JPH10171514A - Method for preparing contour offset tool route for cam - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the life of a tool from being shortened due to the increment of cutting quantity of the tool on the corner part of an offset route and the excess of tool load at the time of the offset working of contours. SOLUTION: In the case of preparaing a contour offset tool route to be applied to a metal mold by using a tool shape model in a CAM system, the uncut shape 23 of the metal mold is judged from an offset route 22 existing just before an offset route on which a tool shape model 21 tries to advance. Then the length 27 of a circular arc on the model 21 within a range from a rectangular direction to the advancing direction of an offset route 24 to which the model 21 tries to advance up to a direction directing the center 26 of the model 21 to an intesection 25 between the model 21 and the uncut shape 23.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a CA for creating a contour offset tool path to a mold using a tool shape model in a CAM (Computer Aided Machining) system.
The present invention relates to a method for creating a contour offset tool path for M.

[0002]

2. Description of the Related Art Conventionally, when a die is machined by direct engraving, processing is usually performed along a shape like a scanning line as shown in FIG. In such machining, when the tool 1 is advanced in the tool advancing direction (in this case, the x direction) to remove the uncut portion 3 (the allowance) from the final mold shape, the tool 1
If the machining is performed such that the leading end of the tool 1 is inserted, the tool 1 may be damaged. In addition, when the tool 1 has a highly undulated shape and advances along the mold portion 5 having a steep slope, the cutting amount and the tool load increase, thereby shortening the tool life.

In some cases, contour line processing is used as a method for solving such problems of an increase in the cutting amount and tool load. In such contour processing, since the tool does not move in the vertical direction (z direction) when the tool advances, fluctuations in the tool load caused by the tool moving in the vertical direction, such as processing along a shape like a scanning line, occur. It is suitable for machining a steep part.

[0004] The above-mentioned contour processing is effective also in the case of a part such as a unit part which is formed by cutting a die from steel, but in this case, since there are many material parts other than the final die shape, rough processing is performed. Contour offset processing using a path offset from the contour path is performed as the cutting path at the time. In the contour offset processing, in order to obtain the final mold shape 7 from the material 6, the tool 8 generates a similar tool path 9 in the vertical direction (z direction), thereby cutting off an excess portion 10 of the material.

[0005] Further, with the advancement of hardware, the speed of mold processing has been accelerated. In this case, processing based on contour processing is also performed.

[0006]

However, when performing contour line offset machining, as shown in FIG. 11, the tool 11 is moved from the offset path 12 to the offset path 13 obtained by offsetting the offset path 12 by the radius of the tool 11. When shifting, the corner 1 of the offset path 13
4 (a two-dimensional corner portion viewed from the vertical direction (in this case, the + z direction)), there is a problem that the cutting amount of the tool 11 increases and the tool load becomes excessive, thereby shortening the tool life. Was. This has been a significant problem in speeding up processing.

At an angle of the corner portion 15 shown in FIG. 12, for example, the tool 16 cuts from the offset path 17 to an offset path 18 obtained by offsetting the offset path 17 by the radius of the tool 16. If this is done, there is also a problem that the uncut portion 19 occurs and the die becomes defective.

According to the first, second and fourth aspects of the present invention, the amount of cutting of the tool at the corner portion of the offset path is increased at the time of contour offset machining, and the tool load becomes excessive, thereby shortening the tool life. It is to solve the problem.

An object of the present invention is to solve the problem that, during contour line offset machining, a remaining portion is left uncut depending on the angle of the corner of the offset path, resulting in defective machining of the mold. .

[0010]

According to the first aspect of the present invention, there is provided a method for creating a contour offset tool path for a CAM, comprising the steps of:
When creating a contour offset tool path to a mold using a tool shape model in an AM system, determine the uncut shape of the mold from the offset path immediately before the offset path that the tool shape model is going to advance. Then, in a range from a direction perpendicular to the traveling direction of the offset path the tool shape model is going to travel, to a direction from the center of the tool shape model to an intersection of the tool shape model and the uncut portion, The present invention is characterized in that an arc length on a tool shape model is determined, and a new contour offset tool path is created so that the arc length becomes equal to or less than a predetermined effective arc length.

