JP2000288752A - Method and device for laser beam machining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a laser beam machining method which has a deep machined groove not realized in a conventional way for a metal material and obtains marking of higher usage. SOLUTION: In a laser beam machining in which a marking part to mark an object to be worked is irradiated with a laser beam set for an output condition for marking, its surface part is fused/evaporation-removed and its trace is used for marking, in a process irradiating a laser beam to a marking part, laser beam irradiating 1a, 1b are repeated in plural times for the same marking part, further, a first irradiating position is made different from a second irradiating position in the range obtained an irradiating width of the laser beam and the property of the object to be worked.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser processing method and apparatus, and more particularly to a laser processing for marking figures, characters, and the like on the surface of a metal material using a laser beam.

[0002]

2. Description of the Related Art A metal that focuses a laser beam to a high energy density using a focusing optical component such as a processing lens and irradiates the workpiece with an assist gas such as oxygen, air, nitrogen, and argon. In laser cutting of materials, it is possible to melt and evaporate and remove only the surface of the workpiece by adjusting the output conditions of this laser beam, processing speed, type of assist gas, injection pressure, etc. A so-called laser marking processing method using a trace for a scribe line or the like has been widely used.

[0003]

As described above, as described above,
In the conventional laser processing method, the processing path of the marking portion created by the NC program or the like must be irradiated with a laser beam set to an extremely small energy, and the processing groove by this method has only a very shallow depth. I couldn't get it. For this reason, if surface treatment such as painting, plating and polishing is performed in the process after the laser marking process, there is a problem that the quality becomes difficult to see or sometimes disappears.

On the other hand, if the energy of the laser beam to be irradiated is set to be large in order to increase the depth of the processing groove, the scattering and adhesion of the molten material around the processing groove when the work is irradiated is increased, and Deteriorate the quality of the workpiece. Also, a method of repeatedly irradiating a marking process with a laser beam having an extremely small energy on the same path a plurality of times is a known method, but it is difficult to remove a melt remaining on a processing groove, and the melt is gradually removed. Is accumulated,
It is difficult to create a machining groove with a uniform depth because it hinders uniform beam irradiation to the machining groove. Furthermore, self-burning (abnormal combustion), etc., due to the increased melt disturbing the appropriate beam irradiation environment It may also cause damage to the processing machine due to triggering or interference with the processing nozzles and sensors. For the reasons described above, conventionally, it has been difficult to perform marking processing with a large depth using a laser beam.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and provides a laser processing with a marking which has a deep machining groove which has not been realized conventionally and has a higher utility value. It is intended to make it possible. Further, with respect to the marking processing by a laser processing machine, it is another object to pay attention to the depth of the processing groove, to obtain a processing groove with a greater depth, and to realize a marking processing capable of controlling the depth.

[0006]

A laser processing method according to the present invention irradiates a laser beam having output conditions and the like set for marking processing to a marking processing portion on which a marking of a workpiece is to be formed. The part is melted and evaporated and removed, and the trace is utilized as marking.In the step of irradiating the laser beam to the marking processing part, while repeating the laser beam irradiation for the same marking processing part a plurality of times, The first irradiation position and the second irradiation position are made different within a range determined from the irradiation width of the laser beam and the characteristics of the workpiece.

Further, a laser processing apparatus according to the present invention
A laser beam with output conditions set for marking processing is applied to the marking processing area where marking is to be formed on the workpiece to melt and evaporate and remove the surface, and the traces are used as marking. When performing the laser marking on the workpiece, when processing to the desired depth or width of the processing groove, the processing conditions for each material, the number of repetitive irradiations to the marking processing portion, the laser beam Holds information on the amount of shift when repeatedly irradiating, and uses the NC controller for laser processing machine or the NC data creation programming device for laser processing to set the settings for performing marking processing according to the desired conditions. It has setting means that can be automatically selected and executed.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 Hereinafter, a laser processing method according to the first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is about to apply a marking method according to this embodiment to a steel plate. In the figure, reference numeral 1a denotes a first irradiation laser beam;
b is the laser beam to be irradiated for the second time, 1c is the traveling direction of the laser beam, and 1d is the axial feed movement.

In the first stage, first, the laser beam 1a irradiates the marking processing portion specified by the NC data or the like, ie, the processing path of the marking portion, and when the processing of the marking portion is completed, the laser beam 1a is irradiated in the second stage. It returns to the start position where irradiation started by axis movement 1d. In the third stage, the processing path irradiated by 1a is irradiated again, but at this time, 1b is slightly shifted from the processing path of 1a. The size of the shift (shift amount) is within the range of the groove width by one processing,
The optimum value for obtaining a stable machining groove is selected in consideration of the beam width, the characteristics of the workpiece, the influence of the melt remaining in the machining groove, and the like. By repeating this step, the depth and width of the processing groove can be increased.

