JP2013078783A - Plasma cutting monitoring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a plasma cutting monitoring device capable of monitoring a cutting state by comparing an outer diameter diameter and a cutting groove width of a current plasma plasma and a cutting groove width over time. It is said.
SOLUTION: An image analysis unit 19 that calculates an outer diameter Dp of a plasma arc 18 and a groove width Wa of a cutting groove 6 from imaged image information captured by a CMOS camera 8 and an image analysis unit 19 The comparison unit 20 that compares the outer diameter Dp of each plasma arc 18 stored in the storage unit 22 with the present and the groove width Wa of the cutting groove 6 is compared by the comparison unit 20. The difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 at the actual cutting time between the present and the foremost is not within a preset allowable range. A cutting state determination unit 14 that determines that an abnormality has occurred in the cutting operation of the plasma cutting device 2.
[Selection] Figure 1

Description

  The present invention relates to a plasma cutting monitoring device that monitors a cutting state of a plasma cutting device that uses a plasma cutting torch to melt and remove a part of a material to be cut.

  Conventionally, a steel plate, a steel pipe, a stainless steel plate, a non-ferrous metal plate, or the like is used as a material to be cut, and the material to be cut is cut using a plasma cutting torch.

  As a cutting apparatus equipped with a plasma cutting torch, an NC cutting apparatus that controls the movement path of the plasma cutting torch by a numerical control (NC) apparatus, and the movement path of the plasma cutting torch by optically following the figure drawn in the drawing Profiling cutting devices to be controlled, semi-automatic cutting devices that run on rails arranged in advance along the line to be cut, etc. are provided, depending on conditions such as the shape of the material to be cut and the shape of the product to be cut The most appropriate one is selected.

  When cutting the material to be cut using the above cutting device and plasma cutting torch, the energy distribution of the plasma arc becomes non-uniform during the cutting due to electrode consumption, etc., and the cutting width may change or become uncut. There is.

  Conventionally, when a non-cutting state is entered, the cutting device is visually stopped and recovered, and if the change in cutting width can be visually determined, the cutting device is stopped and recovered. The arc emits a flash that cannot be seen directly, and the gap between the tip of the plasma cutting torch and the material to be cut is relatively small. In such an environment, it was often impossible to determine until the product was completed.

  Therefore, in Patent Document 1, the cutting width of the cutting groove is imaged and monitored by a CCD (Charge Coupled Device) camera, and in Patent Document 2, an arc between the plasma torch and the material to be cut is detected by the CCD camera. Is observed to monitor the arc length, arc bend, diameter dimension (width dimension), etc., and in Patent Document 3, the cutting part is photographed and monitored with an optical camera to determine the cutting state. .

JP 2002-331383 A JP-A-11-156551 Japanese Patent Laid-Open No. 11-129083

  However, in the technique of the above-mentioned patent document 1, since the CCD camera is rotated following the change in the traveling direction of the cutting torch, the cutting groove can be photographed from directly behind the cutting torch. In addition to the need for a swiveling device having a complicated mechanism, the time until the CCD camera is swung to a predetermined angle corresponding to the traveling direction of the cutting torch cannot confirm the precise cutting groove width, and the cutting torch proceeds. In order to accurately calculate the cutting groove width in consideration of the change in direction and the change in the turning angle of the CCD camera following the change, there is a problem that complicated calculation is required.

  In the technique of Patent Document 2, the change of the plasma arc can be confirmed, but since the cutting groove width is not directly monitored, the change of the cutting groove width cannot be directly confirmed. In addition, since only the arc between the plasma torch and the material to be cut is observed, the imaging direction of the CCD camera is not changed following the change in the traveling direction of the cutting torch.

  In the technique of Patent Document 3, the macro camera and the micro camera are fixed to the cutting torch, and the imaging direction of the camera is not changed following the change in the traveling direction of the cutting torch.

  Further, Patent Documents 1 to 3 do not compare the outer diameter and the cutting groove width of the plasma arc between the present and the forefront over time, but the difference between the outer diameter of the plasma arc and the cutting groove width and the plasma arc. It was not possible to monitor the cutting state based on the positional relationship between the shaft core and the center of the cutting groove.

  The present invention solves the above-mentioned problems, and the object of the present invention is to compare the outer diameter and cutting groove width of the plasma arc between the present and the last over time, or the outer diameter and cutting of the plasma arc. It is an object of the present invention to provide a plasma cutting monitoring device capable of monitoring the cutting state based on the difference between the groove width and the positional relationship between the axis of the plasma arc and the center of the cutting groove.

  In order to achieve the above object, the first configuration of the plasma cutting monitoring device according to the present invention is to cut the cutting state of the plasma cutting device that uses a plasma cutting torch to melt and eliminate part of the material to be cut. A plasma cutting monitoring device for monitoring, imaging means for imaging a plasma arc emitted from a tip of the plasma cutting torch being cut toward the workpiece, and a cutting groove in the vicinity of the plasma arc; The calculation means for calculating the outer diameter diameter of the plasma arc and the groove width of the cutting groove from the captured image information captured by the imaging means, and the calculation means from the captured image information captured by the imaging means The storage means for storing the calculated outer diameter information of the plasma arc and the groove width information of the cutting groove in chronological order, and the calculation means The outer diameter diameter of the plasma arc at the time of actual cutting, the groove width of the cutting groove, the outer diameter diameter of the plasma arc at the time of the last actual cutting stored in the storage means, and the cutting groove A comparison means for comparing the groove width of the plasma arc, the outer diameter diameter of the plasma arc at the time of the current actual cutting, the groove width of the cutting groove, and at the time of the last actual cutting, compared by the comparison means When any difference between the outer diameter of the plasma arc and the groove width of the cutting groove is out of a preset allowable range, it is determined that an abnormality has occurred in the cutting operation of the plasma cutting device. And determining means.

  According to a second configuration of the plasma cutting monitoring apparatus of the present invention, in the first configuration, the storage means is configured to store the plasma arc outside the plasma arc set in advance corresponding to the cutting conditions of the material to be cut. The tolerance value information of each of the diameter and the groove width of the cutting groove is stored, and the comparison means calculates the outer diameter diameter of the plasma arc at the time of actual cutting calculated by the calculation means, Allowable values of the groove width of the cutting groove, the outer diameter of the plasma arc set in advance corresponding to the cutting conditions of the material to be cut stored in the storage means, and the groove width of the cutting groove The outer diameter diameter of the plasma arc at the time of actual actual cutting and the groove width of the cutting groove are compared in advance corresponding to the cutting conditions of the material to be cut. The outer diameter of the set plasma arc And the diameter, in the case where any one of the respective tolerance range of the groove width of the cutting groove is out, the determining means may determine that an abnormality has occurred in the cutting operation of the plasma cutting apparatus.

  The third configuration of the plasma cutting monitoring device according to the present invention is a plasma cutting monitoring for monitoring a cutting state of a plasma cutting device that uses a plasma cutting torch to melt and eliminate a part of the material to be cut. An apparatus for imaging a plasma arc emitted from a tip of the plasma cutting torch being cut toward the workpiece and a cutting groove in the vicinity of the plasma arc, and imaging by the imaging unit The outer diameter diameter of the plasma arc and the groove width of the cutting groove are calculated from the captured image information, and one half of the difference between the outer diameter diameter of the plasma arc and the groove width of the cutting groove. And calculating the spacing between the outer periphery of the plasma arc and the groove edge of the cutting groove on the side close to the outer periphery, the outer diameter diameter of the plasma arc, the groove width of the cutting groove, 2 minutes difference between A calculating means for calculating a difference between a value of 1 and a spacing between the outer periphery of the plasma arc and the groove edge of the cutting groove on the side close to the outer periphery; and captured image information captured by the imaging means The value of one half of the difference between the outer diameter diameter of the plasma arc calculated by the calculation means and the groove width of the cutting groove, the outer periphery of the plasma arc, and the cutting on the side close to the outer periphery Storage means for storing difference information between the spacing distances of the grooves and the groove edges in chronological order, the outer diameter diameter of the plasma arc at the time of actual cutting calculated by the calculation means, and the grooves of the cutting grooves The difference between the half value of the difference between the width, the outer circumference of the plasma arc, and the spacing between the groove edge of the cutting groove on the side close to the outer circumference, and the forefront stored in the storage means The outer diameter of the plasma arc at the time of actual cutting and the cutting A comparison means for comparing a value of a half of the difference between the groove width of the groove and a difference between an outer periphery of the plasma arc and a separation interval between the groove edge of the cutting groove on the side close to the outer periphery; The outer diameter diameter of the plasma arc at the time of actual cutting and the half of the difference between the groove width of the cutting groove, the outer circumference of the plasma arc, compared by the comparison means, The difference between the separation distance from the groove edge of the cutting groove on the side close to the outer periphery, the difference between the outer diameter diameter of the plasma arc at the time of the last actual cutting, and the groove width of the cutting groove When the difference between the value of 1 and the separation interval between the outer periphery of the plasma arc and the groove edge of the cutting groove on the side close to the outer periphery deviates from a preset allowable range, And determining means for determining that an abnormality has occurred in the cutting operation.