According to a second aspect of the present invention, there is provided a contour offset tool path creating method for a CAM, wherein when creating a new contour offset tool path such that the arc length becomes equal to or less than the effective arc length, the tool shape model is created. At the limit where the upper arc length becomes the effective arc length, the intersection of the tool path model and the offset path that the tool configuration model is going to travel and the center of the tool configuration model at this time are determined, and following this intersection, Finding a circle of the tool shape model, centered on the constituent points of the point sequence on the offset path on which the tool shape model is about to advance, among these circles,
The tool shape model obtains a tool center movable range in which cutting can be performed by hitting the constituent point, and within this tool center movable range, the tool at a limit where the arc length of the tool shape model becomes the effective arc length. The center of the circle of the shape model is determined, and the center of the tool shape model determined within the tool center movable range and the tool center movable range determined within the tool center movable range is determined within the tool center movable range. A point consisting of the center of the tool shape model at the limit where the arc length on the tool shape model becomes the effective arc length until the center of the circle is returned to the contour offset tool path where the tool shape model is going to advance. A new contour offset tool path is created by connecting the columns.

According to a third aspect of the present invention, there is provided a contour offset tool path creating method for a CAM according to the third aspect of the present invention, wherein, in the uncut portion, the new shape is maintained until there is no portion where the arc length of the tool shape model is equal to or less than the effective arc length. It is characterized in that the creation of a contour line offset tool path is repeated.

According to a fourth aspect of the present invention, there is provided a method for creating a contour offset tool path for a CAM, wherein the effective arc length is defined by:
A portion where the tool shape model comes into contact with the uncut portion is a straight line, and a portion where the tool shape model comes into contact with the mold is an arc length when the portion is a straight line.

[0014]

Function and effect of the present invention C according to claim 1 of the present invention
According to the method for creating a contour offset tool path for AM, as shown in FIG. 1A where the horizontal direction is the x direction and the vertical direction is the y direction, the contour offset tool for the mold using the tool shape model in the CAM system is used. When the path is created, the uncut shape 23 of the mold is determined from the offset path 22 immediately before the offset path in which the tool shape model 21 is going to proceed (in this case, the x direction).

Next, similarly, as shown in FIG. 1B where the horizontal direction is the x direction and the vertical direction is the y direction, the tool shape model 22 is about to advance (in this case, the x direction and the y direction). The tool shape model 21 and the uncut portion 23 are viewed from a direction perpendicular to the traveling direction of the path 24.
Is determined within the range from the center 26 of the tool shape model 21 to the intersection 25 with the arc length 27 on the tool shape model 21.

Next, a new contour offset tool path is created so that the arc length 26 becomes equal to or less than a predetermined effective arc length.

Thus, the arc length on the tool shape model,
In other words, by making the portion (contact of the blade of the tool shape model) that the tool shape model contacts with the uncut shape less than a certain value, during contour offset processing, the cutting amount of the tool becomes constant even at the corner of the offset path, Abrupt changes in tool load (cutting load) are eliminated, thereby extending tool life. Further, since the cutting feed deceleration of the tool shape model due to the fluctuation of the tool load becomes unnecessary, the time of the contour offset processing is reduced.

Furthermore, the method according to the present invention does not depend on the shape of the mold, since the contour offset path is created according to the arc length on the tool shape model. A contour offset path with a constant load can be created.

According to the method for creating a contour offset tool path for a CAM according to the second aspect of the present invention, when creating a new contour offset tool path whose arc length is equal to or less than the effective arc length, a tool shape model is created. At the limit where the upper arc length becomes the effective arc length, the intersection between the tool shape model and the offset path where the tool shape model is going to advance and the center of the tool shape model at this time are obtained.

Next, a circle of the tool shape model centering on the point of the point sequence on the offset path on which the tool shape model is going to advance following the intersection is determined. A tool center movable range in which cutting can be performed at a point is determined.

