JP5277548B2 - Transparent protective plate contamination determination apparatus and method for laser processing apparatus, and laser processing method - Google Patents

Description

  The present invention relates to a transparent protective plate contamination determination apparatus and method for a laser processing apparatus, and a laser processing method.

  Laser welding is welding using powerful laser light. 2. Description of the Related Art In recent years, as a laser welding apparatus, a laser beam is emitted using a reflecting mirror to change the irradiation direction and perform welding to welding points in various directions without moving the laser welding apparatus itself. (See, for example, Patent Document 1). Such a technique is called remote welding because welding is performed from a distance.

  On the other hand, in such a laser irradiation apparatus, an optical system such as a reflecting mirror and a lens is housed in a case, and the laser light exit is covered with a protective glass. This protective glass is provided so that spatter generated during laser welding does not damage the optical system inside the laser irradiation apparatus. Therefore, since this protective glass is spattered during welding, it gradually becomes dirty. If the protective glass becomes dirty, the laser light transmitted therethrough will be attenuated.

Conventionally, in order to prevent the laser beam from being attenuated by such dirt on the protective glass, if the dirt on the surface of the protective glass is detected, and if a certain level of dirt is detected, the welding operation is stopped, Replacing the protective glass is performed (for example, see Patent Document 2).
JP-A-10-180471 JP 2005-224836 A

  However, in remote welding, when the dirt detection technique of the protective glass as in Patent Document 2 is used, if there is dirt that attenuates the laser beam somewhere on the surface of the protective glass, the other areas are almost dirty. Even if not, the welding will be interrupted and the protective glass will be replaced or cleaned. In particular, in remote welding, the laser light is converted in various directions through the protective glass, so the area of the protective glass is large, the replacement cost of the protective glass is high, and the downtime of the device is long due to cleaning etc. As a result, the process cost increases.

  Accordingly, an object of the present invention is to determine the degree of contamination on the surface of a transparent protective plate (for example, protective glass) for a laser processing apparatus together with the position thereof, and a transparent protective plate contamination determination device capable of operating a laser welding apparatus more efficiently. It is to provide a laser processing method using the method and the transparent protective plate contamination determination device.

The present invention for solving the above-described problems is a laser processing apparatus provided with a reflecting mirror that changes an irradiation direction of laser light therein and provided with a transparent protective plate that covers an exit port from which the laser light is emitted. A transparent protective plate contamination determination device for determining a degree of contamination of a transparent protective plate, wherein a surface of the transparent protective plate through which the laser beam is transmitted is divided into a plurality of regions, and an arbitrary region is transmitted among the plurality of regions. A measuring means for measuring the amount of the measured light, a judging means for judging the degree of contamination of the transparent protective plate for each arbitrary region from the amount of the light measured by the measuring means, and moving the laser processing apparatus By moving the moving means and the moving means and the reflecting mirror, the light reflected by the reflecting mirror is always irradiated to the measuring means whose position is fixed, and the arbitrary region is sequentially The light To transmit remains, and a control means for controlling said moving means and said reflecting mirror, by controlling the moving means and the reflector, keeping the irradiation direction of the light in a predetermined direction, wherein A transparent protective plate contamination determining apparatus, wherein the amount of the light transmitted through the arbitrary region is measured by relatively moving a position of the transparent protective plate with respect to light transmitted through the transparent protective plate. is there.

Further, the present invention for solving the above-mentioned problems is a laser processing apparatus provided with a reflecting mirror for changing the irradiation direction of the laser beam inside, and provided with a transparent protective plate that covers the exit from which the laser beam is emitted. A transparent protective plate contamination determination method for determining the degree of contamination of the transparent protective plate,
The surface of the transparent protective plate through which the laser light is transmitted is divided into a plurality of regions, and the moving direction of the laser processing apparatus and the reflecting mirror are controlled to keep the light irradiation direction constant. Measuring the amount of the light transmitted through an arbitrary region of the plurality of regions by moving the position of the transparent protective plate relative to the light transmitted through the transparent protective plate; It is a transparent protective plate stain | pollution | contamination determination method characterized by determining the stain | pollution | contamination degree of the said transparent protective plate for every said arbitrary area | regions from quantity.

