JPH0531161B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for creating an NC part program for laser machining, and particularly to a method for creating an NC part program that can improve machining accuracy at corners.

<Prior art> In automatic programming that creates NC data using automatic programming languages such as APT and FAPT, (a) points, straight lines, and arcs are defined using simple symbols (shape definition); point,
Define the tool path using straight lines and circular arcs (motion statement definition) and create a part program using an automatic programming language. (b) Then, use the NC data output table to create a part program using the automatic programming language to the NC device. NC consisting of NC data (EIA code or ISO code) in a format that can be executed by
Convert to data. It is assumed that the tools include a wire in a wire electric discharge machine, a laser beam in a laser beam machine, etc. in addition to normal tools.

For example, in creating _a part program for moving _a tool (laser beam) along a shape consisting of straight lines and circular arcs as shown _in FIG _. and arc C ₁
… PART, REIDAI … (1) MCHN, MILL, ABS … (2) P ₁ = x ₁ , y ₁ P ₂ = x ₂ , y ₂ P ₃ = x ₃ , y ₃ S ₁ = P ₂ , P ₃ ... (3) C ₁ = x ₄ , y ₄ , r ₁ ... (4) P ₅ = x ₅ , y ₅ S ₂ = P ₅ , C ₁ , B ... (5) Then, using these defined points, straight lines, and arcs, CUTTER, 0.3 ……(6) S0800 ……(7) TLLFT ……(8) FROM, P ₁ ……(9) RPD, TO , S ₁ , P ₂ ... (10) FCOD, 500 ... (11) S ₁ C ₁ S ₂ ... FINI PEND and the motion statement along the tool path are defined in an automatic programming language and written to the automatic programming device. Once input, the automatic programming device automatically creates and outputs executable NC data in EIA code or ISO code while referring to the NC data output table.

However, (1) instructs the start of the part program, and "REIDAI" is the heading.

(2) indicates the type of NC machine, MILL for milling, and MILL for turning.
TURN, in the case of a wire cut electrical discharge machine
Use CUT and RAZER for laser processing. "ABS" indicates an absolute command (INCR is used for incremental commands).

(3) means a straight line passing through points P ₂ and P ₃ , (4) means a circular arc with radius r ₁ at the center (x ₄ , y ₄ ), and (5) means a straight line passing through point P ₅ to arc C _1. It means the lower tangent line (straight line) of two tangent lines that touch. However, in the case of the upper tangent line, the alpha alphabet A is used instead of B.

(6) is a beam command that commands a beam diameter of 0.3 mm, (7) is a command that indicates that the laser output is 800 watts (W), and (8) is a command that offsets the tool to the left in the direction of travel (however, TLRGT to offset the tool to the right in the direction), (9) is a coordinate system setting command indicating that the starting point is P ₁ , and (10) is a command to set the cutter at point P ₂ without passing through straight line S ₁ . A command for positioning so as to be in contact with the straight line, (11) is a speed command indicating that the feed speed is 500 mm/min.

By the way, in general, when a corner exists in a tool path, the tool feed rate cannot be kept constant near the corner due to the characteristics of the machine. for example,
If the block b _i and the (i+1)th block b _i+1 of the tool path are perpendicular to each other as shown in FIG. You will need to slow down. In other words, near the corner, the X-axis feed speed V _X becomes the command speed V _C
After decelerating from and reaching zero, the Y-axis feed speed V _Y
is accelerated to the commanded speed V _C.

Acceleration or deceleration of the feed rate at this corner has a negative effect on the accuracy of parts machining, and especially when a high machining speed is required, such as in laser machining, the acceleration or deceleration of the feed rate has a considerable effect on the machining accuracy.

<Problems to be solved by the invention> From the above, it is necessary to create an NC part program so that the machining accuracy at the corner does not deteriorate, but conventionally, the NC part program has been created taking such machining accuracy into consideration. was not carried out.

From the above, the purpose of the present invention is to develop a laser processing method that can suppress the deterioration of processing accuracy at corners.
The object of the present invention is to provide a method for creating an NC part program.

Another object of the present invention is to provide a method for creating an NC part program for laser machining that can maintain machining accuracy at corners using a simple method.

Still another object of the present invention is to make the machining conditions at the corner different from the previous machining conditions when the outside of the corner is a part, for example by reducing the feed rate and laser output a predetermined distance before the corner, and It is an object of the present invention to provide an NC part program creation method that can improve machining accuracy at corners by restoring machining conditions to their original values at a point a predetermined distance afterward.

