JP3870021B2 - Machining path generation method, machining path generation apparatus, and recording medium - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a machining path generation method for creating a machining path in an NC machine tool.
[0002]
[Prior art]
The machining path generator that creates a machining path program for machining a workpiece with an NC machine tool is data to be machined by the operator, that is, machining shape, machining method, tool diameter, finishing allowance, cutting width, etc. Then, a machining route is created based on these. Actually, the format of the NC program by the NC device differs depending on the model of the NC machine tool. Therefore, firstly, general-purpose machining path information independent of the model is created and then converted into an NC program corresponding to each NC device. A post processor is used as a machining path program.
[0003]
As shown in FIG. 7, the conventional machining path creation device includes an input unit 1, a contour machining path creation unit 2, an area machining path creation unit 3, a pocket machining path creation unit 4, and a post processor 5. Has been. The input unit 1 receives the input of information such as a pocket-shaped contour line, pocket top surface height, pocket bottom surface height, tool diameter, tool radial direction depth of cut, tool axis direction depth of cut, and finishing allowance from the operator. Output to the machining path creation unit 2 and the area machining path creation unit 3.
[0004]
The contour machining path creation unit 2 and the area machining path creation unit 3 generate a plurality of contour machining paths by sequentially offsetting the machining paths by the cutting width in the tool radial direction while considering the finishing allowance. The paths are sequentially connected to create a spiral machining path (region machining path) as shown in FIG. Specifically, the contour machining path is created by first creating a first contour machining path offset inward from the desired machining shape contour line by the sum of the tool radius and the finishing allowance. A second contour machining path offset inward from the machining path by the cutting width in the tool radial direction is created. Similarly, the third to kth contour machining paths are created. This is repeatedly executed until no contour processing path can be created on the inner side to obtain a plurality of contour processing paths. During actual machining, cutting is performed in order from the k-th contour machining path. The machining by the contour machining path along the machining shape contour line is referred to as “side machining”.
[0005]
The pocket machining path creation unit 4 sequentially determines the cutting plane height for each cutting width in the tool axis direction from the pocket top surface height to the sum of the pocket bottom surface height and the finishing allowance, and determines the area machining path as the cutting plane height. A pocket machining path is created by sequentially creating and combining each.
[0006]
[Problems to be solved by the invention]
When the pocket shape is roughed by side machining according to the spiral machining path created by such a conventional machining path generation device, it appears at the start of machining from the spiral center (kth contour machining path) or during machining. When a path is sharply bent or when a reciprocating path is machined, the contact length between the tool and the workpiece becomes extremely large as compared with a side-cutting state per one side in a straight part during machining. That is, a state (grooving state) occurs in which the machining portion of the tool extends from the side surface to the entire front surface in the traveling direction. In this state, the cutting load of the tool becomes very large, the tool is damaged, and the wear of the tool due to generation of cutting heat becomes significant.
[0007]
For this reason, when machining is performed according to a path created by a conventional machining path generation device, the feed speed is set to be slow so that the tool load does not become excessive, assuming that the tool load is maximized. For this reason, even in the side cut state portion per side that occupies most of the roughing processing, the feed rate is slowed assuming a load, and there is a problem that the processing efficiency is reduced as a whole.
[0008]
In view of this, a device has been devised, such as recognizing a portion having a large load on the route and reducing the feed rate only in that portion. However, even in this case, tool wear due to increased cutting heat in the grooving state cannot be avoided.
[0009]
On the other hand, trochoidal machining is known as a method of performing grooving while reducing the tool load. Trochoidal machining is a method in which machining is performed by moving the tool in the groove direction while moving the tool in a circular motion. Therefore, the tool moves while drawing a spiral as a whole. Therefore, the width of the groove processed by the trochoidal processing is the sum of the tool diameter and the diameter of the circular motion. Specifically, the machining path in trochoidal machining is as shown in FIG. In trochoidal machining, the contact portion between the tool and the workpiece is one side of the side surface, and the entire front surface of the tool does not hit the groove. For this reason, the same cutting conditions as the side cutting state of the side processing can be specified, and the groove processing can be performed without slowing the cutting speed.