  Furthermore, the present invention for solving the above problem is a laser processing method using the above-described transparent protective plate contamination determination device, wherein the amount of heat input to the member to be processed by the laser beam that passes through each region is calculated as described above. The laser processing method is characterized in that control is performed according to the degree of contamination of each region determined by the determining means.

  According to the present invention configured as described above, the surface of the transparent protective plate is divided into a plurality of regions, and the degree of contamination is determined for each region. In such a case, the transparent protective plate can be used as it is depending on whether or not the laser beam passes therethrough, and the amount of heat input by the laser beam can be controlled according to the degree of contamination. Therefore, it is possible to reduce the number of times the transparent protective plate is washed or replaced, and to reduce the process stop time due to the contamination of the transparent protective plate.

  Hereinafter, embodiments to which the present invention is applied will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic view showing a configuration of a laser welding system using the present invention, and FIG. 2 is an internal structure diagram of a laser irradiation apparatus in the laser welding system.

  First, the laser welding system shown in FIG. 1 directly irradiates a workpiece (not shown), which is a member to be welded as a workpiece, with a laser beam 100 from a laser irradiation device 3 positioned above the workpiece. The workpiece is welded without touching.

  The illustrated laser welding system (hereinafter simply referred to as a system) includes a robot 1 (moving means), a laser irradiation device 3 (laser irradiation means) that is attached to the tip of an arm 2 of the robot 1 and irradiates laser light 100. A laser oscillator 5 that generates laser light, an optical fiber cable 6 that guides laser light from the laser oscillator 5 to the laser irradiation device 3, a robot control device 7 that controls the operation of the robot 1 and the laser irradiation device 3, and a robot control device 7 is composed of a teach box 8 for sending various instructions.

  A protective glass (transparent protective plate) 18 is provided at the exit 19 for emitting the laser light of the laser irradiation device 3.

  Then, as a transparent protective plate contamination determination device (hereinafter simply referred to as a contamination determination device), a calorimeter 51 (measuring means) that measures the amount of heat of the laser light 100 and a protective glass based on the calorific value obtained from the calorimeter 51 A computer 52 for determining the degree of 18 contamination is provided.

  In this system, predetermined teaching data and welding pattern data can be acquired from the CAD system 9 in order to execute the operation of the robot 1. The CAD system 9 does not need to be always connected. In addition, the operator can arbitrarily control the direction of the reflecting mirror 11 and the posture of the robot with respect to the robot by a command from the teach box 8. Further, the direction of the reflecting mirror 11 and the robot posture executed thereby can be stored and reproduced as teaching data.

  The robot 1 is a general multi-axis robot, and the arm 2 is driven in accordance with route data given by the teaching work, and the laser irradiation device 3 can be moved to various three-dimensional positions and directions. A YAG laser is used as the laser oscillator 5, and the laser light generated by the laser oscillator 5 is guided to the laser irradiation device 3 by the optical fiber cable 6.

  The laser irradiation device 3 reflects the guided laser beam with a built-in reflecting mirror 11 and scans a powerful laser beam 100 with respect to a workpiece working point (hereinafter referred to as a welding point). The scanned laser beam 100 is irradiated onto the welding point, and welding of the welding point (formation of a weld bead) is performed according to the shape scanned by the laser irradiation device 3.

  The robot control device 7 controls the operation of the robot 1 while recognizing the posture of the robot 1, and also controls the laser irradiation device 3 (control of the reflecting mirror 11) in order to scan by changing the irradiation direction of the laser beam. Yes. The control of the reflecting mirror 11 is performed so as to draw a welding pattern set in predetermined teaching data. The robot controller 7 also controls ON / OFF of the laser output from the laser oscillator 5.

  The laser irradiation device 3 is configured to freely change the irradiation direction of the input laser light and visible laser light (visible light). That is, as shown in FIG. 2, the laser irradiation device 3 rotates the reflecting mirror 11 (reflecting mirror) for irradiating the laser beam 100 guided by the optical fiber cable 6 toward the welding point, and the reflecting mirror 11. Motors 16 and 17 to be moved and the lens group 12 are provided.

