JP2010125502A - Laser beam machining method, and laser beam machining apparatus - Google Patents

Abstract

[PROBLEMS] To improve the efficiency of welding in plated metal, and to improve the guarantee accuracy of joining quality by terminating laser irradiation so that the joining depth is appropriate. In addition, a laser processing method and a laser processing apparatus that can set welding conditions in a short time and at a low cost are provided.
During irradiation with a low-power laser beam, the state where the intensity of the reflected light once rises and then falls below a first predetermined value continues for a first predetermined time. Based on this, the output intensity of the laser beam is adjusted to a high output, and while the high output laser beam is being irradiated, the intensity of the reflected light increases again and then decreases to a second predetermined value or less. The output intensity of the laser beam is adjusted to 0 based on continuing for the second predetermined time.
[Selection] Figure 2

Description

  The present invention relates to a laser processing method and a laser processing apparatus, and more particularly to a technology for improving the accuracy of welding quality and the efficiency of welding processing in laser beam welding.

Conventionally, a technique for processing a metal with a laser beam, for example, a technique for welding two kinds of metal with a laser beam, is used. In order to improve the processing efficiency at this time, the absorption rate of the laser beam on the metal surface is used. In other words, it is necessary to reduce the reflectance of the laser beam on the metal surface.
It is known that the laser beam absorption rate on the metal surface is improved by melting the metal surface in the processing using the laser beam. For this reason, in the initial stage of processing, a low-power laser beam is irradiated, and after the metal surface is melted and the laser beam absorption rate is improved, a high-power laser beam is irradiated, that is, laser output is stepwise. There is known a technique for improving the processing efficiency by increasing the value (for example, Patent Document 1, Patent Document 2, and Patent Document 3).

In the above prior art, for example, Patent Document 1 discloses processing by irradiating a laser beam with a long wavelength (high output) after irradiating a laser beam with a short wavelength (low output) to melt the metal surface. Techniques for improving efficiency are described.
In Patent Document 2, the reflected light intensity and thermal radiation light intensity of the laser beam from the processing point are measured during the laser beam irradiation, and the reflected light intensity decreases and the degree of increase of the thermal radiation light intensity slows down. A technique for ensuring the quality such as the bonding strength by increasing the intensity of the laser beam at this point is described.
Furthermore, in Patent Document 3, a correction coefficient is obtained by measuring the relationship between the output intensity of the laser beam under optimum welding conditions and the reflectance in advance, and the reflectance of the laser beam is measured during laser welding. However, there is described a technique for improving the processing efficiency and ensuring the bonding quality by controlling the output intensity of the laser beam.
JP-A-5-104276 JP 2004-58141 A JP-A-3-248789

  In the laser welding process, for example, the surface of one of the objects to be welded is plated, and laser welding may be performed from the plated metal side. In this case as well, as described above, the plating portion is first irradiated with a low-power laser beam to melt the plating portion, and the laser beam absorption rate in the object to be processed is improved, and then the high-power laser beam is irradiated. It is possible to improve the processing efficiency by melting the base material. In other words, when the plating part is melted, the absorption rate of the laser beam in the processing object increases and the intensity of the reflected light once decreases, and then the laser beam is changed to a high output, so that it can be efficiently performed in a short time. Welding can be performed.

  However, according to the technique described in Patent Document 1, the laser beam in the processing target is not configured to change the short-wavelength laser beam to the long-wavelength laser beam in response to the intensity change of the reflected light of the laser beam. The laser beam output could not be changed appropriately in response to the increase in the absorption rate of the laser beam, and it was difficult to perform efficient welding as described above.

  Further, not only the bonding strength but also the bonding depth and width affect the bonding quality of laser welding. Here, if the joining depth of the laser welding process is shallow, the penetration is insufficient and the joining strength is reduced. On the other hand, even if the bonding depth is too deep, the bonding strength can be ensured, but on the other hand, other electronic components may be damaged due to melting. In other words, in order to ensure the accuracy of joining quality assurance, laser irradiation in laser welding processing is terminated at an appropriate timing after the metal base material to be joined has melted, thereby reducing the joining depth. It needs to be adjusted.

