JPH0732243A - Recognition of unchipped remaining range - Google Patents

Abstract

PURPOSE:To provide a data processing method to express an unchipped- remaining range as a geometrical data in a process to prepare an NC machining data to move a tool within one flat surface in accordance with a CAD data. CONSTITUTION:At steps S1, S2, a temporary tool route not in consideration of tool interferepce is computed, and in accordance with this temporary tool route, a regular tool route in consideration of the tool interference is computed. At steps S3-S6, from a branchpoint of the temporary tool route and the regular tool route to an original border line element, a toe of a radius line or a perpendicular is drawn down, and at a step S7, a range surrounded by the toe of the radius line or the perpendicular and a border line of a finished shape is grasped as a temporary cut remaining range. At a step 8, a range outside of a circular arc of a tool radius with the branchpoint in its center is geometrically grasped as a regular unchipped-remaining range.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for automatically creating NC data for moving a tool in one plane based on CAD data obtained from a CAD system or the like, and particularly with rough machining. The present invention relates to a method for automatically recognizing an uncut area generated as geometrical data.

[0002]

2. Description of the Related Art Conventionally, there has been proposed a method for automatically creating NC data including a movement path (tool path) of a tool such as an end mill based on CAD data (for example, magazine "Applied Mechanical Engineering" 1990). July issue (pages 167 to 173), JP-A-3-92245 [B23Q15 / 00]). In the method, tool interference is taken into consideration, and a tool path that does not cause cutting into the finished shape is required.

By the way, when a narrow portion such as a curved surface area having a small radius of curvature is included in the finish shape, after rough machining is performed by an end mill having a relatively large tool diameter, a small tool is applied to the remaining uncut area. Finishing is performed using a diameter end mill.

[0004]

However, in the prior art,
After creating NC data for rough machining, the NC data creator draws the finishing shape and tool path on the screen of the display and compares the finishing shape with the tool path to determine the possibility of uncut areas. Therefore, not only is it time-consuming to make this determination, but it is difficult to make this determination in the case of a complicated finish shape. An object of the present invention is to provide a data processing method for representing an uncut area as geometric data, and thereby to quickly and accurately determine an uncut area.

[0005]

According to a method of recognizing an uncut area according to the present invention, in a first step, a tool radius is offset from a contour line representing a final finished shape, and a provisional consideration is made without considering tool interference. The tool path is calculated, and in the second step, a regular tool path in consideration of tool interference is calculated based on the provisional tool path. Then, in a third step, regarding two tool path elements that intersect at the branch point of the temporary tool path and the regular tool path, for the tool path element having an arc, the tool path element from the branch point A radial line extending to the center point is calculated, and for a straight tool path element, a perpendicular line extending perpendicularly from the branch point to the original contour line element serving as the offset reference of the tool path element is calculated. Next, in a fourth step, a region surrounded by the radius line and the perpendicular line and the contour line is geometrically grasped as a temporary uncut region. Then, in a fifth step, the provisional uncut area is divided by an arc having a tool radius centered on the branch point, and the area outside the arc is geometrically grasped as a regular uncut area.

[0006]

In the temporary tool path calculated in the first step, the tool interference is not taken into consideration, so that the tool path draws a loop in the narrow portion of the finished shape. In the second step, the regular tool path in which the tool interference is taken into consideration is calculated by cutting off the loop formed in the temporary tool path. In the third step, a branch point between the temporary tool path and the regular tool path is obtained. The branch point was originally generated by the intersection of two tool path elements obtained by the offset. The tool path element is a circular arc or a straight line. Then, the geometric data (for example, the coordinates of the start point and the end point) of the radius line is calculated for the tool path element of the circular arc, and the vertical line is calculated for the tool path element of the straight line.
In the temporary uncut area that is geometrically grasped in the fourth step, when the tool is moved along the regular tool path for machining, the tool itself is moved regardless of the movement of the tool. The cross section includes a region to be processed. Therefore, in the fifth step, an arc having a tool radius centered on the branch point is drawn to exclude the machining area by the cross section of the tool itself from the temporary uncut area, and machining cannot be performed by the tool. The area, that is, the regular uncut area is grasped.