[0010]
Ideally, trochoidal machining is performed in a spiral machining path that combines movement along the groove direction and movement of the circle in contact with the movement. For convenience, the movement path along the groove direction is circular movement. It can be approximately realized by adding a path for dividing the pitch and moving a circle in contact with each division point. That is, after the tool is circularly moved around a certain point, the tool is slightly moved along the machining path, and the tool is again circularly moved around the predetermined point at the position after the movement. The machining path of the trochoid machining thus created is as shown in FIG. Hereinafter, this approximated trochoidal machining will be described.
[0011]
However, in trochoidal machining, cutting efficiency is low because half of the circular motion is air cut.
[0012]
The present invention has been made in view of the above circumstances, and provides a machining path generation method, a machining path generation apparatus, and a recording medium that can create a machining path with a low tool load without significantly reducing cutting efficiency. Objective.
[0013]
[Means for Solving the Problems]
The present invention for solving the problems of the conventional example described above is a machining path generation method for machining by a machining path created by offsetting an inputted machining shape by a predetermined amount, and offsetting the inputted machining shape by a predetermined amount. Then, the width of the step of generating the basic machining path and the path elements facing each other among the plurality of path elements constituting the basic machining path is the sum of the tool radius and the diameter of the trochoidal circle. times following scope, or a concave corner portion near range, the ratio to the side cutting state per side contact length of the tool when side milling along at least basic machining path and the workpiece is in the straight portion a step larger range by, at least either one is extracted as a trochoidal machining range, the basic machining path present within a trochoidal working range the extracted Generating a trochoidal machining path moving along the path element, characterized in that it comprises the steps of extracting the path element of the basic machining path existing in a range other than the trochoid working range as side milling path. Thereby, it is possible to generate a machining path with a low tool load while maintaining the cutting efficiency.
[0015]
Furthermore, according to one aspect of the present invention, in the step of generating the trochoidal machining path, the path element constituting the concave corner portion of the basic machining path existing in the extracted trochoidal machining range is converted into an arc having a predetermined radius. A machining path is generated, and a trochoid machining path that moves along the machining path is generated .
[0016]
Further, the present invention for solving the problems of the conventional example described above is a machining path generation device for machining with a machining path created by offsetting the input machining shape by a predetermined amount. The maximum width of trochoidal machining in which the width between the means for generating the basic machining path with offset by a distance and the path elements facing each other among the plurality of path elements constituting the basic machining path is the sum of the tool radius and the diameter of the trochoidal circle 2 times or less scope, or a concave corner portion near range, side cutting state per side contact length of the tool when side milling along at least basic machining path and the workpiece is in the straight part of Means for extracting at least one of a range larger than the trochoidal machining range, and basic machining existing in the extracted trochoidal machining range A means for generating a trochoidal machining path that moves along a path element of the path, a means for extracting a basic machining path outside the trochoidal machining range as a side machining path, and the trochoidal machining path and the side machining path are synthesized. And a means for generating a synthetic processing path.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, the machining path creation apparatus of the present embodiment includes an input unit 1, a basic machining path creation unit 12, a trochoid machining path creation unit 13, a side machining path creation unit 14, and a basic machining path. The correction unit 20, the region machining path creation unit 15, the pocket machining path creation unit 16, and the post processor 5 are configured. Here, the input unit 1 and the post processor 5 are the same as those in the prior art, so detailed description thereof will be omitted.
In the following description, as shown in FIGS. 9 and 10, the trochoidal machining depth is defined as the center of the circular motion of the tool (the center of the trochoidal circle) along the machining path when performing trochoidal machining. The maximum amount of trochoidal machining is the sum of the tool radius and the diameter of the trochoidal circle. In trochoidal machining, machining is performed by adding this radius to the tool radius. Accordingly, uncut parts are generated for widths exceeding this.
