TWI399256B - Laser cutting method and laser cutting device - Google Patents

Description

Laser cutting method and laser cutting device

The present invention relates to a laser cutting method and a laser cutting device for cutting a printed circuit board using a laser beam.

The laser beam is excellent in orientation and condensing property, and it is easy to collect light at a small fixed point with a lens, and a high energy density can be obtained. Further, the condensing position of the laser beam can be moved to an arbitrary position on the workpiece by a lens or the like to process a fine and complicated shape. Therefore, laser processing machines are widely used in the field of cutting processing.

The printed circuit board is composed of a laminated structure of a conductor layer and an insulating layer. In general, the conductor layer is made of a metal such as copper, and the insulating layer is made of a resin of an organic compound. Therefore, when the printed circuit board is cut by the laser beam, if the power of the laser beam is large, machining slag such as carbide is generated from the components contained in the printed circuit board, and adheres to the cut surface of the workpiece. Processing slag will significantly reduce the insulation reliability of printed circuit boards. Moreover, the peeled process slag sometimes causes dust to accumulate on the printed circuit. If so, the processing slag will cause the malfunction of the printed circuit board. Further, when the workpiece is made of metal, tantalum, wood, or the like, the processed slag adheres to the cut surface as in the case of the printed circuit board.

As a conventional laser cutting method for suppressing adhesion of the machining slag to the workpiece cut surface, there is a case where the laser beam is scanned a plurality of times along the same track on the workpiece (see, for example, Patent Document 1).

As a conventional laser cutting method for suppressing the adhesion of the processing slag to the workpiece cut surface, there is a laser beam having a weak irradiation power to the cut surface after the cutting (for example, refer to Patent Document 2) ).

[Patent Literature]

(Patent Document 1) Japanese Patent Laid-Open Publication No. 2005-303322

(Patent Document 2) Japanese Patent Laid-Open No. Hei 5-343832

However, in the case of the laser cutting method of Patent Document 1, since the laser beam is repeatedly irradiated on the same cut surface of the workpiece, there is a problem in that the same cut surface is repeatedly heated and cooled so that the processing slag is accumulated.

Further, in the case of the laser cutting method of Patent Document 2, when the cutting is completed, the processing slag adhering to the cut surface of the workpiece is cooled by the laser beam having a weak irradiation power, which is caused by Deterioration of the workpiece material, etc., makes it difficult to absorb the laser beam. Therefore, it is difficult to remove the processed slag from the laser beam with weak power.

The laser cutting method of the present invention is characterized in that a laser beam of the predetermined power is scanned a plurality of times on the workpiece while moving a scanning beam of a predetermined power to a scanning position of the workpiece one by one for each scanning. The light beam thereby cuts off the workpiece.

Further, a laser cutting device according to the present invention includes: a laser oscillator that emits a laser beam; and a collecting lens that condenses a laser beam emitted from the laser oscillator on a workpiece; and controls a device for controlling the power of the laser beam and the scanning position of the laser beam to the workpiece, and moving the scanning position of the laser beam of the predetermined power to the scanning position of the workpiece one by one by a predetermined amount of movement during each scanning The laser beam of the predetermined power is scanned a second time, thereby cutting off the workpiece.

According to the present invention, it is possible to suppress the processing slag from adhering to the cut surface formed by cutting the workpiece.

(Embodiment 1)

Embodiment 1 will be described with reference to Figs. 1 to 5 .

Fig. 1 is a configuration diagram of a laser cutting device according to a first embodiment. The laser cutting device of the first embodiment includes a laser oscillator 1 that emits a laser beam 2, and a plurality of transmission lenses 3, 4, and 5 that transmit the laser beam 2 emitted from the laser oscillator 1 to the workpiece. 7; a collecting lens 6, condensing the transmitted laser beam 2 on the workpiece 7; the XY table 8, loading the workpiece 7 to move in the X-axis and the Y-axis direction; and the control device 9, controlling the lightning according to the data 10 The oscillator 1 is coupled to the XY table 8. The data 10 is information such as a processing program, a beam diameter D to be described later, and the total number n of scans, and is stored in a memory (not shown) after being input to the laser cutting device. Furthermore, the laser beam 2 can be a CW oscillation without downtime, or can be a pulse wave oscillation with a downtime every predetermined time.