[0007]

According to the method of recognizing the uncut area, the geometric data of the uncut area is automatically created, so that the uncut area can be determined quickly and accurately. Moreover, it becomes possible to automatically create NC data for finishing based on the geometric data.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows an example in which a configuration for carrying out the present invention is realized by a computer, and a CPU (1)
On the other hand, the offset calculation means (2) for simply calculating the temporary tool path offset by the tool radius, and the coordinates of the branch point between the regular tool path and the temporary tool path in consideration of tool interference are calculated. A normal offset and branch point calculation means (3) for calculating, a means (4) for calculating the geometric shape of the temporary uncut area, and a means (5) for calculating the regular geometric shape of the uncut area. ), A memory (6) for registering the geometrical shape as data, and an output device (7) such as a display are connected.

The above offset calculating means (2), regular offset and branch point calculating means (3), provisional uncut area calculating means (4), and regular uncut area calculating means (5) are implemented by computer programs. FIG. 2 shows a series of data processing procedures performed by these means. Hereinafter, the data processing procedure will be described with respect to three specific examples of the first example shown in FIGS. 3 to 5, the second example shown in FIGS. 6 to 8, and the third example shown in FIGS. 9 to 11.

Step S1 A contour line representing the final finished shape (Y1 → Y in FIG. 3)
2 → Y3, Y1 → Y2 → Y3 → Y4 in FIG. 6, and Y1 → Y2 → Y3 → Y4 → Y5 in FIG. 9) by a tool radius, and a temporary tool path that does not consider tool interference.
(F1 → F2 → F3 in FIG. 3, F1 → F2 → F in FIG. 6
3 → F4 → F5, and in FIG. 9, F1 → F2 → F3 → F4 → F
5 → F6 → F7) is calculated.

In FIG. 3, since the contour line element Y2 is an arc having a radius smaller than the tool radius R, the element is once replaced with a straight line to connect the end point of the tool path element F1 and the start point of F3. Of the tool path element F2 is calculated. Figure 6
Then, since the contour line elements Y1 and Y2 are bent at 90 degrees, a tool path element F2 having an arc with a central angle of 90 degrees is created. Further, since the contour line element Y3 is an arc having a radius smaller than the tool radius R, the element is once replaced with a straight line, and the intersection of the offset line obtained by offsetting the straight line by the tool radius and the offset line of the contour line element Y2. Is the end point of the tool path element F3. Further, the intersection of the straight line offset line and the offset line of the contour line element Y4 is the end point of the tool path element F4. Similarly, in FIG. 9, since the contour line element Y3 is an arc having a radius smaller than the tool radius R, the element is once replaced with a straight line, and the straight line is offset by the tool radius and the contour line element Y2. , Y4 with the offset line are the end points of the tool path elements F3, F4, respectively.

Since the temporary tool path calculated in the first step does not consider the tool interference, the tool path draws a loop as shown in the drawing in the narrow portion of the finished shape.

Step S2 By separating the loop formed in the tool path from the temporary tool path obtained in step S1,
A regular tool path (indicated by broken lines in FIGS. 4, 7, and 10) in consideration of tool interference is calculated.

In step S3, a branch point X0 between the temporary tool path and the regular tool path is obtained. The branch point X0 is the intersection of the straight tool path elements F1 and F3 in FIG. 3, and is the intersection of the arcuate tool path element F2 and the straight tool path element F5 in FIG.
In FIG. 9, they are the intersections of the tool path elements F2 and F6, which are circular arcs.

Step S4 : Two tool path elements (F1 and F3 in FIG. 3, F2 and F5 in FIG. 6, F2 and F in FIG. 9) intersecting at the branch point X0.
Regarding 6), it is determined whether at least one of the tool path elements is a circular arc. In FIG. 6, F2 is an arc,
In FIG. 9, both F2 and F6 are arcs.