<Means to solve the problem> FIG. 1 is a schematic explanatory diagram of the present invention.

RB is the laser beam, b _i is the offset path of the i-th block, b _i+1 is the offset path of the (i+1)th block, CN is the corner, PT is the part, P is the end point of the i-th block, between QP and PR The spaces between are the machining condition change sections, and the distances l ₁ and l ₂ from the end point P, respectively.
This is the interval.

In addition, in Figure 1 A to D, the outside corner is the part PT.
Figures 1A and B are both cases in which the offset direction is on the right side in the direction of travel and the vehicle turns clockwise at a corner, and Figures 1C and D are both cases in which the offset direction is on the left side in the direction of travel. This is a case where the vehicle turns counterclockwise at a corner.

<Effect> Machining condition change section at corner CN in advance
By setting QP, PR (distance l ₁ , l ₂ ) and the machining conditions (laser beam feed rate and laser output value) in the corresponding section, the motion can be defined without considering the machining condition change section and the machining conditions. Create a sentence.

And when creating the NC part program,
The offset direction and beam path b _i indicating whether to offset the laser beam RB to the right or left side of the traveling direction included in the motion definition statement,
b Based on the bending direction at the corner CN of _i+1, it is determined whether the outside of the beam path at the corner is a part PT, and if the outside of the corner is a part, the machining condition change sections QP and PR set as above are determined. Create an NC part program to meet the specified machining conditions.

In other words, the NC is moved to point Q under the specified machining conditions (the machining conditions specified in the motion definition statement).
Create data, create NC data to move from point Q to P under set machining conditions, and create NC data to move from point P to point R under similarly set machining conditions.

<Embodiment> FIG. 2 is a block diagram of an automatic programming device which is an embodiment of the present invention.

101 is a ROM in which loading programs and the like are stored, 102 is a processor that performs automatic programming processing, and 103 is a RAM.

RAM103 is a storage area 103 that stores the system program STPR read from the floppy disk.
a, a storage area 103b for storing the NC data output table NCDT, and a storage area 103 for storing the correspondence relationship FNT between function codes and NC data output formats.
Storage area 1 to store c and various parameters PRM
03d and a working area 103e.

The NC data output table NCDT stored in the storage area 103b has a plurality of function codes F1 to F9 for specifying the NC data output format for each command as shown in FIG. Each function code is expressed as a 4-digit hexadecimal number, and a collection of several function codes can be used to create one executable NC.
Data is identified.

Also, part of the correspondence between each function code stored in the storage area 103c and the NC data output format is
As shown in the figure. Now, the NC data output format for the coordinate system settings in the NC data output table NCDT in Figure 3 is 8502, 0001, 0101, 0201, 0004, so if you refer to the correspondence between the function code and output format in Figure 4, Coordinate system setting execution format
The NC data is G50X x Y y Z z EOB...(a). Also, the NC data output format for positioning/linear cutting is 8202, 8002, 0001, 0101, 0201, 0141, 0004, so if you refer to the correspondence between function codes and output formats in Figure 4, you can see that positioning/linear cutting is executed. The NC data in the format is G90 (G91) G00 (G01) X x Y y X x F f EOB
...(b) becomes. Furthermore, since the NC data output format for circular cutting is 8202, 8012, 0001, 0101, 0301, 0401, 0004, referring to the correspondence between function codes and output formats in Figure 4, the NC data in the execution format for circular cutting is G90 (G91) G02 (G02) X x Y y I i J j EOB
...(c) becomes.

Returning to FIG. 2, 104 is an NC data storage memory for storing created NC data, 105 is a keyboard, 106 is a display device (CRT),
107 is a disk controller, and FL is a floppy disk.

Fig. 5 is a flowchart of the process of the present invention, Fig. 6 is an explanatory diagram of the corner radius that requires changing the machining conditions, Fig. 7 is an explanatory diagram of the intersection angle that requires changing the machining conditions, and Fig. 8 is a diagram showing the parts inside the corner. This is an explanatory diagram of a certain case, and the processing of the present invention will be described below with reference to FIGS. 1 to 8.