[0018]
The input unit 1 includes a machining shape contour line indicating a pocket shape to be machined by an operator, a pocket top surface height, a pocket bottom surface height, a finishing allowance, a tool diameter of a machining tool indicating a machining condition, and a tool radial direction cut. Input and memorize information such as width and cutting width in the tool axis direction. (Fig. 5, Step 1)
[0019]
Subsequently, the basic machining path creation unit 12 creates a first basic machining path that is a tool center path that is offset inward by an amount corresponding to the sum of the tool radius and the finishing allowance in the first time. To do. From the second time onward, a j-th basic machining path, which is a tool center path obtained by offsetting the previously created j-1 basic machining path inward by the cutting width in the tool radial direction, is created. These basic machining paths correspond to contour machining paths in the prior art. (Fig. 5, Step 2)
[0020]
The basic machining path creation unit 12 confirms whether or not the j-th basic machining path has been made (FIG. 5, step 3). Jump to the process (FIG. 5, step 9). When the j-th basic machining path is formed, the following processing is performed to generate a trochoid machining path.
[0021]
The trochoidal machining path creation unit 13 extracts a trochoidal machining range from the obtained basic machining path, and generates a trochoidal machining path in that range. When a trochoidal machining range where no uncut residue is generated inside when trochoidal machining is performed in the jth basic machining path is generated, and a trochoidal machining path is generated in the extracted range, the trochoidal machining path creation unit 13 firstly selects FIG. As shown in (a), a machining path indicated by a broken line offset inward from the jth basic machining path by the maximum trochoidal machining width is created. Here, out of the intersections of the machining paths indicated by the broken lines, machining outside the intersection of the machining paths (intersection a in FIG. 3A) obtained by offsetting the most distant path element among the path elements constituting the basic machining path. The machining path with the offset of the path element of one basic machining path is positioned below the maximum width of the trochoidal machining from the path element of the opposing basic machining path, and in this part, it can be cut without being left behind by trochoidal machining. It becomes.
[0022]
Subsequently, in order to extract a trochoidal machining range from the basic machining path, the trochoidal machining path creation unit 13 performs trochoidal machining centering on an intersection of machining paths offset from the jth basic machining path (intersection a in FIG. 3A). The intersection point between the arc having the radius of the maximum width and the j-th basic machining path (intersection point b, intersection point c in FIG. 3B) is obtained, and the basic machining path between the intersection points is extracted as the trochoidal machining range (FIG. 3 ( b) Thick line portion of jth basic machining path). The trochoidal machining path creation unit 13 extracts the trochoidal machining range by the same process even in the concave bent part of the basic machining path.
[0023]
That is, as shown in FIG. 4A, the trochoidal machining path creation unit 13 creates a machining path indicated by a broken line offset inward from the jth basic machining path by the maximum trochoidal machining width (see FIG. Find the intersection d) of a). The intersection of the circle having the radius corresponding to the maximum width of the trochoidal machining centered on the obtained intersection and the jth basic machining path (to the intersection e and to the intersection in FIG. 4B) is obtained, and the basic machining path between the intersections is trochoidal. A range is extracted (FIG. 4 (b), a thick line portion of the jth basic machining path). (Figure 5, Step 4)
[0024]
When a trochoidal machining path with a trochoidal circle added to the basic machining path in the extracted trochoidal machining range is generated, the tool center moves on the machining path. For example, as shown in FIG. In the bent portion, cutting occurs in a desired processing shape.
[0025]
In order to prevent this cutting, the trochoidal machining path creation unit 13 detects the concave bending part from the j-th basic machining path in the extracted trochoidal machining range, and configures the concave bending part as shown in FIG. An arc having a radius R greater than or equal to the radius of the trochoidal circle is inserted between the jth basic machining path elements, and the jth basic machining path in the trochoidal machining range is corrected. (Fig. 5, step 5)
[0026]
Further, the trochoidal machining path creation unit 13 divides the j-th basic machining path included in the trochoidal machining range for each trochoidal machining incision amount, and inserts a trochoidal circle having a trochoidal circle diameter designated for each division position. A trochoidal machining path is created (FIG. 3 (c)) (FIG. 5, step 6).
