JPH077295B2 - Toolpath generation method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a tool path generation method for machining a region between an outer closed shape and an inner closed shape along an inner shape.

[Prior Art] FIG. 10 is a diagram showing a hardware configuration of a numerical control device and one screen of a CRT display. (1) is a CPU (central processing unit), and (2) is a control for controlling the CPU (1). Main memory containing programs and machining programs,
(3) is a keyboard for inputting a machining program into the main memory (2), (4) is a CRT display for displaying the machining program, etc. (5) is movement data sent from the CPU (1) Is a servo mechanism for converting the number of pulses to actually move the servo motor (6), (6) is a servo motor, and (7) is a machine tool.

In this specification, the outer shape is offset to the inside by the tool diameter / 2 (the tool diameter / 2 during rough machining + the finishing allowance), the outer reference shape, and the inner shape is the outer tool diameter / 2 (during rough machining). Tool diameter / 2 + finishing allowance) The outer offset shape is called the inner reference shape.

It is also premised that the outer reference shape and the inner reference shape do not have an intersection or the inner reference shape is inside the outer reference shape.

In other words, it is premised that the offset shape based on only the outer shape or the inner shape can be created at least once.

In FIG. 2, (i) is an outer reference shape, (ii) is an inner reference shape, and (iii) is an unworkable shape.

FIG. 3 is an explanation of the AND shape, OR shape, and DIFF shape.

FIG. 3 (i) is an AND shape (A shape × B shape) showing a common part of two closed areas, and (ii) is an OR shape (A shape + B shape) showing one of the two closed areas, (Iii) is 1
DIFF shape (A shape − showing the difference between one closed area and another closed area)
B shape).

The operation of the prior art will be described by taking as an example the case of processing the material shape of FIG. 4 (i) to create the shape of (ii).

That is, when the outside shape and the inside shape such as (9) are input from the screen such as (8) on the CRT display (4) in FIG. 10, the CPU (1) follows the control program on the memory (2). The outer reference shape and the inner reference shape are generated, and the outer reference shape is offset outward one after another.

In the process, OR if it intersects with the inside and outside reference shapes even at one place
Let the shape be the toolpath.

This is processed until the offset shape of the outer reference shape disappears or the outer reference shape is included in the inner reference shape.

After that, the inner reference shape is output and the processing is completed.

FIG. 11 and FIG. 12 show the flow of the above process, and FIG.
FIG. 15 shows an example of toolpath generation when machining the shape shown in FIG. 4, and the details of the toolpath generation will be described below mainly using these figures.

11 and 12, in step 1, the outer closed shape is offset inward by the tool diameter / 2 to create the outer reference shape as shown in FIG. 2 (i), and then in step 2, the inner closed shape is formed. Offset to the outside by tool diameter / 2 / Fig. 2 (ii)
Create an inner reference shape as shown in. Next step 3
The outer reference shape and the inner reference shape are compared with each other, and when both shapes have an overlapping relationship as shown in FIG. 2 (iii), an error (a tool path cannot be generated) is output. If the two shapes do not overlap, the process proceeds to step 4 and the outer reference shape is output.

The outer reference shape output in step 4 is
This is the first tool path shown in Fig. 13 (b).

Next, in step 5, the offset amount is cleared, and in step 6
At step 7, the offset amount + cut amount is taken as the offset amount, and at step 7, the outer reference shape is offset to the inside by the offset amount to create a shape. Next, in step 8, it is determined whether or not there is an offset shape. If yes, the process proceeds to step 9, and in step 9, it is determined whether the offset shape is inside the outer reference shape. If it is not inside, a tool path based on the offset shape or the like can be generated. Therefore, the process proceeds to step 10, and in step 10, it is determined whether or not the offset shape overlaps the inside reference shape.
If they do not overlap, a tool path based on the offset shape can be generated, so the offset shape is output in step 11. When the offset shape is output in step 11, the process returns to step 6 again, and in step 6, an offset amount is created by adding the cut amount to the generated offset amount of the output offset shape. repeat. And step 10
Then, when the offset shape overlaps the inner reference shape,
The process shifts to step 12 in FIG. 12, an OR shape of the offset shape and the inner reference shape as shown in FIG. 3 (ii) is created, and the OR shape is output in step 13.

The OR shape output in step 13 is the tool path shown in FIGS. 13 (c) and 14 (d).

When the OR shape is output in step 13, the process returns to step 6, and the above steps are repeated thereafter. If it is determined in step S8 that there is no offset shape, it is possible to generate a tool path based on that offset shape. Therefore, the inner reference shape is output and the output shown in FIG. 14 (e) is output. A tool path based on the generated tool path is generated, and the tool path generation process ends.

