JP2764941B2 - Setting the cutter path - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for setting a trajectory of a cutter when a cutter is moved to perform a cutting process, and in particular, programming for NC (numerical control) milling. In this case, the present invention relates to a method for obtaining a cutter trajectory so that no machining residue occurs.

Conventional technology The cutter trajectory for NC milling basically follows the shape of the target surface to be cut, but in terms of machining efficiency, useless movement is minimized. ,
At the same time, it is necessary to make the trajectory such that no unprocessed portion occurs. Therefore, since the surface to be cut and the path of the cutter can be used as numerical information, conventionally, the information of the surface to be cut and the information of the cutter are processed and the shape of the surface to be cut and the path of the cutter are superimposed on the CRT. The figure having the same diameter as the cutter is moved along the displayed cutter trajectory, and the degree of overlap of the moving area of the figure at that time is visually checked to determine the remaining machining (that is, The location where the figure does not pass) is checked to see if there is any unprocessed portion.
Ultimately, the cutter trajectory was set so that there was no remaining machining. When the CRT is not used, the cutting surface and the cutter path are superimposed on the drawing and
By replacing the graphic on the CRT with a check plate of the same diameter as the cutter along the cutter path,
The cutter trajectory has been determined by the same procedure as described above.

On the other hand, a method of checking interference of processing information has been proposed in Japanese Patent Application Laid-Open No. Sho 59-36810. This is a method in which a plurality of pieces of processing information are converted into color information and displayed on a color graphic, and the interference part becomes a mixed color, thereby recognizing the interference of the processing information. In this method, if one piece of processing information is information of a surface to be cut and the other piece of processing information is information of a cutting area associated with the movement of the cutter, the remaining part of the processing does not interfere with both pieces of information. Since it becomes a single color, the unprocessed portion can be recognized.

Problems to be Solved by the Invention However, in the above-mentioned conventional method of checking the presence or absence of remaining machining by moving a check plate or a figure along a cutter locus projected on a CRT, and correcting the cutter locus if necessary, Workers visually check the presence or absence of unprocessed parts, which lacks certainty and reduces work efficiency. As a result, oversight of unprocessed parts may cause damage to cutting tools and machine tools during actual machining. In some cases, there has been a problem that the working time becomes longer as the shape of the surface to be cut becomes more complicated.

If the method of JP-A-59-36810 described above is diverted to the work of setting a cutter locus, a color graphic display is required, so that equipment costs are increased, and a non-interference area (that is, unprocessed area) is required. Is small, there is a problem that it is easy to make an error in the determination of the presence or absence of the unprocessed portion when judging from the color tone of the mixed color or the single color.

The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a method of setting a cutter locus that can reliably and easily detect the remaining machining and correct the cutter locus, and can be performed with inexpensive equipment.

Means for Solving the Problems In order to achieve the above object, the present invention provides a method for obtaining a trajectory for moving a cutter along a processing location, and a method for obtaining a trajectory for moving a cutter along a processing location. The processing location is modeled by a plurality of line segments included in the plane of the processing location and the information of the line segment is stored, and the cutter is moved so that the cutter crosses at least a part of the processing location. A temporary movement locus is determined and information of a cutting area when the cutter is moved along the temporary movement locus is stored. Further, the cutter when moving along the work piece and the temporary movement locus. The ratio of the line segment included in the cutting region of the cutter increases based on the information of the line segment in a state where the cutting region is overlapped with the information of the cutting region of the cutter. In this manner, the temporary movement locus of the cutter is corrected to set the cutter locus.

According to the method of the present invention, first, a processing location is modeled by a plurality of line segments included in the plane, the information is stored, and a temporary trajectory for moving the cutter along the processing location is formed. The information of the cutting area when the cutter is moved along the temporary trajectory is stored. Then, the modeled processed portion and the temporary cutter locus are overlapped. This is performed, for example, by calculating the intersection between the line segment and the cutting area. Then, by comparing the information of the line segment with the information of the cutting area, it is determined whether or not the line segment is included in the cutting area. Therefore, if there is a line segment that is not included in the cutting area, the portion of the line segment is not subjected to the cutting process and is left unprocessed, so that the temporary trajectory is corrected (for example, cutting in the radial direction of the cutter). The trajectory is set so that all the line segments are included in the cutting area by reducing the amount). Therefore, according to the method of the present invention, it is possible to obtain a cutter trajectory in which no machining remains by numerical processing of each information.

Embodiments Next, the present invention will be described in detail based on embodiments.