Next, within the movable range of the tool center,
The center of the circle of the tool shape model at the limit where the arc length of the tool shape model becomes the effective arc length is determined.

The center of the circle of the tool shape model determined within the movable range of the tool center and the tool shape model determined within the movable range of the tool center is determined by the center of the circle of the tool shape model determined within the movable range of the tool center. The calculation is repeatedly performed until the tool shape model returns to the contour offset tool path to be advanced.

A new contour offset tool path is created by connecting a sequence of points formed from the center of the tool shape model at the limit where the arc length on the tool shape model thus obtained becomes the effective arc length.

By creating a new contour offset tool path in this way, the arc length on the tool shape model can be made equal to or less than a certain value. , The cutting amount is constant, and the tool load (cutting load) does not suddenly fluctuate, thereby extending the tool life. Also,
Since the cutting feed deceleration of the tool shape model due to the fluctuation of the tool load becomes unnecessary, the time of the contour offset processing is reduced.

According to the method for creating a contour offset tool path for a CAM according to the third aspect of the present invention, a new contour line is created until there is no portion of the uncut shape where the arc length of the tool shape model is less than the effective arc length. Repeat creation of offset tool path. By repeatedly creating a new contour offset tool path in this way, it is possible to prevent the occurrence of machining defects in the mold due to the generation of uncut portions during contour offset processing.

According to the method of preparing a contour offset tool path for a CAM according to the fourth aspect of the present invention, the effective arc length is determined by setting a portion where the tool shape model is in contact with the uncut shape to be a straight line, and the tool shape model is a metal. The arc length when the part in contact with the mold is a straight line. By using such an effective arc length, the tool load at the time of contour line offset machining can be made constant, and the tool load (cutting load)
Abrupt fluctuations are eliminated, thereby extending tool life. Further, since the cutting feed deceleration of the tool shape model due to the fluctuation of the tool load becomes unnecessary, the time of the contour offset processing is reduced.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a method for creating a contour offset tool path for a CAM according to the present invention will be described in detail with reference to the drawings. In the drawings, the horizontal direction is the x direction, and the vertical direction is the y direction. Further, in this embodiment, it is assumed that the tool shape model advances from the x direction to the y direction when processing the corner of the die. FIG. 2 shows a CAM according to the present invention.
It is a flow chart of an embodiment of a contour line offset tool path creation method for use. In this processing flow, first,
In step S <b> 1, the uncut portion 32 of the final mold shape 31 is offset by the radius of the tool shape model 33 from the offset route 35 immediately before the offset path 34 where the tool shape model 33 is going to advance, that is, the immediately preceding offset path 35. (FIG. 3).

Next, in step S2, the offset path 34 on which the tool shape model 33 is about to advance.
The determination arc length 36 on the tool shape model 33 in a range from a direction perpendicular to the traveling direction (y direction) to a direction from the center of the tool shape model 33 to the intersection of the tool shape model 33 and the uncut portion 32. At the limit where the determined arc length 36 becomes the effective arc length, the intersection of the offset path 34 where the tool shape model 33 is going to advance and the tool shape model 33 and the center of the tool shape model at this time are determined by the load. The change point b1 and the load change center point a1 are obtained (FIG. 4). In the present embodiment, the effective arc length is determined when the portion where the tool shape model 33 contacts the uncut portion 32 is a straight line, and the portion where the tool shape model 33 contacts the final mold shape 31 is a straight line. Let it be the arc length.

Next, in step S3, it is determined whether or not there is a load change point b1, that is, whether or not a portion where the determination arc 36 is longer than the effective arc length exists in the uncut portion 32. If it is determined that there is, step S
4, the tool shape model 3 following the load change point b1
A circle of the tool shape model 33 is obtained, centered on the constituent point b2 of the point sequence on the offset path 34 where 3 is about to proceed. In this circle, the tool shape model 33 has the constituent point b
In step 2, a tool center movable range 37 in which cutting can be performed is determined. In this case, if the tool shape model 33 exists above one end d1 of the tool center movable range 37, the tool shape model 33 will cut and mix the final mold shape 31, and the tool shape model 33 will be shifted to the tool center. If it exists below the other end d2 of the movable range 37, the tool shape model 33 comes to hit another point of the uncut shape 32 (FIG. 5).