However, according to the techniques described in Patent Document 2 and Patent Document 3, although the configuration is such that the output intensity of laser irradiation is controlled based on changes in the reflected light intensity or reflectance of the laser light, the laser irradiation is performed. Since a technique for terminating at an appropriate timing is not disclosed, the above-described problem that the depth of the junction becomes too deep may occur.
Further, in the laser welding processing in the prior art, it is necessary to finish the welding at an appropriate timing as described above, and it is necessary to perform many preliminary experiments in order to set such welding conditions. The cost of expenses was great.

  Therefore, in the present invention, by controlling the output of the laser irradiation based on the intensity change of the reflected light, the efficiency of the welding process in the plated metal can be improved, and the joining depth becomes appropriate. Thus, the laser processing method and the laser processing apparatus that can improve the guarantee accuracy of the joint quality and can set the welding conditions in a short time and at a low cost by terminating the laser irradiation as described above. Is to provide.

  The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described.

  That is, in claim 1, the laser beam irradiation means capable of adjusting the output intensity of the laser beam irradiated to the workpiece to a low output or a high output, and the intensity of the reflected light of the laser beam at the workpiece are measured. Reflected light intensity measuring means; and laser beam output intensity adjusting means for adjusting the output intensity of the laser beam from the laser beam irradiating means based on the intensity of the reflected light measured by the reflected light intensity measuring means; The workpiece is formed by forming a plated portion on the surface of a base material, and the laser beam irradiating means irradiates a low-power laser beam. From the state where the intensity of the reflected light measured by the reflected light intensity measuring means is once increased due to melting of the plated portion of the workpiece surface. Based on the above, the laser beam output intensity adjusting means adjusts the output intensity of the laser beam from the laser beam irradiation means to a high output, and the laser beam irradiation means irradiates a high output laser beam. The laser beam output intensity is based on the fact that the intensity of the reflected light measured by the reflected light intensity measuring means has decreased from a once increased state due to melting of the workpiece base material during The adjusting means adjusts the output intensity of the laser beam from the laser beam irradiation means to zero.

  According to a second aspect of the present invention, the laser beam output intensity adjusting means obtains in advance the intensity of reflected light that has risen once in advance while the laser beam irradiation means is irradiating a low-power laser beam based on experimental results. In addition, when the value is reduced based on a numerical value corresponding to a state in which the plated portion of the workpiece surface is melted, and falls below a first predetermined value for a first predetermined time, the laser beam from the laser beam irradiation means The output intensity is adjusted to a high output, and while the laser beam irradiating means is irradiating a high output laser beam, the intensity of the reflected light that has risen once is obtained in advance by experimental results. The laser beam output intensity from the laser beam irradiating means is reduced to 0 when the value falls below a second predetermined value, which is set based on a numerical value corresponding to the melted state, for a second predetermined time. It is intended to integer.

  In Claim 3, the laser beam irradiation means which can adjust the output intensity of the laser beam irradiated with respect to a workpiece | work to low output or high output, and the reflection which measures the intensity | strength of the reflected light of the said laser beam in the said workpiece | work A light intensity measuring means; and a laser beam output intensity adjusting means for adjusting an output intensity of the laser beam from the laser beam irradiation means based on the intensity of the reflected light measured by the reflected light intensity measuring means. The workpiece is configured by forming a plated portion on the surface of a base material, and the workpiece surface is plated while the laser beam irradiation means is irradiating a low-power laser beam. Based on the fact that the intensity of the reflected light measured by the reflected light intensity measuring means has decreased from a state where it has once increased due to melting of the portion, The output intensity of the laser beam from the laser beam irradiation means is adjusted to a high output by the beam output intensity adjusting means, and the mother of the workpiece is being irradiated while the laser beam irradiation means is irradiating a high output laser beam. Based on the fact that the intensity of the reflected light measured by the reflected light intensity measuring means has decreased from a once raised state due to melting of the material, the laser beam output means adjusts the laser beam irradiation means. The output intensity of the laser beam from is adjusted to zero.