Fig. 2 is an explanatory view showing the specifications of the XY table of the first embodiment. The XY table 8 has a larger opening portion 8a than the processed shape 7a formed by cutting the workpiece 7. Thereby, when the workpiece 7 is cut, it is possible to prevent the XY table 8 from being damaged by the laser beam 2 being irradiated onto the XY table 8 through the workpiece 7. It is also possible to prevent the back side of the workpiece 7 from being irradiated by the laser beam 2 passing through the workpiece 7 on the XY table 8.

Next, the laser cutting method of the first embodiment will be described. In addition, in the following description, when the beam diameter set at the condensing position of the laser beam 2 is D (mm), and the power of the laser beam 2 is P ₁ (W), the laser beam 2 is scanned 1 The workpiece 7 can be cut off once.

In the present embodiment, the workpiece 7 is cut by scanning the laser beam 2 a plurality of times. Also, the scanning position of the laser beam 2 is moved at each scanning. At this time, as shown in the following formula (1), the movement amount S (mm) of the scanning position for each scan is set to a value larger than 0 and D/n or less. In addition, n is the total number of scans (n≧2).

0<(moving amount S of scanning position per scan)≦D/n...(1)

Here, the movement amount S is an point at any point on the previous scanning path, and is equal to the point where the line orthogonal to the tangent of the previous scanning path of point A and the current scanning path are point B, which is equal to The distance between point A and point B.

Further, as shown in the following formula (2), the power P ₂ (W) of the laser beam 2 per scan is set to be P ₁ /n or more and less than the value of P ₁ .

P ₁ >(power P ₂ of laser beam 2 per scan) ≧P ₁ /n... (2) Further, S and P _{2 are} determined according to equations (1) and (2), which are laser The operator of the cutting device is either operated by the control device 9.

A specific example of the first embodiment will be described with reference to Figs. 3 and 4 . Fig. 3 is an explanatory view showing an example of a specification and a processed shape of a workpiece in a specific example of the first embodiment. Fig. 3(a) is a top view of the workpiece 7, and Fig. 3(b) is a cross-sectional view of the workpiece 7. The workpiece 7 is made of a square of 60 mm × 60 mm and has a thickness of 1 mm. Further, the processed shape 7a formed by cutting the workpiece 7 is formed into a square shape of 30 mm × 30 mm. The workpiece 7 is a printed circuit board in which a glass fiber cloth 13 is immersed in a laminated structure of an insulating layer and a conductor layer of the epoxy resin 14.

Table 1 below shows the results of the experiment when scanning once using the conventional laser cutting method. In the experiment of Table 1, three types of D = 0.2 mm and P ₂ = 80, 100, and 120 (W) were set, and the workpiece 7 was scanned only once for the laser beam 2 as shown in Fig. 3. Furthermore, the laser cutting method used in this experiment is equivalent to the conventional laser cutting method. Table 1 shows the results of the respective experiments, showing whether the workpiece 7 can be cut and whether the slag is attached to the cut surface to a visual extent. The cutting of the workpiece 7 here means that the laser beam 2 has penetrated the workpiece 7, and does not include the case where the laser beam 2 is only at an intermediate point between the surface and the back surface of the workpiece 7.

As shown in Table 1, when P ₂ = 80 (W) was set, the workpiece was not cut, but the workpiece 7 could not be cut. On the other hand, when P ₂ = 100 or 120 (W), the workpiece 7 can be cut, but the processing slag adheres to the cut surface. Therefore, when the conventional laser cutting method is used, the value of the power P ₂ of the laser beam is not obtained, and the workpiece 7 can be cut, and the machining slag is not adhered to the cut surface. The following is based on the results of this experiment to set P ₁ =100 (W).