If it is determined in step 9 that the offset shape exists inside the outer reference shape, it is possible to generate a tool path based on the offset shape. Therefore, the inner reference shape is output and shown in FIG. 14 (e). A tool path based on the output as shown is generated, and the tool path generation processing is ended.

Finally, the reason for generating the tool path based on the inner reference shape is to avoid uncut parts as shown in Fig. 15.

The coordinate values of the tool paths calculated one after another by the above calculation are sent to the servo mechanism (5) and converted into the number of pulses for actually moving the servo motor (6), and this is sent to the servo motor (6) to make the work. Move the machine (7) to process into the specified shape.

[Problems to be Solved by the Invention] Since the conventional numerical control device is configured as described above, if the inner shape is deviated from the center of the outer shape as shown in FIG. Moreover, the same part (a) is repeatedly cut, which causes a problem that machining time is significantly increased. By the way, in the case of FIG. 16, the part (a) is 2 to 7.
Overlap in the path.

The present invention has been made in order to solve the above problems, and an object of the present invention is to obtain a numerical control device in which an efficient tool path is generated by eliminating the above-mentioned overlapping paths and the machining time is shortened.

[Means for Solving Problems] A tool path generation method according to the present invention is a tool path generation method for machining a region between an outer closed shape and an inner closed shape along an inner shape, including the steps (a): Generating an outer reference shape in which the outer closed shape is offset inward by a predetermined amount and an inner reference shape in which the inner closed shape is offset outward by a predetermined amount, (b) the outer reference shape is inwardly offset by a predetermined amount Generating an offset shape, and (c) when the outer offset shape and the inner reference shape intersect at one location, generate an OR shape of both the shapes,
After that, a step of generating a DIFF shape (outer offset shape-inner reference shape) of both shapes is performed.

[Operation] According to the tool path generation method of the present invention, when processing the region between the outer closed shape and the inner closed shape along the outer shape, first, the outer reference shape is obtained by offsetting the outer closed shape inward by a predetermined amount. An inner reference shape is generated by offsetting the shape and the inner closed shape outward by a predetermined amount, and then an outer offset shape is generated by offsetting the outer reference shape inward by a predetermined amount. Then, the generated outer offset shape is compared with the above-mentioned inner reference shape, and when there is one intersection so as not to generate a duplicate tool path, an OR shape of both shapes that will become a tool path is generated. , And then generate DIFF shapes for both shapes that will be the toolpath. If the outer offset shape and the inner reference shape do not intersect with each other, or if the outer offset shape and the inner reference shape intersect at two or more locations, the same processing as in the related art, for example, the outer offset shape and the inner reference shape is performed. If the two do not intersect, the outer offset shape is used as the tool path, and if the outer offset shape and the inner reference shape intersect at two or more locations, the OR shape of both shapes may be used as the tool path.

[Embodiment of the Invention] An embodiment of the present invention will be described below with reference to FIGS. 1 to 9.

That is, when the material shape in FIG. 4 (i) is processed to create the shape in (ii), the screen like (8) on the CRT display (4) in FIG. When the outer shape and the inner shape are input, the CPU (1) generates a tool path as shown in FIGS. 5 and 6 according to the control program on the memory (2).

5 and 6, in step 1, the outer closed shape is offset inward by the tool diameter / 2 to create the outer reference shape as shown in FIG. 2 (i), and then in step 2, the inner closed shape is formed. Offset to the outside by tool diameter / 2 / Fig. 2 (ii)
Create an inner reference shape as shown in. Next step 3
The outer reference shape and the inner reference shape are compared with each other, and when both shapes have an overlapping relationship as shown in FIG. 2 (iii), an error (a tool path cannot be generated) is output. If the two shapes do not overlap, the process proceeds to step 4 and the outer reference shape is output.

The outer reference shape output in step 4 is the first tool path shown in FIG. 8 (b).

Next, in step 5, the offset amount is cleared, and in step 6
At step 7, the offset amount + cut amount is taken as the offset amount, and at step 7, the outer reference shape is offset to the inside by the offset amount to create a shape. Next, in step 8, it is determined whether or not there is an offset shape. If yes, the process proceeds to step 9, and in step 9 it is determined whether or not the offset shape is inside the inner reference shape. If it is not inside, a tool path based on the offset shape or the like can be generated. Therefore, the process proceeds to step 14, and in this step 14, it is judged whether or not there is one intersection between the offset shape and the inside reference shape. .

