JP3516560B2 - Laser processing method - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a laser cutting method for cutting a hole such as a round hole or a square hole in a workpiece such as a steel plate by a laser beam and assist gas.
In particular, the present invention relates to a laser processing method capable of eliminating adverse effects on products due to burning (abnormal combustion).

[0002]

2. Description of the Related Art Using laser light and assist gas,
The conventional processing method for cutting a workpiece such as a steel plate into a predetermined shape is to empirically find the optimum cutting conditions from the material and plate thickness of the workpiece, and then perform nozzle cutting based on the cutting conditions. The workpiece is positioned at the cutting start point, laser light is emitted from the nozzle, and processing is started at a predetermined cutting speed from the cutting start point.

In the vicinity of the introduction line portion of the hole shape of the thick steel plate, the small hole machining portion or the corner portion of the machining shape, the normal machining speed and the laser output machining conditions are changed to control for each material and plate thickness. Processing is performed based on the processing conditions such as the processing speed, laser output, assist gas pressure, pulse duty, etc. set in the machine, and after processing a specified length, switching to normal processing conditions again and processing. ing. In particular, the nozzle moving speed and the laser output are reduced in order to secure a machined shape in the small hole machining and the corner portion in the machining of a steel plate having a thickness of 9 mm or more, for example.

For example, in the case of small hole drilling of a workpiece 11 made of a steel plate, as shown in FIG. 11, a hole drilling line L3 is provided along a lead-in line L1 from a piercing point P1 at the start of the drilling.
The introduction groove 14 is formed by cutting to the upper processing start point P2. Further, at the portion reaching the hole drilling line L3, the hole drilling line L3 is entered and machined at a predetermined angle, a right angle, or a small arc locus. Then, by moving the nozzle from the processing start point P2 in the direction of the arrow of the hole processing line L3 and returning the nozzle to the processing start point P2, the hole processing groove 16 is formed, and the predetermined hole 17 is formed in the workpiece 11. Is forming.

[0005]

However, due to the turbulent flow of the assist gas ejected from the nozzle at the point P4 immediately before the machining end point P2 (also the same point as the machining start point P2) of the hole machining groove 16, Since heat is accumulated in the material 11 to be processed, melting loss occurs and there is a problem that a desired processed shape cannot be obtained. In the groove near the cutting start point P2, since the movement of the nozzle is changed by almost 90 degrees, the speed is temporarily slowed down, and even if the laser processing conditions are changed, compared to other processing parts.
Wide width (cutting groove width). Further drilling line L
At the cutting start point P2 of No. 3, if the introduction groove 14 is included,
The width of the groove is considerably wide, and the assist gas flows into the introduction groove 14 immediately before the end of the hole machining at the point P4 immediately before the machining end point, and the assist gas is turbulent to maintain the normal kerf width. In the vicinity of the point P4 immediately before, the following problem occurs.

Hole 1 having a diameter smaller than the plate thickness of the workpiece 11
In the processing of No. 7, as shown in FIG.
As shown in (a), the shape of the hole 171 on the front surface is circular to some extent, and the outer peripheral edge of the scrap portion 19 on the inner side is also substantially circular, and there is no particular problem. However, on the back surface of the material 11 to be processed, a scraped portion 191 is formed in the scrap portion 19 as shown in FIG. Part 1
There is a problem that the inner peripheral surface 172a corresponding to 91 has an irregular shape. Further, a residue 20 of the molten metal of the workpiece 11 is generated between the missing portion 191 and the inner peripheral surface 172a, and the residue 20 is scraped on the scrap portion 19 and the inner peripheral surface 1.
72a is welded, the drop of the scrap portion 19 from the hole 172 is prevented, and there is a problem that the drilling is impossible. Particularly, when the hole diameter is small, the scrap portion 19 becomes small and the weight thereof becomes light.
The welding force makes it difficult for the scrap portion 19 to drop.