[0027]
The side machining path creation unit 14 extracts a part other than the trochoid machining range extracted by the trochoid machining path creation unit 13 from the jth basic machining path as a side machining range, and is created by the trochoid machining path creation unit 13. A machining path combined with the trochoid machining path is created (FIG. 3C) (FIG. 5, step 7).
[0028]
With this process, one machining path is created by combining the trochoid machining path and the side machining path for machining the region within the input machining shape.
[0029]
The basic machining path correction unit 20 corrects the j-th basic machining path included in the trochoidal machining range extracted by the trochoid machining path creation unit 13 to a machining path that is considered to have been subjected to side machining. In this example, the path element of the jth basic machining path included in the trochoidal machining range (FIG. 3 (b), the bold line portion of the basic machining path) is the intersection of the machining paths offset from the jth basic machining path (FIG. 3 ( This is realized by replacing with an arc having a radius corresponding to the maximum width of the trochoidal machining centering on the intersection point a) of a). (FIG. 3D) (FIG. 5, Step 8)
[0030]
The modified jth basic machining path is used when the basic machining path creation unit 12 creates the j + 1th basic machining path. Then, the process jumps to step 2 to execute the next offset process.
[0031]
The area machining path creation unit 15 creates a transfer path between adjacent machining paths based on the combined machining path of the plurality of side surface machining paths and the trochoidal machining path created by the above processing, and has a predetermined plane height. A region machining path is generated. (Fig. 5, step 9)
Thereby, a machining path as shown in FIG. 6 is created with respect to the machining path shown in the prior art of FIG.
[0032]
The pocket machining path creation unit 16 determines the cutting plane height for each cutting width in the tool axis direction from the pocket top surface height to the sum of the pocket bottom surface height and the finishing allowance, and the machining path shown in FIG. Sequentially created and combined to create a pocket machining path. (FIG. 5, step 10)
[0033]
The basic machining path creation unit 12, the trochoid machining path creation unit 13, the side machining path creation unit 14, the basic machining path modification unit 20, the area machining path creation unit 15, and the pocket machining path creation unit 16 are CPU (central). It may be realized as software executed in the arithmetic processing unit. In this case, the CPU reads the software from a computer-readable recording medium and generates a machining path.
[0034]
In the detailed description of the invention, the machining path generation method has been described by taking the area machining in the pocket machining as an example, but the present invention is not limited to the area machining in which all the areas in the designated machining shape are machined. Needless to say, the present invention can be applied within a range that does not depart from the gist of the present invention, such as contour processing for processing along the processed shape.
[0035]
【The invention's effect】
According to the present invention, there is provided a machining path generation method for machining by a machining path that is created by offsetting an input machining shape by a predetermined amount, and the uncut material is left by trochoidal machining when a tool is moved along the machining path. Is a machining path generation method in which a machining path other than the above range is a trochoidal machining path, and a machining path other than the above range is a side machining path, while maintaining cutting efficiency. A machining path with a low tool load can be generated.
[Brief description of the drawings]
FIG. 1 is a configuration block diagram of a machining path generation device of the present invention.
FIG. 2 is an explanatory view showing prevention of cutting of a concave bent portion by trochoidal processing.
FIG. 3 is an explanatory diagram showing a method for setting a trochoid processing range.
FIG. 4 is an explanatory diagram showing a method for setting a trochoid processing range of a concave bent portion.
FIG. 5 is a flowchart of a machining path generation method of the present invention.
FIG. 6 is an explanatory diagram showing an example of a machining path created by the machining path generation device of the present invention.
FIG. 7 is a configuration block diagram of a conventional machining path generation device.