In addition, the system program STPR and NC data output table for creating the NC part program for laser processing from the floppy disk FL are provided in advance.
It is assumed that NCDT, function code/NC data output format correspondence relationship FNT, and parameter PRM are stored in each storage area 103a to 103d of RAM 103. In addition, the parameter PRM includes the machining condition change sections QP and PR at the corner (see Figure 1), data that specifies the machining conditions in this section, and the angle A _S that is the criterion for determining whether to change the machining conditions. ,
Assume that radius R _S is included.

However, if the i-th block and the (i+1)-th block are straight lines (see Figure 1), the machining condition change section
QP and PR are the distances l ₁ and l ₂ from the end point P of the i-th block
The processing conditions are determined by the laser beam feed rate.
It is specified by V ₁ , V ₂ and laser output values E ₁ , E ₂ .
Furthermore, when the (i+1)th block is a circular arc (see Fig. 6), the machining condition change sections QP ₁ , P ₂ R are the distance l ₁ from the i-th block end point (arc starting point) P ₁ and the (i-th
+1) Distance from the end point of the block (end point of the arc) l ₂
It is specified by

(1) First, if you create and input a figure definition statement and a motion definition statement that does not take into account machining condition change sections or machining conditions in these sections, the processor 1
02 is 1→i.

(2) Next, the end point of the i-th block is calculated from the figure definition statement and the motion definition statement.

(3) When the end point of the i-th block is found, it is checked whether the end point is the end point of the laser beam path.

(4) If it is the end point of the passage, use the coordinate value of the end point to
Create the block NC data and complete the NC part program creation process.

(5) On the other hand, if it is not the end of the path in step (3), it is checked whether the outside of the corner at the end of the i-th block is a part.

In addition, when the offset direction of the laser beam is on the right side in the direction of travel and turns clockwise at the end point corner (see Fig. 1 A and B), and when the offset direction is on the left side in the direction of travel and turns counterclockwise at the end point corner. In the case of bending (see Figure 1 C and D), the inside of the corner becomes the part.

(6) If the outside of the corner is not a component, in other words, if the inside of the corner is a component, a process is performed to determine whether or not to insert an escape passage into the corner, and a process to create NC data based on the determination result. Execute.

FIGS. 8A to 8D are examples of escape passages EP inserted into corner parts, and the i-th block and the (i+1)-th block
The intersection of offset paths b _i and b _i+1 of the block is P _E ,
If the points at a distance l from the intersection P _E in the extending direction of each offset passage are Q and R, then the line segment P _E Q
→ Arc tangent to Q and R → line segment RP _E. In other words, the escape passage is a passage in which the machining speed does not change at the corner.

(7) On the other hand, if the outside corner is a part, the (i+
1) Check whether the block is an arc.
In addition, if the radius of the corner arc exceeds a predetermined value, the speed change of the laser beam at the corner will not affect the machining accuracy, so in the present invention, the corner arc radius R (see Fig. 6) is set in advance. If the radius is larger than a certain radius R _S , the machining conditions are not changed even if the outside of the corner is a part.

(8) Therefore, in step (7), if it is an arc, calculate the corner radius R, and if it is not an arc, calculate the corner radius R in step (13).
Fly to the steps.

(9) Now, if it is a circular arc and the corner arc radius R is found, it is determined whether R< _RS .

(10) If R≧ _RS , the i-th block (straight line block) and the (i+1)th block are processed without changing the machining conditions.
Create NC data for the block (arc block).

(11) However, if R< _RS , the machining condition change sections QP ₁ , P ₁ P ₂ , P ₂ R specified by l ₁ and l ₂ set in the parameter storage area 103d (see Fig. 6) )
so that the machining conditions set above are met.
Create NC data.

In other words, create NC data that moves to point Q under predetermined machining conditions (the machining conditions specified in the motion definition statement), and from point Q to point _P1 , create NC data that moves under the machining conditions set with _l1 . Create data, and create NC data to move from point P ₁ to point P ₂ with the same machining conditions as between QP ₁ , and move from point P ₂ to point R with the machining conditions set with l ₂ . Create NC data to Note that the laser output value is set using the S code.

(12) Then, after completing steps (10) and (11), i+
Increment i by 2→i and repeat the process from step (2) onwards.

(13) On the other hand, if the result of the determination in step (7) is that the (i+1)th block is a straight line, the intersection angle A (see FIG. 7) between the i-th block and the (i+1)th block is calculated.

(14) Next, angle A and the preset angle A _S
Distinguish the size of the

Now, if the corner angle A is an obtuse angle and is quite large, the change in speed at the corner will not affect the machining accuracy, so in the present invention, if the corner angle A is larger than the preset angle A _S The machining conditions are not changed even if the outside of the corner is a part.