  According to a fourth aspect of the present invention, the laser beam output intensity adjusting means obtains in advance the intensity of the reflected light that has once increased while the laser beam irradiating means irradiates a low-power laser beam based on experimental results. In addition, when the value is reduced based on a numerical value corresponding to a state in which the plated portion of the workpiece surface is melted, and falls below a first predetermined value for a first predetermined time, the laser beam from the laser beam irradiation means While the output intensity is adjusted to high output and the laser beam irradiating means is irradiating the high output laser beam, the intensity of the reflected light that has once increased is obtained in advance by experimental results. When the laser beam irradiation means falls below a second predetermined value, which is set based on a numerical value corresponding to the melted state, for a second predetermined time, the output intensity of the laser beam from the laser beam irradiation means is 0. It is intended to be adjusted.

  As effects of the present invention, the following effects can be obtained.

  According to the present invention, in the laser welding process, the efficiency of the welding process in the plated metal can be improved, and by terminating the laser irradiation so that the bonding depth becomes appropriate, the bonding quality can be improved. The guarantee accuracy can be improved, and further, welding conditions can be set in a short time and at a low cost.

Next, embodiments of the invention will be described.
FIG. 1 is a schematic view showing a laser processing apparatus according to the present invention.
FIG. 2 is a graph showing the transition of the laser beam output intensity and the reflected light intensity of the laser beam in the laser processing method according to the present invention.
FIG. 3 is a flowchart showing the laser processing method according to the present invention.
It should be noted that the technical scope of the present invention is not limited to the following embodiments, and is widely applied to the entire scope of technical ideas that the present invention truly intends, as will be apparent from the matters described in the present specification and drawings. It extends.

[Laser processing apparatus 10]
First, a laser processing apparatus 10 according to the present invention will be described with reference to FIG.
As shown in FIG. 1, a laser processing apparatus 10 according to the present invention includes a laser beam irradiation unit 11, a reflected light intensity measurement unit 12, and a laser beam output intensity adjustment unit 13.

The laser beam irradiation means 11 for irradiating the workpiece W with the laser beam L is, for example, a YAG laser, and the output intensity thereof is reduced by changing the wavelength of the laser beam L with which the workpiece W is irradiated. Or it is comprised so that adjustment to high output is possible.
The reflected light intensity measuring means 12 is an optical sensor, for example, and measures the intensity of the reflected light R of the laser beam L on the workpiece W.
The laser beam output intensity adjusting means 13 is a control device having an input function, a display function, a storage function, a communication function, various calculation functions, and the like, and the reflected light measured by the reflected light intensity measuring means 12. It has a function of adjusting the output intensity of the laser beam L from the laser beam irradiation means 11 based on the intensity of R.

  That is, in the laser processing apparatus 10, the laser beam irradiation unit 11 irradiates the workpiece W with the laser beam L, and the reflected light intensity measurement unit 12 determines the intensity of the reflected light R of the laser beam L on the workpiece W. Based on the measured intensity of the reflected light R, the laser beam output intensity adjusting unit 13 adjusts the output intensity of the laser beam L from the laser beam irradiation unit 11 to perform laser welding. It is.

The workpiece W in the present embodiment is composed of a first joining object A and a second joining object B as shown in FIG. That is, the first joining object A and the second joining object B are joined to each other at the joint shown by the broken line in FIG. 1 by the laser beam L emitted from the laser processing apparatus 10 according to the present invention. It is.
Here, as for the 1st joining target object A arrange | positioned at the laser processing apparatus 10 side, the surface of the base material is plated. That is, the laser welding process according to the present invention is performed from the plated first object A to be joined. In the first joining object A in the present embodiment, there are copper, iron, stainless steel and the like as the material used for the base material, and tin and nickel are the material used for the plating part.