  Further, a fourth configuration of the plasma cutting monitoring apparatus according to the present invention is that, in the third configuration, the storage means stores an outside of the plasma arc set in advance corresponding to the cutting condition of the material to be cut. The difference between the diameter and the half of the difference between the groove width of the cutting groove and the separation distance between the outer periphery of the plasma arc and the groove edge of the cutting groove on the side close to the outer periphery. Permissible value information is stored, and the comparison means is a value that is half the difference between the outer diameter diameter of the plasma arc at the time of actual cutting calculated by the calculation means and the groove width of the cutting groove, and The difference between the outer circumference of the plasma arc and the separation interval between the groove edge of the cutting groove on the side close to the outer circumference and the cutting conditions of the workpiece to be stored stored in the storage means are preset. 2 minutes of the difference between the outer diameter of the plasma arc and the groove width of the cutting groove Comparing the value of 1 with the allowable value of the difference between the outer circumference of the plasma arc and the spacing between the groove edge of the cutting groove on the side close to the outer circumference and compared by the comparison means, The value of one half of the difference between the outer diameter diameter of the plasma arc at the time of cutting and the groove width of the cutting groove, the outer periphery of the plasma arc, and the groove edge of the cutting groove on the side close to the outer periphery Is a half value of the difference between the outer diameter diameter of the plasma arc set in advance corresponding to the cutting condition of the material to be cut and the groove width of the cutting groove, And the determination means is configured to perform a cutting operation of the plasma cutting device when it is out of an allowable range of a difference between the outer periphery of the plasma arc and a separation interval between the groove edge of the cutting groove on the side close to the outer periphery. It is characterized by determining that an abnormality has occurred.

  According to a fifth configuration of the plasma cutting monitoring device of the present invention, in the first to fourth configurations, the imaging means is fixed to the plasma cutting device in the vicinity of the plasma cutting torch, and the calculating means Is the angle of deviation between the cutting progress direction of the plasma cutting torch and the linear direction connecting the plasma arc and the imaging means, and Wi is the groove width of the cutting groove imaged by the imaging means. The groove width Wi of the cutting groove imaged by the imaging means is corrected to the actual groove width Wa of the cutting groove by the formula of Wa = Wi × | cos θ | And

  According to the first configuration of the plasma cutting monitoring device according to the present invention, the outer diameter diameter of the plasma arc at the time of actual cutting and the groove width of the cutting groove based on the captured image information captured by the imaging unit When the difference between the outer diameter diameter of the plasma arc at the time of the last actual cutting and the groove width of the cutting groove is out of the preset allowable range, the cutting operation of the plasma cutting device is performed. It can be determined that an abnormality has occurred. As a result, even when used outside the standard specification, monitoring can be performed based on the outer diameter diameter of the plasma arc and the groove width of the cutting groove at the time of the last successful cutting.

  In addition, when one imaging means is fixed to the plasma cutting apparatus in the vicinity of the plasma cutting torch, the traveling direction of the plasma cutting torch is in a direction perpendicular to the straight line connecting the plasma cutting torch and the imaging means. If it changes, the groove width of the cutting groove cannot be imaged. In that case, by monitoring the outer diameter of the plasma arc, it is possible to monitor continuously regardless of the traveling direction of the plasma cutting torch.

  According to the second configuration of the plasma cutting monitoring device according to the present invention, the outer diameter diameter of the plasma arc at the current actual cutting time and the groove width of the cutting groove based on the captured image information captured by the imaging means And the cutting operation of the plasma cutting device when any of the outer diameter diameter of the plasma arc and the groove width of the cutting groove set in advance corresponding to the cutting conditions of the material to be cut falls outside the permissible ranges. It can be determined that an abnormality has occurred. Thus, it is only necessary to monitor the outer diameter diameter of the plasma arc at the time of the last cutting, the outer diameter diameter of the plasma arc at the current actual cutting, and the groove width of the cutting groove on the basis of the groove width of the cutting groove. However, the standard may gradually shift, but the actual actual diameter based on the preset outer diameter of the plasma arc corresponding to the cutting conditions of the material to be cut and the groove width of the cutting groove. The outer diameter of the plasma arc during cutting and the groove width of the cutting groove can be monitored.

  According to the third configuration of the plasma cutting monitoring device according to the present invention, the outer diameter diameter of the plasma arc at the current actual cutting time and the groove width of the cutting groove based on the captured image information captured by the imaging means And the difference between the outer circumference of the plasma arc and the spacing between the groove edge of the cutting groove on the side close to the outer circumference and the plasma arc at the time of the last actual cutting The difference between the outer diameter and the half value of the difference between the groove width of the cutting groove and the separation distance between the outer periphery of the plasma arc and the groove edge of the cutting groove on the side close to the outer periphery, When one of the values falls outside the preset allowable range, it can be determined that an abnormality has occurred in the cutting operation of the plasma cutting device. Thus, even when used outside the standard specification, the plasma arc outer diameter at the time of the last successful cutting and the value of the difference between the groove width of the cutting groove and the plasma Monitoring can be performed based on the difference between the outer circumference of the arc and the spacing between the groove edge of the cutting groove on the side close to the outer circumference.

  According to the fourth configuration of the plasma cutting monitoring apparatus according to the present invention, the outer diameter diameter of the plasma arc at the time of actual cutting and the groove width of the cutting groove based on the captured image information captured by the imaging unit The difference between the half value of the difference between the outer circumference of the plasma arc and the spacing between the groove edge of the cutting groove on the side close to the outer circumference corresponds to the cutting condition of the material to be cut. The value of a half of the difference between the preset outer diameter of the plasma arc and the groove width of the cutting groove, the outer periphery of the plasma arc, and the groove edge of the cutting groove on the side close to the outer periphery It can be determined that an abnormality has occurred in the cutting operation of the plasma cutting apparatus when the difference from the difference with the separation interval is outside the allowable range. As a result, the outer diameter of the plasma arc at the time of the last cutting and the value of the difference between the groove width of the cutting groove, the outer circumference of the plasma arc, and the cutting groove on the side close to the outer circumference Based on the difference between the separation distance from the groove edge and the current outer diameter of the plasma arc at the time of actual cutting, and the difference between the groove width of the cutting groove and the outer circumference of the plasma arc, The standard may be shifted gradually only by monitoring the difference between the gap between the cutting groove on the side close to the outer circumference and the edge of the cutting groove. The half value of the difference between the set outer diameter of the plasma arc and the groove width of the cutting groove, and the distance between the outer periphery of the plasma arc and the groove edge of the cutting groove on the side close to the outer periphery One half of the difference between the outer diameter of the plasma arc at the time of actual cutting and the groove width of the cutting groove on the basis of the difference from the interval Value, and an outer periphery of the plasma arc, the difference between the separation distance between the groove edge of the cutting groove of the side close to the 該Gaishu monitor.

  According to the fifth configuration of the plasma cutting monitoring device of the present invention, the groove width Wi of the cutting groove imaged by the imaging unit corresponding to the change in the traveling direction of the plasma cutting torch and the optical axis angle of the imaging unit is actually calculated. Even when a single imaging means is fixedly provided in the plasma cutting device, the traveling direction of the plasma cutting torch is the same as that of the plasma cutting torch. The actual cutting groove is obtained by simple calculation based on the groove width Wi of the cutting groove picked up by the image pickup means, except that the groove width of the cutting groove cannot be picked up by changing in a direction orthogonal to the straight line connecting the image pickup means. The groove width Wa can be obtained accurately.

It is a perspective explanatory view showing the configuration of the plasma cutting monitoring device according to the present invention. It is perspective explanatory drawing which shows a mode that a plasma arc and a cutting groove are imaged simultaneously by an imaging means. It is a block diagram which shows the structure of the control system of the plasma cutting monitoring apparatus which concerns on this invention. (A), (b) explains how the groove width Wi of the cutting groove imaged by the imaging means is corrected to the actual groove width Wa of the cutting groove in the horizontal direction in response to a change in the traveling direction of the plasma cutting torch. It is a figure to do. (A) is a figure which shows an example of the captured image of the plasma arc and cutting groove which were imaged by the imaging means, (b) is a line drawing explaining the captured image of (a). (A)-(d) is a figure explaining a mode that the space | interval of the outer periphery of the plasma arc imaged with the imaging means and the edge of a cutting groove is measured, and the deviation of this plasma arc is measured.

  An embodiment of the plasma cutting monitoring apparatus according to the present invention will be specifically described with reference to the drawings.

  First, the structure of 1st Embodiment of the plasma cutting | disconnection monitoring apparatus 1 based on this invention is demonstrated using FIGS. 1 to 5, reference numeral 1 denotes a cutting operation state of a plasma cutting apparatus 2 that uses a plasma cutting torch 5 to melt and eliminate a part of a material to be cut 10 such as a steel plate, a stainless steel plate, and a non-ferrous metal plate. Is a plasma cutting monitoring device 1 for monitoring

  The plasma cutting device 2 includes an NC cutting device that controls movement and operation of the plasma cutting torch 5 by a numerical control (NC) device, and a scanning cutting device that moves the plasma cutting torch 5 by optically copying a previously drawn figure. It is possible to apply to.