Table 2 below shows the results of the experiment when scanning twice using the laser cutting method of the first embodiment. In the experiment of Table 2, the laser beam 2 was scanned twice for the workpiece 7 shown in Fig. 3 by the laser cutting method of the first embodiment. Further, three types of D = 0.2 (mm) and P ₂ = 40, 50, and 60 (W) are set, and three types of S = 0.08, 0.10, and 0.12 (mm) are set in the respective values of P ₂ . Table 2 is the result of each experiment as shown in Table 1, which shows whether the workpiece 7 can be cut and whether the slag is attached to the cut surface to a visual extent.

Table 3 below shows the results of the experiment when the scanning was performed four times using the laser cutting method of the first embodiment. In the experiment of Table 3, the laser beam 2 was scanned four times for the workpiece 7 shown in Fig. 3 by the laser cutting method of the first embodiment. Further, three types of D = 0.2 (mm) and P ₂ = _{20, 25} , and 30 (W) are set, and three types of S = 0.04, 0.05, and 0.06 (mm) are set in the respective values of P ₂ . Table 3 is the result of each experiment as shown in Table 1, which shows whether the workpiece 7 can be cut and whether the slag is attached to the cut surface to a visual extent.

In the experiment of Table 3, n = 4 (times), P ₁ = 100 (W), so D / n = 0.05 (mm), P ₁ / n = 25 (W). Therefore, when S = 0.04, 0.05 (mm) of the formula (1) is satisfied, and P ₂ = 25 and = 30 (W) of the formula (2) are satisfied, good results can be obtained.

Fig. 4 is a view showing a state in which the workpiece shown in Fig. 3 is cut by scanning the laser beam four times and using the laser cutting method of the first embodiment. At this time, n=4 (times), D=0.2 (mm), and P ₁ =100 (W). Therefore, according to formula (1) and formula (2), it is necessary to satisfy S≦0.05 and P ₂ ≧25. Therefore, in the example of Fig. 4, S = 0.05 (mm) and P ₂ = 25 (W) are set.

Figure 4 (a) shows the first scan, Figure 4 (b) shows the second scan, Figure 4 (c) shows the third scan, and Figure 4 (d) shows The situation at the time of the fourth scan. Further, in each of Figs. 4(a) to 4(d), the upper view is a view of the workpiece 7 as seen from above, the processed shape 7a is shown by a 2-point chain line, and the laser beam 2 is shown by a thick line arrow. Scan position 20. On the other hand, in the respective drawings of Figs. 4(a) to 4(d), the lower drawing shows a cross-sectional view of the workpiece 7, and shows the scanning position 21 in the plane direction and the cut surface 22 formed by scanning.

In the case of Fig. 4(a), the scanning position 20 is located at the outer side of the processed shape 7a at a ratio of 0.075 mm which is 1.5 times S. In the case of Fig. 4(b), the scanning position 20 is located on the outer side of the processed shape 7a by 0.025 mm which is 0.5 times S. In the case of Fig. 4(c), the scanning position 20 is located inside the processed shape 7a at 0.025 mm which is 0.5 times S. In the case of Fig. 4(d), the scanning position 20 is located inside the processed shape 7a at a ratio of 0.075 mm which is 1.5 times S. Thus, in the example of Fig. 4, the scanning position 20 of the laser beam 2 is shifted by 0.05 mm in the inner direction from the periphery of the processed shape 7a at each scanning, thereby cutting the workpiece 7 to form the processed shape 7a. .