  The reflecting mirror 11 is supported so as to be independently rotatable about the X axis and the Y axis perpendicular to the Z axis, with the vertical axis passing through the mirror surface as the Z axis. The motor 16 and the motor 17 change the direction of the reflecting mirror 11 into a three-dimensional direction by combining the rotational positions of the respective motors. Therefore, the reflecting mirror 11 is attached so as to be able to emit laser light incident from the optical fiber cable 6 in a three-dimensional direction. By rotating the reflecting mirror 11 in a three-dimensional direction, a welding pattern having a predetermined shape can be drawn at a welding point set on the workpiece.

  The amount of heat input can also be adjusted by the moving speed (rotation speed) of the reflecting mirror 11. That is, if the moving speed of the laser beam that draws the welding pattern on the workpiece by the movement of the reflecting mirror 11 is slowed, the amount of laser light incident per unit time at the welding point increases and the amount of heat input at the welding point increases. . On the other hand, if this is speeded up, the amount of laser light incident per unit time decreases, and the amount of heat input at the welding point decreases.

  The change of the laser light intensity by changing the moving speed of the reflecting mirror 11 is performed according to an instruction from the robot controller 7. This laser beam intensity change instruction is performed in advance according to the position of the welding pattern (details will be described later).

  The lens group 12 includes a collimating lens 121 for collimating laser light emitted from the end of the optical fiber cable 6 and a condensing lens 122 for condensing the laser light 100 that has become parallel light on the workpiece. Composed. Then, by changing the position of the condensing lens 122, the laser irradiation device 3 changes the position where the laser beam connects the store according to the distance from the welding point to the reflecting mirror 11. It should be noted that such a change of the focal position (condenser lens position changing operation) is taught in advance together with the teaching of the movement path by the robot.

  As shown in FIG. 3, the laser oscillator 5 includes a visible laser beam oscillation source 502 such as a semiconductor laser in addition to a YAG laser oscillation source 501. Whether to emit visible light or laser light for welding is switched by a switching mirror 503 inside the laser oscillator 5. That is, when the switching mirror 503 is at the solid line position, YAG laser light is output to the optical fiber cable 6, and when it is at the dotted line position, visible laser light is output to the optical fiber cable 6. Visible laser light is used when visually confirming the path of the laser light.

  The switching mirror 503 is switched by an instruction from the robot controller 7 or manually.

  The computer 52 serving as a contamination degree determination device has a function as a control unit so that a laser beam is always applied to the calorimeter 51 and passes through the surface of the protective glass divided into a plurality of regions. The movement of the mirror 11 is controlled.

  Here, the effect | action of dividing the inside of a protective glass surface into a some area | region is demonstrated.

  FIG. 4 is a plan view showing a protective glass surface.

  In this embodiment, when determining the degree of contamination of the protective glass surface, the portion through which the laser beam is transmitted is divided into a plurality of regions as shown in FIG. The figure shows a case of 16 divisions. Each region is identified by giving coordinate numbers X1 to 4 in the horizontal direction and Y1 to 4 in the vertical direction (the names or coordinates are used to identify each region). Therefore, for example, the lower left area in the figure is specified as “X1, Y1”, the upper right area as “X4, Y4”, and “Xn, Yn (where n is 1 to 4)”.

  Note that the number of divisions and how to obtain the coordinate position are not limited to such examples.

  As shown in FIG. 4, dirt 201 to 204 on the surface of the protective glass 18 due to sputtering is present at various positions in various ways (in the illustrated case, the darker part of the dirt 201 to 204 is more dirty). Occurs). Therefore, in the present embodiment, the stains generated in various ways in this way at various positions are inspected for each region, and the degree of contamination is determined for each region.

  The determination of the degree of contamination for each region is performed by transmitting the laser beam to each region of the protective glass 18 and measuring the amount of heat of the laser beam at that time.

  The calorific value is measured by the calorimeter 51. For the calorimeter 51, for example, a thermal element can be used. The laser beam applied to the calorimeter 51 is not necessarily focused on the focal position of the lens system 12 of the laser welding apparatus 3. For example, as shown in FIG. 5, the position of the calorimeter 51 may be shifted with respect to the focus position P of the laser beam for irradiation. This is because when measuring the amount of heat, first measure the amount of heat (referred to as the reference amount of heat) as a reference in the absence of dirt, and measure the area where the degree of dirt is unknown. This is because it is not always necessary to measure at the in-focus position where the laser beam is most concentrated because it is only necessary to check the presence and degree of contamination.