  In this embodiment, a case where an NC cutting device is used will be described. In the plasma cutting apparatus 2 shown in FIG. 1, a traveling carriage 12 is placed on a pair of rails 11 laid in parallel, and a transverse carriage 3 is mounted on the traveling carriage 12 in a direction perpendicular to the rails 11. .

  A plasma cutting torch 5 that moves up and down via a lifting device 4 is attached to the traversing carriage 3. In the vicinity of the plasma cutting torch 5, the plasma cutting device 2 includes a plasma arc 18 emitted from the tip of the plasma cutting torch 5 being cut toward the workpiece 10 and a cutting groove 6 in the vicinity of the plasma arc 18. A single CMOS (Complementary Metal Oxide Semiconductor) image sensing camera (hereinafter simply referred to as “CMOS camera”) 8 serving as an imaging means for simultaneously imaging is fixed via a support member 7.

  A CMOS image sensor (Complementary Metal Oxide Semiconductor Image Sensor) mounted on the CMOS camera 8 is an IC (Integrated Circuit) that includes a photodiode that converts light into an electrical signal and a plurality of CMOS transistors. For example, an Orca (registered trademark) series CMOS camera 8 equipped with a chipset consisting of a CMOS image sensor manufactured by Pixim and an image processor can be applied.

  Such a CMOS camera 8 employs a multi-sampling method in which each pixel samples with an optimal exposure time according to the brightness of the subject. In the conventional CCD camera, sampling was performed once or twice / pixel (@ 1/30 sec). However, in the CMOS camera 8 of the present embodiment, for example, 144 times / pixel every frame (@ 1/60 sec). Can be sampled. Further, the exposure is calculated from two different slopes of a short exposure time in a bright place and a long exposure time in a dark place, thereby enabling reduction of fixed pattern noise (FPN). In this way, intense arc plasma light such as the plasma arc 18 is reduced by a wide dynamic range (120 dB) that can express the gradation between the dark part and the bright part in detail, as shown in FIG. In addition, the plasma arc 18 emitted from the tip of the plasma cutting torch 5 being cut toward the workpiece 10 and the cutting groove 6 in the vicinity of the plasma arc 18 can be clearly imaged simultaneously.

  Then, as shown in FIG. 2, the plasma arc 18 emitted from the tip of the plasma cutting torch 5 being cut by the CMOS camera 8 toward the workpiece 10 and the cutting groove 6 near the plasma arc 18 are simultaneously formed. An image analysis unit that takes an image, processes the captured image, and calculates the outer diameter Dp of the actual plasma arc 18 and the groove width Wa of the cutting groove 6 from the captured image information captured by the CMOS camera 8 Calculated according to 19.

  Note that the CMOS camera 8 is provided with an illumination device or the like for irradiating the material to be cut 10 with light to make a captured image of the groove width Wa of the cutting groove 6 clear. In the figure, reference numeral 17 denotes an imaging area by the CMOS camera 8.

  The traveling carriage 12 is driven by a traveling motor 12 a and travels in a traveling direction e along the rail 11, and the traversing carriage 3 is driven by the transverse motor 3 a and traverses in a transverse direction f that is perpendicular to the rail 11. . In addition, the plasma cutting torch 5 is driven by an elevating motor 4a and moves up and down.

  Each of the motors 3a, 4a, 12a is controlled by an NC (Numerical Control) device incorporated in a control panel 9 provided in the traveling carriage 12. The control panel 9 incorporates a controller 15 of the plasma cutting monitoring apparatus 1 shown in FIG.

  In the plasma cutting device 2 configured as described above, information on the shape to be cut from the material to be cut 10 is stored in the storage unit 22 of the NC device incorporated in the control panel 9, and the traveling motor 12a and traversing are performed according to this shape information. By driving and controlling the motor 3a, the plasma cutting torch 5 can be moved in a single stroke including a curve, and the plasma cutting torch 5 is operated in the moving process, so It is possible to cut the figure.

  In this embodiment, a commercially available CMOS camera 8 is used, and the dimensional analysis ability is 0 in order to measure the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 of the workpiece 10. It is set to be 1mm.

  In the present embodiment, the CMOS camera 8 is integrally attached to the support member 7 provided on the traversing carriage 3 together with the lighting device and the like. In other words, the CMOS camera 8 and the illumination device have a preset value for the height of the material 10 to be cut by the plasma cutting torch 5 and the horizontal distance from the plasma cutting torch 5, and the CMOS camera 8. The directional angle of the optical axis 8a of the CMOS camera 8 is set to a predetermined height when the illumination device or the like and the CMOS camera 8 are set in advance. The angle is set such that it can intersect with the image in the vicinity of the rear of the plasma cutting torch 5 of the cutting groove 6 formed in FIG.

  Next, the configuration of the control system of the plasma cutting monitoring apparatus 1 will be described with reference to FIG. In FIG. 3, the CMOS camera 8 includes an image of the outer diameter Dp of the plasma arc 18 emitted from the tip of the plasma cutting torch 5 that is cutting the workpiece 10 toward the workpiece 10 and the plasma arc 18. And has a function of capturing an image of the groove width Wa of the cutting groove 6 formed in the vicinity of the image, and transmits the captured image information (image signal) to the image analysis unit 19 serving as calculation means.

  The image analysis unit 19 binarizes or multi-values the transmitted image signal, and outputs signals corresponding to the image of the outer diameter Dp of the plasma arc 18 and the image of the groove width Wa of the cutting groove 6. The extracted image signal of the extracted image is transmitted to the comparison unit 20 as a comparison unit and the image display unit 21 as a display unit.

  An input unit 13 serving as an input means is a plasma arc 18 set in advance corresponding to the cutting conditions of various materials to be cut 10 such as the type and thickness of the material to be cut 10 or the type of the plasma cutting torch 5. The reference outer diameter Dp and the groove width Wa of the reference cutting groove 6 and their permissible tolerances, or the reference outer diameter Dp and the groove width Wa of the reference cutting groove 6 are predetermined. The allowable outside diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 are input using a keyboard and other various input devices in consideration of the allowable range of the above. When the groove width Wa of the reference cutting groove 6 and the allowable range are input, the allowable outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 may be automatically calculated. The allowable outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 may be directly input.

  Here, as a specific example of the allowable range of the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6, if it is set to a desired value according to the cutting quality performance of the plasma cutting torch 5 and the cutting application. For example, the allowable ranges of the outer diameter Dp of the plasma arc 18 at the time of actual actual cutting and the groove width Wa of the cutting groove 6 are outside of the plasma arc 18 at the time of the last actual cutting that is a predetermined time later from the present. What is necessary is to expect about ± 20% of the diameter Dp and the groove width Wa of the cutting groove 6.

  For example, when the plasma arc current of the plasma cutting torch 5 is 400 A, when the outer diameter Dp of the plasma arc 18 is set to 4 mm and the groove width Wa of the cutting groove 6 is set to 5 mm, the outer diameter of the plasma arc 18 is set. The allowable range of the diameter Dp is set to ± 25% as a standard, and ± 15% when accuracy is important. The allowable range of the groove width Wa of the cutting groove 6 is set to ± 20% as a standard, and ± 10% when accuracy is important.

  At the start of cutting, data of the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 at the time of the first actual cutting are stored in the storage unit 22 as initial values, and data scanning is performed at any time during cutting. The data of the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 at the time of actual cutting are updated as needed and stored in the storage unit 22. Then, the outer diameter Dp of the forefront plasma arc 18 and the groove width Wa of the cutting groove 6 that are traced back for a predetermined time from the present time, and the outer diameter Dp of the latest plasma arc 18 and the groove width Wa of the cutting groove 6 that are current. The comparison unit 20 compares and determines the data. If the predetermined allowable range is not satisfied, the cutting state determination unit 14 determines that an abnormality has occurred in the cutting operation of the plasma cutting apparatus 2. After it is determined that an abnormality has occurred in the cutting operation of the plasma cutting device 2, the outer diameter of the plasma arc 18 at the time of actual cutting is newly started after replacement of the electrode and nozzle provided at the tip of the plasma cutting torch 5 The data of the diameter Dp and the groove width Wa of the cutting groove 6 are stored in the storage unit 22 as initial values and updated as needed, so that the cutting operation of the plasma cutting apparatus 2 can be continuously monitored.

  Further, the allowable ranges of the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 at the time of actual actual cutting are the reference of the plasma arc 18 set in advance corresponding to the cutting conditions of the material 10 to be cut. The outer diameter Dp and the groove width Wa of the reference cutting groove 6 may be expected to be about ± 20%. In this case, it is configured such that the allowable range can be appropriately changed by an operator in consideration of quality and cost. The outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 are determined by the cutting speed of the plasma cutting device 2 and a gas such as an inert gas or oxygen gas injected as an assist gas or a combustion gas to the outer periphery of the plasma arc 18. Since it varies depending on the flow rate, it is difficult to provide an allowable range under operating conditions other than standard specifications. In order to cope with this, the automatic input and the forced input within the allowable range can be appropriately selected.