If the number is not one, the process proceeds to step 15. In step 15, the OR shape of the offset shape and the inner reference shape as shown in FIG. 3 (ii) is created, and in step 16, the OR shape is output.

The OR shape output in this step is shown in Fig. 8 (d).
It becomes the tool path shown by.

Although not shown, when the offset shape does not overlap the inner reference shape as in the conventional case, the offset shape itself is output as shown in FIG. 8 (c).

Then, when the offset shape or the OR shape is output, the process returns to step 6 again, and in step 6, an offset amount is created by adding the cut amount to the offset amount that generated the output offset shape, and the above steps are repeated thereafter. If it is determined in step 14 that the intersection between the offset shape and the inner reference shape is one, the process proceeds to step 17 in FIG. 6 to create an OR shape of the offset shape and the inner reference shape, and then to step 18. Output the OR shape.

The OR shape output in step 18 is shown in Fig. 8 (e).
It becomes the tool path shown by.

Then, in step 19, the DIFF between the offset shape and the inner reference shape in step 14 as shown in FIG.
A shape (offset shape-inner reference shape) is created, and the DIFF shape is output in step 20.

The DIFF shape output in step 20 becomes the tool path shown in FIG. 9 (f). The tool path is created in order to avoid uncut parts as shown in FIG. 9 (g).

Then, in step 21, the offset amount is cleared, and step
In step 22, the offset amount + cut amount is set as the offset amount, and in step 23, a shape in which the DIFF shape is offset inward by the offset amount is created. Next, at step 24, it is judged whether or not there is a DIFF-shaped offset shape, and if it exists, at step 25, the DIFF-shaped offset shape is output.

When the offset shape of the DIFF shape is output in step 25, the process returns to step 22 again, and in step 22, an offset amount is created by adding the cut amount to the offset amount that generated the output offset shape. Repeat the steps you did.

If it is determined in step 24 that there is no offset shape, it means that the tool path based on the offset shape cannot be generated, and the tool path generation processing is terminated. If it is determined in step S8 that there is no offset shape, the tool path based on that offset shape cannot be generated as in the conventional case. Therefore, the inner reference shape is output and as shown in FIG. 14 (e). A toolpath is generated based on the output, and the toolpath generation processing is ended.

If it is determined in step 9 that the offset shape exists inside the inner reference shape, it is not possible to generate the toolpath based on the offset shape as in the conventional method. Therefore, the inner reference shape is output, and FIG. A tool path based on the output as shown in (e) is generated, and the tool path generation processing is ended.

The reason why the tool path based on the inner reference shape is generated in steps 8 and 9 is to avoid uncut portions as shown in FIG. 15 as in the conventional case.

The coordinate values of the tool paths calculated one after another by the above calculation are sent to the servo mechanism (5) and converted into the number of pulses for actually moving the servo motor (6), and this is sent to the servo motor (6) to make the work. Move the machine (7) to process into the specified shape.

[Advantages of the Invention] As described above, according to the present invention, since the duplicate tool paths are not created, the machining time can be shortened.

[Brief description of drawings]

1 to 9 are diagrams relating to the present invention, FIG. 1 is a diagram showing a hardware configuration of a numerical control device and one screen of a CRT display, and FIG. 2 is a diagram for explaining an inner reference shape and an outer reference shape. Figure 3 is a figure for explaining AND shape, OR shape, and DIFF shape, and Figure 4 is a figure showing the workpiece, 5
6 and 6 are flowcharts for explaining the operation,
7 to 9 are diagrams for explaining the tool path, and FIG.
FIGS. 16 to 16 are diagrams relating to a conventional example, FIG. 10 is a diagram showing a hardware configuration of a numerical control device and one screen of a CRT display, and FIGS. 11 and 12 are flowcharts for explaining the operation, 13 to 15 are diagrams for explaining the tool path, and FIG. 16 is a diagram for explaining the defect. The same reference numerals in the drawings indicate the same or corresponding parts,
(1) is CPU, (2) is memory, (3) is keyboard,
(4) is a CRT display.

Claims (1)

[Claims] 1. A method for generating a tool path for machining a region between an outer closed shape and an inner closed shape along an inner shape, comprising: (a) an outer reference shape in which the outer closed shape is offset inward by a predetermined amount; A step of generating an inner reference shape in which the inner closed shape is offset to the outside by a predetermined amount, (b) a step of generating an outer offset shape in which the outer reference shape is inwardly offset by a predetermined amount, and (c) the outer offset shape When there is only one intersection between the inside reference shape and the inside reference shape, an OR shape for both shapes is generated,
After that, a step of generating a DIFF shape (outer offset shape-inner reference shape) of both shapes is provided, and a tool path generation method.