  In the measurement of the amount of heat, the amount of heat is measured by transmitting a laser beam in each area of the protective glass surface. At this time, the laser welding apparatus 3 is fixed (that is, the protective glass surface is not moved), and the laser beam is scanned on the protective glass surface so that each region transmits the laser light only by moving the reflecting mirror 11. May be. However, in this case, since the irradiation direction of the laser light changes, the calorimeter 51 must be moved accordingly.

  Therefore, in the present embodiment, the laser welding apparatus 3 (that is, the protective glass surface) is moved so that the laser light irradiation direction itself is not moved and the laser light is always irradiated to one point. . Thus, the protective glass 18 is moved relative to the laser beam while the calorimeter 51 is not moved, and the laser beam 100 is transmitted through each region.

  FIG. 6 is a drawing for explaining a method for moving the protective glass surface relative to the laser light.

  In order to move the protective glass surface relative to the laser light, as shown in the drawing, the orientation of the laser welding apparatus 3 is changed (controlled) by changing the orientation of the robot 1 and the orientation of the reflecting mirror 11 is changed. By changing (controlling), each region set on the protective glass 18 can be scanned with the laser light while the irradiation direction of the laser light 100 is kept constant.

  However, when the orientation of the laser welding apparatus 3 is changed, if the posture of the robot 1 is changed, the optical path length of the laser light from the lens 12 to the calorimeter 51 may change. If the optical path length changes, the measured heat quantity will change. Therefore, in order to prevent such an optical path length from changing, the posture of the robot 1 is changed with the center of the reflecting mirror 11 as a fulcrum so that the center of the reflecting mirror 11 does not move in space. This is because the distance from the reflecting mirror 11 to the lens 121 does not change even when the orientation of the reflecting mirror 11 is substantially changed, whereas the position of the reflecting mirror 11 in the space changes when the posture of the robot 1 is changed. This is to prevent the distance between the reflecting mirror 11 and the calorimeter 51 from changing greatly. Note that the robot posture control is not described here because an existing robot control technique may be used.

  Next, a method for scanning the protective glass surface will be described. FIG. 7 is an explanatory diagram for explaining a scanning method for transmitting laser light on the protective glass surface.

  There are two methods for scanning the protective glass surface. First, as shown in FIG. 7A, a laser beam is transmitted through all the areas of the protective glass surface divided into a plurality of areas, and contamination determination is performed in all areas. Second, as shown in FIG. 7 (b), only a region (pattern) to which laser light is to be transmitted at the time of welding is selectively scanned among a plurality of regions, and only the degree of contamination of that portion is determined. Is the method.

  Hereinafter, the method for determining the degree of contamination and the control at the time of welding using the result will be described using the method shown in FIG. 7A and the method shown in FIG. 7B, respectively.

  First, in the method shown in FIG. 7A, the laser light is transmitted through all the regions, and the amount of heat of the laser light is measured for each region. At this time, the laser beam is transmitted through several places in one area, and the amount of heat is measured, and the value of the smallest amount of heat is set as the value of the amount of heat in the area. ) Is stored together with a name for identifying the region (coordinates and symbols of the region). Here, the smallest value is stored as the calorific value of the region in order to consider the possibility of transmitting the most dirty part in the region when the laser beam is transmitted through the region during welding. is there.

  The reason why laser light is transmitted through a plurality of locations in one area is to know how much dirt is generated in one area when the size of one area is larger than the beam diameter of the laser light. This is because several measurement results are required in one region. The number of laser beams that can be transmitted in one region is small if one region is small and the number of portions that transmit the laser beam is small. On the other hand, if one area is large, it is better to increase the number of parts to be transmitted. Most preferably, the size of one region should be approximately the same as the diameter of the light beam of the laser beam passing therethrough. By doing so, it can be set as the calorie | heat amount measurement of one area | region.