  An error on the captured image when the CMOS camera 8 cannot capture the image directly in front of the cutting groove 6 and is imaged from an oblique direction is corrected as follows. As shown in FIGS. 4A and 4B, the image analysis unit 19 includes a cutting progress direction a of the plasma cutting torch 5 and an optical axis 8 a that is a linear direction connecting the plasma arc 18 and the CMOS camera 8. When the angle of deviation in the horizontal direction is θ, the groove width of the cutting groove 6 imaged by the CMOS camera 8 is Wi, and the groove width of the actual cutting groove is Wa, the calculation formula is Wa = Wi × | cos θ | The groove width Wi of the cutting groove 6 imaged by the CMOS camera 8 is corrected to the actual groove width Wa of the cutting groove 6.

  As shown in FIGS. 4A and 4B, the image analysis unit 19 has an optical axis 8 a which is a cutting direction a of the plasma cutting torch 5 and a linear direction connecting the plasma arc 18 and the CMOS camera 8. , And a straight line connecting the CMOS camera 8 with a point where the plasma arc 18 intersects the upper surface of the workpiece 10 and the upper surface of the workpiece 10 (not shown). When the angle in the height direction formed by the optical axis 8a is θ1, the groove width of the cutting groove 6 imaged by the CMOS camera 8 is Wi, and the groove width of the actual cutting groove is Wa, Wa = Wi × The groove width Wi of the cutting groove 6 imaged by the CMOS camera 8 can be corrected to the actual groove width Wa of the cutting groove 6 by the calculation formula of | cos θ | / | sin θ1 |.

  The control unit 15 acquires cutting progress direction information from the cutting direction information of a specific figure stored in the storage unit 22 that stores NC (numerical control) data designed in advance, and plasma is obtained from the cutting progress direction information. The cutting progress direction a of the cutting torch 5 is specified.

  Accordingly, the groove width Wi of the cutting groove 6 imaged by the CMOS camera 8 corresponding to the change in the cutting progress direction a of the plasma cutting torch 5 and the angle θ of the optical axis 8a of the CMOS camera 8 is set to the actual cutting groove 6. Even when one CMOS camera 8 is fixed and provided in the plasma cutting device 2, the cutting progress direction a of the plasma cutting torch 5 is shown in FIG. Except when a) changes in a direction orthogonal to the optical axis 8a that is a straight line connecting the plasma cutting torch 5 and the CMOS camera 8 at 90 ° and 270 °, and the groove width Wa of the cutting groove 6 cannot be imaged. For example, the actual groove width Wa of the cutting groove 6 can be accurately obtained by simple calculation based on the groove width Wi of the cutting groove 6 imaged by the CMOS camera 8.

  The cutting progress direction a of the plasma cutting torch 5 changes in a direction perpendicular to the optical axis 8a which is a straight line connecting the plasma cutting torch 5 and the CMOS camera 8 shown at 90 ° and 270 ° in FIG. When the groove width Wa of the cutting groove 6 cannot be imaged, the cutting state determination unit 14 cuts the plasma cutting device 2 based only on the outer diameter Dp of the plasma arc 18 at the time of actual cutting. It is determined whether or not an abnormality has occurred in the operation.

  Since the normal plasma arc 18 is substantially cylindrical, the outer diameter Dp of the plasma arc 18 is taken by the CMOS camera 8 even if the angle θ of the optical axis 8a of the CMOS camera 8 changes. The data can be used without correction.

  Reference numeral 22 denotes a storage unit 22 serving as a storage unit. The outer diameter diameter Dp information of the plasma arc 18 calculated by the image analysis unit 19 from the captured image information captured by the CMOS camera 8 and the groove width Wa information of the cutting groove 6. Are stored in chronological order. The control unit 15 is provided with a timer that defines the time series stored in the storage unit 22.

  The comparison unit 20 goes back for a predetermined time from the current outer diameter Dp of the plasma arc 18 at the actual cutting time calculated by the image analysis unit 19, the groove width Wa of the cutting groove 6, and the current value stored in the storage unit 22. The outer diameter Dp of the plasma arc 18 at the time of the last actual cutting is compared with the groove width Wa of the cutting groove 6. Here, the time difference between the present time and the forefront time is preferably a time difference of about 10 mm in terms of a cutting distance for cutting the workpiece 10 by the plasma cutting torch 5. For example, when the cutting speed at which the workpiece 10 is cut by the plasma cutting torch 5 is 3000 mm / min (50 mm / sec), the time for the cutting distance to be 10 mm is 200 msec. Therefore, the range of the time difference between the present and the forefront is preferably 100 msec to 500 msec.

  Reference numeral 14 denotes a cutting state determination unit serving as a determination unit. The outer diameter Dp of the plasma arc 18 at the time of actual actual cutting, the groove width Wa of the cutting groove 6, and a predetermined value from the present are compared by the comparison unit 20. The difference between the outer diameter Dp of the plasma arc 18 at the time of the last actual cutting back in time and the groove width Wa of the cutting groove 6 is the outer diameter Dp of the plasma arc 18 from a preset allowable range. When at least one of the groove widths Wa of the cutting groove 6 is deviated, it is determined that an abnormality has occurred in the cutting operation of the plasma cutting device 2.

  Further, the storage unit 22 stores allowable value information of the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 set in advance corresponding to the cutting conditions of the workpiece 10. ing. The comparison unit 20 then calculates the outer diameter Dp of the plasma arc 18 at the time of actual cutting calculated by the image analysis unit 19, the groove width Wa of the cutting groove 6, and the object to be cut stored in the storage unit 22. The permissible values of the outer diameter Dp of the plasma arc 18 set in advance corresponding to the cutting conditions of the material 10 and the groove width Wa of the cutting groove 6 are compared.

  Then, the outer diameter Dp of the plasma arc 18 at the time of actual actual cutting and the groove width Wa of the cutting groove 6 compared by the comparison unit 20 are set in advance corresponding to the cutting conditions of the material 10 to be cut. At least one of the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 deviates from the respective allowable ranges of the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6. In this case, the cutting state determination unit 14 determines that an abnormality has occurred in the cutting operation of the plasma cutting device 2.

  A reference outer diameter Dp of the plasma arc 18 and a reference groove width Wa of the cutting groove 6 set in advance corresponding to the cutting conditions of the workpiece 10 are input by the input unit 13. Based on this, the allowable range of ± 20% of the reference outer diameter Dp of the plasma arc 18 and the reference groove width Wa of the cutting groove 6 is automatically calculated. Alternatively, the allowable range of the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 may be automatically calculated based on a cutting condition program for the workpiece 10. Alternatively, an arbitrary allowable range may be input by the input unit 13, and the allowable outer diameter Dp of the plasma arc 18 and the allowable groove width Wa of the cutting groove 6 may be automatically calculated from the allowable range.

  The comparison unit 20 then detects the allowable outer diameter Dp of the plasma arc 18 input by the input unit 13, the allowable groove width Wa of the cutting groove 6, and the current actual detected by image analysis by the image analysis unit 19. The outer diameter Dp of the plasma arc 18 at the time of cutting is compared with the groove width Wa of the cutting groove 6.

  The comparison unit 20 also compares the outer diameter Dp of the plasma arc 18 at the time of actual actual cutting, the groove width Wa of the cutting groove 6, and the plasma arc 18 at the time of the last actual cutting that is a predetermined time later from the present. Each difference between the outer diameter Dp and the groove width Wa of the cutting groove 6 is compared with a preset allowable range of the difference. At this time, the allowable range of the difference between the present outermost diameter Dp of the plasma arc 18 and the groove width Wa of the cut groove 6 can also be an allowable range of ± 20%.

  Then, the comparison information is sent to the cutting state determination unit 14, and at least one of the compared outer diameter diameter Dp of the plasma arc 18 at the actual cutting time and the groove width Wa of the cutting groove 6 is plasma. When the allowable outer diameter Dp of the arc 18 and the allowable groove width Wa of the cutting groove 6 deviate, the cutting state determination unit 14 determines that an abnormality has occurred in the cutting operation of the plasma cutting device 2.

  The image display unit 21 includes a display, a printer, and the like. The display displays an image of the outer diameter Dp of the plasma arc 18 and an image of the groove width Wa of the cutting groove 6 based on an image signal transmitted from the CMOS camera 8.

  When the cutting state determination unit 14 determines that an abnormality has occurred in the cutting operation of the plasma cutting device 2, the cutting abnormality information is transmitted to the control unit 15, and an alarm device 16 provides an alarm such as a buzzer as a defective cutting avoidance means. A warning is given to the operator by sounding or turning on the patrol light, or the cutting stop control of the plasma cutting device 2 is performed to avoid defective cutting at an early stage and then return.