Next, in step S5, within the tool center movable range 37, the center of the circle of the tool shape model 33 at the limit where the arc length 36 of the tool shape model 33 becomes the effective arc length (effective arc length limit point). ) Is determined as the next route composing point a2. At this time, the traveling direction vector is a vector heading from the previous route composing point (= load change center point a1) to the route composing point a2 (FIG. 6).

Next, in step S6, it is determined whether or not the path composing point a2 (effective arc length limit point) exists on the offset path 34 where the tool shape model 33 is going to travel. If it is determined that the path does not exist on the offset path 34, the path point a2 is set as the next load change center point in step S7, and the steps are repeated until the path point an (n is a natural number) becomes a point on the offset path 34. S4 to S6 are repeated.

If it is determined in step S6 that the path component point an exists on the offset route 34, that is, if it is determined that the route component point an has returned to the original offset route 34, the route component points a1 to a4 created in steps S4 to S6 are determined.
A new contour offset tool path 38 is created by connecting the point sequence of an (FIG. 7), and the process returns to step S1.

The uncut portion 39 is formed by machining the uncut portion 32 along the new contour offset tool path 38 by the tool shape model 33 (FIG. 7).
Next, the contour offset tool path 38 is set as the offset path immediately before the offset path 34 in which the tool shape model 33 is going to travel, that is, the offset path immediately before the offset path 34, and whether or not there is a load change point bn (n is a natural number) in step S3. Or
That is, until it is determined that the portion where the determination arc 36 is longer than the effective arc length does not exist in the uncut portion, the step S1 is performed.
Repeat steps S8 to S8 to create new contour offsets 38 and 4.
0, 41 and 42 are created (FIG. 8).

In step S3, the load change point bn (n
If it is determined that there is no natural number), it is determined in step S9 whether a new contour offset tool path exists. If it is determined that a new contour offset tool path exists, in step S10, a new contour offset (38, 40, 41, 42 in FIG. 8).
To the original contour offset tool path 34, and this processing flow ends. . On the other hand, if it is determined that there is no new contour offset tool path, the processing flow ends without changing the original contour offset tool path 34.

In the present embodiment, by making the judgment arc 36 equal to or less than the effective arc length, the contour arc offset machining can be performed.
The cutting amount of the tool is constant even at the corner portion of the offset path, and the tool load (cutting load) does not fluctuate sharply, thereby extending the tool life. Further, since the cutting feed deceleration of the tool shape model 33 due to the fluctuation of the tool load becomes unnecessary, the time of the contour offset processing is reduced.

The arc length 36 on the tool shape model 33
Since the contour offset path is created according to the above, the contour offset path having a constant tool load can be created even when the mold has a complicated shape, regardless of the shape of the mold.

Further, the creation of new contour offset tool paths 38, 40, 41, 42 is repeated until there is no portion of the uncut portion 32 in which the judgment arc 36 is shorter than the effective arc length. By repeating the creation of the new contour line offset tool paths 38, 40, 41, 42 in this way, it is possible to prevent the occurrence of machining defects of the mold due to the generation of uncut portions during contour line offset machining.

Further, the effective arc length is set in the tool shape model 3
3 is a straight line when the portion in contact with the uncut portion 32 is a straight line, and the tool shape model 33 has an arc length when the portion in contact with the final mold shape 31 is a straight line. The load can be kept constant, and there is no sharp fluctuation of the tool load (cutting load), thereby extending the tool life. Further, since the cutting feed deceleration of the tool shape model due to the fluctuation of the tool load becomes unnecessary, the time of the contour offset processing is reduced.

The present invention is not limited to the above embodiment, and various changes and modifications are possible. For example, the effective arc length is defined as the arc length when the portion where the tool shape model 33 contacts the uncut portion 32 is a straight line, and the portion where the tool shape model 33 contacts the final mold shape 31 is a straight line. However, the arc length may be such that the tool load is slightly larger or slightly smaller than this arc length.