  In actual operation, as shown in FIG. 7 (a), as in the locus of the laser beam (scanning pattern T1), the protective glass surface is scanned so that the laser beam is transmitted a plurality of times in each region. The amount of heat at that time is continuously measured. Note that the scanning pattern T1 for measuring the calorific value is not limited to the illustrated pattern, and may be another scanning pattern. If the degree can be determined in each region, the skipped portion is measured. There may be.

  The measured calorific value is once stored in the computer 52 and then compared with a predetermined reference value to determine the degree of contamination. Here, as the reference value, the amount of heat when the laser light passes through the protective glass without contamination can be used.

  However, since this reference value serves as a reference for the amount of heat measured as the dirt determination, a value other than this may be used. For example, a value of about 90% transmittance is competed as a reference value in advance, and it is determined that there is dirt only when the amount of heat measured to withstand dirt judgment falls below this reference value. May be.

  The determined degree of contamination of each area is stored in the computer 52. The stored degree of dirt is then used to control the laser light when performing welding.

  The method using the dirt determination result may be an appropriate method depending on the laser welding method, but here, two methods will be described.

  In laser welding (particularly remote welding), there are roughly two welding methods. The first method is to stop the movement of the laser beam. The second is a method of welding while drawing a predetermined welding pattern continuously.

  First, for the first welding method, there are two methods of using the determination data for the degree of contamination.

  The first method of use is a method of transmitting laser light while avoiding areas with a high degree of contamination so that the laser light does not pass through areas with a high degree of contamination. Specifically, if the region where the laser beam has been transmitted before the contamination degree determination does not obtain a predetermined amount of heat in the contamination region after the contamination degree inspection, the posture of the robot 1 is changed. Thus, the laser beam is transmitted through an area determined to have no (or little) contamination.

  Here, the predetermined amount of heat is a threshold value for determining whether or not to use the region. For example, the amount of heat when passing through a protective glass without dirt (measured by the calorimeter 51). The region where the amount of heat at the time of contamination determination is less than 80% when the amount of heat of the laser beam per unit time (hereinafter the same) is 100% is not used. Note that such a threshold value varies depending on the amount of heat of laser light and the material of the member to be welded in a state where there is no contamination. For example, when the heat amount that can be welded from the beginning is set, the threshold value is increased to 90% of the original, and the heat amount in a clean state is increased with a margin more than the heat amount that can be welded. If it has been set, it may be set as appropriate, such as about 70%.

  In order to change the posture of the robot, it is determined by referring to the teaching data whether or not the laser beam is transmitted through an area where the contamination level is high, and if the laser beam is transmitted through an area where the contamination level is high. If so, the robot posture data in the teaching data is rewritten so that the laser beam is transmitted through a non-dirty area or an area with a low degree of dirt, and thereafter there is no (or little) dirt according to the rewritten data. Make sure that welding is done from the area. For such rewriting of teaching data, for example, the teaching data may be rewritten by changing the robot posture from the teaching box 8 while visually observing which region the laser light is transmitted through irradiation with visible laser light. .

  Next, the second method of use in welding with stopping the movement of the laser beam is to use the region where the degree of contamination is high as it is, but lengthen the laser irradiation time to contaminate the heat input to the welded member. It is a method of making the state without the same level.

  In this method, basically, in a contaminated area, the laser irradiation time in that area is lengthened in order to increase the amount of heat input to the member to be welded by the laser light in accordance with the degree of dirt in that area. Specifically, for example, if the amount of heat when the degree of contamination is not dirty is 100%, and there is a region where the amount of heat has decreased by 10%, the irradiation time of the laser beam is increased when the laser beam passes therethrough. is there. Further, a range reference for dividing the degree of contamination in stages may be determined in advance, and the laser irradiation time may be increased for each range.

  Next, a method for using the dirt determination result in the second welding method will be described.

  Also in the second welding method, it is possible not to use a region with a high degree of contamination as in the first usage method. However, since the second welding method performs welding while drawing a predetermined welding pattern continuously, it is difficult to change the posture of the robot 1 only when it reaches a dirty area in the continuous welding pattern. Therefore, it is necessary to recreate teaching data that avoids a region with a high degree of contamination throughout the entire welding pattern.