[Laser processing method]
Next, the laser processing method according to the present invention will be described with reference to FIGS.
FIG. 2 is a graph showing the transition of the output intensity of the laser beam L and the intensity of the reflected light R of the laser beam L in the laser processing method according to the present invention.
That is, in FIG. 2, the horizontal axis represents time, and the upper side of the horizontal axis represents the output intensity of the laser beam L irradiated to the workpiece W by the laser beam irradiation means 11. That is, the section P1 and the section P2 in FIG. 2 are irradiated with the low-power laser beam L by the laser beam irradiation means 11, and the sections P3 and P4 in FIG. It is shown that the laser beam L having a higher output than that in the section P2 is irradiated.

  On the other hand, the lower side of the horizontal axis indicates the intensity of the reflected light R of the laser beam L on the workpiece W measured by the reflected light intensity measuring means 12. That is, it is a transition of the intensity of the reflected light R when the laser processing apparatus 10 performs laser welding on the workpiece W, and the intensity of the reflected light R increases in each of the section P1 and the section P3 in FIG. It has been shown that it became smaller after a while.

As shown in FIG. 2, the laser processing method according to the present invention is measured by the reflected light intensity measuring means 12 while the laser beam irradiating means 11 is irradiating a low-power laser beam L (section P1). On the basis of the fact that the intensity of the reflected light R that has been temporarily increased and then decreased to the first predetermined value D1 or less (point A1) continues for the first predetermined time T1 (section P2). The laser beam output intensity adjusting means 13 adjusts the output intensity of the laser beam L from the laser beam irradiation means 11 to a high output (point B1).
Further, while the laser beam irradiation means 11 is irradiating the high-power laser beam L (section P3), the intensity of the reflected light R measured by the reflected light intensity measurement means 12 increases again. Based on the fact that the state (point A2) that has decreased below the second predetermined value D2 has continued for the second predetermined time T2 (section P4), the laser beam output intensity adjusting means 13 performs the laser beam irradiation. The output intensity of the laser beam L from the means 11 is adjusted to 0 (point B2 / section P5).

The flow of the laser processing method according to the present invention will be described in detail with reference to FIG.
First, the laser beam irradiation means 11 irradiates the workpiece W with a low-power laser beam L (step S1). At this time, the reflected light intensity measuring means 12 simultaneously measures the intensity of the reflected light R of the laser beam L on the workpiece W.

Next, whether or not the state in which the intensity of the reflected light R measured by the reflected light intensity measuring means 12 once increases and then decreases to the first predetermined value D1 or less continues for the first predetermined time T1. Is determined by the laser beam output intensity adjusting means 13 (step S2).
If it is determined in step S2 that the laser beam L has been absorbed for the first predetermined time T1, ie, the plating portion has melted, the absorption rate of the laser beam L on the object to be processed has increased and the intensity of the reflected light R has once decreased. Proceed to S3. If it is determined that the first predetermined time T1 has not been continued, that is, the plated portion has not yet melted, the process proceeds to step S1, and the processes of steps S1 to S2 are repeated.

  In step S3, the laser beam irradiation means 11 changes the laser beam L for the workpiece W to a high output (step S3). At this time, the reflected light intensity measuring unit 12 continues to measure the intensity of the reflected light R of the laser beam L on the workpiece W.

Next, whether or not the state in which the intensity of the reflected light R measured by the reflected light intensity measuring means 12 has increased again and then decreased to the second predetermined value D2 or less has continued for a second predetermined time T2. Is determined by the laser beam output intensity adjusting means 13 (step S4).
In step S4, the second predetermined time T2 is continued, that is, because the metal base material is melted, the absorptance of the laser beam L on the object to be processed is increased, and the intensity of the reflected light R is once reduced, and an appropriate bonding depth is obtained. If it is determined that the base material has melted, the process proceeds to step S5. If it is determined that the second predetermined time T2 has not been continued, that is, the base material has not yet been melted to an appropriate joining depth, the process proceeds to step S3, and the processes of steps S3 to S4 are repeated.