Steps S5 and S6 For the tool path element of the circular arc, geometric data (coordinates of the start point and the end point) representing the foot of the radial line extending from the branch point to the center point of the tool path element is calculated. Further, for a straight tool path element, the geometric data (the coordinates of the start point and the end point) representing the foot of the perpendicular line that extends vertically from the branch point to the original contour line element that has become the offset reference of the tool path element. calculate. In FIG. 4, perpendicular legs L5 (X0 → X1) and L4 (X0 → X2) are created from the branch point X0 to the tool path elements Y1 and Y3. In FIG. 7, since the branch point X0 exists on the tool path element F2 having a circular arc, the foot L5 (X0 of the radius line extending from the branch point X0 to the center point X2 of the tool path element F2
→ X2) is created. Further, in FIG. 7, since the branch point X0 is also a point on the straight tool path element F5, a perpendicular leg L4 (X0 → X1) is created from the branch point X0 to the original element Y4 of the tool path element F5. To be done. Further, in FIG. 10, since the branch point X0 is a point on the tool path elements F2 and F6 having a circular arc, the leg L5 of the radial line extending from the branch point X0 to the center points X1 and X2 of the tool path elements F2 and F6, L4 is created respectively.

Step S7 As shown in FIG. 4, FIG. 7, and FIG. 10, respectively, an area A surrounded by the leg of the radius line or the perpendicular and the contour line (closed area surrounded by the elements L1 to L5, respectively) ) Is geometrically grasped as a temporary uncut area, and the geometric data is registered in the memory (6) of FIG.

Step S8 As shown in FIGS. 5, 8 and 11, respectively, the provisional uncut area is divided by an arc L0 having a tool radius R centered at a branch point X0, and an area outside the arc is cut off. The area B (closed areas surrounded by L0 to L3, respectively) is geometrically grasped as a regular uncut area, and the geometric data is registered in the memory (6) of FIG. ) Output as a figure.

According to the above method, the uncut area can be grasped as the geometrical shape data based on the NC data for rough machining, so that the uncut area can be quickly and accurately determined even in the case of a complicated finish shape. Not only can you recognize it,
NC for later finishing based on the geometry data
Data can be created automatically.

The above description of the embodiments is for explaining the present invention, and should not be construed as limiting the invention described in the claims or reducing the scope. The configuration of each part of the present invention is not limited to the above-mentioned embodiment, and it goes without saying that various modifications can be made within the technical scope described in the claims.

[Brief description of drawings]

FIG. 1 is a block diagram showing a functional structure for implementing the present invention.

FIG. 2 is a flowchart showing a procedure for recognizing an uncut area.

FIG. 3 is an explanatory diagram of a process of calculating a provisional tool path in the first example.

FIG. 4 is an explanatory diagram of steps up to calculation of a temporary uncut area in the first example.

FIG. 5 is an explanatory diagram of steps up to calculation of a regular uncut area in the first example.

FIG. 6 is an explanatory diagram of a process of calculating a provisional tool path in the second example.

FIG. 7 is an explanatory diagram of a process for calculating a provisional uncut area in the second example.

FIG. 8 is an explanatory diagram of a process until a regular uncut area is calculated in the second example.

FIG. 9 is an explanatory diagram of a process of calculating a provisional tool path in the third example.

FIG. 10 is an explanatory diagram of a process for calculating a provisional uncut area in the third example.

FIG. 11 is an explanatory diagram of a process for calculating a regular uncut area in the third example.

[Explanation of symbols]

 (1) CPU (2) Offset calculation means (3) Regular offset, branch point calculation means (4) Temporary uncut area calculation means (5) Regular uncut area calculation means

Claims (1)

[Claims] 1. In the process of creating NC machining data for moving a tool in one plane based on CAD data, a tool radius is offset from a contour line representing a final finish shape to consider tool interference. No, a first step of calculating a temporary tool path, a second step of calculating a regular tool path in consideration of tool interference based on the temporary tool path, the temporary tool path and a regular tool For two tool path elements that intersect at the branch point of the path, for a circular tool path element, a radius line extending from the branch point to the center point of the tool path element is calculated, and for a straight tool path element The third step of calculating a perpendicular line extending perpendicularly from the branch point to the original contour line element serving as the offset reference of the tool path element, and the radius line and the perpendicular line and the contour line. The fourth step of geometrically grasping the area surrounded by the circle as a temporary uncut area, and dividing the temporary uncut area by an arc of a tool radius centered on the branch point, and outside the arc. And a fifth step of geometrically grasping the area as a regular uncut area, and a method for recognizing an uncut area.