The generation of the above-mentioned residue 20 will be explained as follows. That is, as shown in FIG. 9 , when the nozzle 12 is moved to the left in FIG. 9 , the laser beam 13 emitted from the nozzle 12 to the workpiece 11 is cut to the right toward the lower end of the workpiece 11. A delay occurs, and an uncut portion 111 is formed below the work material 11. Then, while continuing this state, the laser beam 13 flows out into the introduction groove 14 together with the assist gas in the process of moving the laser beam 13 from the point P4 immediately before to the processing start point P2. As a result, since the uncut portion 111 deviates from the normal cutting condition including the assist gas, the uncut portion 111 melts and becomes the residue 20. The residue 20 welds the scrap portion 19 to the peripheral surface 172a of the hole 172 to prevent the residue from falling. To be done.

Therefore, according to the conventional processing method, not only the processed shape of the hole 172 on the back surface side is deformed but also the workpiece 1 is processed.
There is a problem that the relationship between the thickness of No. 1 and the size of the hole 17 is restricted as shown by the chain line curve in FIG. That is, in FIG. 6, the thickness of the workpiece 11 is plotted on the horizontal axis and the hole diameter is plotted on the vertical axis, and the relationship between the minimum workable hole diameter and the thickness capable of obtaining an appropriate machined shape is obtained. Is. According to this graph, for example, when the material SS40 of the workpiece 11 has a thickness of 10 mm, the hole diameter is 8 mm or more and the thickness is 15 m.
m, the hole diameter is 12 mm or more, and the thickness is 20 mm,
There is a problem that the hole diameter is restricted to 22 mm or more.

The present invention has been made by paying attention to the problems existing in such a conventional technique, and the first purpose thereof is to relax the restrictions on the thickness and hole diameter of the workpiece. It is possible to provide a laser processing method capable of reliably and appropriately performing hole processing on a workpiece.

A second object of the present invention is to provide, in addition to the first object, a laser processing method capable of properly forming a cut groove. A third object of the present invention is, in addition to the above-mentioned first or second object, is to provide a laser processing method capable of performing an operation of returning a nozzle to a processing start point and improving processing efficiency.

A fourth object of the present invention is, in addition to any one of the first to third objects, is to machine a material to be machined along a hole machining line in which an elliptical shape or a plurality of arcs are formed in a web shape. It is to provide a laser processing method capable of performing hole processing more appropriately when performing.

A fifth object of the present invention is, in addition to any one of the first to third objects, is to provide a laser processing method capable of more appropriately processing a square hole. A sixth object of the present invention is, in addition to the above first object,
It is to provide a laser processing method capable of improving the processing efficiency.

[0013]

The invention according to claim 1 is
To achieve the above Symbol purpose, the laser beam output from the nozzle irradiates the workpiece, a laser processing method of drilling by jetting assist gas along the laser beam, piercing point After cutting the work material along the cutting introduction line to the processing start point on the hole drilling line,
A workpiece is cut along a hole drilling line from the processing start point to a cutting end point to form a cutting groove, and then the nozzle is returned to the processing starting point, and the cutting groove is defined from the processing starting point. In the laser processing method of cutting the workpiece along the hole drilling line in the opposite direction to the cutting end point
Set the cut end point on the straight line of the square hole drilling line.
It has been set .

According to a second aspect of the present invention, the second
In order to achieve the above object, in claim 1, the incision cutting of the workpiece from the processing start point to the cutting end point is partially performed on the hole processing line, and the cutting processing condition is higher than the normal cutting processing speed. It is performed at a low speed and under a condition lower than a normal laser output.

In order to achieve the third object of the present invention, the laser light and the assist gas are once stopped at the time when the cutting and cutting are completed, and the nozzle is started to be machined. It returns to the point and switches to normal cutting processing conditions at the processing start point.

[0016]

[0017]