(15) Therefore, if A>A _S , the NC data of the i-th block is created without changing the machining conditions.

(16) However, if A > A _S , the machining conditions set in the machining condition change sections QP and PR (see Figure 1) specified by l ₁ and l ₂ set in the parameter storage area Create NC data so that

In other words, create NC data to move to point Q under predetermined machining conditions (the machining conditions specified in the motion definition statement), and create NC data to move from point Q to point P under the machining conditions set with _l1 . Create NC data to move from point P to point R using the machining conditions set with _l2 .

(17) Then, after completing steps (6), (15), and (16), increment i by i+2→i, and perform subsequent steps.
(2) Repeat the following process.

Note that at the corner portion, the machining speed (laser beam feed rate) and laser output value are set to be smaller than the machining speed and laser output value up to that point.

Furthermore, in the above example, each block has _one machining condition change section _, but as shown in _FIG . It is also possible to provide a configuration in which the processing speed and the laser output value are set to gradually decrease or increase, respectively.

<Effects of the Invention> According to the present invention, the machining condition change section and machining conditions at a corner are set, and when the outside of the corner is a part, the machining conditions at the corner are changed to the machining conditions set above. Since the machine is configured to machine under these machining conditions, for example, the feed rate and laser output can be changed at a predetermined distance before the corner, and the machining conditions can be restored to the original machining conditions at a predetermined distance after passing the corner. It is possible to create an NC part program that can prevent a decrease in machining accuracy at corners using a simple method.

[Brief explanation of drawings]

Fig. 1 is a schematic explanatory diagram of the present invention, Fig. 2 is a block diagram of an automatic programming device implementing the present invention, Fig. 3 is an explanatory diagram of an NC data output table, and Fig. 4 is a diagram of function codes and NC data output formats. Correspondence diagram, Fig. 5 is a flowchart of the process of the present invention, Fig. 6 is an explanatory diagram of corner radius that requires changing machining conditions, Fig. 7 is an explanatory diagram of intersection angle that requires changing machining conditions, and Fig. 8 is a diagram of corner radii that requires changing machining conditions. An explanatory diagram when there are parts inside, Fig. 9 is an explanatory diagram when inserting multiple machining condition change sections in a corner, Fig. 10 is an explanatory diagram of the conventional automatic programming method, and Figs. 11 and 12 are FIG. 3 is a diagram illustrating the drawbacks of the conventional method. RB...Laser beam, b _i ...Offset path of the i-th block, b _i+1 ...Offset path of the (i+1)th block, PT...Part, P...End point of the i-th block, between QP and PR Interval: Machining condition change interval.

Claims (1)

[Claims] 1. A figure definition statement that defines a figure and a motion definition statement that defines a path of a laser beam are input, and these definition statements are used for laser processing that can be executed by an NC device using an NC data output table. In the method of converting and outputting to an NC part program, the machining condition change section at the corner and the machining conditions in that section are set in advance, and the motion definition statement is created without considering the machining condition change section and machining conditions. From the offset direction that indicates whether to offset the beam to the right or left side of the direction of movement contained in the motion definition statement and the bending direction at the corner of the beam path, it is determined that the outside of the beam path at the corner is the part. an NC part program for laser processing, characterized in that the NC part program is created so that the set machining conditions are applied in the machining condition change section if the outside of the corner is a part; How to make. 2. The method of creating an NC part program for laser machining according to claim 1, wherein the machining conditions are such that the feed rate and laser output value are lowered in the machining condition change section than before. 3. The method for creating an NC part program for laser machining according to claim 2, characterized in that a plurality of machining condition change sections and machining conditions are set in the corner portion. 4 Set the angle A _S of the corner part in advance, find the angle A at the corner part of the beam path, determine the magnitude of the angle A and the set angle A _S , and find if A<A _S and the outside of the corner is 2. The method for creating an NC part program for laser processing according to claim 1, wherein in the case of a part, the NC part program is created so that the machining conditions set in the machining condition change section are met. 5 Set the corner arc radius R _S in advance,
If there is an arc at the corner of the beam path, determine the size of the arc radius R and the previously set arc radius R _S , and if R < R _S and the outside of the corner is a part, change the machining condition change section. 2. The method for creating an NC part program for laser machining according to claim 1, wherein the NC part program is created to meet the set machining conditions.