JP2018089667A - Laser cutting device - Google Patents

Abstract

A laser cutting apparatus capable of removing dross adhering to a cut surface of a workpiece without generating secondary foreign matter without contact. A laser oscillator that oscillates a laser beam, a processing head that collects the laser beam at a focal position and irradiates the workpiece, and ejects an assist gas supplied from a gas supply device, and the processing head. An air blower is provided behind the head and ejects gas supplied from a gas supplier onto the cut surface of the workpiece. [Selection drawing] Fig. 1

Description

  The present disclosure relates to a cutting apparatus using a laser, and more particularly to cutting a sheet-like workpiece such as an electrode sheet.

  A wound-type lithium ion battery has a structure in which a separator sheet is sandwiched between a positive electrode sheet and a negative electrode sheet, and a roll of three sheets is packed into a cylindrical can, and an electrolytic solution is injected therein and sealed. It has become. The electrode sheet has a three-layer structure in which an activator is applied to both surfaces of a metal foil such as an aluminum foil or a copper foil having a thickness of about 10 μm. The electrode sheet is formed by applying an active layer to a wide sheet of metal foil, and is cut into a desired width.

  In cutting an electrode sheet using a mechanical cutter, the blade of the cutter is deteriorated due to wear, resulting in a problem of quality deterioration such as generation of burrs. Therefore, it is necessary to replace the cutter periodically. In particular, the method of cutting with a roll cutter while winding the original fabric is excellent in productivity because continuous cutting is possible, but if the cutter needs to be replaced, the productivity is lowered.

  Therefore, cutting using laser technology has been studied. In laser cutting, since the work is irradiated and melted by irradiating the focused laser beam with high energy density and the melted portion is blown off with an assist gas, cutting without contact is possible. Therefore, it is possible to eliminate the occurrence of burrs due to deterioration of the apparatus such as a mechanical cutter (see, for example, Patent Document 1).

JP 2015-24416 A

  In laser cutting, secondary products generated during cutting may become foreign matter. In particular, as the thinning technology progresses, contamination of foreign matters becomes a serious quality problem even if it is very small. Therefore, as in Patent Document 1, a sheet cutting apparatus having a mechanism for eliminating secondary products generated during laser cutting is required.

  Patent Document 1 provides a cutting device that removes fumes and cutting materials by air blowing and suction. However, depending on the sheet material, other secondary products may be generated, which may be a problem. One of them is dross that has been re-solidified without being melted at the time of cutting. The dross that cannot be completely removed by the assist gas and adheres to the cut surface becomes a foreign substance when it is peeled off in a subsequent winding process or the like, which leads to a quality problem.

  Dross adhesion can be reduced by optimizing the cutting conditions, but some sheet materials are difficult to completely eliminate. Therefore, a means for forcibly removing the dross in the post-processing step is necessary. However, in the method of removing by applying a brush or the like, further secondary foreign matter generation is feared due to wear of the brush or the like.

In order to solve the above-described problems, the present invention provides a laser oscillator that oscillates a laser beam, condenses the laser beam at a focal position, irradiates a workpiece, and an assist gas supplied from a gas supplier A laser cutting device comprising: a processing head that ejects; and an air blow device that is provided behind the processing head and that ejects gas supplied from a gas supply device to a cut surface of the workpiece.

  Thereby, dross can be forcibly peeled off without generating secondary foreign matter, and the processing quality is improved.

  The air blow device preferably includes at least two gas ejection heads, and the main stream of gas ejected from each of the gas ejection heads has a predetermined angle with respect to both cut surfaces of the workpiece. The predetermined angle is preferably 15 to 45 degrees. Thereby, dross can be removed more efficiently.

Moreover, it is preferable that the assist gas flow ejected from the machining head and the gas flow ejected from each ejection head of the air blowing device are in a positional relationship such that they do not interfere with each other.
It is possible to prevent the dross removal effect from deteriorating due to the gas flows interfering with each other.

  The laser cutting apparatus of the present invention can remove the attached dross in a non-contact manner by blowing high-pressure gas onto the cut surface after laser cutting, and the processing quality is improved.

The whole block diagram of the laser cutting device in the embodiment of the present invention The figure which shows the state of melt removal and residual dross by assist gas at the time of laser cutting The figure which shows the state of the removal of the dross by the gas ejected from the gas ejection head Diagram showing the relationship between gas spray angle and dross removal rate Diagram showing the positional relationship between the machining nozzle and air blow device

  EMBODIMENT OF THE INVENTION Below, the form for implementing this invention is demonstrated, referring a figure.

(Embodiment)
FIG. 1 is an overall configuration diagram of a laser cutting device according to an embodiment of the present invention. The laser cutting device uses a laser beam to cut the electrode sheet 100 as a workpiece in the longitudinal direction.

  The original sheet of the electrode sheet 100 is a wide and long sheet wound in a roll shape, and is set on the feed roller 106. The cut electrode sheet 100 is taken up by a take-up roller 107. That is, the electrode sheet 100 moves linearly with respect to the processing head 103 described later.

  Laser light is oscillated from a laser oscillator 101 and guided to a processing head 103 by a transmission fiber 102. The laser light is collimated by a collimating lens inside the processing head, then passes through the condensing lens, is condensed toward the focal position, and is irradiated from the tip nozzle of the processing head 103.

  The processing head 103 is connected to a gas supply device 104, and the supplied gas is ejected from the tip nozzle as an assist gas in the direction coaxial with the laser beam. The gas supply device 104 may be any device that can supply high-pressure gas, and a compressor or a compression cylinder can be used. Compressed air is mainly used as the assist gas, but oxygen or nitrogen may be used depending on the material of the electrode sheet 100.