  In step S5, the irradiation of the laser beam L from the laser beam irradiation means 11 is stopped (step S5), and then the process is terminated.

In the laser processing method described above, the first predetermined value D1 and the first predetermined time T1 are set based on numerical values corresponding to a state in which the surface of the workpiece W is melted, which is obtained in advance from experimental results. Yes. Specifically, when the low-power laser beam L is irradiated, the plating portion melts, and the intensity of the reflected light R in the process of increasing the absorption rate of the laser beam L on the surface of the workpiece W is measured by experiment. A first predetermined value D1 is set based on the numerical value of the intensity of the reflected light R obtained at that time, and the first predetermined time is determined based on the time during which the intensity of the reflected light R has decreased to D1 or less and continued. T1 is set. For example, the first predetermined value D1 is a state in which the intensity of the reflected light R once increases and then decreases and begins to stabilize (a state in which the intensity of the reflected light R changes gradually), that is, the section shown in FIG. The intensity of the reflected light R in the state corresponding to the beginning portion of P2 may be set to about the intensity, and the intensity of the reflected light R obtained experimentally for the state corresponding to the section P2 is considered in consideration of variations in the molten state. It is better to set a slightly larger value. Further, the first predetermined time T1 may be set to such an extent that it can be reliably determined that the plated portion has melted, so that the entire period in which the intensity of the reflected light R once decreases and then stabilizes is reduced. Instead, the laser processing time can be shortened by quickly shifting the intensity of the laser beam L to a high output as part of the period as shown in FIG.
The second predetermined value D2 and the second predetermined time T2 are also set based on numerical values corresponding to a state in which the base material of the workpiece W is melted to a predetermined depth, which is obtained in advance from experimental results. It is configured to do. Specifically, when the base material of the workpiece W is melted when the high-power laser beam L is irradiated, the absorptance of the laser beam L in the workpiece W is increased, and the intensity of the reflected light R is temporarily reduced. The intensity of the reflected light R in the process of melting the base material to the joining depth is measured by experiment. A second predetermined value D2 is set based on the numerical value of the intensity of the reflected light R obtained at that time, and the second predetermined time is determined based on the time during which the intensity of the reflected light R has decreased to D2 or less. T2 is set. For example, the second predetermined value D2 is a state in which the intensity of the reflected light R once rises during the irradiation of the high-power laser beam L and then begins to stabilize (the change in the intensity of the reflected light R becomes gentle). State), that is, the intensity of the reflected light R in the state corresponding to the start portion of the section P4 shown in FIG. 2, and considering the variation in the molten state, the experiment is performed on the state corresponding to the section P4. It may be set to a value slightly larger than the intensity of the reflected light R obtained as a result.
By setting the first predetermined value D1, the first predetermined time T1, the second predetermined value D2, and the second predetermined time T2 as described above, the object to be processed, the bonding depth, the bonding width, etc. Processing can be performed correspondingly. For example, when the joining depth of the base material by the laser beam irradiation means 11 is deep or the joining width is wide, it takes time for the base material to melt to an appropriate joining depth. The time T2 is set long. On the contrary, when the junction depth is shallow or the junction width is narrowed, the second predetermined time T2 is set short.

In the present embodiment, in steps S2 and S4, the state in which the intensity of the reflected light R is temporarily increased from the first increased value to the first predetermined value D1 or the second predetermined value D2 or less is the first predetermined value. Although it is determined whether or not the time T1 has continued for the second predetermined time T2, it is possible to adopt a configuration different from the present configuration. In other words, the intensity change of the reflected light R is determined at a reduced ratio, and instead of the first predetermined value D1 and the second predetermined value D2, the first predetermined ratio R1 and the second predetermined ratio R2 from the peak value. It can also be configured to determine whether or not the state that has been reduced only by the first predetermined time T1 and the second predetermined time T2.
Here, the first predetermined ratio R1 is set based on a numerical value corresponding to a state in which the surface of the workpiece W is melted, which is obtained in advance by an experimental result in the same manner as described above. Specifically, when the low-power laser beam L is irradiated, the plating portion melts, and the intensity of the reflected light R in the process of increasing the absorption rate of the laser beam L on the surface of the workpiece W is measured by experiment. The first predetermined ratio R1 is set based on the ratio of the intensity of the reflected light R obtained from that time and the peak value.
In addition, the second predetermined ratio R2 is also set based on a numerical value corresponding to a state in which the base material of the workpiece W is melted to a predetermined depth, which is obtained in advance by experimental results. Specifically, when the base material of the workpiece W is melted when the high-power laser beam L is irradiated, the absorptance of the laser beam L in the workpiece W is increased, and the intensity of the reflected light R is temporarily reduced. The intensity of the reflected light R in the process of melting the base material to the joining depth is measured by experiment. The second predetermined ratio R2 is set based on the ratio at which the intensity of the reflected light R is reduced from the peak value.

As described above, in the laser processing method according to the present invention, at the beginning of the processing (section P1), the low-power laser is irradiated, and after the intensity of the reflected light R is once increased, the plated portion is melted first. The high-power laser is irradiated after the state (point A1) that has decreased below the predetermined value D1 or by the first predetermined ratio R1 from the peak value continues for the first predetermined time T1 (section P2). It is configured.
As a result, the absorption rate of the laser beam L is increased when the plated portion is melted, and the intensity of the reflected light R is once reduced. Therefore, by changing the laser beam L to a high output at an appropriate time at that stage, Welding can be performed efficiently in time.

Further, while the laser beam irradiation unit 11 is irradiating the high-power laser beam L (section P3), the intensity of the reflected light R measured by the reflected light intensity measurement unit 12 increases again. From the second predetermined value D2 or less, or based on the fact that the reduced state (point A2) from the peak value by the second predetermined ratio R2 continues for the second predetermined time T2 (section P4), The laser beam output intensity adjusting means 13 is configured to stop the irradiation of the laser beam L from the laser beam irradiation means 11.
By setting the second predetermined value D2, the second predetermined ratio R2, or the second predetermined time T2 as described above, the base material of the first joining target A is more appropriately melted. The irradiation of the laser beam L can be terminated at a proper timing. That is, the joining depth of laser welding can be made appropriate, and the guarantee accuracy of joining quality can be improved.

Further, in the laser processing method according to the present invention, the first predetermined value D1, the first predetermined ratio R1, the first predetermined time T1, the second predetermined value D2, and the second predetermined ratio R2 as described above. The second predetermined time T2 is set based on numerical values and ratios obtained in advance from experimental results.
As a result, the timing for changing and ending the output of the laser beam L can be made appropriate, laser processing is performed in accordance with various processing conditions, and the appropriate bonding depth and width, that is, the appropriate bonding strength. It becomes possible to obtain. That is, even if the portion to be processed is in a narrow range, the other electronic components are not damaged by melting and can be processed in an appropriate range.
In addition, it is not necessary to perform many preliminary experiments to set the welding conditions, and it is possible to reduce time and cost.