Fig. 5 is a photograph of a cut surface when a conventional laser cutting method is used and a cut surface when the laser cutting method of the first embodiment is used. Fig. 5(a) is a photograph of the cut surface 22 of the workpiece 7 when n = 1 (times), D = 0.2 (mm), and P ₂ = 100 (W) using the conventional laser cutting method. In Fig. 5(a), the power of the laser beam 2 irradiated to the cut surface 22 is as large as 100 W, so that a large amount of processed slag formed by carbide adheres to the cut surface 22.

On the other hand, Fig. 5(b) uses the laser cutting method of the first embodiment, and n = 4 (times), D = 0.2 (mm), S = 0.05 (mm), and P ₂ = 25 (W). A photograph of the cut surface 22 of the workpiece 7 at the time. In Fig. 5(b), the power of the laser beam 2 irradiated to the cut surface 22 formed for each scan is as small as 25 W, so that the cut surface 22 hardly adheres to the slag at each scanning. Further, since the scanning position of the laser beam 2 is shifted by 0.2 mm in each scanning, the laser beam 2 of 25 W is irradiated a plurality of times on the same cut surface 22, so that the adhesion of the machining slag can be suppressed. If so, at the last cut surface 22, only the laser beam power of 25 W of the fourth and fourth scans is irradiated. Therefore, the cut surface 22 formed lastly hardly adheres to the processing slag.

Furthermore, in the formula (1), S=D/6n or more is preferable. In other words, when the following formulas (3) and (2) are satisfied, the adhesion of the processing slag can be effectively suppressed.

D/6n≦ (movement amount S of scanning position per scan)≦D/n...(3)

Further, in the above specific example, the scanning position of the laser beam is sequentially moved to the inner side by 0.05 mm in the periphery of the processed shape 7a at each scanning to cut the workpiece 7 to form the processed shape 7a. Not limited to this. In other words, for example, the scanning position of the laser beam may be shifted by 0.05 mm in the outer direction in the outer direction of the processed shape 7a at each scanning to cut the workpiece 7 to form the processed shape 7a.

Further, as described above, the workpiece 7 is formed of a printed circuit board, but it may be formed of any material as long as it is processed by a laser beam. That is, the workpiece may be made of metal, tantalum, wood, or the like.

According to the first embodiment, the generation of the machining slag can be suppressed during the cutting of the workpiece. Therefore, it is possible to suppress the adhesion of the processing slag to the cut surface formed by cutting the workpiece.

Further, in the first embodiment, the amount of movement S of the scanning position for each scanning and the power P ₂ of the laser beam 2 for each scanning are described as being constant for each scanning, but the present invention is not limited thereto. That is, as long as the formulas (1) and (2) can be satisfied, S and P ₂ may be different for each scan. At this time, the same effects as in the first embodiment can be obtained.

(Embodiment 2)

Embodiment 2 will be described with reference to Fig. 6 . It is to be noted that the portions that are different from the first embodiment will be mainly described, and the description of the same portions as those of the embodiment will be omitted.

In the laser cutting device shown in Fig. 1 of the first embodiment, the laser beam 2 is moved to the condensing position of the workpiece 7 by the movement of the XY table 8 in the X-axis direction and the Y-axis direction. However, the body of the XY table 8 is so heavy that the movement of the condensing position becomes slow, and the time required to complete the cutting of the workpiece 7 is elongated. In the second embodiment, the time required to cut the workpiece is shortened while using the laser cutting method described in the first embodiment.

Fig. 6 is a view showing the configuration of a laser cutting device according to a second embodiment. The laser cutting device according to the second embodiment includes a laser oscillator 1 that emits a laser beam 2, and a plurality of transmission lenses 3 and 4 that transmit the laser beam 2 emitted from the laser oscillator 1 to a later-described one. Driving the lens 30; rotating the driving lens 30, transmitting the transmitted laser beam 2 to the workpiece 7 at an arbitrary angle; the collecting lens 6 condensing the transmitted laser beam 2 on the workpiece 7; 31. Control the laser oscillator 1 and the driving lens 30; and fix the table 32 to load the workpiece 7.