According to a fourth aspect of the present invention, there is provided a laser processing method of irradiating a laser beam output from a nozzle onto a workpiece, and jetting an assist gas along the laser beam to drill a hole. After cutting the workpiece from the point along the cutting introduction line to the processing start point on the hole processing line, cut the workpiece from the processing start point along the hole processing line to the cutting end point to form a notch groove Then, in the laser processing method of returning the nozzle to the processing start point and cutting the workpiece along the hole processing line to the cutting end point, if the hole to be processed has a quadrangular shape, piercing is performed . when cutting the lead wire after the cutting from the outside of the hole to be machined, as with respect to one side of the square hole processing line coincides with the direction of cutting the lead wire, the other from the machining start point Cuts are taking a means of forming a groove on.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to FIGS. This embodiment is a processing method in which a circular hole 17 having a predetermined radius is cut in the workpiece 11. FIG. 4 shows a laser beam 1 so as to be close to the upper surface of a workpiece 11 such as a steel plate having a predetermined thickness.
3 and a path for moving the nozzle 12 for irradiating the assist gas. This path, laser beam and assist gas generation conditions, laser output, assist gas pressure, pulse duty
As for the processing conditions such as the tee and the processing speed, appropriate conditions are stored in advance in the memory of the control device (not shown) according to the material, thickness, hole diameter, etc. of the workpiece 11. Then, by selecting a condition suitable for the hole diameter of the workpiece 11 to be machined and moving the nozzle 12, the hole machining is carried out under an appropriate condition.

Therefore, the cutting work of the hole 17 will be described with reference to FIGS. As shown in FIG. 2A, first, a predetermined position of the workpiece 11, that is, the piercing point P1.
At, the laser beam 13 and the assist gas are output from the nozzle 12 to form a small hole having a diameter substantially equal to the beam diameter.

Next, as shown in FIG. 2B, from the piercing point P1 to a specific point on the hole machining line L3, that is, the machining start point P2, along the hole shape introduction line L1, the nozzle 1
2 is moved to form the introduction groove 14. In this process,
The nozzle moving speed and laser output processing conditions are set lower than normal processing conditions.

Next, the nozzle 12 is moved from the machining starting point P2 along the arcuate hole machining line L3 in the clockwise direction in FIG. The cutting groove 15 having a circular arc shape is cut.
The nozzle center P3 at the tip of the cut groove 15 becomes the cut end point, and the laser light is temporarily stopped at this point P3. The cut end point P3 is formed in the hole 17 as described later.
It also becomes the processing end point where the processing of is finished at the final stage.

Next, in FIG. 2C, the nozzle 12 is returned from the cut end point P3 along the cut processing line L2. Then, at the processing start point P2, the processing is switched to normal processing conditions and cutting is performed counterclockwise along the hole processing line L3 to form the circular hole processing groove 16 as shown in FIG. The drilling groove 16 is formed toward the cut end point P3, and the center point P4 of the nozzle that processes the tip of the drilling groove 16 approaches the end point P3 as shown in FIG.

When the nozzle at the point P4 immediately before the end of machining is moved to the end point P3 from this approaching state, the cut groove 1
The hole machining groove 16 is connected to 5. In this step, the cut groove 15 is formed in advance with a predetermined kerf width along the hole drilling line L3. Further, in the case of hole processing, the advancing direction of the nozzle is tangential to the circular arc, so that the larger the circular arc radius, the more approximate it is to a straight line. Therefore, since the assist gas linearly escapes to the kerf portion of the predetermined width at the end point P3 of the hole machining of the workpiece 11, the assist gas on the front surface side and the rear surface side of the workpiece 11 escapes linearly. It does not spread in all directions. It should be noted that the condition becomes even better in the case of an arc having a large radius. Therefore, the drilled groove 16 is smoothly connected to the cut groove 15 with the same kerf width.

Since the assist gas is linearly discharged at the processing end point of the hole processing, the melt is also linearly discharged to the kerf portion,
The melt does not remain in the drilling groove 16 as a residue. Therefore, the scrap portion 19 can be smoothly dropped from the hole 17. Further, the cutting end portion P3, especially the workpiece 11
It is possible to obtain a stable and high-quality drilled shape at all times by eliminating the loss on the back surface side.

Further, in the small hole drilling, which has hitherto been a subject of laser processing, it has become possible to make a small hole smaller than the diameter of the plate thickness dimension, for example, about 1/3 of the plate thickness. This is clear from the graph of FIG. That is, as shown by the machining limit curve shown by the solid line in FIG. 6, when the plate thickness is, for example, 19 mm, the hole diameter is about 7 mm, and it is possible to machine a hole having a smaller diameter than the conventional one.