  Next, a procedure for monitoring the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 at the time of actual actual cutting by the plasma cutting monitoring apparatus 1 configured as described above will be described. First, information on a figure to be cut from the material to be cut 10 is input from the input unit 13 provided on the control panel 9 of the plasma cutting apparatus 2, and information on the material and thickness of the material to be cut 10, The reference outer diameter Dp of the plasma arc 18 set in advance corresponding to the cutting conditions of the workpiece 10, the reference groove width Wa of the cutting groove 6, the outer diameter of the plasma arc 18 at the time of actual actual cutting The allowable range of the difference between the diameter Dp and the reference outer diameter Dp, the allowable range of the difference between the groove width Wa of the cutting groove 6 and the reference groove width Wa, and the forefront that has been back for a predetermined time from the current actual cutting The allowable range of the difference in the outer diameter Dp of the plasma arc 18 and the allowable range of the difference in the groove width Wa of the cutting groove 6 or the allowable outer diameter Dp of the plasma arc 18 and the cutting groove 6 Enter the allowable groove width Wa and the like.

  Next, while irradiating light from an illumination device or the like, a plasma arc 18 emitted from the tip of the plasma cutting torch 5 toward the workpiece 10 on the surface of the workpiece 10 and a plasma cutting torch in the vicinity of the plasma arc 18 The image of the part where the cutting groove 6 is formed by the cutting by 5 is picked up by operating the CMOS camera 8, and the standby for capturing the picked-up image is performed. The preparation for starting cutting is completed through the above procedure.

  Next, the plasma cutting device 2 is operated, and the traveling motor 12a and the traverse motor 3a are driven in accordance with the drive signal from the control unit 15 provided in the control panel 9 to move the plasma cutting torch 5 in the direction to be cut. Let

  The timing at which the image of the outer diameter Dp of the plasma arc 18 emitted from the tip of the plasma cutting torch 5 being cut toward the workpiece 10 and the image of the groove width Wa of the cutting groove 6 is plasma cutting. It corresponds to the cutting speed of the material 10 to be cut by the torch 5.

  The image picked up by the CMOS camera 8 is binarized or multi-valued by the image analysis unit 19, and image signals of an image of the outer diameter Dp of the plasma arc 18 and an image of the groove width Wa of the cutting groove 6 are extracted. Then, it is transmitted to the comparison unit 20 and the image display unit 21.

  As the cutting progresses, images of the outer diameter Dp of the plasma arc 18 and the image of the groove width Wa of the cutting groove 6 are periodically taken. If the outer diameter Dp of the plasma arc 18 or the groove width Wa of the cutting groove 6 is increased or decreased in the course of the cutting process, the image of the outer diameter Dp of the plasma arc 18 and In the comparison unit 20 to which the image of the actual outer diameter Dp of the plasma arc 18 and the value of the groove width Wa of the cutting groove 6 are transmitted from the image of the groove width Wa of the cutting groove 6, the outside of the plasma arc 18 of a predetermined time before The cutting diameter determination unit 14 compares the diameter Dp and the groove width Wa of the cutting groove 6, and the cutting state determination unit 14 determines the current outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 at the present actual cutting time from a predetermined value. The difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 at the time of the last actual cutting back in time from the allowable range set in advance, or the outer diameter Dp of the plasma arc 18 or the cutting groove 6 When at least one of the groove widths Wa is removed It is determined to be abnormal cutting operation of the plasma cutting apparatus 2 has occurred. Based on this cutting abnormality information, the alarm device 16 is activated by the control unit 15 to issue an alarm to the operator.

  Alarms issued by the alarm device 16 include a buzzer or a patrol light, a display on the display of the image display unit 21, etc., which are selected and adopted. Further, the control unit 15 performs necessary measures such as stop control of the plasma cutting device 2 and is restored.

  In the comparison unit 20, the outer diameter Dp of the plasma arc 18 at the time of actual actual cutting, the groove width Wa of the cutting groove 6, and the reference of the plasma arc 18 set in advance corresponding to the cutting conditions of the material 10 to be cut. Are compared with the reference groove width Wa of the cutting groove 6, and the difference between the two is within the preset allowable range, the outer diameter Dp of the plasma arc 18 or the groove of the cutting groove 6. When at least one of the widths Wa is removed, it is determined that an abnormality has occurred in the cutting operation of the plasma cutting device 2. Based on this cutting abnormality information, the alarm device 16 is activated by the control unit 15 to issue an alarm to the operator.

  According to the above configuration, the outer diameter Dp of the plasma arc 18 at the time of actual cutting, the groove width Wa of the cutting groove 6, and the predetermined time from the present based on the captured image information captured by the CMOS camera 8. The plasma cutting device when the difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 deviates from a preset allowable range at the time of the last actual cutting traced back. It can be determined that an abnormality has occurred in the cutting operation of No. 2. As a result, even when used outside the standard specification, monitoring is performed based on the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 at the time of the last cutting, which is a predetermined time after the normal cutting. I can do it.

  When one CMOS camera 8 is fixed to the plasma cutting device 2 in the vicinity of the plasma cutting torch 5, the traveling direction of the plasma cutting torch 5 connects the plasma cutting torch 5 and the CMOS camera 8. When it changes in the direction orthogonal to the optical axis 8a which becomes a straight line, the groove width Wa of the cutting groove 6 cannot be imaged. In that case, by monitoring the outer diameter Dp of the plasma arc 18, the plasma cutting torch 5 Continuous monitoring is possible regardless of the direction of travel.

  Further, based on the captured image information captured by the CMOS camera 8, the outer diameter Dp of the plasma arc 18 at the time of actual actual cutting and the groove width Wa of the cutting groove 6 are the cutting conditions of the workpiece 10. If any one of the outer diameters Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 set in advance corresponds to the above, the cutting operation of the plasma cutting device 2 is abnormal. Can be judged. As a result, the outer diameter Dp of the plasma arc 18 at the time of the last cutting retroactive for a predetermined time from the present time, and the outer diameter Dp of the plasma arc 18 at the time of actual cutting based on the groove width Wa of the cutting groove 6 Although the standard may be gradually shifted by simply monitoring the groove width Wa of the cutting groove 6, the outer diameter diameter of the plasma arc 18 set in advance corresponding to the cutting conditions of the material to be cut 10 The outer diameter Dp of the plasma arc 18 at the time of actual cutting and the groove width Wa of the cutting groove 6 can be monitored on the basis of Dp and the groove width Wa of the cutting groove 6.

  Next, a second embodiment of the plasma cutting monitoring apparatus 1 according to the present invention will be described with reference to FIG. In addition, what was comprised similarly to the said 1st Embodiment attaches | subjects the same code | symbol, and abbreviate | omits description.

  In the present embodiment, the image analysis unit 19 serving as the calculation means uses the outer diameter diameter Dp of the plasma arc 18 and the groove of the cutting groove 6 from the captured image information captured by the CMOS camera 8 in the same manner as in the first embodiment. The width Wa is calculated. Then, a half value of the difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 is calculated. Further, as shown in FIGS. 6A to 6D, left and right separation intervals L1 and L2 between the outer periphery of the plasma arc 18 and the groove edge of the cutting groove 6 on the side close to the outer periphery are calculated. Further, the difference between the outer diameter Dp of the plasma arc 18 and the difference between the groove width Wa of the cutting groove 6, the outer circumference of the plasma arc 18, and the cutting groove 6 on the side close to the outer circumference. The difference between the separation distances L1 and L2 from the groove edge is calculated.

  The storage unit 22 serving as a storage means is a difference of 2 between the outer diameter Dp of the plasma arc 18 calculated by the image analysis unit 19 from the captured image information captured by the CMOS camera 8 and the groove width Wa of the cutting groove 6. Information on the difference between the value of 1 and the spacing L1, L2 between the outer circumference of the plasma arc 18 and the groove edge of the cutting groove 6 on the side close to the outer circumference is stored in chronological order.

  The comparison unit 20 serving as a comparison means is a half of the difference between the outer diameter Dp of the plasma arc 18 at the time of actual cutting calculated by the image analysis unit 19 and the groove width Wa of the cutting groove 6. Value, the difference between the left and right separation intervals L1 and L2 between the outer periphery of the plasma arc 18 and the groove edge of the cutting groove 6 on the side close to the outer periphery, and a predetermined time from the current stored in the storage unit 22 The half of the difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6, the outer circumference of the plasma arc 18, and the vicinity of the outer circumference. The difference between the left and right spacing intervals L1, L2 from the groove edge of the cutting groove 6 on the side to be cut is compared.

  The cutting state determination unit 14 serving as a determination means is a half of the difference between the outer diameter Dp of the plasma arc 18 at the time of actual cutting and the groove width Wa of the cutting groove 6 compared by the comparison unit 20. The difference between the value of 1 and the distance L1, L2 between the left and right of the outer periphery of the plasma arc 18 and the groove edge of the cutting groove 6 on the side close to the outer periphery, and the actual The value of one half of the difference between the outer diameter Dp of the plasma arc 18 at the time of cutting and the groove width Wa of the cutting groove 6, the outer periphery of the plasma arc 18, and the cutting groove 6 on the side close to the outer periphery If the difference between the left and right spacing distances L1, L2 from the groove edge of the groove is out of the preset allowable range, the outer shape of the plasma arc 18 may be lost for some reason, The energy distribution is uneven and the axis of the plasma arc 18 is the center of the cutting groove 6 It is determined that shift et determines that an abnormality has occurred in the cutting operation of the plasma cutting apparatus 2.