[Brief description of the drawings]

FIG. 1 is a diagram for explaining the concept of a method for creating a contour offset tool path for a CAM according to the present invention.

FIG. 2 is a flowchart of an embodiment of a method for creating a contour offset tool path for a CAM according to the present invention.

FIG. 3 is a diagram for explaining step S1 of the flowchart in FIG. 2;

FIG. 4 is a diagram for explaining step S2 of the flowchart in FIG. 2;

FIG. 5 is a diagram for explaining step S4 of the flowchart in FIG. 2;

FIG. 6 is a diagram for explaining step S5 of the flowchart in FIG. 2;

FIG. 7 is a diagram for explaining step S8 of the flowchart in FIG. 2;

FIG. 8 is a diagram illustrating a created new contour offset tool path.

FIG. 9 is a diagram for explaining conventional scanning line processing.

FIG. 10 is a diagram for explaining contour offset processing.

FIG. 11 is a diagram for explaining a problem of an increase in tool load when machining a corner portion in contour line offset machining.

FIG. 12 is a diagram for explaining a problem of uncut portion when processing a corner portion by contour offset processing.

[Explanation of symbols]

1,8,11,16 Tool 2,7,31 Final mold shape 3,32 Uncut shape (removal allowance) 4,5 Die part 6 Material 9 Tool path 10 Extra part of material 12,13,17, 18, 22, 24, 34, 35, 3
8, 40, 41, 42 Offset path 14, 15 Corner 19, 39 Uncut portion 21, 33 Tool shape model 23 Uncut portion 25 Intersection 26 Center 27 Arc length 36 Judgment arc length 37 Tool center movable range a1 Load change Center point a2 Path configuration point b1 Load change point b2 Configuration point d1, d2 End of movable range of tool center

Claims (4)

[Claims] When creating a contour offset tool path to a mold using a tool shape model in a CAM system, the tool shape model is shifted from an offset path immediately before the offset path on which the tool shape model is about to advance. Judging the uncut shape, from the direction perpendicular to the traveling direction of the offset path the tool shape model is going to travel, from the direction from the center of the tool shape model to the intersection of the tool shape model and the uncut shape Determining an arc length on the tool shape model within a range, and creating a new contour offset tool path such that the arc length becomes equal to or less than a predetermined effective arc length. Contour offset tool path creation method. 2. When creating a new contour offset tool path such that the arc length is equal to or less than the effective arc length, the tool is at the limit where the arc length on the tool shape model becomes the effective arc length. The intersection of the offset path on which the shape model is going to advance and the tool shape model and the center of the tool shape model at this time are obtained, and the point sequence on the offset path on which the tool shape model is going to travel following this intersection Focusing on the constituent points,
A circle of the tool shape model is obtained, and a tool center movable range in which the tool shape model can perform a cutting process while hitting the constituent point is obtained, and the tool shape model is obtained within the tool center movable range. Finding the center of the circle of the tool shape model at the limit where the arc length of the effective arc length becomes the center of the circle of the tool shape model obtained within the tool center movable range and the tool center movable range, The center of the circle of the tool shape model obtained within the tool center movable range is repeatedly obtained until the center of the circle of the tool shape model returns to the contour offset tool path where the tool shape model is going to advance, and the arc length on the tool shape model is the effective arc. A new contour offset tool path is created by connecting a sequence of points from the center of the tool shape model at the length limit. Characterized in that, CAM for contour offset tool path creation method according to claim 1, wherein. 3. The method according to claim 2, wherein the new contour contour tool path is repeatedly created until there is no portion of the uncut portion whose arc length of the tool shape model is equal to or less than the effective arc length. Item C or Item 2
Contour offset tool path creation method for AM. 4. An effective arc length when a portion where the tool shape model contacts the uncut portion is a straight line and a portion where the tool shape model contacts the mold is a straight line. The contour line offset tool path creation method for a CAM according to any one of claims 1 to 3, characterized in that: