JP3520200B2 - Loop generation method in tool path - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an offset shape which is generated when a predetermined shaped object is obtained by cutting a workpiece by moving a processing tool. It relates to the processing of the interference loop. 2. Description of the Related Art Conventionally, a molded article has been obtained by performing cutting using a cutting apparatus driven by a computer. In such a cutting apparatus, a rod-shaped processing tool such as a drill is attached, and the rod-shaped processing tool is driven to cut a molding material into an arbitrary shape. In such a cutting process, it is necessary to perform offset processing based on the contour shape in consideration of the thickness of the bar-shaped processing tool, and to move the bar-shaped processing tool along the obtained offset shape. Is For example, when the contour shape of the cutting portion is the contour shape 21 shown in FIG. 8, the offset shape 22 is generated at a portion separated from the contour shape 21 by a radius r of the diameter of a rod-shaped processing tool (not shown). In this case, a portion of the offset shape 22 corresponding to the side gh and the h-side portion of the side hi in the contour shape 21 becomes a triangle jkl. However, when the rod-shaped processing tool is moved along the offset shape 22 including the triangle jkl to perform the cutting, the portions of the sides gh and hi in the contour shape 21 are hollowed out, and the processing accuracy is deteriorated. There is. For this reason, a portion forming a closed loop such as a triangle jkl in the offset shape 22 is deleted, and cutting is performed using data of the offset shape 23 without a closed loop shown in FIG. Japanese Patent Application Laid-Open No. 1-255007 discloses such a technique.
There is an official gazette. [0006] In the above method, when the contour shape is a slightly more complicated shape, for example,
In the case of the contour shape 24 shown in FIG.
5 includes two closed loops mno, opq. Of these two closed loops mno and opq, the closed loop mno is originally an interference loop and should be deleted, but the closed loop opq is a non-interference loop and a part corresponding to this is to be processed while leaving the corresponding part. However, in the above-mentioned conventional technology,
Since all of these closed loops were removed, cutting of a contour shape corresponding to non-interfering closed loops was not performed. For this reason, in the case of a complicated contour shape, there has been a problem that accurate cutting corresponding to the contour shape cannot be performed. The present invention has been made in view of such circumstances, and an interference loop is removed, and a non-interference loop is not removed, and accurate cutting corresponding to a contour shape can be performed. It is an object of the present invention to provide a method for generating a loop in a tool path in which a loop element can be effectively connected when a loop is generated in a process. [0009] [Means for Solving the Problems] To achieve the above object, claim 1 of the loop generation method in the tool path according to the present invention, based on the contour shape, the dimensions of the tool
A method for generating a loop in a tool path using an offset shape formed in consideration of a determined offset distance as a tool path, wherein the offset shape is divided at each intersection point of the offset shape into a plurality of loop elements, and is configured by these loop elements. If each of the loops includes a loop element that intersects the contour shape or the distance between the contour shape is smaller than the offset distance, the loop is removed from the offset shape as an interference loop, and the loop is removed. Is the interference loop
Loop element and a non-interference loop element other than the interference loop exist.
Standing and, upon generation of each loop in the first aspect, by setting the direction of travel such that the internal side of the profile shape is positioned in a predetermined direction, sequentially connecting each loop element from the starting point of one loop element . When there are a plurality of loop elements at the connection destination, the left and right sides of the traveling direction of the connection source loop element are closest in angle to the connection source loop element, the traveling directions are the same, and the interference / non-interference loop element select the same loop element as a connection destination, once the loop element used is not used to terminate the generation of the the loop-loop elements on the connection destination is eliminated, it proceeds to generate the next loop. This makes it possible to easily determine whether the closed loop is an interference loop or a non-interference loop, and leaves the non-interference loop.