  Further, in the present embodiment, the storage unit 22 stores the difference between the outer diameter Dp of the plasma arc 18 set in advance corresponding to the cutting conditions of the workpiece 10 and the groove width Wa of the cutting groove 6. The permissible value information of the difference between the one-half value and the left and right separation intervals L1, L2 between the outer periphery of the plasma arc 18 and the groove edge of the cutting groove 6 on the side close to the outer periphery is stored. .

  For example, when the plasma arc current of the plasma cutting torch 5 is 400 A, the outer diameter Dp of the plasma arc 18 is 4 mm, the groove width Wa of the cutting groove 6 is 5 mm, and the outer periphery of the plasma arc 18 is close to the outer periphery. When the left and right separation distances L1 and L2 with respect to the groove edge of the side cutting groove 6 are each set to 1 mm, the allowable range of the separation distances L1 and L2 is ± 20% as a standard, and ± when accuracy is important Set to 10%.

  The comparison unit 20 then calculates a value that is a half of the difference between the outer diameter Dp of the plasma arc 18 during actual cutting calculated by the image analysis unit 19 and the groove width Wa of the cutting groove 6, and The difference between the left and right separation intervals L1 and L2 between the outer periphery of the plasma arc 18 and the groove edge of the cutting groove 6 on the side close to the outer periphery, and the cutting conditions of the workpiece 10 stored in the storage unit 22 Correspondingly, a preset half value of the outer diameter Dp of the plasma arc 18 and the difference between the groove width Wa of the cutting groove 6, the outer circumference of the plasma arc 18, and the side close to the outer circumference. The allowable values of the difference between the left and right separation intervals L1, L2 from the groove edge of the cutting groove 6 are compared.

  The cutting state determination unit 14 compares the value of the difference between the outer diameter Dp of the plasma arc 18 during actual cutting and the groove width Wa of the cutting groove 6, compared by the comparison unit 20, The difference between the left and right separation intervals L1 and L2 between the outer periphery of the plasma arc 18 and the groove edge of the cutting groove 6 on the side close to the outer periphery is set in advance corresponding to the cutting conditions of the material 10 to be cut. The half value of the difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6, the outer periphery of the plasma arc 18, and the groove edge of the cutting groove 6 on the side close to the outer periphery When the distance between the left and right separation distances L1 and L2 deviates from the allowable range, the plasma arc 18 is biased by magnetic blowing (a phenomenon in which the arc is deflected by the magnetic action of the current), etc. It is determined that an abnormality has occurred in the cutting operation.

  FIG. 6A shows a state in which the cutting operation of the plasma cutting apparatus 2 is normal, and FIG. 6B shows the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 during actual cutting. FIG. 6C shows the state when the difference becomes small, and FIG. 6C shows the state when the difference between the outer diameter Dp of the plasma arc 18 during actual cutting and the groove width Wa of the cutting groove 6 becomes large. FIG. 6 (d) shows a state where the energy distribution in the plasma arc 18 is biased and the axis of the plasma arc 18 is shifted from the center of the cutting groove 6.

  Here, the value of a half of the difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6, the outer periphery of the plasma arc 18, and the cutting groove 6 on the side close to the outer periphery. As a specific example of the allowable range of the difference between the left and right separation distances L1, L2 with respect to the groove edge, it may be set to a desired value according to the cutting quality performance of the plasma cutting torch 5 and the cutting application. The value of the difference between the outer diameter Dp of the plasma arc 18 at the time of actual cutting and the groove width Wa of the cutting groove 6, the outer periphery of the plasma arc 18, and the vicinity of the outer periphery The allowable range of the difference between the left and right spacing distances L1, L2 with respect to the groove edge of the side cutting groove 6 is the outer diameter Dp of the plasma arc 18 at the time of the last actual cutting, which is a predetermined time back from the present, and the cutting The value of half of the difference from the groove width Wa of the groove 6, the outer periphery of the plasma arc 18, and the outer periphery The ± 20% of the difference between the respective spaced intervals L1, L2 left between the groove edge of the cutting groove 6 of the neighboring side may if expected acceptable range.

  In addition, a value half the difference between the outer diameter Dp of the plasma arc 18 at the time of actual cutting and the groove width Wa of the cutting groove 6, the outer periphery of the plasma arc 18, and the vicinity of the outer periphery The allowable range of the difference between the left and right separation intervals L1 and L2 from the groove edge of the cutting groove 6 on the side to be cut is the reference outer diameter of the plasma arc 18 set in advance corresponding to the cutting conditions of the workpiece 10 What is necessary is to expect about ± 20% of the value of a half of the difference between the diameter Dp and the groove width Wa of the reference cutting groove 6.

  According to the configuration of the present embodiment, the difference between the outer diameter Dp of the plasma arc 18 at the time of actual cutting and the groove width Wa of the cutting groove 6 based on the captured image information captured by the CMOS camera 8. Between the outer circumference of the plasma arc 18 and the left and right spacing distances L1 and L2 between the groove edge of the cutting groove 6 on the side close to the outer circumference and a predetermined time from the present. Further, the outer diameter Dp of the plasma arc 18 at the time of the last actual cutting and the value of the difference between the groove width Wa of the cutting groove 6, the outer periphery of the plasma arc 18, and the vicinity of the outer periphery It is determined that an abnormality has occurred in the cutting operation of the plasma cutting device 2 when the difference between the left and right separation distances L1, L2 from the groove edge of the side cutting groove 6 deviates from a preset allowable range. I can do it. As a result, the difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 at the time of the last cutting, which is a predetermined time after the normal cutting, even when used outside the standard specification. Monitoring can be performed on the basis of the difference between the half value and the left and right separation intervals L1, L2 between the outer periphery of the plasma arc 18 and the groove edge of the cutting groove 6 on the side close to the outer periphery.

  Further, based on the captured image information captured by the CMOS camera 8, a value that is a half of the difference between the outer diameter Dp of the plasma arc 18 at the actual actual cutting time and the groove width Wa of the cutting groove 6. The difference between the left and right separation intervals L1, L2 between the outer periphery of the plasma arc 18 and the groove edge of the cutting groove 6 on the side close to the outer periphery corresponds to the cutting conditions of the workpiece 10 in advance. The half value of the difference between the set outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6, the outer periphery of the plasma arc 18, and the cutting groove 6 on the side close to the outer periphery. It can be determined that an abnormality has occurred in the cutting operation of the plasma cutting device 2 when the difference between the left and right separation distances L1 and L2 from the groove edge is outside the allowable range.

  As a result, the value of one half of the difference between the outer diameter Dp of the plasma arc 18 at the time of the most recent cutting back from the present time and the groove width Wa of the cutting groove 6, and the outer circumference of the plasma arc 18 The outer diameter Dp of the plasma arc 18 at the time of actual cutting and the cutting groove 6 on the basis of the difference between the left and right separation intervals L1, L2 from the groove edge of the cutting groove 6 on the side close to the outer periphery. Of the difference between the groove width Wa and the spacing L1, L2 on the left and right of the outer periphery of the plasma arc 18 and the groove edge of the cutting groove 6 on the side close to the outer periphery. However, there is a possibility that the reference will gradually shift. However, the outer diameter Dp of the plasma arc 18 set in advance corresponding to the cutting conditions of the material 10 to be cut and the groove width of the cutting groove 6 One half of the difference from Wa, the outer circumference of the plasma arc 18 and the cutting near the outer circumference The difference between the outer diameter Dp of the plasma arc 18 at the time of actual cutting and the groove width Wa of the cutting groove 6 on the basis of the difference between the left and right separation distances L1, L2 with respect to the groove edge 6 The difference between the one-half value and the left and right separation intervals L1 and L2 between the outer periphery of the plasma arc 18 and the groove edge of the cutting groove 6 on the side close to the outer periphery can be monitored.

<First Reference Example>
Further, as a configuration of the first reference example, the image analysis unit 19 serving as a calculation unit calculates the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 from the captured image information captured by the CMOS camera 8. The difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 is calculated. That is, it corresponds to the sum of the left and right separation intervals L1 and L2 shown in FIG.

  The storage unit 22 serving as a storage means stores allowable value information on the difference between the outer diameter Dp of the plasma arc 18 set in advance corresponding to the cutting conditions of the workpiece 10 and the groove width Wa of the cutting groove 6. To do. The comparison unit 20 serving as a comparison unit is stored in the storage unit 22 and the difference between the outer diameter Dp of the plasma arc 18 at the time of actual cutting calculated by the image analysis unit 19 and the groove width Wa of the cutting groove 6. The allowable value of the difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 is compared.