In the laser cutting device of the second embodiment, the condensing position of the laser beam 2 to the workpiece 7 is moved by the rotation of the driving lens 30. Using this laser cutting device, using the laser cutting method of Embodiment 1 with n=4 (times), D=0.2 (mm), S=0.05 (mm), P ₂ =25 (W) As a result of the cutting, the workpiece 7 can be cut, and almost no carbide adheres to the cut surface. Furthermore, since the weight of the driving lens 30 is lighter than that of the XY table 8, the movement of the condensing position is fast. As a result, compared with the use of the laser cutting device of the first embodiment, the time required for cutting can be shortened by a factor of 1/4.

According to the second embodiment, in addition to the effects of the first embodiment, the time required for the laser cutting can be shortened.

Further, in the second embodiment, the position where the laser beam 2 is focused on the workpiece 7 is moved by the rotation of the driving lens 30, but is not limited thereto. For example, the driving lens 30 may be moved in the X-axis direction and the Y-axis direction to move the condensing position of the laser beam 2 to the workpiece 7. The effect as in Embodiment 2 can also be obtained at this time.

Further, in the laser cutting device shown in Fig. 6, the XY table 8 shown in Fig. 1 is added, and the control device 31 controls the laser oscillator 1, the driving lens 30, and the XY table 8. The effect as in Embodiment 2 can also be obtained at this time.

(Embodiment 3)

Embodiment 3 will be described with reference to Fig. 7. It is to be noted that the differences from the second embodiment will be mainly described, and the description of the same portions as those of the second embodiment will be omitted.

In the laser cutting device shown in Fig. 6 of the second embodiment, the laser beam 2 deflected by the rotatable driving lens 30 is condensed on the surface of the workpiece 7 by the collecting lens 6. Therefore, since the irradiation of the surface of the workpiece 7 by the laser beam 2 is not perpendicular, the cut surface is not perpendicular to the surface of the workpiece 7, and the cutting accuracy cannot be improved. In the third embodiment, the accuracy of the workpiece cutting is improved while the laser cutting method described in the first embodiment is employed.

Fig. 7 is a view showing the configuration of a laser cutting device according to a third embodiment. The laser cutting device according to the third embodiment includes a laser oscillator 1 that emits a laser beam 2, and a plurality of transmission lenses 3 and 4 that transmit the laser beam 2 emitted from the laser oscillator 1 to a later-described one. Driving the lens 30; rotating the driving lens 30, transmitting the transmitted laser beam 2 to the workpiece 7 at an arbitrary angle; the telecentric lens 40, concentrating the transmitted laser beam 2 on the workpiece 7; a control device 31 for controlling the laser oscillator 1 and the driving lens 30; and a fixed table 32 for loading the workpiece 7.

The telecentric f θ lens 40 has a characteristic of satisfying Y=f×θ when the set image height is Y, the focal length is f, and the incident angle is θ. And the telecentric f θ lens 40 is a telecentric lens that can vertically illuminate the workpiece 7 by the laser beam 2 deflected by the driving lens 30.

In the laser cutting device of the third embodiment, the laser beam 2 deflected by the driving lens 30 is vertically condensed on the surface of the workpiece 7 via the telecentric f θ lens 40. Using this laser cutting device, n=4 (times), D=0.2 (mm), S=0.05 (mm), P ₂ =25 (W), and using the laser cutting method of Embodiment 1 As a result of the laser cutting, in addition to the effects of the second embodiment, a cut surface perpendicular to the surface of the workpiece 7 can be obtained.

According to the third embodiment, in addition to the effect of the second embodiment, the cut surface perpendicular to the surface of the workpiece 7 can be obtained, and the precision of the laser cut can be improved.