Only the interference loop can be eliminated. As a result, it is possible to perform a cutting process of an accurate shape closer to the contour shape to be obtained. That is, in such processing, it is preferable to determine whether a loop is an interference loop or a non-interference loop, and to effectively generate each loop. For this reason, here, first, the offset shape is divided at each intersection into a plurality of loop elements, and the direction in which the loop elements are connected is, for example, such that the inner side of the contour shape is located on the left side in the traveling direction. , Etc., so as to be in a certain direction. [0013] When one end of a certain loop element is set as a start point and successive loop elements are connected sequentially from the start point, if there are a plurality of loop elements at the connection destination, a loop element that satisfies the following conditions is selected. That is, one or two loop elements having the same traveling direction as the connection source loop element, the left and right sides of the traveling direction being closest to the connection source loop element, and the connection source loop element. And a loop element satisfying the condition that interference and non-interference are the same are selected as connection destinations. Also, among the selections made above,
If there are two selectable loop elements, select the loop element on the side where the connection source loop exists, do not use the loop element that has been used once, and create the loop when there is no loop element at the connection destination Is completed, the process proceeds to the generation of the next loop, and the same processing is repeated to generate all loops. That is, when there is only one loop element that can be selected on the left and right in the traveling direction of the connection source loop element, that loop element is selected as the connection destination. If there are loop elements that can be selected on the left and right sides of the traveling direction of the connection source loop element, respectively, the side where the previously connected loop is located, in other words, the starting point of the loop Select a loop element that has a direction that attempts to close the loop toward. By performing such a series of processing,
A loop can be efficiently generated, and by repeating this processing for all loop generations, more efficient processing can be performed. Next, a method for generating a loop in a tool path according to the present invention will be described in detail with reference to the drawings. FIG. 1 shows an example of a cutting apparatus for performing a method for generating a loop in a tool path according to the present invention. That is, in FIG. 1, an input device 1 receives data such as shape data of a cutting portion and information necessary for cutting, such as a tool speed, and sends the data to the memory 3 via the connected CPU 2. Remember. The CPU 2 operates in accordance with a program stored in the memory 3 while performing arithmetic processing based on various data and information, and drives the bar-shaped processing tool 5 of the connected cutting section 4 to perform processing. The workpiece 6 is cut. The memory 3 has a storage unit for storing various data.
In particular, the contour shape data storage section 7 for storing contour shape data of the cutting portion and the CPU 2 based on the contour shape data.
Is provided with an offset shape data storage unit 8 for storing offset shape data calculated by performing an offset process. Using such a cutting device, a method for generating a loop in a tool path according to the present invention is performed according to a flowchart shown in FIG. Here, a description will be given of a cutting process in which the outer part of the contour 9 is cut and removed by using the shape data of the contour 9 shown in FIGS. 3 and 4 so that the inner part of the contour 9 is raised in a plane. . In this case, first, the shape data of the contour shape 9 is stored in the contour shape data storage unit 7 of the memory 3. Then, based on the contour shape data, the CPU
By performing the offset processing in Step 2, the data of the offset shape 10 in which the tool path is moved to the outside of the contour of the contour shape 9 by the radius R of the rod-shaped processing tool 5 is created, and the offset shape data storage unit 8 To memorize. Next, as shown in FIG. 3, the offset shape 10 is divided at intersections a and b, and a plurality of loop elements LE are divided.
0, LE1, LE2, LE3, and LE4. Here, assuming that the starting point is o, LE0 is between the starting point o and the intersection a, LE1 is between the intersection a and the intersection b, LE2 is a loop that exits the intersection b and returns to the intersection b again, and LE2 is between the intersection b and the intersection a. LE3, a portion between the intersection point a and the start point o is set as five loop elements LE4. Then, each of the divided loop elements LE
For 0, LE1, LE2, LE3, and LE4, it is determined whether they are interference loop elements or non-interference loop elements. This judgment is made for each loop element LE0, LE
When 1, LE2, LE3, and LE4 intersect with the contour shape 9 or the distance between the contour shape 9 is smaller than the radius of the rod-shaped processing tool 5, it is regarded as an interference loop element. This is an interference loop element. In this case, the loop elements LE1 and LE3 are interference loop elements. Next, a loop is generated according to the flowchart of FIG. This loop is generated by sequentially connecting the loop elements, and the connection proceeds in the direction indicated by the arrow in FIG. That is, the inside of the corresponding contour shape 9 is always located on the left side in the traveling direction of the loop element. Then, the flowchart shown in FIG. 2 is started. First, in step 1 shown in the drawing, it is determined whether or not all loop elements have been used. In this process, a used loop element used once is not used again. Here, since all the loop elements are not used, the determination is NO, and the process proceeds to step 2. In step 2, the next unused loop element is:
That is, starting from the starting point o, the first loop element LE0
To get. Then, the process proceeds to step 3, where the loop element L
Add E0 to the loop to be created. Next, in step 4, it is determined whether or not there is an intersection at the end point of the loop element LE0. Since the end point of the loop element LE0 is the intersection point a, the determination becomes YES and the process proceeds to step S5. In step 5, a loop element to be connected is selected. Here, when there are a plurality of loop elements as connection destination loop elements, those that satisfy the following conditions are selected. First, a loop element whose traveling direction is the same as that of the connection source loop element is selected, and the left and right sides of the traveling direction are closest to the connection source loop element, and
Non-interference selects the same loop element as the connection destination. In this case, since the connection source loop element is the loop element LE0, those having the same traveling direction are the loop elements LE1 and LE4. Therefore,
The loop element LE3 is first excluded from the candidates. Then
The loop elements on the left and right in the traveling direction are also the loop elements LE1 and LE4, of which the loop element LE1 is an interference loop element. For this reason, the loop element LE1 is also excluded from the connection destination candidates, and the remaining loop element LE4 is selected as the connection destination. Then, the process proceeds to step 6, where it is determined whether or not there is a connection destination. Since the loop element LE4 has been selected as described above, the result is YES, and the process proceeds to step 7. Here, the loop element LE4 is also added to the loop, and the process returns to Step 4. In step 4, the loop element L
It is determined whether or not there is an intersection at the end point of E4. However, since the end point of the loop element LE4 is the start point o, the result is NO.