  For example, if the material is expected to promote combustion by oxidation, efficient laser cutting can be performed by using oxygen as the assist gas. On the other hand, if the oxidation of the material adversely affects the battery production, a gas with low reactivity such as nitrogen may be used.

  In laser cutting, the positional relationship between the workpiece and the laser beam focal point greatly affects the cutting quality, so the vicinity of the processing head 103 holds the electrode sheet 100 from above and below by the support roller 108, and the electrode sheet 100 is shaken vertically. Suppressed.

  The electrode sheet 100 is melted by irradiating the laser beam which is condensed and has a high energy density. The melted portion is blown downward by the assist gas and collected by the dust collector 105. In this embodiment, since the electrode sheet 100 moves and the processing head 103 and the apparatus connected to the processing head are all fixed, the optical system does not shift during cutting, and stable cutting is possible.

  FIG. 2 is a cross-sectional view of the electrode sheet 100 immediately below the processing head 103. In laser cutting, most of the melt 201 in the cutting groove can be removed by the assist gas ejected from the nozzle at the tip of the processing head 103, but the melt remaining along the wall surface without falling off the cutting groove is film-like dross. 200 is formed. In the present embodiment, an air blow device 109 is provided on the winding roller side behind the processing head 103 for the purpose of removing the dross 200.

  The air blow device 109 is branched and connected from the gas supply device 104 connected to the processing head 103, and is provided with a gas pressure adjusting valve (not shown) in each path. Note that another gas supply device different from the gas supply device 104 may be connected to the air blowing device 109.

  The air blow device 109 is intended to remove the dross 200 attached to the cutting groove by air blow (jet gas), but it is effective even when gas is blown from directly above (perpendicular to the electrode sheet). Have However, in order to exert more effect, as shown in FIG. 3, the position of the gas ejection head 110 is such that the main flow of the gas ejected from the gas ejection head 110 of the air blowing device 109 is at an angle Θ with respect to the cut surface. Is adjusted.

  FIG. 4 is a graph showing the relationship between the angle Θ and the removal rate of dross attached to the cut surface. The solid line shows the dross removal rate of the cut surface of the electrode sheet on the spray side, and the broken line shows the dross removal rate of the cut surface of the electrode sheet on the opposite side. As can be seen from the figure, when the angle of 30 degrees is given to the cut surface, the highest removal effect is obtained, and good results are obtained in the range of 15 degrees to 45 degrees.

  Moreover, as shown by a broken line, the dross removal rate of the cut surface of the opposite electrode sheet is deteriorated. Therefore, as shown in FIG. 5, in order to air blow the opposite cut surface, another gas ejection head 111 is provided so that the main flow of the gas to be ejected is at an angle Θ with respect to the opposite cut surface. .

  By the way, dross is cooled, so that it leaves | separates from a processing head, adhesion of dross of a cut surface becomes firm, and it becomes difficult to peel off. Moreover, it becomes difficult to peel off as the dross becomes longer as one film-like lump. Therefore, it is desirable to provide the gas ejection heads 110 and 111 of the air blow device 109 as close to the machining head as possible. On the other hand, if the pressure is too close, the high-pressure assist gas is ejected from the machining head 103. Therefore, even if the gas is ejected in the vicinity thereof, the gas flows interfere with each other and the dross removal effect is reduced.

Three regions surrounded by a two-dot chain line in FIG. 5 indicate the range of influence of each gas flow. The processing head 103 and the gas ejection head 1 are arranged so that these three regions do not contact (interfere) with each other.
10 and the position of the gas ejection head 111 are adjusted.

  In FIG. 5, the two gas ejection heads 110 and 111 are crossed so that the gas flows ejected from the two gas ejection heads 110 and 111 do not interfere with each other, and the two gas flow directions are the cutting directions of the electrode sheet. It is shifted to the left and right in the figure.

  In addition, what is necessary is just to select optimal conditions according to the characteristic of adhesion dross for the shape and gas pressure of the gas ejection head of an air blower. In the present embodiment, the number of gas ejection heads in the air blower is two. However, the number of ejection heads may be increased to improve the removal effect as long as the gas flow does not interfere. In the present embodiment, the workpiece is an electrode sheet. However, the present invention is not limited to this, and it is needless to say that the workpiece can be applied to a sheet-like workpiece.

  As described above, the laser cutting device of the present invention is optimal for cutting an electrode sheet.

DESCRIPTION OF SYMBOLS 100 Electrode sheet 101 Laser oscillator 102 Transmission fiber 103 Processing head 104 Gas supply machine 105 Dust collector 106 Feed roller 107 Winding roller 108 Support roller 109 Air blow apparatus 110, 111 Gas ejection head 200 Dross

Claims (4)

A laser oscillator that oscillates laser light;
A processing head for condensing the laser beam at a focal position and irradiating the workpiece with an assist gas supplied from a gas supply device, and
An air blow device that is provided behind the processing head and ejects a gas supplied from a gas supply device to a cut surface of the workpiece;
A laser cutting device comprising: 2. The air blow device according to claim 1, wherein the air blowing device includes at least two gas ejection heads, and a main flow of gas ejected from each of the gas ejection heads has a predetermined angle with respect to both cut surfaces of the workpiece. Laser cutting device. The laser cutting device according to claim 2, wherein the predetermined angle is 15 degrees to 45 degrees. 4. The laser cutting device according to claim 2, wherein the assist gas flow ejected from the machining head and the gas flow ejected from each ejection head of the air blowing device are in a positional relationship such that they do not interfere with each other.

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