  Of course, such a method is also possible. However, since it takes a lot of time to recreate the teaching data, it is preferable to apply the second usage method with a slight modification. That is, when transmitting a region having a high degree of contamination among regions that are transmitted when drawing a predetermined welding pattern, the moving speed of the reflecting mirror 11 is slowed down, and the member to be welded when the region is transmitted The amount of heat input is increased. By this method, it is only necessary to instruct to change a part of the speed of the reflecting mirror 11 in the teaching data without correcting the teaching data such as the robot posture change for drawing the welding pattern. Therefore, a relatively simple correction is sufficient.

  However, in the case of a region where the degree of contamination is too high (for example, a region where the measured amount of heat is less than 50%) or the region of the contamination is wide (for example, the measured amount of heat is less than 75%) If the area becomes more than half of the protective glass surface), if you continue to use these areas as they are, there will be too many areas where the speed for drawing the welding pattern has to be reduced. Cause the work time to be delayed. Therefore, in these cases, it is better to change the entire teaching data so as to use a region with a low degree of contamination as the entire welding pattern, or to wash or replace the protective glass itself.

  Next, the method shown in FIG. 7B selectively scans only a region (pattern) that is planned to transmit laser light during a welding operation among a plurality of regions, and determines only the degree of contamination of that portion. It is a method to do.

  In this method, the amount of heat is measured by irradiating the calorimeter 51 with the laser light by relatively moving the surface of the protective glass so that the laser beam becomes a welding pattern in actual welding. Then, the value of the heat quantity in each area is stored in a storage device (for example, a hard disk) in the computer 52 together with a name for identifying the area (area coordinates, symbols, etc.). Then, the contamination is determined by comparing the measured heat quantity with a reference value. The determination result is stored in the computer 52 together with the name and coordinates of each area. The reference value is the same as described above.

  There is only one use of the dirt determination result measured by this method. In a dirty area, the amount of heat input to the member to be welded by laser light is increased in accordance with the degree of dirt in the area. That is, the laser irradiation time in each region is lengthened according to the degree of contamination. More specifically, for example, if the degree of contamination is 100% and the amount of heat is 100%, and there is a region that has been reduced by 10% as a result of the contamination determination, Increase the irradiation time. Further, a range reference for dividing the degree of contamination in stages may be determined in advance, and the laser irradiation time may be increased for each range.

  When the method shown in FIG. 7B is used, the degree of contamination in the region to be the welding pattern is too high (for example, there is a region in which the measured amount of heat is less than 50%). Or, if the area of dirt is wide (for example, the area where the measured heat quantity is less than 75% is more than half of the welding pattern), if these areas are used as they are, welding There are too many areas where the speed for drawing the pattern has to be reduced, which causes the work time of the entire welding process to be delayed. Therefore, in these cases, instead of the above-described method shown in FIG. 7A for scanning the entire surface of the protective glass, the amount of laser light on the entire surface of the protective glass is measured once again, and there is a region with low contamination. If this is the case, change the entire teaching data so that the entire weld pattern uses a low-stained area, or clean or replace the protective glass itself without performing such a full scan. Better.

  FIG. 8 is a diagram illustrating an example of a welding pattern.

  The welding pattern is, for example, S-shaped as shown in FIG. 8 (a), C-shaped as shown in FIG. 8 (b), and shown in FIG. 8 (c) at one welding point B of the member W to be welded. Various shapes such as an I shape (bar shape) can be used.

  In addition, in the state which stopped the laser welding apparatus 3, when irradiating a laser beam toward several welding points by changing the direction of a reflective mirror, in order to judge dirt on a protective glass surface according to them It is preferable to set the scanning path.

  FIG. 9 is a flowchart showing an operation procedure for determining the degree of contamination described above.

  In the contamination degree determination, as posture control of the robot 1, teaching data for relatively moving the protective glass 18 with the laser light irradiation point directed toward the calorimeter 51 is used in advance. Prepare as.

  First, the computer 52 instructs the robot controller 7 to execute laser irradiation toward the calorimeter 51 using the teaching data for determining the degree of contamination (S1). At this time, a scanning pattern for scanning the surface of the protective glass 18 is input to the computer 52 in advance. In response to this command, the robot controller 7 controls the robot posture and the movement of the reflecting mirror 11 so as to obtain a predetermined scanning pattern by the laser beam, and irradiates the laser beam.