In the laser processing method according to this embodiment, an appropriate shift amount at the time of beam irradiation is affected by a beam width irradiated at the time of marking processing and characteristics of a workpiece. For example, when the shift amount is small with respect to the beam width, it becomes susceptible to the melt remaining in the processing groove, and it is difficult to obtain a stable processing groove depth and quality. Further, when the shift amount is large, the depth of the processing groove becomes small, and when the shift amount is larger than the beam width, one processing groove is not formed. Therefore, when the beam width, the characteristics of the workpiece, and the like are taken into consideration, there is an optimum shift amount for performing deep marking processing of the processing groove. Since the optimum shift amount varies depending on the marking beam processing conditions and the type of the workpiece, an appropriate size must be set in each case.

FIG. 2 shows the state of beam irradiation when the marking section is dug. By repeating the steps of the first embodiment, it is possible to increase the depth of the processing groove of the marking processing portion to some extent, but it does not increase beyond a certain depth. This is because the deeper the processing groove, the lower the energy density of the irradiated laser beam, and the more difficult it becomes to melt the workpiece. In FIG. 2, a laser beam focusing point 2a
The beam cross section of the portion has the highest energy density. FIG. 3A shows the state of the energy intensity distribution in the cross section 2a. From FIGS. 2 and 3, it can be said that the energy density decreases as the distance from the focal point 2a increases, and the energy density at the cross section 2d in FIG. 2 does not have energy for melting the workpiece. 3d in FIG. 3 is the intensity distribution at the cross section 2d.

Therefore, in this case, the energy density of the beam cross section at the position 2c in FIG. 2 is considered to be a limit point at which the workpiece can be melted, that is, a threshold value. Therefore, when trying to obtain a groove deeper than this,
A method of changing the position of the focal point in accordance with the depth of the groove and holding a portion having a high energy density at the position of the irradiation surface can be considered. However, if the depth is about several millimeters, it is not necessary to take such a complicated processing method for a sufficient marking processing. Rather, based on this phenomenon,
It is necessary to set an efficient beam irradiation position shift amount and the number of times of processing without wasting the processing time unnecessarily.

FIG. 4 is a pictorial illustration of a state of a melt generated in a processing groove when a marking is performed by repeatedly irradiating the same processing path with a beam. It is sectional drawing. FIG. 9 shows an example of a conventional processing method to be compared. In FIG. 9, 9a → 9b → 9c shows the case where the beam irradiation position is not shifted and the same position is repeatedly irradiated with the beam. In the case of the method shown in FIG. 9, since the melt remaining in the processing groove absorbs energy even when the next beam is irradiated, the depth of the processing groove does not easily increase. In addition, since the molten material accumulates irregularly, when the beam is irradiated to the large accumulated portion, the molten material may cause self-burning (abnormal combustion) or interfere with the processing nozzles and sensors, etc. May also be damaged.

4a → 4b → 4c shown in FIG. 4 shows a state in which the optimum beam irradiation position shift amount is set and the beam is repeatedly irradiated. When the next beam is irradiated, the melt remaining in the machining groove accumulates so that the beam is shifted toward the opposite side, and the influence of the melt on the beam irradiation position becomes very small. . Therefore, a uniform and deep machining groove can be efficiently completed in a short time. The melt remaining in the processing groove can be easily removed with a brush or the like after the processing.

FIG. 5 shows the results obtained by using a mild steel material as a workpiece and changing the shift amount, which is the most important parameter in performing high quality marking, to irradiate the beam five times each. It is the experimental result which measured the depth of the processed groove | channel obtained. From this result, if the shift amount is 0.1 mm or less, the efficiency of removing the melt is poor, so that it is difficult to obtain a machining groove having a uniform depth. If it is 3 mm or more, the processing groove is shallow, and the unevenness of the inner surface of the groove becomes large. Therefore, in this case, it can be understood that the shift amount of 0.1 to 0.3 mm is optimal. In addition, since the processing groove width in the single irradiation at this time was about 0.6 mm, it can be seen that the optimum shift amount with respect to the beam width is 20 to 50% of the groove width.

FIG. 6 shows a method equivalent to the experiment of FIG.
It is the experimental result which measured the depth of the processing groove | channel obtained when increasing the number of times each time and irradiating a beam. From this result, it was hardly possible to change the depth of the processing groove when the shift amount was 0.3 mm or more, but the depth of the processing groove was still in the range of 0.1 to 0.3 mm which is considered to be the optimum shift amount. Could be increased. From this,
It can be said that the depth of the processing groove can be selected by the number of times of repeated beam irradiation.

FIG. 7 shows the measurement results of the processing groove width according to the embodiment shown in FIGS. Naturally, the processing groove width increases as the shift amount increases and the number of repetitive processing increases, but by storing such information, the beam irradiation frequency can be selected from the processing groove width. It can be said that.

Embodiment 2 FIG. FIG. 8 is a diagram for selecting a marking processing condition, a beam irradiation shift amount, and the number of times of processing required for processing from information on the depth or width of a processing groove.
This is an example of a configuration using an NC control device or an NC data creation programming device for laser processing.