1. . . Laser oscillator

2. . . Laser beam

3, 4, 5. . . Transmission lens

6. . . Condenser lens

7. . . Workpiece

7a. . . Processing shape

8. . . XY table

8a. . . Opening

9. . . Control device

10. . . data

13. . . Glass fiber cloth

14. . . Epoxy resin

20. . . Scan position

twenty one. . . Scan position

twenty two. . . Cut surface

30. . . Driving lens

31. . . Control device

32. . . Fixed workbench

D. . . Beam diameter

Fig. 1 is a configuration diagram of a laser cutting device according to a first embodiment.

Fig. 2 is a specification diagram of the XY table of the first embodiment.

Fig. 3 (a) and (b) are diagrams showing an example of a workpiece specification and a processed shape in a specific example of the first embodiment.

4(a) to 4(d) are views showing a state in which the workpiece shown in Fig. 3 is cut by the laser beam cutting method of the first embodiment by scanning the laser beam four times.

Fig. 5 (a) and (b) are photographs showing a cut surface when a conventional laser cutting method is employed and a cut surface when the laser cutting method of the first embodiment is employed.

Fig. 6 is a view showing the configuration of a laser cutting device according to a second embodiment.

Fig. 7 is a view showing the configuration of a laser cutting device of the third embodiment.

1. . . Laser oscillator

2. . . Laser beam

3, 4, 5. . . Transmission lens

6. . . Condenser lens

7. . . Workpiece

8. . . XY table

9. . . Control device

10. . . data

Claims (8)

A laser cutting method characterized in that a predetermined amount of movement of a laser beam of a predetermined power to a workpiece is sequentially performed by moving a predetermined movement amount in a horizontal direction orthogonal to a scanning path for each scanning position The laser beam of the predetermined power is scanned to thereby cut off the workpiece. The laser cutting method according to claim 1, wherein the laser beam having a beam diameter D at the condensing position and a power of P ₁ is capable of cutting the workpiece by scanning once, The method of the following formulas (1) and (2) is satisfied, and the scanning position of the laser beam of the predetermined power P ₂ is successively moved by a predetermined movement amount S in the horizontal direction orthogonal to the scanning path at each scanning. And scanning the workpiece with the laser beam of the predetermined power P ₂ n times, thereby cutting the workpiece, 0<S≦D/n... (1) P ₁ >P ₂ ≧P ₁ /n... 2) Among them, in the above formulas (1) and (2), n ≧ 2 . The laser cutting method of claim 2, wherein the predetermined amount of movement S or the predetermined power P ₂ is slightly the same for each scan. The laser cutting method of claim 1, wherein the laser beam is derived from CW oscillation without downtime, or pulse wave oscillation with downtime. A laser cutting device characterized by comprising: a laser oscillator that emits a laser beam; a collecting lens that condenses the laser beam emitted from the laser oscillator onto the workpiece; and a control device that controls the power of the laser beam and the scanning of the workpiece by the laser beam And cutting the workpiece by scanning the laser beam of the predetermined power a plurality of times on the workpiece by sequentially moving the scanning position of the laser beam of the predetermined power to the scanning position of the workpiece by a predetermined movement amount for each scanning. The scope of the patent when the laser cutting apparatus as item 5, wherein the beam diameter D is the condensing position of the laser beam and the power P _1, i.e. 1 via the scan of the workpiece can be cut, to be able to The method of the following formulas (1) and (2) is satisfied, and the scanning position of the laser beam of the predetermined power P ₂ is successively moved by a predetermined movement amount S in the horizontal direction orthogonal to the scanning path at each scanning. And scanning the workpiece with the laser beam of the predetermined power P ₂ n times, thereby cutting the workpiece, 0<S≦D/n... (1) P ₁ >P ₂ ≧P ₁ /n... 2) Among them, in the above formulas (1) and (2), n ≧ 2 . The laser cutting device of claim 5, wherein the driving lens is provided on an optical path between the laser oscillator and the collecting lens, and is movable or rotatable. The laser cutting device of claim 5, wherein the collecting lens is a telecentric f θ lens.