  The computer 52 acquires the calorimetric measurement result by the calorimeter 51 simultaneously with the start of laser irradiation (S2). The acquired result is stored together with the acquisition time.

  Subsequently, the computer 52 receives from the robot control device that the operation based on the teaching data for dirt determination has been completed (S3: Yes), and the laser beam that moves according to the acquired heat value and scanning pattern for each time passes through each region. The amount of heat in each region is obtained by comparing with the time to perform (S4). At this time, when the scanning pattern is set so that the laser beam is transmitted through a plurality of locations in one region, the lowest heat value in one region is recorded as the heat amount of the region. Note that the robot control apparatus outputs a signal indicating that after the completion of one scanning pattern, as teaching data executed when the degree of contamination is determined.

  Subsequently, the computer 52 compares the reference value with the recorded value of the amount of heat in each area to determine the degree of contamination (S5). Then, the process ends.

  The obtained degree of contamination of each area may be stored in the storage device of the computer 52 so that it can be retrieved later. Of course, the data may be output to a display or printer connected to the computer 52 on the spot.

  Thereafter, as described above, the determination result of the degree of contamination is used for adjusting the heat input amount during actual welding, changing teaching data, or cleaning or replacing the protective glass.

  Although the embodiment of the present invention has been described above, the present invention is not limited to such an embodiment.

  For example, as another embodiment, the degree of contamination may be determined by irradiating visible light from the laser irradiation device 3 and measuring the visible light wax. As described above, the laser oscillator has a function of irradiating visible light (visible laser) so that the locus of the laser light can be seen in addition to the laser light actually used for welding. . Therefore, this visible laser is transmitted through each area set in the protective glass, and the amount of light is electrically converted by a photoelectric converter such as a Cd cell, solar cell, photodiode, CCD type (or MOS type) area sensor. By measuring, the degree of contamination can be determined from the amount of light that passes through each region of the protective glass. In this case, in particular, when a solar cell, an area sensor, or the like is used, the measurement area can be widened. Therefore, only by switching the irradiation light to the visible laser, the robot posture (that is, the movement of the laser irradiation device 3) and Even if the movement of the reflecting mirror 11 is exactly the same as that of the welding operation capability machine, the irradiated visible laser does not deviate from a wide measurement area. Therefore, it is not necessary to separately teach the robot posture and the Hann's copying motion for the dirt determination.

  Even in the case of using a visible laser in this way, the basic method for determining dirt, that is, dividing the protective glass surface into a plurality of areas and performing the dirt determination for each area is the same as in the above-described embodiment. Good. In addition, even when a visible laser is used, the determination result indicates how much light transmittance falls below 100% transmittance when the state is not soiled. It can be used to control the amount of heat input by the laser beam.

  Further, as another embodiment, the area of the protective glass surface is not divided into equal sizes, but the portion where the presence or absence of dirt is desired to be finely divided is divided into fine and small areas, and the influence of the dirt is not great. The portion may be roughly divided. Specifically, for example, as shown in FIG. 10, the central portion 301 of the protective glass, which is a portion through which laser light is often transmitted during welding, is finely divided, and the peripheral portion 302 is roughly divided. By doing in this way, the division | segmentation number of protection glass can be decreased and the processing time at the time of dirt determination can be made quick.

  In addition, it goes without saying that the present invention can be variously modified.

  The present invention is suitable for welding and processing using a laser such as laser welding and laser cutting.

1 is a schematic view of a laser welding system. It is an internal structure figure of a laser irradiation apparatus. It is an internal structure figure of a laser oscillator. It is a top view which shows an example of the area | region division of a protective glass surface. It is a figure which shows an example of the irradiation state of the laser beam with respect to a calorimeter. It is drawing for demonstrating the method for moving a protective glass surface relatively with respect to a laser beam. It is explanatory drawing explaining the scanning method at the time of permeate | transmitting the laser beam in a protective glass surface. It is drawing which shows the example of a welding pattern. It is a flowchart which shows the operation | movement procedure of dirt degree determination. It is a top view which shows the other example of the area | region division of a protective glass surface.

