CN110293325B - Thick plate laser cutting method - Google Patents

Abstract

The invention relates to a thick plate laser cutting method, which is characterized by: step 1: fixing an electromagnetic coil on a laser cutting head, which can move with the laser cutting head; step 2: vertically placing and fixing the workpiece to be cut; step 3 : Define the corner cutting lead-in section and lead-out section in the laser cutting track; Step 4: Start the laser cutting system, start the cutting auxiliary gas, start the electromagnetic field power supply, and the laser beam vertically irradiates the surface of the workpiece to be cut to realize the thick plate laser cutting; Step 5 : When the laser beam moves to the starting point of the corner cutting lead-in section, adjust the power of the electromagnetic field to start cutting the corner area; Step 6: When the laser beam moves to the end point of the corner cutting lead-out section, adjust the electromagnetic field power to end the corner area cutting; Step 7 : When reaching the cutting end point, turn off the laser generator, turn off the power of the electromagnetic field, and turn off the auxiliary gas for cutting to complete the cutting process. Compared with the prior art, the present invention has a good cutting effect.

Description

A kind of thick plate laser cutting method

technical field

The invention relates to a laser cutting method, in particular to a thick plate laser cutting method.

Background technique

At present, laser cutting technology has been widely used in sheet metal processing, metallurgical equipment, construction machinery, precision accessories, craft gifts, household appliances and many other fields. At present, the traditional laser cutting of metal mainly uses the optical system in the cutting head to converge on the surface of the material to melt it, and provide auxiliary gas to blow the melted material to achieve cutting. However, when using fiber lasers to cut thick stainless steel plates, the laser energy is intensively accumulated at the corners, which is easy to cause the phenomenon of "reverse jetting" at the corners, which makes the cutting impossible.

Published on May 7, 2014, the publication number is "CN 103771694 A", and the invention patent titled "Laser Cutting Method and Cutting System" discloses a laser cutting method and cutting system for a glass substrate. The cutting method In order to increase the stress damage point on the substrate when laser cutting forms the cutting line by forming a cutting auxiliary line outside the cutting line, it is convenient for the division and separation of the substrate after cutting, but this method still has problems: when using pulsed laser cutting Or the laser cutting power is low, and the formed cutting lines cannot separate the substrates well.

Published on May 25, 2016, the publication number is "CN 103906597 B", and the invention patent titled "laser cutting method and cutting device" discloses the laser cutting method and cutting device. Flowing around the laser beam, the material to be processed is melted by the energy of the laser beam irradiated to the material to be processed and the energy of the oxidation reaction between the material to be processed and the cutting gas, and the molten metal is discharged by the kinetic energy of the cutting gas, but this The method still has a problem: the material to be processed is excessively melted, so that it is difficult to ensure the desired workpiece shape near the end point of cutting.

Published on January 4, 2019, the publication number is "CN 109128502 A" and the invention patent titled "A device for rotating electromagnetic-magnetic field synchronous auxiliary laser welding" discloses a rotating electromagnetic-magnetic field synchronous auxiliary laser The welding device, the present invention can realize the simple, fast and continuous adjustment of the strength of the rotating magnetic field and the constant electric field, and ensure the synchronous movement of the electric and magnetic fields with the welding laser beam. Laser process parameters such as helium shielding gas flow rate, thereby improving the quality of laser welding seam formation.

SUMMARY OF THE INVENTION

The purpose of the present invention is to solve the problem that the "reverse spray" phenomenon of molten metal occurs upward at the corner of the thick plate laser cutting, resulting in the inability to continue cutting.

The technical scheme of the present invention is to provide a thick plate laser cutting method, which is characterized in that:

Step 1: Fix the electromagnetic coil on the laser cutting head, which can move with the laser cutting head.

Step 2: Place and fix the workpiece to be cut vertically.

Step 3: Define the corner cutting lead-in and lead-out segments in the laser cutting track.

Step 4: Start the laser cutting system, start the cutting auxiliary gas, start the electromagnetic field power supply, and the laser beam vertically irradiates the surface of the workpiece to be cut to realize the thick plate laser cutting.

Step 5: When the laser beam moves to the starting point of the corner cutting lead-in section, adjust the power of the electromagnetic field to start cutting the corner area.

Step 6: When the laser beam moves to the end point of the corner cutting lead-out section, adjust the power of the electromagnetic field to end the corner area cutting.

Step 7: When the cutting end point is reached, turn off the laser generator, turn off the power of the electromagnetic field, and turn off the auxiliary gas for cutting to complete the cutting process.

Further, in step 2, the workpiece to be cut is a stainless steel plate.

Further, the thickness of the workpiece to be cut is 15-30 mm.

Further, in step 3, the corners of the workpiece to be cut are in the form of arcs or straight lines intersecting corners.

Further, in step 3, the corner cutting introduction section is a straight line cutting area starting from the corner termination point.

Further, the length d ₁ of the corner cutting introduction section is 10-30 mm.

Further, in step 3, the corner cutting lead-out section is a straight line cutting area away from the starting point of the corner.

Further, the length d ₂ of the corner cutting lead-out section is 10-20 mm.

Further, in step 4, nitrogen gas is selected as the cutting auxiliary gas, and the purity is 99.999%.

Further, the cutting auxiliary gas pressure is 1.5-3 MPa.

Further, in step 4, the electromagnetic field power supply is started, and the electromagnetic field generated by the electromagnetic coil is 0.1-1 T in size.

Further, in step 5, the power source of the electromagnetic field is adjusted so that the magnitude of the electromagnetic field generated by the electromagnetic coil is increased.

Further, the magnitude of the electromagnetic field is 0.5~5 T.

Further, in step 6, the power source of the electromagnetic field is adjusted so that the magnitude of the electromagnetic field generated by the electromagnetic coil is reduced.

Further, the magnitude of the electromagnetic field is 0.1~1 T.

The beneficial effects of the present invention are:

1) In the present invention, by adding an electromagnetic field in the laser cutting process, an external force - Lorentz force can be provided to the laser cutting molten metal in the ejection direction, so that the flow of the molten metal in the laser cutting area towards the ejection direction is more efficient. Orderly, especially the flow of molten metal in the cutting area at the corner of the thick plate is effectively controlled to achieve an orderly flow, which greatly improves the cutting effect of laser cutting thick plate and avoids the phenomenon of "reverse spray" of molten metal at the corner.

2) In the present invention, a large external force is provided for the molten metal in the cutting area by applying an electromagnetic field, which can reduce the consumption of laser power and shielding gas, and reduce operating costs.

3) Using the method of the present invention, the cutting rate at the corner of the thick plate is large, and the cutting efficiency is improved.

Description of drawings

Figure 1 is a schematic diagram of the cutting area at the corner of the thick plate.

Figure 2 is a schematic diagram of a conventional laser cutting process at the corner of a thick plate.

FIG. 3 is a schematic diagram of the laser cutting process of the thick plate according to the present invention.

FIG. 4 is a schematic diagram of a cutting path according to a specific embodiment.

FIG. 5 is a schematic diagram of a cutting path according to the second embodiment.

Among them: 1. Laser cutting head, 2. Laser beam, 3. Lorentz force direction, 4. Coaxial shielding gas, 5. Slotting, 6. Weld pool, 7. Workpiece to be cut, 8. Electromagnetic coil, 9 , Reverse spray molten metal, 10, Plasma, 11, Corner cutting lead-in section starting point, 12, Corner starting point, 13, Corner ending point, 14, Corner cutting lead-out section ending point, 15, Electromagnetic field power supply.

Specific implementation 1:

The technical solutions of the present invention will be described in detail below with reference to the accompanying drawings 1-4 and specific embodiments.

As shown in Figures 1-4, in an embodiment of the present invention, a thick plate laser cutting method includes the following steps.

Step 1: Fix the electromagnetic coil 8 on the laser cutting head 1, and can move with the laser cutting head 1; in this example, the adjustable range of the electromagnetic field is 0.1~5 T.

Step 2: Place and fix the workpiece 7 to be cut vertically; in this example, the thickness of the workpiece 7 to be cut is 15 to 30 mm.

Step 3: Define the corner cutting lead-in section and lead-out section in the laser cutting track; in this example, the corner of the workpiece to be cut is an arc, and the corner cutting lead-in section is a straight line cutting area 12 from the corner starting point, and its length is d ₁ It is 10~30 mm, and the corner cutting lead-out section is a straight line cutting area starting from the corner termination point 13, and its length _d2 is 10~20 mm.

Step 4: Start the laser cutting system, start the auxiliary gas for cutting, start the electromagnetic field power supply 15, and the laser beam 2 vertically irradiates the surface of the workpiece to be cut; in this example, when the starting direction of cutting is vertical cutting, adjust the size of the electromagnetic field to 0.2~0.3T , the cutting auxiliary gas pressure is 1.5~3 MPa.

Step 5: When the laser beam 2 moves to the starting point 12 of the corner cutting introduction section, adjust the electromagnetic field power source 15 to start cutting the corner area; in this example, adjust the electromagnetic field power source 15 to increase the electromagnetic field generated by the electromagnetic coil 8 and adjust the size of the electromagnetic field is 0.5 to 1 T.

Step 6: When the laser beam 2 moves to the corner cutting end point 13, that is, after entering the horizontal cutting, adjust the electromagnetic field power source 15 to end the corner area cutting; in this example, adjust the electromagnetic field power source 15 so that the electromagnetic field generated by the electromagnetic coil 8 decreases. is small, and the magnitude of the electromagnetic field is adjusted to 0.3~0.8 T.

Step 7: When reaching the cutting end point, turn off the laser generator, turn off the electromagnetic field power supply 15, and turn off the cutting auxiliary gas to complete the cutting process.

In this embodiment, by adding an electromagnetic field during the laser cutting process, an external force—Lorentz force in the ejection direction can be provided to the laser cutting molten metal, so that the flow of the molten metal in the laser cutting area toward the ejection direction is more efficient. In particular, the flow of molten metal in the cutting area at the corner of the thick plate is effectively controlled to achieve an orderly flow, which greatly improves the cutting effect of laser cutting thick plate and avoids the phenomenon of "reverse spray" of molten metal at the corner.

Specific implementation 2:

Another embodiment of the present invention will be described in detail with reference to FIG. 5 .

In this embodiment, the thick plate laser cutting method includes the following steps:

Step 1: Fix the electromagnetic coil 8 on the laser cutting head 1, and can move with the laser cutting head 1; in this example, the adjustable range of the electromagnetic field is 0.1~5 T.

Step 2: Place and fix the workpiece 7 to be cut vertically; in this example, the thickness of the workpiece 7 to be cut is 15 to 30 mm.

Step 3: Define the corner cutting lead-in section and lead-out section in the laser cutting track; in this example, the corner of the workpiece to be cut is a straight line intersecting corner, and the corner cutting lead-in section is a straight line cutting area 11 away from the starting point of the corner, and its length is d ₁ is 10~30 mm, and the leading section of the corner cutting is a straight line cutting area starting from the corner termination point 13, and its length d ₂ is 10~20 mm.

Step 4: Start the laser cutting system, start the cutting auxiliary gas, start the electromagnetic field power supply 15, and the laser beam 2 vertically irradiates the surface of the workpiece to be cut; The auxiliary gas pressure is 1.5~3 MPa.

Step 5: When the laser beam 2 moves to the starting point 12 of the corner cutting introduction section, adjust the electromagnetic field power source 15 to start cutting the corner area; in this example, adjust the electromagnetic field power source 15 to increase the size of the electromagnetic field generated by the electromagnetic coil 8 and the size of the electromagnetic field. Adjusted to 0.8~1.2 T.

Step 6: When the laser beam 2 moves to the corner cutting end point 13, that is, after entering the vertical cutting, adjust the electromagnetic field power source 15 to end the corner area cutting; in this example, adjust the electromagnetic field power source 15 so that the electromagnetic field generated by the electromagnetic coil 8 decreased, and the magnitude of the electromagnetic field was adjusted to 0.3–0.5 T.

Step 7: When reaching the cutting end point, turn off the laser generator, turn off the electromagnetic field power supply 15, and turn off the cutting auxiliary gas to complete the cutting process.

The above embodiments are common implementations of the present invention, but the embodiments of the present invention are not limited by the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principle of the present invention shall be regarded as equivalent substitutions, and are included within the protection scope of the present invention.

Claims (7)

1. A thick plate laser cutting method is characterized by comprising the following steps:

step 1: the electromagnetic coil (8) is fixed on the laser cutting head (1) and can move along with the laser cutting head (1);

step 2: vertically placing and fixing a workpiece (7) to be cut, wherein the workpiece (7) to be cut is a thick plate with the thickness of 15-30 mm;

and step 3: defining a corner cutting lead-in section and a corner cutting lead-out section in a laser cutting track;

and 4, step 4: starting a laser cutting system, starting cutting auxiliary gas, starting an electromagnetic field power supply (15), and vertically irradiating the surface of the workpiece (7) to be cut by a laser beam (2) to realize laser cutting of the workpiece (7) to be cut;

and 5: when the laser beam (2) moves to the starting point (11) of the corner cutting lead-in section, the electromagnetic field power supply (15) is adjusted, so that the electromagnetic field generated by the electromagnetic coil (8) is increased, and the corner area cutting is started;

step 6: when the laser beam (2) moves to the end point (14) of the corner cutting leading-out section, the electromagnetic field power supply (15) is adjusted, so that the electromagnetic field generated by the electromagnetic coil (8) is reduced, and the corner area cutting is finished;

and 7: when the cutting end point is reached, the laser generator is closed, the electromagnetic field power supply (15) is closed, the cutting auxiliary gas is closed, and the cutting process is completed.

2. The laser cutting method for slabs according to claim 1, characterized in that: in the step 1, in the laser cutting system, the size of an electromagnetic field generated by an electromagnetic coil (8) is 0.1-5T.

3. The laser cutting method for slabs according to claim 1, characterized in that: and 3, in the laser cutting system, the corner of the workpiece to be cut is in the form of an arc or a straight line intersection corner.

4. The laser cutting method for slabs according to claim 1, characterized in that: in the step 3, in the laser cutting system, the corner cutting lead-in section length d in the laser cutting track₁10-30 mm.

5. The laser cutting method for slabs according to claim 1, characterized in that: in the step 3, in the laser cutting system, the length d of the corner cutting lead-out section in the laser cutting track₂10 to 20 mm.

6. The laser cutting method for slabs according to claim 1, characterized in that: and 4, in the laser cutting system, the pressure of the cutting auxiliary gas is 1.5-3 MPa.

7. The laser cutting method for slabs according to claim 1, characterized in that: and 4, selecting nitrogen as the cutting auxiliary gas in the laser cutting system.

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