  The cutting state determination unit 14 serving as a determination unit is configured so that the difference between the outer diameter Dp of the plasma arc 18 at the actual cutting and the groove width Wa of the cutting groove 6 compared by the comparison unit 20 is the difference of the plasma arc 18. When the difference between the outer diameter Dp and the groove width Wa of the cutting groove 6 is outside the allowable range, it is determined that an abnormality has occurred in the cutting operation of the plasma cutting device 2.

  Here, as a specific example of the allowable range of the difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6, a desired value according to the cutting quality performance of the plasma cutting torch 5 and the cutting application. For example, ± 20 of the difference between the reference outer diameter Dp of the plasma arc 18 set in advance corresponding to the cutting conditions of the workpiece 10 and the groove width Wa of the reference cutting groove 6 It is enough to expect about%.

  According to the above configuration, the difference between the outer diameter Dp of the plasma arc 18 at the time of actual cutting and the groove width Wa of the cutting groove 6 is determined based on the captured image information captured by the CMOS camera 8. It can be determined that an abnormality has occurred in the cutting operation of the plasma cutting device 2 when the cutting material 10 deviates from the preset allowable range corresponding to the cutting conditions. By monitoring the difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6, the change in the energy distribution of the plasma arc 18 can be monitored.

<Second Reference Example>
Further, as a configuration of the second reference example, the image analysis unit 19 serving as a calculation unit includes an outer diameter diameter Dp of the plasma arc 18 and a groove width Wa of the cutting groove 6 from captured image information captured by the CMOS camera 8. And the difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 is calculated. That is, it corresponds to the sum of the left and right separation intervals L1 and L2 shown in FIG.

  The storage unit 22 serving as a storage unit stores difference information between the outer diameter Dp of the plasma arc 18 calculated by the image analysis unit 19 from the captured image information captured by the CMOS camera 8 and the groove width Wa of the cutting groove 6. Store in chronological order.

  The comparison unit 20 serving as a comparison unit is configured to store the difference between the outer diameter Dp of the plasma arc 18 at the time of actual cutting calculated by the image analysis unit 19 and the groove width Wa of the cutting groove 6 in the storage unit 22. The difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 at the time of the last actual cutting that is a predetermined time after the stored current is compared.

  The cutting state determination unit 14 serving as a determination unit compares the difference between the outer diameter Dp of the plasma arc 18 at the actual actual cutting and the groove width Wa of the cutting groove 6 compared by the comparison unit 20 from the present. A plasma cutting device when the difference between the outer diameter Dp of the plasma arc 18 at the time of the last actual cutting back a predetermined time and the difference between the groove width Wa of the cutting groove 6 deviates from a preset allowable range It is determined that an abnormality has occurred in the cutting operation of No. 2.

  Further, the storage unit 22 stores allowable value information on the difference between the outer diameter Dp of the plasma arc 18 set in advance corresponding to the cutting conditions of the workpiece 10 and the groove width Wa of the cutting groove 6. The comparison unit 20 calculates the difference between the outer diameter Dp of the plasma arc 18 at the time of actual cutting calculated by the image analysis unit 19 and the groove width Wa of the cutting groove 6 and the object to be cut stored in the storage unit 22. The allowable diameter of the difference between the outer diameter Dp of the plasma arc 18 set in advance corresponding to the cutting conditions of the material 10 and the groove width Wa of the cutting groove 6 is compared.

  The cutting state determination unit 14 determines that the difference between the outer diameter Dp of the plasma arc 18 at the actual cutting and the groove width Wa of the cutting groove 6 compared with the comparison unit 20 is the cutting of the material 10 to be cut. If the plasma cutting device 2 is out of the allowable range of the difference between the outer diameter Dp of the plasma arc 18 set in advance and the groove width Wa of the cutting groove 6 in accordance with the conditions, the cutting operation of the plasma cutting device 2 is abnormal. to decide.

  Here, as a specific example of the allowable range of the difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6, a desired value according to the cutting quality performance of the plasma cutting torch 5 and the cutting application. For example, the allowable range of the difference between the outer diameter Dp of the plasma arc 18 at the time of actual actual cutting and the groove width Wa of the cutting groove 6 is the most recent actual value that is a predetermined time after the present. The allowable range may be about ± 20% of the difference between the outer diameter Dp of the plasma arc 18 at the time of cutting and the groove width Wa of the cutting groove 6.

  Further, it is possible to expect about ± 20% of the difference between the reference outer diameter Dp of the plasma arc 18 set in advance corresponding to the cutting conditions of the workpiece 10 and the groove width Wa of the reference cutting groove 6. It ’s fine.

  According to the above configuration, based on the captured image information captured by the CMOS camera 8, the difference between the outer diameter Dp of the plasma arc 18 at the actual actual cutting time and the groove width Wa of the cutting groove 6, and the current Plasma cutting is performed when the difference between the outer diameter Dp of the plasma arc 18 at the time of the last actual cutting that is a predetermined time later than the difference between the groove width Wa of the cutting groove 6 deviates from a preset allowable range. It can be determined that an abnormality has occurred in the cutting operation of the device 2. As a result, the difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 at the time of the last cutting that is a predetermined time after the normal cutting even when used outside the standard specification is obtained. Can be monitored as a reference.

  Further, based on the captured image information captured by the CMOS camera 8, the difference between the outer diameter Dp of the plasma arc 18 at the time of actual cutting and the groove width Wa of the cutting groove 6 is the difference in the material 10 to be cut. An abnormality occurs in the cutting operation of the plasma cutting device 2 when the outside diameter Dp of the plasma arc 18 set in advance corresponding to the cutting conditions and the groove width Wa of the cutting groove 6 deviate from the allowable range. Can be judged. As a result, the outer diameter of the plasma arc 18 at the time of actual cutting based on the difference between the outer diameter Dp of the plasma arc 18 at the time of the last cutting that is a predetermined time after the present and the groove width Wa of the cutting groove 6. By simply monitoring the difference between the diameter Dp and the groove width Wa of the cutting groove 6, the reference may gradually shift, but a plasma arc set in advance corresponding to the cutting conditions of the material 10 to be cut. Based on the difference between the outer diameter Dp of 18 and the groove width Wa of the cutting groove 6, the difference between the outer diameter Dp of the plasma arc 18 at the time of actual actual cutting and the groove width Wa of the cutting groove 6 is Can be monitored.

<Third reference example>
Further, as a configuration of the third reference example, the image analysis unit 19 serving as a calculation unit includes an outer diameter Dp of the plasma arc 18 from the captured image information captured by the CMOS camera 8, a groove width Wa of the cutting groove 6, and Is calculated. Further, a half value of the difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6 is calculated. Further, the left and right separation intervals L1, L2 between the outer periphery of the plasma arc 18 and the groove edge of the cutting groove 6 on the side close to the outer periphery are calculated. Then, the value of a half of the difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6, the outer circumference of the plasma arc 18, and the cutting groove 6 on the side close to the outer circumference. The difference between the left and right separation intervals L1, L2 from the groove edge is calculated.

  The storage unit 22 serving as a storage means is a half of the difference between the outer diameter Dp of the plasma arc 18 set in advance corresponding to the cutting conditions of the workpiece 10 and the groove width Wa of the cutting groove 6. Information on the difference between the left and right spacing distances L1 and L2 between the value and the outer periphery of the plasma arc 18 and the groove edge of the cutting groove 6 on the side close to the outer periphery.

  The comparison unit 20 serving as a comparison means is a value half the difference between the outer diameter Dp of the plasma arc 18 at the actual cutting time calculated by the image analysis unit 19 and the groove width Wa of the cutting groove 6. The difference between the left and right separation distances L1 and L2 between the outer periphery of the plasma arc 18 and the groove edge of the cutting groove 6 on the side close to the outer periphery, and the outer diameter of the plasma arc 18 stored in the storage unit 22 One-half of the difference between the diameter Dp and the groove width Wa of the cutting groove 6, and the left and right separations of the outer periphery of the plasma arc 18 and the groove edge of the cutting groove 6 on the side close to the outer periphery The difference between the intervals L1 and L2 is compared with an allowable value.

  The cutting state determination unit 14 serving as a determination unit is a half of the difference between the outer diameter Dp of the plasma arc 18 at the actual cutting and the groove width Wa of the cutting groove 6 compared by the comparison unit 20. The difference between the outer diameter of the plasma arc 18 and the spacing distance between the left and right of the groove edge of the cutting groove 6 on the side close to the outer periphery is the outer diameter Dp of the plasma arc 18 and the cutting groove 6. Of the difference between the groove width Wa and the spacing L1, L2 on the left and right of the outer periphery of the plasma arc 18 and the groove edge of the cutting groove 6 on the side close to the outer periphery. It is determined that an abnormality has occurred in the cutting operation of the plasma cutting device 2 when it is outside the allowable range.

  In addition, a value half the difference between the outer diameter Dp of the plasma arc 18 at the time of actual cutting and the groove width Wa of the cutting groove 6, the outer periphery of the plasma arc 18, and the vicinity of the outer periphery The allowable range of the difference between the left and right separation intervals L1 and L2 from the groove edge of the cutting groove 6 on the side to be cut is the reference outer diameter of the plasma arc 18 set in advance corresponding to the cutting conditions of the workpiece 10 What is necessary is to expect about ± 20% of the value of a half of the difference between the diameter Dp and the groove width Wa of the reference cutting groove 6.