Explanation of symbols

1 ... Robot,
2 ... arm,
3 ... Laser irradiation device,
5 ... Laser oscillator,
6 ... Optical fiber cable,
7 ... Robot controller,
8 ... Teach box,
9 ... CAD system,
11 ... Reflector,
12 ... lens group,
18 ... protective glass,
21 ... Teaching data storage unit,
22 ... Robot controller,
23. In-area welding data storage unit,
23 ... Welding pattern storage unit,
24 ... Welding pattern generator,
25. Laser beam scanning control unit,
26 ... instruction part,
51 ... Calorimeter,
52 ... Computer,
100: Laser light,
121 ... collimating lens,
122 ... Condensing lens.

Claims (11)

Transparent protection for determining the degree of contamination of the transparent protective plate of a laser processing apparatus provided with a reflecting mirror that changes the irradiation direction of the laser light and provided with a transparent protective plate that covers the exit from which the laser light is emitted A board dirt judging device,
A measuring unit that divides a surface of the transparent protective plate through which the laser beam is transmitted into a plurality of regions, and measures an amount of light transmitted through an arbitrary region of the plurality of regions;
From the amount of light measured by the measurement means, a determination means for determining the degree of contamination of the transparent protective plate for each arbitrary region;
Moving means for moving the laser processing apparatus;
By moving the moving means and the reflecting mirror, the light reflected by the reflecting mirror is always irradiated to the measuring means whose position is fixed, and the light is sequentially transmitted through the arbitrary region. Control means for controlling the moving means and the reflecting mirror , and
By controlling the moving means and the reflecting mirror, the position of the transparent protective plate is moved relative to the light transmitted through the transparent protective plate while keeping the light irradiation direction constant. And measuring the amount of the light transmitted through the arbitrary region. The transparent protective plate contamination determination apparatus according to claim 1, wherein the arbitrary region is all of the plurality of divided regions. The arbitrary area is a transparent protective plate blot determination device according to claim 1, characterized in that the area of the plan to transmit the laser beam during welding. It said measuring means includes a transparent protective plate blot determination apparatus according to any one of claims 1-3, characterized in that said laser beam is a calorimeter for measuring the heat quantity when illuminated. The said measuring means is a photoelectric converter which measures the light quantity of the visible light reflected so that it may permeate | transmit the said transparent protective plate with the said reflecting mirror, The any one of Claims 1-3 characterized by the above-mentioned. Transparent protective plate dirt judgment device. Transparent protection for determining the degree of contamination of the transparent protective plate of a laser processing apparatus provided with a reflecting mirror that changes the irradiation direction of the laser light and provided with a transparent protective plate that covers the exit from which the laser light is emitted A method for determining board contamination,
The surface of the transparent protective plate through which the laser light is transmitted is divided into a plurality of regions, and the moving direction of the laser processing apparatus and the reflecting mirror are controlled to keep the light irradiation direction constant. Measuring the amount of the light transmitted through an arbitrary region of the plurality of regions by moving the position of the transparent protective plate relative to the light transmitted through the transparent protective plate; A transparent protective plate contamination determination method, comprising: determining a degree of contamination of the transparent protective plate for each of the arbitrary regions from an amount. The transparent protective plate contamination determination method according to claim 6 , wherein the arbitrary region is all of the plurality of divided regions. The arbitrary area is a transparent protective plate blot determination method according to claim 6, wherein the a region of the plan to transmit at least said laser beam. The transparent protective plate contamination determination method according to any one of claims 6 to 8 , wherein the light transmitted through the arbitrary region of the transparent protective plate is the laser light or visible light. A laser processing method using the transparent protective plate blot determination device according to claim 1 to 5, wherein,
A laser processing method, wherein an amount of heat input to a member to be processed by the laser light transmitted through each region is controlled according to a degree of contamination of each region determined by the determination unit. A laser processing method using the transparent protective plate blot determination device according to claim 1 to 5, wherein,
A laser processing method in which the laser beam is emitted while avoiding a region having a degree of contamination determined that the laser beam is attenuated in the region determined by the determination unit.

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