JP5178358B2 - Torch descending speed control method, control program, control system, and machining apparatus - Google Patents

Description

  The present invention relates to a method for controlling a descending speed of a torch used in a plasma processing apparatus, a laser processing apparatus, a gas cutting apparatus, etc., a control program, a control system and a processing apparatus to which this method is applied.

Conventionally, when a workpiece is machined using a torch, in order to prevent the torch from interfering with the workpiece, it is common to descend a long distance from above the workpiece at a low speed.
Therefore, in order to shorten the descent time of the torch, for example, when plasma arc cutting or plasma arc welding is performed on a workpiece such as a steel plate, the torch is controlled to a predetermined height in a short time by controlling the descent speed of the torch. A technique for moving is disclosed (for example, see Patent Document 1).

  In the above control method, when the initial setting of the torch is performed, the approximate position is detected by lowering the torch at a relatively high speed and bringing it into contact with the workpiece, and then the torch is placed on the workpiece surface of the workpiece. The torch is lifted by a predetermined distance in the vertical direction (Z-axis direction) perpendicular to the workpiece, and then the torch is lowered at a relatively low speed to form a machining point on the workpiece. The method of detecting the reference point is adopted.

The method described in Patent Document 1 can accurately detect the reference point in a shorter time than the conventional method of detecting the accurate reference point of the workpiece by lowering the initial sensor at a low speed from the beginning. Has advantages.
JP 2001-198679 A

  However, in the method described in Patent Document 1, since it rises by a predetermined distance in the Z-axis direction and descends again at a low speed, when the torch descends to the reference point, an extra operation occurs and the operation time is long. There was a problem.

  The present invention has been made in view of such circumstances, and provides a torch descending speed control method, control program, control system, and machining apparatus that can shorten the operation time for the torch to descend from the origin to the reference point. The purpose is to provide.

In order to solve the above problems, the present invention proposes the following means.
According to the first aspect of the present invention, the workpiece can be moved relative to a surface plate formed along the XY plane and on which the workpiece is placed, and a machining point is formed on the workpiece to form the workpiece. A torch that moves a torch that switches between a high speed and a low speed between an origin at which the torch waits in a Z-axis direction orthogonal to the XY plane and a reference point at which the torch forms the machining point. In the speed control method, when the XY coordinate of the current machining point is within a predetermined region set with reference to the XY coordinate of the previous machining point, the torch is moved to the current machining point at the current machining point. The platen was moved at a high speed longer than the high-speed movement distance at the coordinate position (X _H, Y _H ) where the position in the Z-axis direction is the highest , and the high-speed movement distance at the current descent was measured in the previous machining. The original The moving distance from a point to the reference point in the previous machining is a distance corrected by a predetermined amount .

The invention described in claim 2 is a platen that is formed along the XY plane and on which the workpiece can be placed, and is disposed above the platen, at the intersection of the torch axis and the workpiece. A torch that forms the processing point to process the workpiece, an X-axis direction drive unit that relatively moves the torch and the surface plate in the X-axis direction, and the torch and the surface plate in the Y-axis direction. A Y-axis direction drive unit that relatively moves; and a Z-axis direction drive unit that moves the torch in the Z-axis direction orthogonal to the XY plane and that can control the moving speed of the torch at least at a high speed and a low speed. A control unit that drives the X-axis direction drive unit, the Y-axis direction drive unit, and the Z-axis direction drive unit, and a reference point at which the torch forms the machining point from an origin at which the torch waits And a distance detecting means for detecting the distance in the Z-axis direction. A control program for controlling the lowering speed of the torch in the processing device,
The high-speed moving distance H _i of the torch at the time of i (natural number) processing,
If i = 1,
H _i = H ₀
In i ≧ 2, when the XY coordinates of the machining point to be processed at the i-th time are within a predetermined area set with reference to the XY coordinates of the machining point at the i-1th machining,
H _i > H ₀
And
H (i) = H (i-1) + L (i-1) -B
H ₀ : High-speed movement distance at the start of machining
L (i-1): Distance traveled by the torch at low speed in the (i-1) -th processing.
B: A correction value set in advance is used.