Proceed to step 8. Thus, the current loop is closed, and one loop including the loop elements LE0 and LE4 is generated. Next, the next empty loop is prepared, and the same processing is performed from step 1. Next loop element LE1
Is obtained as an unused loop element in step 2,
In step 3, it is added to the next generated loop. Then, the process proceeds to a step 4, wherein the loop element L
Since the end point of E1 is the intersection point b, the determination as to whether or not there is an intersection point at the end point of the loop element is determined as YES, and step 5 is performed.
Proceed to. Then, in step 5, a connection destination loop element is selected. Here, those having the same traveling direction as the loop element LE1 are the exit side and the LE3 of the loop element LE2, so that the entry side of the loop element LE2 is first excluded from the candidates. Next, of the remaining loop elements, the loop element LE3 is the same interference loop element as the loop element LE1, but since the loop element LE2 is a non-interference loop element, the loop element LE3 is connected to the loop element LE1. Selected as the destination. Then, in step 6, it is determined that there is a connection destination, and in step 7, the loop element LE3 is added to the loop. Next, returning to step 4 again, it is determined whether or not there is an intersection at the end point of the loop element LE3. However, since the end point of the loop element LE3 is the intersection point a, the result is YES, and the flow returns to step 5. move on. In step 5, a connection destination is selected. However, since all of the loop elements LE0, LE1, and LE4 preceding the loop element LE3 have been used, there is no connection destination (step 6), and the loop element LE1 is not used.
And an interference loop composed of LE3. Next, proceeding to step 8, a next empty loop is prepared, and the process is repeated from step 1. Here, since the next loop element is the loop element LE2, this is obtained as an unused loop element in step 2 and added to the next loop generated in step 3. Next, at step 4, the loop element LE2
It is determined whether or not there is an intersection at the end point of the loop element. The loop element LE2 forms a loop with one loop element.
Is the start point, and the end point is also the intersection b, so that the answer is YES,
Proceed to step 5. In step 5, the connection destination is selected, but there is no connection destination because both the loop elements LE1 and LE3 ahead of the loop element LE2 have been used. Therefore, the result of step 6 is NO, and the process proceeds from step 8 to step 1. Here, since all the loop elements have been used, the result is YES, and the loop generation processing ends. Finally, the loop composed of the loop elements LE1 and LE3, which are interference loops, is removed, and the tool path 11 located on the outer periphery of the contour 9 and the contour 9
The tool path 12 corresponding to the concave portion is obtained in the state shown in FIG. Next, a case where the contour shape is different from the above-described contour shape 9 and there are two selectable loop elements at the connection destination will be described. For example, as shown in FIG. 5, two loop elements 14 satisfying selectable conditions on the left and right sides of the loop element 13 of the connection source,
When the loop element 15 exists, a loop element located on the side of the loop 16 including the loop element 13 is selected as a connection destination loop element. In this case, the loop element 14 is selected. As described above, in this embodiment, since only the interference loop among the closed loops is removed and the processing is performed while the non-interference loop remains, processing of an accurate shape closer to the contour shape 9 to be obtained is performed. You will be able to get things. Prior to performing this series of processing, each loop can be effectively generated. In particular,
Entry from non-interfering loop element to interfering loop element,
By preventing the reverse approach and connecting the non-interfering loop elements or the interfering loop elements, more effective processing can be performed. In the above-described embodiment, the interference loop composed of the loop elements LE1 and LE3 is generated once and then removed in the post-processing. However, this is not necessarily generated from the beginning. Good. by this,
Further, the loop can be efficiently generated. In particular, in the case of the offset shape 18 of the contour shape 17 shown in FIG. 6, the loop elements divided at the intersections c, d, e, and f are LE5, LE6, LE7, and LE.