By the way, the cut groove 15 shown in FIG.
If the formation angle from the machining start point P2 to the end point P3 regarding the piercing point P1 of
Is appropriately set depending on the diameter of the hole 17, the thickness of the workpiece 11, and the like. For example, if the diameter of the hole is small, 90
If it is large, it is set to 30 degrees.
Further, when the thickness is thin, the formation angle α is set small, and when it is large, the formation angle α is set large.

Here, the operation and effect based on each configuration in the above-mentioned embodiment will be described below. (A) In the above-described embodiment, the incision cutting of the workpiece 11 from the processing start point P2 to the cutting end point P3 is partially performed, and the cutting conditions are a speed slower than the normal cutting processing speed and a normal cutting speed. Since it is performed under the condition lower than the output, the cut groove 15 can be formed reliably and properly. (B) In the above-described embodiment, the laser light and the assist gas are temporarily stopped at the time when the cut cutting is finished, the nozzle is returned to the processing start point P2, and the normal cutting processing conditions are switched at the processing point. Therefore, the operation of returning the nozzle to the processing start point can be quickly performed, and the processing efficiency can be improved.

The present invention is not limited to the above embodiment, but can be embodied as follows. (1) In the case where the hole 17 to be machined has a quadrangular shape as shown in FIG. 7, from the piercing point P1 toward the machining start point P2 of the linear hole machining line L3 under conditions lower than the normal machining conditions. The introduction groove 14 is formed, and a linear cut groove 1 having a predetermined length is formed from this point to the cut end point P3.
5 is also formed under conditions lower than the normal processing conditions.
After that, the nozzle is returned to the machining start point P2, the machining condition is switched to the normal machining condition, and the rectangular hole machining groove 16 is machined along the hole machining line L3.

In this embodiment, since the tip of the drilling groove 16 linearly faces the cutting end point P3 at the drilling end portion, when the drilling groove 16 is finally machined, it faces on the arc-shaped machining line of the above embodiment. Compared with the method, the processing work can be performed more reliably and properly. (2) As shown in FIG. 8, when the hole machining introduction line L1 after piercing is cut from the outside of the hole 17, the introduction line L1 should be aligned with the direction with respect to one side of the square hole machining line L3. The introduction groove 14 is formed under processing conditions lower than the normal processing conditions. Next, a cutting groove 15 is formed along the cutting line L2 on the other side from the processing start point P2 under processing conditions lower than normal processing conditions, and when the nozzle moves to the cutting end point P3, the laser output is stopped. . Next, the nozzle is returned from the cut end point P3 to the processing start point P2. Finally, at the point P2, the normal machining conditions are switched to and the nozzle is moved along the direction of the arrow of the hole machining line L3 from the machining start point P2 toward the machining end point P3 to form the hole machining groove 16.

Also in this embodiment, since the cut groove 15 and the processed groove 16 are linearly opposed to each other at the processing end portion, the same effect as that of the embodiment shown in FIG. 7 is obtained .

( 4) As shown in FIG. 10, when machining the hexagonal hole 17, the introduction groove 14 is set at the machining start point P2 of the hexagonal corner. In addition, the machining end is set on the side of the hexagon. When the cut end point P3 ′ is set at the corner of the hexagon as shown on the left side of FIG. 10, when the inclination angle θ between the cut groove 15 and the drilling groove 17 is a hexagon, 1
Since the angle is 20 degrees, the restrictions on the thickness and the hole diameter of the work piece can be relaxed as compared with the case where the cut end point is a point having an inclination angle of 90 degrees or less, and the work piece Holes can be processed properly. Move The light without stopping the nozzle at a low speed as it is to the normal working direction - (5) in the processing method of the embodiments other than the previous you facilities embodiment, after forming the cut groove 15, the point P3 delle Then, at the processing start point P2, processing is switched to normal processing conditions.
(6) For example, the cutting end point is set on the curve having the largest curvature among the hole machining lines irregularly formed by the elliptical hole and other smooth curves.

In this case, it is possible to more appropriately perform the hole drilling in the work material.

[0034]

EXAMPLES Examples of the present invention will be described below. The diameter is 6 for the material SS400 of the work material 11 and the thickness of 16 mm.
When making a hole of mm, the following laser processing conditions are used. As the above-mentioned normal processing conditions, laser output: 20
00 W, cutting speed: 800 mm / min, assist gas (oxygen gas) pressure: 0.4 Kg / cm ² were used.