According to the torch lowering speed control method and control program according to the present invention, when machining is performed within a predetermined region in which the displacement in the Z-axis direction with respect to the machining point in the previous machining is small, the high-speed travel distance of the torch in the Z-axis direction Therefore, the torch moving time (falling time) can be shortened while suppressing the torch from interfering with the workpiece.
Further, when the i-th machining is performed within a predetermined region set with the (i-1) -th machining point as a reference, the high-speed movement distance H (i) is set to the high-speed movement at the (i-1) -th machining point. Since it is determined from the distance H (i-1) and the correction amount B, the high-speed moving distance H (i) is longer than the high-speed moving distance at the coordinate position (X _H, Y _H ) where the position in the Z-axis direction is the highest. In addition, the travel time of the torch can be shortened.
In this specification, the processing point means a point formed on the processing surface when the torch processes the workpiece, and the processing point and the nozzle tip of the torch face each other with a processing gap secured. The position is taken as the reference point of the torch.
Further, the predetermined area is, for example, an area in which a predetermined length is determined from the machining point in the X-axis direction and the Y-axis direction, and the predetermined length has a small displacement in the Z-axis direction from the processing point and the torch moves. A range where no interference occurs is preferable. The lengths in the positive and negative directions in the X-axis direction and the Y-axis direction may be the same from the machining point, or one or both of the X-axis direction and the Y-axis direction may be asymmetric in the axial direction. Moreover, it is good also considering circular and another shape as a predetermined area | region.

The invention described in claim 3 is a control system, comprising the control program according to claim 2 .

The invention described in claim 4 is a processing apparatus, and includes the control system according to claim 3 .

According to the torch lowering speed control method, control program, control system, and machining apparatus according to the present invention, when the current machining point is within a predetermined area set with reference to the previous machining point, the previous machining point Since the high-speed movement distance is increased based on the high-speed movement distance and the correction amount, the high-speed movement distance at each machining point is the highest in the Z-axis direction while suppressing the torch from interfering with the workpiece. It is possible to shorten the descent time of the torch by making it longer than the high-speed moving distance at the coordinate position (X _H, Y _H ).
Further, since the high-speed moving distance H (i) at the current machining point is determined from the high-speed moving distance H (i-1) at the (i-1) -th machining point and the correction amount B, the movement time of the torch is efficiently determined. It can be shortened. As a result, production efficiency can be improved.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a perspective view schematically showing the configuration of a processing apparatus according to an embodiment of the present invention. Reference numeral 1 indicates a processing apparatus, reference numeral 2 indicates a plasma torch (hereinafter referred to as a torch), and reference numeral 11 indicates a control apparatus. Yes. In this embodiment, the processing apparatus 1 is a plasma processing apparatus.

  The processing apparatus 1 includes a torch 2, a surface plate 3, a torch holding member 10 that holds the torch 2, a control device 11, and the torch 2 on the surface plate 3 in the X-axis direction (traveling direction) and Y-axis direction ( And a drive unit 15 that moves in the Z-axis direction (vertical direction).

The surface plate 3 is for placing a workpiece to be processed by the torch 2, and is a carriage that moves in a traveling direction (hereinafter referred to as the X-axis direction) on a rail placed in parallel to the surface plate 3. Is disposed, and a torch holding member 10 (to be described later) disposed on the carriage is movable in a transverse direction (hereinafter referred to as a Y-axis direction). The upper surface of the surface plate 3 includes an X-axis and a Y-axis. It is set as the flat surface along XY surface comprised from these.
The surface plate 3 is inevitably formed with the highest coordinate position (X _H, Y _H ) in the Z-axis direction position (height direction) on the surface on which the workpiece W is placed.

The torch 2 has an origin (standby position) in the Z-axis direction during machining, and from this origin to the reference point in the Z-axis direction when the torch 2 forms a machining point on the workpiece W and performs machining. Considering the distance, the high-speed moving distance H _{0 at} the XY coordinate position at which the torch 2 waits at the start of machining is set. Note that the coordinate position (X _0, Y ₀ ) where the torch 2 waits before starting machining and the coordinate position (X _1, Y ₁ ) where machining starts are determined by the Z-axis direction position (height direction) of the surface plate 3. Needless to say, it is not always the highest coordinate position (X _H, Y _H ).