FIG. 8 is an explanatory diagram showing an example of a machining path created by a conventional machining path generation device.
FIG. 9 is an explanatory view showing a machining path in ideal trochoid machining.
FIG. 10 is an explanatory diagram showing a machining path in general trochoidal machining.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Input part, 2 Contour processing path creation part, 3 area | region machining path creation part, 4 Pocket machining path creation part, 5 Post processor, 12 Basic machining path creation part, 13 Trochoid machining path creation part, 14 Side surface machining path creation part, 15 region machining path creation unit, 16 pocket machining path creation unit, 20 basic machining path modification unit.

Claims (5)

In a machining path generation method for machining by a machining path created by offsetting the input machining shape by a predetermined amount,
Creating a basic machining path by offsetting the input machining shape by a predetermined amount;
A range where the width of the path elements facing each other among the plurality of path elements constituting the basic machining path is not more than twice the maximum width of the trochoidal machining, which is the sum of the tool radius and the diameter of the trochoidal circle , or a concave corner At least one of the peripheral ranges, in which the contact length between the tool and the workpiece is larger than the side cutting state per one side of the linear portion when side machining is performed along at least the basic machining path. Extracting a trochoid processing range,
Generating a trochoidal machining path that moves along a path element of a basic machining path that exists within the extracted trochoidal machining range;
Extracting a path element of a basic machining path existing in a range other than the trochoid machining range as a side machining path ;
Machining path generation method comprising: a. The machining path generation method according to claim 1,
  The peripheral area around the concave corner is the maximum width of the trochoidal machining centered on the intersection of the path element constituting the concave corner and the offset line offset inward by the maximum trochoidal width of the path element constituting the concave corner. A machining path generation method characterized by being in a range surrounded by a circle having a radius of. In the processing path generation method according to claim 1 or 2 ,
The step of generating the trochoidal machining path generates a machining path obtained by converting a path element constituting the concave corner portion into an arc having a predetermined radius among the basic machining paths existing within the extracted trochoidal machining range, A machining path generation method, characterized by generating a trochoid machining path that moves along. In a processing path generation device that processes by a processing path created by offsetting the input processing shape by a predetermined amount,
Means for generating a basic machining path by offsetting the input machining shape by a predetermined amount;
A range where the width of the path elements facing each other among the plurality of path elements constituting the basic machining path is not more than twice the maximum width of the trochoidal machining, which is the sum of the tool radius and the diameter of the trochoidal circle , or a concave corner At least one of the peripheral ranges where the contact length between the tool and the workpiece becomes larger than the side cutting state per one side in the straight portion when side machining is performed along at least the basic machining path. Means for extracting as a trochoid processing range;
Means for generating a trochoidal machining path that moves along a path element of a basic machining path existing in the extracted trochoidal machining range;
Means for extracting a basic machining path other than the trochoidal machining range as a side machining path;
Means for generating a synthetic machining path obtained by synthesizing the trochoidal machining path and the side surface machining path;
A machining path generation apparatus comprising: A machining path generation program for machining with a machining path created by offsetting an input machining shape by a predetermined amount,
A module for generating a basic machining path by offsetting the input machining shape by a predetermined amount;
A range where the width of the path elements facing each other among the plurality of path elements constituting the basic machining path is not more than twice the maximum width of the trochoidal machining, which is the sum of the tool radius and the diameter of the trochoidal circle , or a concave corner At least one of the peripheral ranges where the contact length between the tool and the workpiece becomes larger than the side cutting state per one side in the straight portion when side machining is performed along at least the basic machining path. A module to extract as the trochoid processing range;
A module for generating a trochoidal machining path that moves along a path element of a basic machining path existing in the extracted trochoidal machining range;
A module for extracting a basic machining path other than the trochoid machining range as a side machining path;
A module for generating a synthetic machining path obtained by synthesizing the trochoidal machining path and the side surface machining path;
A computer-readable recording medium storing a machining path generation program including

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