Further, as the processing conditions lower than usual, the laser output is 900 W and the cutting speed is 100 mm / m.
in, assist gas (oxygen gas) pressure: 0.4 Kg / cm
² was used.

[0036]

As described above, the invention according to claim 1 can alleviate the restrictions on the thickness and hole diameter of the work material, and can surely and properly perform the hole drilling on the work material. It has an excellent effect that it can be performed. Also, the corner
Shaped holes can be processed more properly.

According to the second aspect of the present invention, in addition to the effect of the first aspect of the invention, the notch groove can be formed reliably and properly. According to the invention of claim 3, in addition to the effect of the invention of claim 2, the operation of returning the nozzle to the processing start point is performed, and the processing efficiency can be improved.

[0038]

The invention 請 Motomeko 4, any of claims 1 to 3
In addition to the effects of the invention described above, it is necessary to process a square hole.
Ri can be appropriately performed.

[Brief description of drawings]

FIG. 1 is a plan view showing an embodiment of a laser processing method embodying the present invention.

2A, 2B, and 2C are plan views illustrating a process of processing the introduction groove and the cut groove, respectively.

FIG. 3 is a plan view illustrating a process of forming a hole-groove.

FIG. 4 is a perspective view illustrating a hole processing method.

5A and 5B are cross-sectional views showing a groove processing step, respectively.

FIG. 6 is a graph showing the relationship between the thickness of the workpiece and the hole diameter.

FIG. 7 is a plan view showing another embodiment of the present invention.

FIG. 8 is a plan view showing another embodiment of the present invention.

FIG. 9 shows a shape of a groove formed by a laser processing method .
Sectional drawing to show .

FIG. 10 is a plan view showing another embodiment of the present invention.

FIG. 11 is a plan view showing a conventional method for processing a hole.

12A is a plan view showing the shape of the upper part of a hole formed by a conventional processing method, and FIG. 12B is a plan view showing the shape of the lower part of the hole.

[Explanation of symbols]

11 ... Work material, 14 ... Cutting introduction groove, 15 ... Cutting groove, 16 ... Hole processing groove, P1 ... Piercing point, P
2 ... Cutting start point, P3 ... Cutting end point, P4 ... Point immediately before cutting end point P3, L1 ... Cutting introduction line, L2
… Cutting line, L3… Hole line.

Claims (4)

(57) [Claims] 1. A laser processing method of irradiating a laser beam output from a nozzle to a workpiece, and jetting an assist gas along the laser beam to drill a hole. After cutting the workpiece along the hole drilling line to the machining start point, cut the workpiece from the machining start point along the hole drilling line to the cutting end point to form a notch groove, and then perform the machining In the laser processing method of returning the nozzle to the starting point and cutting the workpiece from the processing starting point in the direction opposite to the cutting groove along the hole processing line to the cutting end point , the cutting end point is a square shape. Set on the straight line of the hole processing line
Laser processing method . 2. The cutting cut of the work material from the processing start point to the cutting end point is partially performed on a hole processing line according to claim 1, and the cutting processing condition is a speed slower than a normal cutting processing speed, And a laser processing method performed under a condition lower than a normal laser output. 3. The laser light and the assist gas are stopped once at the time of cutting and cutting according to claim 2,
A laser processing method in which a nozzle is returned to a processing start point and normal cutting processing conditions are switched at the processing start point. 4. A laser beam output from a nozzle is processed.
Irradiate the material and assist along the laser light
A laser processing method for injecting gas to machine holes,
From the ashing point along the cutting introduction line On the hole drilling line
After cutting the workpiece to the processing start point of
From the point to the end point where the material is cut along the hole drilling line
Cut to form a kerf, then start the machining
Return the nozzle to the notch and cut along the hole
In the laser processing method that cuts the material to the end point
Te, if there is a hole to be machined of a rectangular shape, piercing
Cut from the outside of the hole to be machined
When cutting, one side of the square hole drilling line
Cut from the machining start point to the other side so that the directions match.
A laser processing method in which a groove is formed.