  The torch holding member 10 holds the torch 2 and can move with the torch 2 in the X-axis direction and the Y-axis direction, and also moves the torch 2 in the Z-axis direction. Further, the torch 2 is rotatable at a desired inclination angle with respect to the vertical.

  As shown in FIG. 2, the control device 11 includes a control unit 12 and a driver 13. In this embodiment, the control device 11 has an HDD (hard disk) not shown, and the HDD has a control program. Is stored.

The control unit 12 includes an input unit (not shown), and is configured such that an NC control program (not shown) in which the operation order of the machining apparatus 1 including the torch 2 is defined can be input to the control unit 12. In the NC control program, for example, data such as the XY coordinate position of the machining point, the tilt angle of the torch 2, the moving speed, and the moving amount are described.
The control unit 12 is connected to a Z-axis direction position sensor (not shown), and the distance in the Z-axis direction from the origin to the reference point when the torch 2 descends is detected and input by the Z-axis direction position sensor. It has become so.

  The driver 13 includes an X-axis driver 13X, a Y-axis driver 13Y, and a Z-axis driver 13Z. Based on the X-axis direction control signal, the Y-axis direction control signal, and the Z-axis direction control signal output from the control unit 12, the driver 13 The axial direction drive unit 15X, the Y-axis direction drive unit 15Y, and the Z-axis direction drive unit 15Z can be driven and controlled.

  The drive unit 15 moves the cart on which the torch holding member 10 is arranged in the traveling direction (X-axis direction) and the torch holding member 10 in the transverse direction (Y-axis direction) on the cart. A Y-axis direction drive unit 15Y, and a Z-axis direction drive unit 15Z that is provided above the torch holding member 10 and moves the torch 2 in the vertical direction (Z-axis direction). The direction driving unit 15Y drives the torch holding member 10 in the X-axis direction and the Y-axis direction based on the X-axis direction control signal and the Y-axis direction control signal output from the control unit 12 to the driver 13, thereby driving the torch 2 It is moved to a predetermined XY coordinate position.

The Z-axis direction drive unit 15Z is connected to the torch 2 by a member (not shown) that can convert rotation to linear motion, such as a ball nut, and the Z-axis direction control output from the control unit 12 to the driver 13 Based on the signal, the torch 2 can be driven in the Z-axis direction to move the torch 2 to a predetermined height.
The Z-axis driver 13Z can perform high-speed movement control that moves the torch 2 at least at high speed and low-speed movement control that moves at low speed.

Next, a method for controlling the descending speed of the torch 2 according to the embodiment of the present invention will be described with reference to FIGS.
FIG. 3 is a diagram illustrating an example of a flow relating to the Z-axis direction movement control of the torch 2. In FIG. 3, the control related to the X-axis direction control and the Y-axis direction control is omitted.
1) High-speed moving distance H ₀ where the torch 2 descends by high-speed movement control, and a correction amount B (B <L ₀ )
L ₀ ; Sets the low speed movement distance at the XY coordinate position where the torch 2 waits. (Step S1)
The high-speed moving distance H ₀ is an initial high-speed moving distance at the start of machining. When the torch 2 is lowered at the highest coordinate position (X _H, Y _H ) of the surface plate 3, the torch 2 is moved to the surface plate. A distance is set in consideration of safety that can be lowered without colliding with 3.
2) Next, the coordinates (X _i, Y _i ) of the machining point are taken into the control unit 12. (Step S2)
At this time, the coordinate position (X _0, Y ₀ ) where the torch 2 stands by does not need to be particularly recognized.
3) Next, regarding the Z-axis direction movement control of the torch 2, data related to the number of machining operations (order) (i = 1) is set. (Step S3)
4) It is determined whether or not the processing number i = 1. (Step S4)
If i is not 1, the process proceeds to step S5.
If i = 1, the process proceeds to step S7 without determining whether the first machining point is the predetermined area of the XY coordinate position where the torch 2 is waiting when machining starts.

5) Whether the XY coordinates (X _i , Y _i ) of the machining point P _i to be machined at the i-th time are within a predetermined area (A _{i-1) with} respect to the XY coordinates of the machining point at the previous time ( _i−1) . Judge whether. (Step S5)
Here, whether or not the machining point (X, Y) coordinates to be machined in the i-th time is within a predetermined area (A _{i-1) with} respect to the XY coordinates of the previous (i-1) -th machining point is shown in FIG. To determine as shown in FIG.