Schematic which shows the laser processing apparatus which concerns on this invention. The figure which showed transition of the laser beam output intensity in the laser processing method which concerns on this invention, and the reflected light intensity of a laser beam. The figure which showed the flowchart in the laser processing method which concerns on this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Laser processing apparatus 11 Laser beam irradiation means 12 Reflected light intensity measurement means 13 Laser beam output intensity adjustment means L Laser beam R Reflected light W Work A 1st joining object B 2nd joining object

Claims (4)

A laser beam irradiation means capable of adjusting the output intensity of the laser beam irradiated to the workpiece to a low output or a high output;
Reflected light intensity measuring means for measuring the intensity of reflected light of the laser beam in the workpiece;
A laser beam output intensity adjusting unit that adjusts the output intensity of the laser beam from the laser beam irradiation unit based on the intensity of the reflected light measured by the reflected light intensity measuring unit; A laser processing method,
The workpiece is configured by forming a plated portion on the surface of the base material,
While the laser beam irradiating means irradiates a low-power laser beam, the plated portion of the workpiece surface melts, so that the intensity of the reflected light measured by the reflected light intensity measuring means is once Based on the decrease from the raised state, the laser beam output intensity adjusting means adjusts the output intensity of the laser beam from the laser beam irradiation means to a high output,
While the laser beam irradiating means irradiates the high-power laser beam, the intensity of the reflected light measured by the reflected light intensity measuring means is temporarily increased by melting the base material of the workpiece. The laser beam output intensity adjusting means adjusts the output intensity of the laser beam from the laser beam irradiation means to 0 based on the fact that the state has been lowered from
The laser processing method characterized by the above-mentioned. The laser beam output intensity adjusting means is configured such that the intensity of reflected light that has once increased while the laser beam irradiating means is irradiating a low-power laser beam is obtained on the basis of the experimental result. The output intensity of the laser beam from the laser beam irradiating means is set to a high output when it is lowered for a first predetermined time below a first predetermined value, which is set based on a numerical value corresponding to the molten state of the plated portion. Adjust
While the laser beam irradiation means is irradiating a high-power laser beam, the intensity of the reflected light once increased is based on a numerical value corresponding to the molten state of the base material obtained in advance by experimental results. The output intensity of the laser beam from the laser beam irradiating means is adjusted to 0 when the value falls below the second predetermined value for a second predetermined time.
The laser processing method according to claim 1, wherein: A laser beam irradiation means capable of adjusting the output intensity of the laser beam irradiated to the workpiece to a low output or a high output;
Reflected light intensity measuring means for measuring the intensity of reflected light of the laser beam in the workpiece;
A laser beam output intensity adjusting means for adjusting an output intensity of the laser beam from the laser beam irradiation means based on the intensity of the reflected light measured by the reflected light intensity measuring means. And
The workpiece is configured by forming a plated portion on the surface of the base material,
While the laser beam irradiating means irradiates a low-power laser beam, the plated portion of the workpiece surface melts, so that the intensity of the reflected light measured by the reflected light intensity measuring means is once Based on the decrease from the raised state, the laser beam output intensity adjusting means adjusts the output intensity of the laser beam from the laser beam irradiation means to a high output,
While the laser beam irradiating means irradiates the high-power laser beam, the intensity of the reflected light measured by the reflected light intensity measuring means is temporarily increased by melting the base material of the workpiece. The output intensity of the laser beam from the laser beam irradiation means is adjusted to 0 by the laser beam output intensity adjusting means based on the fact that the state has been lowered from
The laser processing apparatus characterized by the above-mentioned. The laser beam output intensity adjusting means is configured such that the intensity of reflected light that has once increased while the laser beam irradiating means is irradiating a low-power laser beam is obtained on the basis of the experimental result. The output intensity of the laser beam from the laser beam irradiating means is set to a high output when it is lowered for a first predetermined time below a first predetermined value, which is set based on a numerical value corresponding to the molten state of the plated portion. Adjusted,
While the laser beam irradiation means is irradiating a high-power laser beam, the intensity of the reflected light once increased is based on a numerical value corresponding to the molten state of the base material obtained in advance by experimental results. The output intensity of the laser beam from the laser beam irradiating means is adjusted to 0 when the value falls below the second predetermined value set for a second predetermined time.
The laser processing apparatus according to claim 3, wherein:

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