8, LE9, LE10, LE11, LE12, LE1
3, a complex structure composed of 10 loop elements of LE14. In this case, all the other loop elements LE6, LE7, LE except the loop elements LE5, LE14
8, LE9, LE10, LE11, LE12, LE13
Is an interference loop element, the processing becomes extremely simple if a loop composed of these loop elements is not generated from the beginning. That is, as shown in FIG. 7, the tool path 19 including the loop elements LE5 and LE14
Can be easily obtained. As described above, in the method for generating a loop in the tool path according to the present invention, the distance between each loop element constituting the offset shape and the contour shape is smaller than or intersects with the offset distance. In such a case, a loop including this loop element is removed from the offset contour as an interference loop. As a result, the non-interference loop can be left, and only the interference loop can be removed, so that it is possible to perform a cutting process of an accurate shape closer to the contour shape to be obtained. In generating each loop, the offset shape is divided at intersections into a plurality of loop elements, and the traveling direction connecting the loop elements is made constant. Then, the left and right sides of the traveling direction of the connection source loop element are closest in angle to the connection source loop element, the traveling directions are also equal, and the same interference / non-interference loop element is selected as the connection destination. For this reason, it is possible to prevent the non-interfering loop element from entering the interfering loop element and vice versa, and to connect the non-interfering loop elements or the interfering loop elements with each other to achieve a more effective operation. Processing can be performed. Further, when there are two loop elements that can be selected under the above conditions, by selecting the loop element on the side where the connection source loop exists, a more effective loop can be generated. . Then, by performing such a series of processing for generating all loops,
The entire loop generation process is efficient.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a configuration diagram of a cutting device used in an example of the present invention. FIG. 2 is a flowchart showing the order of processing. FIG. 3 is an explanatory diagram showing a contour shape and an offset shape. FIG. 4 is an explanatory diagram showing a contour shape and a tool path obtained by correction. FIG. 5 is an explanatory diagram illustrating a selection method when there are two selectable loop elements. FIG. 6 is an explanatory diagram showing another contour shape and an offset shape. FIG. 7 is an explanatory diagram showing another contour shape and a tool path obtained by correction. FIG. 8 is a plan view showing a contour shape and an offset shape according to the related art. FIG. 9 is an explanatory diagram illustrating a contour shape and a tool path obtained by correction according to the related art. FIG. 10 is an explanatory diagram showing a contour shape and an offset shape according to another conventional technique. [Description of Signs] 9, 17 ... contour shapes 10, 18 ... offset shapes 11, 12, 19 ... tool paths 16 ... loops a, b, c, d, e, f ... intersection points o ... starting points R ... rod-shaped processing tools Radius LE0, LE1, LE2, LE3, LE4, LE5, L
E6, LE7, LE8, LE9, LE10, LE11,
LE12, LE13, LE14, 13, 14, 15
… Loop element

Claims (1)

(57) [Claims] [Claim 1] Determined by the dimensions of the tool based on the contour shape
Offset shape formed considering the full offset distance
A loop generation method in a tool path having the following as a tool path, wherein an offset shape is divided at each intersection point of the offset shape into a plurality of loop elements, and each loop constituted by these loop elements intersects the contour shape. or if it contains a small loop element than the distance offset distance between the contour, removes from the offset shape the loop as an interference loop element, the said loop and the interference loop element the interference loop Less than
There is an outside non-interfering loop element, and when generating each loop, set the traveling direction so that the inner side of the contour shape is located in a fixed direction, and connect each loop element sequentially from the start point of one loop element If there are multiple loop elements at the connection destination, the angles are closest to the connection source loop elements on the left and right sides of the traveling direction of the connection source loop element, the traveling directions are the same, and interference / non-interference the loop element is the same loop element selected as the connection destination, once the loop element used is not used to terminate the generation of the loop elements to the destination is eliminated the loop, in the tool path proceeds to the generation of the next loop How to create a loop.