FIG. 1 is a flowchart for explaining an example of the method of the present invention. First, in step 1, a temporary trajectory for moving the cutter is calculated. This is performed, for example, by performing predetermined geometric figure processing on the machined shape 1 shown in FIG. In that case, a cutting area by the cutter is obtained based on the diameter of the cutter to be used, and information on the cutting area is stored.
Further, as shown in FIG. 3, the machining shape 1 is modeled by a plurality of line segments 3 included therein (step 2),
The information is stored. That is, the machined portion was replaced with a plurality of line segments contained therein, and the line segments were modeled by a cutting area 4 and a line segment 3 determined based on the temporary trajectory 2 as shown in FIG. The processing shape 1 is superimposed (step 3). This can be performed, for example, as an intersection calculation between the cutting area 4 and the line segment 3 based on the stored information.

Then, it is determined whether there is any unprocessed portion (step 4). This can be performed by comparing the information of the cutting region 4 with the information of the line segment 3 to determine whether or not the line segment 3 is included in the cutting region. If it is included in region 4, that is, step 4
If the judgment result is "No", it means that there is no remaining machining, so the temporary trajectory 2 is adopted as the cutter trajectory (step 5). On the other hand, if the result of the determination in step 4 is “yes”, that is, if there is a line segment 3 not included in the cutting area 4, the state is as shown in FIG. 5, for example. Cutting depth (2nd
The cut amount in the direction indicated by the arrow in the figure) is reduced (step 6). The amount of reduction is set in advance to a fixed amount, and whenever there is remaining machining, the cut amount is reduced by the fixed amount. Since there is a limit value of the cutting amount depending on the configuration of the cutter and the machine tool to be used, it is determined whether or not the reduced cutting amount is equal to or less than the limit value (step 7). Step 7 below the limit value
If the determination result is "yes", it is determined that the correction of the cutter locus is impossible, and the temporary locus set first is adopted as the cutter locus, and the remaining machining is output (step 8). This is output as a seal from a printer, for example, and is output as a graphic display on the screen when a CRT is used. On the other hand, if the determination result in step 7 is “NO”, the temporary trajectory is corrected by replacing the value of the cutting depth with a reduced value and recalculating the cutter trajectory (step 9). The scanning process returns to before step 3 and sequentially executes the steps described above. That is, the temporary trajectory is corrected in a direction in which the ratio of the line segment included in the cutting area 4 increases. If all the line segments are included in the cutting area 4 based on the corrected cutter trajectory, the result of the determination in step 4 becomes “No”, and the corrected trajectory acts as the cutter trajectory (step 5). . If the correction is insufficient, the trajectory is corrected again in the same manner as described above, and the corrected trajectory is
Is determined as to whether or not all are included.

The contents of each of the scanning processes described above can be performed by numerical processing using a known computer.

Effects of the Invention As is apparent from the above description, according to the method of the present invention, the processing shape is modeled by a plurality of line segments, and the determination of the presence or absence of the remaining processing is made by comparing the information with the information of the cutting area of the cutter. Therefore, according to the present invention, it is possible to reliably and efficiently set a cutter trajectory with no remaining machining. Accordingly, it is possible to prevent the cutter trajectory from becoming unnecessarily long due to the reliable determination of the remaining machining, and as a result, it is possible to perform efficient machining such as milling. Further, since graphic display is not particularly required, setting of the cutter trajectory can be performed at low cost without requiring expensive equipment such as a color graphic display.

[Brief description of the drawings]

FIG. 1 is a flow chart for explaining an example of the method of the present invention, FIG. 2 is a schematic diagram showing a processed shape and a temporary trajectory subjected to geometrical figure processing, and FIG. 3 is a line segment model of the processed shape. FIG. 4 is a schematic diagram showing a state in which a cutting area by a cutter and a line segment model are superimposed, and FIG. 5 is a schematic diagram showing a state in which residual machining occurs. 1 ... processing shape, 2 ... temporary locus, 3 ... line segment, 4 ... cutting area.

Claims (1)

(57) [Claims] In obtaining a trajectory for moving a cutter along a processing location, the processing location is modeled by a plurality of line segments included in the plane of the processing location and information on the line segments is stored. In addition, the temporary movement locus of the cutter is determined so that the cutter crosses at least a part of the processed portion, and information on a cutting area when the cutter is moved along the temporary movement locus is stored. Further, based on the information of the line segment and the information of the cutting region of the cutter in a state in which the processing location and the cutting region of the cutter when moved along the temporary movement trajectory are overlapped, the line segment is Setting a cutter locus by correcting a temporary movement locus of the cutter so as to increase a ratio of the cutter included in a cutting area of the cutter.