An NC control device of a laser processing machine or a programming device for creating NC data for laser processing includes:
The processing conditions for marking according to the material of the workpiece, the shift amount at the time of beam irradiation that is optimal for each processing condition for marking, and when the processing condition for each marking is repeatedly irradiated with the optimum shift amount to the workpiece It has information about the depth and width of the processing groove with respect to the number of irradiations, and when processing is performed, information on the quality of the required marking processing, such as the material of the workpiece and the depth and width of the processing groove. By entering
The processing conditions for marking according to the material of the workpiece, the shift amount at the time of beam irradiation that is optimal for each processing condition for marking, and when the processing condition for each marking is repeatedly irradiated with the optimum shift amount to the workpiece From a plurality of pieces of information about the depth and width of the processing groove with respect to the number of irradiations, the marking processing conditions, the amount of shift at the time of beam irradiation, and the number of times of repeated beam irradiation are automatically selected and executed according to the desired conditions. Can be.

In this example, first, the type of the material of the workpiece is input. Based on this information, a marking processing condition and a shift amount of the beam irradiation position according to the processing condition are selected. Next, the required depth or width of the marking process is input. Here, if the depth is input, the necessary number of times of processing is selected from the information on the number of repetitive irradiations and the depth of the processing groove with the optimum amount of shift of the selected marking condition. If the width of the processing groove is input, the necessary number of processing is selected from the information on the number of times of repeated irradiation and the width of the processing groove in the selected marking condition by the optimum shift amount. Thereby, the marking processing conditions, the shift amount of the beam irradiation position, and the number of times of repeated irradiation are set and executed.

[0021]

As described above, according to the laser processing method of the present invention, in the marking processing using a laser beam, the influence of the molten material due to the irradiation of the beam remaining in the processing groove in the previous process is reduced. The effect is that deep and uniform processing grooves can be obtained.

When there is a demand for the depth and width of a processing groove in the marking processing using a laser beam, the selection of the marking processing condition, the optimum shift amount of the beam repetitive irradiation, the beam repetition, By automatically selecting the number of times of irradiation using an NC controller of a laser processing machine or a programming device for creating NC data for laser processing, it is possible to efficiently obtain marking quality as required. Play.

[Brief description of the drawings]

FIG. 1 is a diagram showing a laser processing method according to a first embodiment of the present invention.

FIG. 2 is an explanatory view showing a state of beam irradiation when a processing groove by the marking processing is deepened.

FIG. 3 is an explanatory diagram showing a state of a beam energy density according to an irradiation position in the state of FIG. 2;

FIG. 4 is an explanatory view showing a state of a melt generated in a processing groove when there is a beam irradiation position shift amount when the same marking processing section is repeatedly irradiated with a beam.

FIG. 5 is a diagram illustrating a relationship between a shift amount and a processing groove depth in a marking process in which a beam is irradiated to the same marking processing unit five times.

FIG. 6 is a diagram showing a relationship between a shift amount and a machining groove depth in a marking process in which the same marking portion is irradiated with a beam ten times at a time.

FIG. 7 is a diagram showing measurement results of the marking grooves shown in FIGS. 5 and 6;

FIG. 8 is a flowchart of an example of a configuration by an NC control device or an NC data creation programming device for laser processing for selecting a marking processing condition, a shift amount of beam irradiation, a processing frequency, and the like.

FIG. 9 is an explanatory view showing a state of a melt generated in a processing groove when a beam is repeatedly irradiated on the same path by a conventional processing method.

[Explanation of symbols]

1a Laser beam irradiated for the first time in marking processing 1b Laser beam irradiated for the second time in marking processing 1c Propagation direction of laser beam 1d Axial feed movement 2a 3a Energy intensity distribution at beam position indicated by energy intensity distribution of 3a 2b 3b The beam position indicated by 2c The beam position indicated by the energy intensity distribution of 3c 2d The beam position indicated by the energy intensity distribution of 3d 3a The energy intensity distribution by the beam cross section of 2a 3b The energy intensity distribution by the beam cross section of 2b The energy intensity by the beam cross section of 3c 2c Distribution 3d Energy intensity distribution by 2d beam cross section

Claims (2)

[Claims] 1. A laser beam having output conditions and the like set for a marking process is irradiated to a marking processing portion where a marking of a workpiece is to be formed, and its surface is melted and evaporated to remove the trace as a marking. In the laser processing method to be utilized, in the step of irradiating the laser beam to the marking processing section, the laser beam irradiation is repeated a plurality of times on the same marking processing section, and the irradiation width of the laser beam and the characteristics of the workpiece are determined. A laser processing method characterized by differentiating a first irradiation position and a second irradiation position within the obtained range. 2. A laser beam having output conditions and the like set for a marking process is irradiated to a marking processing portion where a marking of a workpiece is to be formed, and its surface is melted and evaporated to remove the trace as a marking. In the laser processing apparatus to be utilized, when performing the laser marking processing on the workpiece, when processing to a desired depth or width of a processing groove, a processing condition for each material, a processing condition for a marking processing part. Holds information on the number of repetitive irradiations and the amount of shift when repetitively irradiating a laser beam, and performs marking processing according to desired conditions using an NC controller for laser processing machine or NC data creation programming device for laser processing. A laser processing apparatus having setting means for automatically selecting and executing settings for performing Place.