Then, i-th machining point is a predetermined area _{(A i-1)} (hatched portion) a predetermined region when located inside of (A in as _{P i} shown in FIG. 4 _{(P i-1) i-1} ), and if it is located outside the predetermined area (A _i-1 ) of P _i like P _ia , it is determined to be outside the predetermined area (A _i-1 ). .

Further, as indicated by P _ia in FIG. 5, when the position is not within the predetermined area (A _i-1 ) of the previous processing point (P _i-1 ), the processing point (P _i-2 ) of the previous time is also displayed. Is located within a predetermined predetermined area (A _i-2 ) of the previous machining point (P _i-1 ) but not within a predetermined predetermined area (A _i-1 ) of the previous machining point (P _i-1 ). _It depends on whether or not it is located within a predetermined area (A _i-1 ) of _i-1 ).

Further, for example, as shown in FIG. 6, piercing is performed with the position where the torch 2 is lowered as the start point Ps (i−1), and then the cut groove is processed and moved to the end point Pe (i−1). In this case, the selection may be made so as to determine whether or not the _i- th machining point P _i is within the predetermined area (A _i-1 ) based on the XY coordinates of the end point Pe (i-1). In FIG. 6, (P _i ) is located within a predetermined area (A _i-1 ), and (P _ia ) is located outside the predetermined area (A _i-1 ).

6) Next, when the machining point in the i (≧ 2) -th machining is within a predetermined area of the machining point of the previous machining,
i-th high-speed moving distance H _i = H _i−1 + L _i−1 −B
It is said. (Step S6)
here,
(I-1) High-speed moving distance H _{i-1 for the first time}
(I-1) Low-speed transfer distance L _{i-1 for the first time}
7) Next, when i = 1, and when the machining point in the i-th machining is not within the predetermined area (A _i-1 ) of the machining point of the last (i-1) machining,
High speed travel distance H _i = H ₀
It is said. (Step S7)
8) The torch 2 descends at a high speed based on the set high _- speed moving distances H _i−1 , H _i , H _{i + 1} and then descends at a low speed to execute plasma processing such as piercing. (Step S8)
9) When lowering the torch 2 in step S8, to detect the low-speed movement distance L _i of i-th by the Z-axis direction sensor (not shown), and stores in a memory (not shown) low-speed movement distance L _i. (Step S9)
10) When the end of cutting is not instructed, the process proceeds to step 11 and the processing is continued, and when the end of cutting is instructed, the processing is ended. (Step S10)

  Next, with reference to FIGS. 7 to 9, the high speed moving distance and the low speed moving distance when the torch 2 descends will be described. 7 shows the case of the first and second machining, FIG. 8 shows the case where the XY coordinates of the machining point after the movement are within a predetermined area of the machining point before the movement, and FIG. 9 shows the machining point P (i after the movement. FIG. 3 is a diagram for explaining the relationship between the high-speed movement distance and the low-speed movement distance in the Z-axis direction of the torch 2 when the XY coordinates of -1) do not belong to a predetermined region of a processing point P (i-2) (not shown) before movement. is there.

The high-speed / low-speed switching point at P ₀ shown in FIGS. 7 to 9 is that the torch 2 is moved from the high speed when the torch 2 is temporarily lowered at the XY coordinate position (X _0, Y ₀ ) at the start of machining. The switching height for switching to low speed is shown, which is located at a distance of H ₀ downward from the origin in the height direction.
Further, when the total movement distance (from the origin to the reference point) at the XY coordinate position where the torch 2 is waiting is T ₀ and the high-speed movement distance is H ₀ , as shown in FIG.
Total travel distance T ₀ = high speed travel distance H ₀ + low speed travel distance L ₀ at the XY coordinate position where the torch 2 stands by.

Further, the high-speed moving distance H1 in the _first machining is as shown in FIG. 7B, and it is determined whether or not the machining point is within a predetermined region of the XY coordinate position waiting when the machining of the torch 2 is started. Without moving, the high-speed moving distance H 1 at the first machining point P ₁ = high-speed moving distance H ₀
It is said.

