Fast-speed laser scoring method

Abstract

A fast-speed laser scoring method is provided, in which a set of related laser scoring device is used to simultaneously score lines on the upper surface and the lower surface of an oriented silicon steel strip, which is being fed and traveling forwards on a production line, with high-focalized continuous wave laser beam; the lines scored on the upper surface and the lines scored on the lower surface have the same space between every two adjacent scored lines but are staggered each other in order to reduce iron loss evenly. The space between every two adjacent scored lines on the same surface is 6-12 mm, laser power is 1000-3000 W and scanning speed is 100-400 m/min. The machining rate of the scoring method and device attains 1.5-2 times the one of conventional scoring methods which can not simultaneously score the upper and lower surfaces of a steel strip at a time. The lines scored on a steel strip by the method can reduce iron loss of the strip by 10-16%.

Claims

1. A fast-speed laser scoring method comprising: moving an oriented silicon steel strip in a forward direction on a production line; and operating a laser scoring device at a constant power of 1000-3000 W to simultaneously create score lines on both an upper surface and a lower surface of the moving oriented silicon steel strip at a constant scanning speed of 100-400 m/min using focalized continuous wave laser beams moving in a direction transverse to said forward direction, wherein the score lines on the upper surface and on the lower surface have a same spacing of 6-12 mm between every adjacent ones of the score lines, wherein the score lines on the upper surface are staggered with respect to the score lines on the lower surface.

Description

BRIEF DESCRIPTION OF DRAWINGS

(1) FIG. 1 is a schematic diagram of optical path of laser irradiation according to the invention;

(2) FIG. 2 shows an interrelation between iron loss of oriented silicon steel sheet and width of magnetic domain (silicon steel sheet product of grade R090 with 0.23 mm thickness);

(3) FIG. 3 shows an interrelation between machining rate of a laser scoring machine and space of the scored lines (continuous laser source, double laser head, machining rate of the laser scoring machine at scanning speed of 250 m/min); and

(4) FIG. 4 shows the embodiments of the invention, i.e., the relationships between the space of every two adjacent scored lines and the percent of iron loss reduction of silicon steel sheet of 0.23 mm NSGO in both the embodiments and the comparative objects (CO.sub.2 gas continuous wave laser with 10.6 m wave length, 0.28 mm facula diameter, 2000 W laser power, 250 m/min scanning speed).

DETAILED DESCRIPTION OF THE INVENTION

(5) The invention is now described in detail in reference to the accompanying drawings and the embodiments.

(6) Referring to FIG. 1, the fast-speed laser scoring method employs a laser scoring device and is able to simultaneously score lines on both the upper and lower surfaces of an oriented silicon steel strip which is being fed and traveling forwards on a production line with high-focalized continuous wave laser beam. The lines scored on the upper surface and the lines scored on the lower surface have the same space between every two adjacent scored lines but are staggered with respect to each other in order to reduce iron loss evenly. The space between every two adjacent scored lines on the same surface is 6-12 mm, laser power is 1000-3000 W, and scanning speed is 100-400 m/min.

(7) Let's take it for example to describe that to use CO.sub.2 gas continuous wave laser with 10.6 m wave length and double laser projectors to make scoring simultaneously on each side of the strip steel. The related data are given in Table 1.

(8) TABLE-US-00001 TABLE 1 scoring steel sheet laser scanning scanning scanning machine highest P17/50, W/kg iron loss No. thickness mm power W speed m/min breadth mm space mm speed m/min before scoring after scoring reduction % embodiment 1 0.23 2000 250 1200 6 102 0.88 0.75 14.77 embodiment 2 0.23 7 120 0.89 0.74 16.85 embodiment 3 0.23 8 138 0.89 0.75 15.73 embodiment 4 0.23 9 156 0.87 0.74 14.94 embodiment 5 0.23 10 174 0.87 0.75 13.79 embodiment 6 0.23 11 192 0.89 0.77 13.48 embodiment 7 0.23 1000 150 1200 10 112 0.88 0.75 14.77 embodiment 8 0.23 1500 200 140 0.87 0.75 13.79 embodiment 9 0.23 2500 300 200 0.89 0.76 14.61 embodiment 10 0.23 3000 350 220 0.88 0.76 13.64 comparative 0.23 2000 250 1200 3 48 0.91 0.81 10.99 object 1 comparative 0.23 4 66 0.89 0.78 12.36 object 2 comparative 0.23 5 84 0.89 0.78 12.36 object 3 comparative 0.23 6 102 0.90 0.81 10.00 object 4 comparative 0.23 7 120 0.87 0.80 8.05 object 5 comparative 0.23 1000 150 1200 5 56 0.87 0.78 10.34 object 6 comparative 0.23 1500 200 70 0.89 0.80 10.11 object 7 comparative 0.23 2500 300 100 0.88 0.78 11.36 object 8 comparative 0.23 3000 350 110 0.88 0.80 9.09 object 9

(9) As can be seen in FIG. 2, as the width of magnetic domain is decreased, iron loss drops down gradually. But when the width is less than a certain dimension (0.2 mm or so), iron loss rises up steeply.

(10) As can be seen in FIG. 3, there is a proportional relation between the highest machining rate of the scoring machine and the space between every two adjacent scored lines, the wider the space is, the higher the highest machining rate of the scoring machine is allowed to be.

(11) Relationships between the space of every two adjacent scored lines and the percent of iron loss reduction in both the embodiments and the comparative objects are shown in FIG. 4. As can be seen in Table 1 and FIG. 4, under the conditions that all the laser source, steel sheet thickness, laser power, scanning speed, scanning breadth are the same, in comparison to scoring on one surface of the steel sheet, scoring simultaneously on the upper surface and the lower surface of the steel sheet can have a wider interline space, a higher machining rate of the scoring machine, and can attain a greater iron loss reduction percent.

(12) To sum up the above, the scoring method of the invention is capable of scoring lines simultaneously on both upper surface and lower surface of a steel strip, and so is superior to the scoring methods of the prior arts in scoring speed and scoring efficiency.