  According to the above configuration, the difference between the outer diameter Dp of the plasma arc 18 at the time of actual cutting and the groove width Wa of the cutting groove 6 based on the captured image information captured by the CMOS camera 8 is two minutes. The difference between the value of 1 and the spacing L1, L2 between the outer periphery of the plasma arc 18 and the groove edge of the cutting groove 6 on the side close to the outer periphery is the cutting condition of the material 10 to be cut. Correspondingly, it can be determined that an abnormality has occurred in the cutting operation of the plasma cutting device 2 when it deviates from the preset allowable range. The value of one half of the difference between the outer diameter Dp of the plasma arc 18 and the groove width Wa of the cutting groove 6, the outer periphery of the plasma arc 18, and the groove edge of the cutting groove 6 on the side close to the outer periphery By monitoring the difference between the left and right separation distances L1 and L2, the deviation of the center position of the plasma arc 18 on the left and right of the cutting groove 6 around the plasma arc 18 and the energy distribution of the plasma arc 18 Can be monitored for left and right bias.

  As an application example of the present invention, the present invention can be applied to a plasma cutting monitoring device that monitors a cutting state of a plasma cutting device that uses a plasma cutting torch to melt and remove a part of a material to be cut.

Dp ... plasma arc outer diameter L1, L2 ... separation distance Wa between outer circumference of plasma arc and groove edge of cutting groove ... groove width Wi of actual cutting groove ... groove width 1 of imaged cutting groove ... plasma cutting monitoring device 2 ... Plasma cutting device 3 ... Traverse carriage 3a ... Traverse motor 4 ... Lifting device 4a ... Lifting motor 5 ... Plasma cutting torch 6 ... Cutting groove 7 ... Support member 8 ... CMOS camera (imaging means)
8a: Optical axis 9: Control panel
10 ... Material to be cut
11… Rail
12… Travel cart
12a ... traveling motor
13… Input section
14 ... Cutting state determination unit (determination means)
15 Control unit
16… Alarm device
17… Shooting area
18 Plasma arc
19 Image analysis unit (calculation means)
20… Comparison part (comparison means)
21 Image display section
22 ... Memory part (memory means)
a ... cutting direction b ... point e ... traveling direction f ... transverse direction

Claims (5)

A plasma cutting monitoring device that monitors a cutting state of a plasma cutting device that melts and removes a part of a material to be cut using a plasma cutting torch,
Imaging means for imaging a plasma arc emitted from the tip of the plasma cutting torch being cut toward the material to be cut, and a cutting groove in the vicinity of the plasma arc;
A calculation means for calculating an outer diameter diameter of the plasma arc and a groove width of the cutting groove from captured image information captured by the imaging means;
Storage means for storing the outer diameter information of the plasma arc calculated by the calculation means from the captured image information captured by the imaging means, and the groove width information of the cutting grooves, in chronological order;
The outer diameter diameter of the plasma arc at the time of actual actual cutting calculated by the calculating means, the groove width of the cutting groove, and the outside of the plasma arc at the time of the last actual cutting stored in the storage means A comparison means for comparing the diameter and the groove width of the cutting groove;
The outer diameter diameter of the plasma arc at the current actual cutting, the groove width of the cutting groove, the outer diameter of the plasma arc at the last actual cutting, and the cutting, compared by the comparison means A judging means for judging that an abnormality has occurred in the cutting operation of the plasma cutting device when any of the difference between the groove width and the groove width deviates from a preset allowable range;
A plasma cutting monitoring device characterized by comprising: The storage means stores information on each allowable value of the outer diameter of the plasma arc set in advance corresponding to the cutting conditions of the material to be cut and the groove width of the cutting groove,
The comparison means includes an outer diameter diameter of the plasma arc at the time of actual actual cutting calculated by the calculation means, a groove width of the cutting groove, and a cutting condition of the material to be cut stored in the storage means. The outer diameter diameter of the plasma arc that is set in advance corresponding to, and the respective allowable values of the groove width of the cutting groove,
The plasma in which the outer diameter of the plasma arc at the time of actual actual cutting and the groove width of the cutting groove, which are compared by the comparison means, are set in advance corresponding to the cutting conditions of the material to be cut The determination means determines that an abnormality has occurred in the cutting operation of the plasma cutting device when any one of the outer diameter diameter of the arc and the groove width of the cutting groove is out of the permissible ranges. The plasma cutting monitoring apparatus according to claim 1. A plasma cutting monitoring device that monitors a cutting state of a plasma cutting device that melts and removes a part of a material to be cut using a plasma cutting torch,
Imaging means for imaging a plasma arc emitted from the tip of the plasma cutting torch being cut toward the material to be cut, and a cutting groove in the vicinity of the plasma arc;
The outer diameter diameter of the plasma arc and the groove width of the cutting groove are calculated from the captured image information captured by the imaging means, and the difference between the outer diameter diameter of the plasma arc and the groove width of the cutting groove Of the plasma arc, the distance between the outer periphery of the plasma arc and the groove edge of the cutting groove on the side close to the outer periphery is calculated, the outer diameter diameter of the plasma arc, and the cutting A calculation means for calculating a difference between a half value of a difference between the groove width of the groove, and an interval between the outer periphery of the plasma arc and the groove edge of the cutting groove on the side close to the outer periphery;
A half value of the difference between the outer diameter diameter of the plasma arc calculated by the calculation means from the captured image information taken by the imaging means and the groove width of the cutting groove, and the outer circumference of the plasma arc Storage means for storing the difference information between the gap between the cutting groove on the side close to the outer periphery and the separation interval in chronological order;
The outer diameter diameter of the plasma arc at the time of actual actual cutting calculated by the calculating means and a value that is half the difference between the groove width of the cutting groove, the outer periphery of the plasma arc, and the outer periphery The difference between the separation distance from the groove edge of the cutting groove on the side close to the outer diameter, the outer diameter diameter of the plasma arc at the time of the last actual cutting stored in the storage means, and the groove width of the cutting groove A comparison means for comparing a half value of the difference between the difference between the outer circumference of the plasma arc and the spacing between the groove edge of the cutting groove on the side close to the outer circumference;
The outer diameter diameter of the plasma arc at the time of actual actual cutting compared with the comparison means, a value half the difference between the groove width of the cutting groove, the outer circumference of the plasma arc, The difference between the separation distance from the groove edge of the cutting groove on the side close to the outer circumference, the difference between the outer diameter diameter of the plasma arc at the time of the last actual cutting, and the groove width of the cutting groove When the difference between the value of 1 and the spacing between the outer periphery of the plasma arc and the groove edge of the cutting groove on the side close to the outer periphery deviates from a preset allowable range, the cutting of the plasma cutting device A determination means for determining that an abnormality has occurred in the operation;
A plasma cutting monitoring device characterized by comprising: The storage means includes a half value of a difference between an outer diameter diameter of the plasma arc set in advance corresponding to a cutting condition of the material to be cut and a groove width of the cutting groove, and the plasma. Tolerance value information of the difference between the outer circumference of the arc and the separation interval between the cutting groove on the side close to the outer circumference is stored,
The comparison means includes a value that is half the difference between the outer diameter of the plasma arc at the actual cutting calculated by the calculation means and the groove width of the cutting groove, and the outer circumference of the plasma arc. The plasma arc outside the plasma arc set in advance corresponding to the difference between the separation distance from the groove edge of the cutting groove on the side close to the outer periphery and the cutting condition of the material to be cut stored in the storage means The difference between the diameter and the half of the difference between the groove width of the cutting groove and the separation distance between the outer periphery of the plasma arc and the groove edge of the cutting groove on the side close to the outer periphery. Compare with the tolerance value,
Compared by the comparison means, the outer diameter of the plasma arc at the time of actual cutting and the value of the difference between the groove width of the cutting groove, the outer circumference of the plasma arc, and the outer circumference The difference between the separation distance from the groove edge of the cutting groove on the adjacent side is the outer diameter diameter of the plasma arc set in advance corresponding to the cutting condition of the material to be cut, and the groove width of the cutting groove. The judgment means when the difference between the half value of the difference between the outer circumference of the plasma arc and the separation interval between the groove edge of the cutting groove on the side close to the outer circumference is deviated. 4. The plasma cutting monitoring device according to claim 3, wherein it is determined that an abnormality has occurred in the cutting operation of the plasma cutting device. The imaging means is fixed to the plasma cutting device in the vicinity of the plasma cutting torch,
The calculating means is θ which is the angle of deviation between the cutting progress direction of the plasma cutting torch and the linear direction connecting the plasma arc and the imaging means, and Wi is the groove width of the cutting groove imaged by the imaging means. When the groove width of the cutting groove is Wa,
Wa = Wi × | cos θ |
The plasma cutting according to any one of claims 1 to 4, wherein the groove width Wi of the cutting groove imaged by the imaging means is corrected to the groove width Wa of the actual cutting groove by the following calculation formula. Monitoring device.