Further, if the machining point P ₂ in the second processing is within a predetermined region of the first processing point (A _1), the total distance traveled T _2, high-speed moving distance H _2, the low-speed movement distance L ₂ is, FIG. 7 is as shown (c), the low-speed movement distance L ₂ is the distance corrected upward as the correction amount B with respect to the low-speed movement distance L ₁ detected at the first processing point.

Figure 8 (a), (b) , (c) is, (i-1) -th machining point _{P i-1} is (i-2) th predetermined region of the machining point _{P i-2 (A i-} 2 ), I, (i + 1) -th machining points P _i , P _{i + 1} are (i-1), i-th machining points P _i-1 , P _i of predetermined areas (A _i-1 ), (A when in _i) in a machining point _{P i-1} of the i-1 -th machining, i-th and the machining point _{P i} in the processing, i + 1 th processing point in the processing of _{P i + 1} of the high-speed moving distance _{H i- 1} , H _i , H _{i + 1} , and low-speed moving distances L _i−1 , L _i , L _{i + 1} are shown.

Figure 9 (a), (b) , (c) is, (i-1) -th machining point _{P i-1} is (i-2) th predetermined region of the machining point _{P i-2 (A i-} 2 ), I, (i + 1) -th machining points P _i , P _{i + 1} are (i-1), i-th machining points P _i-1 , P _i of predetermined areas (A _i-1 ), (A when in _i) in a machining point _{P i-1} of the i-1 -th machining, i-th and the machining point _{P i} in the processing, i + 1 th processing point in the processing of _{P i + 1} of the high-speed moving distance _{H i- 1} , H _i , H _{i + 1} , and low-speed moving distances L _i−1 , L _i , L _{i + 1} are shown.
In this case, the high _- speed movement distance H _i-1 = H _{0 at} the (i-1) -th processing point P _i-1 .
And
Fast moving distance _{H i} in the i-th machining point _{P i}
= High _- speed moving distance H _{i-1 of} machining point P _i-1 + Low _- speed moving distance L _i-1 -B of machining point P _i-1
i + 1 th of the high-speed movement distance in the machining point _{P i H i}
= Slow moving distance of the high-speed moving distance _{H i} + machining point _{P i} of the machining point _{P i L} i -B
It is said.

According to the flowchart (control program) of the above embodiment, when i related to the number of machining is 2 or more and the machining point P _i is a predetermined area (A _i-1 ) of the previous machining point P _i-1. , while suppressing the torch 2 from interfering with the surface plate 3, the total movement time when the torch 2 is lowered at a low speed from the origin of the Z-axis direction to a high-speed moving distance H _i only descends at high speed then the reference point, can torch 2 to shorten the Z-axis direction of the origin from the high-speed moving distance H ₀ only fast by the difference in total travel time when lowered at a low speed and thereafter until the reference point lowering torch 2 travel time (falling time) .
The time ΔT to be shortened is as follows. When v is a speed in a low speed movement and V is a speed in a high speed movement,
ΔT = (H _i −H ₀ ) × (1 / v) − (H _i −H ₀ ) × (1 / V)
Shortened.

  The present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the spirit of the invention. For example, in the above-described embodiment, the torch 2 is Although the case of the torch used in the plasma processing apparatus has been described, the present invention is not limited to plasma processing, and may be used for a torch used for laser processing or gas cutting.

Moreover, in the said embodiment, when the control program which controls the descending speed of the torch 2 exists in the predetermined area | region (A _i-1 ) of the (i-1) -th processing point P _i-1 , the high-speed moving distance In the calculation of H _i, the case where the high speed movement distance H _i = H _i−1 + L _i−1 −B has been described, but the (i−1) -th high speed movement distance H _i−1 or the low speed movement distance L You may use the correction amount by another relative parameter | index or calculation method with respect to _i-1 .

  In the above embodiment, the case where the control program for controlling the descending speed of the torch 2 is stored in the HDD of the control device 11 in advance has been described. However, the control program is recorded on a readable recording medium, It is also possible to cause the operation according to the above-described embodiment to be performed by causing the control unit 12 to read and execute the control program recorded on the recording medium. Here, the “readable recording medium” means a portable medium such as a flexible disk, a magneto-optical disk, a ROM, a volatile memory (RAM), a CD-ROM, or a storage device such as a hard disk built in the control system 20. I mean.

