steps of: