JP2815350B2 - Laser cutting method for coated steel - 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 a steel material having a surface coated.

[0002]

2. Description of the Related Art Conventionally, in a laser cutting method of a steel material to be coated whose surface is coated, a cutting result is influenced by a component of a coating film and a thickness of the coating film, and a good cut surface can be obtained. Since there is a relatively high frequency of cases that do not occur, it is common to remove the coating film by machining with a grinder or the like before cutting, especially when it is desired to obtain a good cut surface. However, in the machining, there is great dissatisfaction with the work efficiency, and a more efficient method of removing the coating film has been demanded. Also, various methods have been tried to enable good cutting without removing the coating film, but generally, the cutting speed is lower and the cutting efficiency is lower than laser cutting of the same material steel without coating. Is common and does not lead to a fundamental solution to the problem.

[0003] JP-A-60-174289, JP-A-60-174289
Japanese Patent Application No. 96383 discloses a method for cutting steel materials using a laser. This cutting method is illustrated in FIG.
As shown in (a) and (b), in a method of cutting a material (base material) 1 having a coating 7 of a synthetic resin or the like formed on its surface by a laser, first, the coating 7 is weakened by a laser having a weak energy.
(FIG. 3A), followed by a second step of cutting the base material 1 with strong energy (FIG. 3B). If this method is used for cutting the steel material to be coated, it is possible to improve the work efficiency as compared with the removal of the coating film by machining such as a grinder.

[0004]

However, Japanese Patent Application Laid-Open No.
According to the cutting methods described in JP-A-174289 and JP-A-60-96383, there is a problem that the material constituting the coating such as the synthetic resin removed in the first step lands on the condenser lens 5. Was. The present invention has been made in view of the above problems, and provides a laser cutting method of a steel material to be coated, which can suppress flying of the coating material to a condenser lens 5 in the method of cutting the steel material to be coated by laser. The purpose is to do.

[0005]

According to the laser cutting method for a steel material to be coated of the present invention, a marking step of burning a coating film coated on a cutting line and its vicinity with a laser, and a step of cutting the cutting line after the completion of the marking step. along a cutting step of laser cutting, the focal point of the laser in the marking process and a position spaced from the surface of the cutting steel, and switching
In the cutting process, the laser focus is located on the steel material to be cut.
And supplying an assist gas is a means for solving the above problem.

[0006]

According to the laser cutting method of the steel material to be coated of the present invention, the portion where the coating film has been burned off in the marking step becomes the marking for executing the cutting step. Since a laser is used for both the marking step and the cutting step, it is possible to eliminate or simplify the replacement of the equipment at the time of transition between the marking step and the cutting step by sharing a laser device. Also, since the laser focus in the marking process is located away from the surface of the steel material to be cut, that is, the laser beam condensing lens is located further away from the surface of the steel material to be coated, the collection of the coating material removed by the laser is removed. Flying to the optical lens can be suppressed. Also cutting
In the process, the condenser lens is coated more than the marking process.
Located near the surface of steel material, but supplies assist gas
While cutting, the melt of steel material is assist gas
Is blown off and the landing on the condenser lens is suppressed.
You.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention is shown in FIG.
This will be described with reference to FIG. In the drawing, reference numeral 1 denotes a steel material, 2
Is a coating film, 3 is a cutting line, 4 is a marking line, 5 is a condenser lens, and 6 is a cutting nozzle. The steel material 1 is coated with a coating film 2 on the entire surface. In the laser cutting method for a steel material to be coated according to the present embodiment, first, a steel material 1 to be cut is set on a laser processing machine, and a marking line 4 is drawn on the steel material 1 as shown in FIG. The marking line 4 is shown in FIG.
As shown in (a), the height of the condensing lens 5 and the cutting nozzle 6 from the surface of the steel material 1 is adjusted, and a laser beam is irradiated in a state where the focal point is separated from the steel material 1.
Only burn off to form. In addition, the marking line 4 is
The laser beam is formed to have a width set by an irradiation width corresponding to a separation distance between the focal point of the laser and the surface of the steel material 1. In this marking step, the laser may be set to a laser output and a laser speed at which the steel material 1 does not melt.

When the formation of the marking line 4 is completed,
As shown in FIG. 2B, the focusing lens 5 and the cutting nozzle 6 are moved to move the laser focus on the cutting line 3 with the focal point of the laser as the surface of the steel material 1 to cut the steel material 1. During laser cutting, oxygen is supplied as an assist gas.

In the laser cutting method for the steel material to be coated, the marking line 4 can be formed and cut by adjusting the condenser lens 5 and the cutting nozzle 6 in the vertical direction without changing the processing equipment. The cutting efficiency is improved. Further, if the operation of the condenser lens 5 and the cutting nozzle 6 is controlled and stored in the laser processing machine by the control device, the horizontal movement of the condenser lens 5 and the cutting nozzle 6 can be performed both when the marking line 4 is formed and when the cutting line is cut. The movement in the direction can be performed by the same program, and the work efficiency can be further improved. Furthermore, since the focal point of the laser in the marking step is set at a position separated from the surface of the steel material to be cut, it is possible to suppress the coating material from flying onto the condenser lens 5. In the cutting process, the condenser lens
5 is closer to the surface of the coated steel material than the marking process
However, the molten steel is blown away by the assist gas.
To prevent it from flying to the condenser lens 5.
Can be.

[0010] In addition, according to the laser cutting method of the present embodiment, there is no switching of the processing equipment between the marking and the cutting, and as a result of the improvement of the cutting speed after the marking,
The tact time of the entire cutting operation is reduced.

As described above, the shortening of the tact time is realized by eliminating the work of switching the processing equipment and shortening the cutting time. The shortening of the cutting time is, for example, in the case of wash primer materials used for shipbuilding and bridges, Table 1
As shown in the figure, when the plate thickness is 6 mm, it is less than half of the case where the coating film 2 is not removed by the marking step.

[0012]

[Table 1]

On the other hand, the tact time of the entire cutting operation is generally shorter when the marking is performed and when the marking is not performed as a result of a test using an actual laser processing machine. It has been found.

For example, a steel material 1 having a thickness of 9 mm is cut to a cutting length of 10 mm.
0mm, rapid traverse length 50m, rapid traverse speed 24000mm /
The test was performed using a processing machine under the conditions of min and a marking speed of 100,000 mm / min. Since the cutting speed can be cut at 1100 mm / min with the marking, whereas the cutting speed is 700 mm / min without the marking, the cutting time is 143 minutes without the marking and about 91 minutes with the marking. The fast-forward time was about 2 minutes, and the marking time was about 10 minutes. As a result, even if the laser cutting method includes that the marking time is added and that the rapid traverse time is twice as long in the cutting step and the marking step, the tact time of the entire cutting operation is reduced. As a result, the coating film 2 is reduced by about 30% as compared with the case where the coating film 2 is not removed by the marking step.

Therefore, in the laser cutting method, not only a good cut surface can be obtained, but also when the plate thickness is thin or the cutting length is long, the tact time is shortened, and the above-mentioned effect is more remarkably achieved. Demonstrate. In addition, since the focal point of the laser in the marking step is set at a position separated from the surface of the steel material to be cut, it is possible to prevent the coating material from flying onto the condenser lens 5 in the marking step.

[0016]

As described above, according to the laser cutting method for steel material to be coated of the present invention, a marking step of burning off a coating film coated on a cutting line and its vicinity with a laser, and after the completion of the marking step, With a cutting step to cut along the cutting line, the focus of the laser in the marking step and a position separated from the surface of the steel material to be cut,
In the cutting process, focus the laser on the steel material to be cut.
Since it is located and blows assist gas, the exchange work of the processing equipment is unnecessary or simple when moving between the respective steps, and the cutting speed of the steel material after removing the coating film increases, so the cutting work An excellent effect of shortening the entire tact time, obtaining a good cut surface, and suppressing the flying of the molten material of the coating material and the steel material to the condenser lens is achieved.

[Brief description of the drawings]

FIG. 1 is an overall view showing a marking line formed on the surface of a steel material to be cut and a cutting line.

2A is a schematic cross-sectional view showing a positional relationship between a focusing lens and a cutting nozzle at the time of marking, and FIG. 2B is a schematic sectional view showing a positional relationship between a focusing lens and a cutting nozzle at the time of cutting.

FIG. 3 is a view showing a laser cutting method disclosed in JP-A-60-174289, which shows (a) a step of removing a synthetic resin film, and (b) a step of cutting a base material. is there.

[Explanation of symbols]

 Reference Signs List 1 steel material 2 coating film 3 cutting line

Claims (1)

(57) [Claims] 1. A marking step of burning off a coating film coated on a cutting line and its vicinity with a laser, and a cutting step of laser cutting along the cutting line after completion of the marking step. Set the focal point away from the surface of the steel material to be cut, and
The laser focus on the steel material to be cut
A laser cutting method for a steel material to be coated, characterized by supplying an assist gas together with the laser beam.