  Moreover, in the said embodiment, although the processing apparatus 1 to which the torch 2 moves with respect to the fixed surface plate 3 was demonstrated, the surface plate 3 moves or both the surface plate 3 and the torch 2 can move. Needless to say, the present invention can be applied to various processing apparatuses.

It is a perspective view showing a schematic structure of a processing device concerning one embodiment of the present invention. It is a figure which shows schematic structure of the control apparatus which concerns on one Embodiment of this invention. It is a figure which shows the flow of the control program which concerns on one Embodiment of this invention. It is a figure explaining whether the processing point in the i-th processing which concerns on one Embodiment of this invention is a predetermined area | region of the i-1th processing point. It is a figure explaining the predetermined area | region of the process point of the i-1th time concerning one Embodiment of this invention. It is a figure explaining the predetermined | prescribed area | region when the process point of the i-1th time moves concerning one Embodiment of this invention. Machining point P _1, fast moving distance in the Z-axis direction of the torch in P _2, is a diagram illustrating an example of the relationship between the low-speed travel, and the correction amount B. It is a figure explaining the relationship between the high speed movement distance of the Z axis | shaft direction of a torch, the low speed movement distance, and the correction amount B in case the process point _Pi-1 exists in the area | region of _Pi-2 . It is a figure explaining the relationship between the high speed movement distance of the Z axis | shaft direction of a torch, the low speed movement distance, and the correction amount B in case the process point _Pi-1 is outside the area | region of _Pi-2 .

Explanation of symbols

1 machining apparatus 2 torch 3 platen 12 control unit 13 drivers 15X X-axis direction driving section 15Y Y-axis direction driving section 15Z Z axis direction drive unit _{A i-1, A i} predetermined area _{H 0, H i-2,} H i ₋₁ , H _i , H _{i + 1} High-speed moving distance L _i-2 , L _i−1 , L _i , L _{i + 1} Low-speed moving distance T _i-2 , T _i−1 , T _i , T _{i + 1} Total moving distance B Correction amount

Claims (4)

A torch that is formed along the XY plane and is movable relative to a surface plate on which the workpiece is placed, and that forms a machining point on the workpiece and processes the workpiece. A torch lowering speed control method for switching between a high speed and a low speed between an origin at which the torch waits in a perpendicular Z-axis direction and a reference point at which the torch forms the machining point.
When the XY coordinates of the current machining point are within a predetermined area set with reference to the XY coordinates of the previous machining point,
The torch is moved at a high speed longer than the high-speed moving distance at the coordinate position (X _H, Y _H ) at which the position of the surface plate in the Z-axis direction is the highest at the current machining point ,
And the high-speed moving distance in the current descent is a distance obtained by correcting the moving distance from the origin measured in the previous machining to the reference point in the previous machining by a predetermined amount. Control method. A surface plate that is formed along the XY plane and on which a workpiece can be placed;
A torch that is disposed above the surface plate and forms the machining point at the intersection of the torch axis and the workpiece, and processes the workpiece;
An X-axis direction drive unit that relatively moves the torch and the surface plate in the X-axis direction;
A Y-axis direction drive unit that relatively moves the torch and the surface plate in the Y-axis direction;
A Z-axis direction drive unit configured to move the torch in the Z-axis direction orthogonal to the XY plane and to control the moving speed of the torch at least at a high speed and a low speed;
A controller that drives the X-axis direction drive unit, the Y-axis direction drive unit, and the Z-axis direction drive unit;
A distance detecting means for detecting a distance in the Z-axis direction from an origin at which the torch waits to a reference point at which the torch forms the machining point; and a control program for controlling a descending speed of the torch in a machining apparatus. And
The high-speed moving distance H _i of the torch at the time of i (natural number) processing,
If i = 1,
H _i = H ₀
In i ≧ 2, when the XY coordinates of the machining point to be processed at the i-th time are within a predetermined area set with reference to the XY coordinates of the machining point at the i-1th machining,
H _i > H ₀
And
H (i) = H (i-1) + L (i-1) -B
H ₀ : High-speed movement distance at the start of machining
L (i-1): Distance traveled by the torch at low speed in the (i-1) -th processing.
B: A control program characterized by a preset correction value . A control system comprising the control program according to claim 2 . A processing apparatus comprising the control system according to claim 3 .

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