JPWO2008153028A1 - Laser processing method and wire for oil ring - Google Patents

Abstract

Disclosed is a laser processing method for a member having an edge. In this method, a laser beam is formed on one surface of the member having an edge and having protrusions formed in the edge region, the two surfaces intersecting with the edge interposed therebetween, and the edge region. Light is irradiated to melt the protrusions and the edge region, and the resulting melt is moved to the other surface. The laser processing method can be suitably applied to the oil ring. The oil ring has left and right rail portions and a web portion that connects the rail portions. The web part has a plurality of through-holes formed by melting, and the remelted solidified material adheres to the wall surface of the through-hole, and there is a protrusion as a molten solidified substance on the outer surface of the web part. do not do.

Description

  The present invention relates to a member laser processing method for removing protrusions formed on a member with a laser beam and an oil ring wire processed by the method.

  When the member is processed, a part of the removed member may remain in a protruding shape in the edge region (here, the edge region refers to a portion including the edge and its vicinity). For example, when a plate-shaped member is irradiated with laser light to open a through-hole, an assist gas is ejected to remove the melt or evaporated gas, but the melt is sputtered as laser light until the hole penetrates. It scatters to the irradiation surface (front surface) side, and after penetrating, it flows out as dross on the laser light passage surface (back surface) side and adheres to the periphery of the opening of the through hole. By optimizing the assist gas injection pressure, spatter or dross adhesion can be prevented to a considerable level, but the pressure is not necessarily the optimum pressure for through-hole processing, and the material of the member It is difficult to define an appropriate gas pressure according to the thickness and the like, and it is difficult to prevent the gas from being completely attached. Moreover, it is also effective to apply a spatter or dross adhesion preventing agent to the member surface, but it cannot be said that it can be completely prevented.

Therefore, it is conceivable that spatter or dross is allowed to adhere at the time of through-hole processing, and it can be removed thereafter. For example, Patent Documents 1, 2, and 3 disclose the technique.
The laser processing method in Patent Document 1 is shown in FIGS. 9A and 9B. As shown in FIG. 9A, Patent Document 1 discloses a processing step of performing processing by irradiating a laser beam and an assist gas to a processing portion of a processing object, and a dross of the processing portion as shown in FIG. 9B. In order to remove the dross, a technical idea including a dross removing step in which dross removal is performed by irradiating the laser beam and the assist gas again to the processing portion is disclosed. The purpose of this technique is to improve the accuracy of the processed shape, and the technical feature is that the dross attached to the processed surface, that is, the side wall of the hole is blown away.

In the laser cutting method in Patent Document 2, laser cutting is performed after irradiating a laser beam, and then laser cutting is performed with this hole as a starting point. Prior to laser cutting, the nozzle attached to the periphery of the hole during piercing is used. Has a technical feature in that it is melted by irradiating a laser to a range including the periphery of the hole, and is blown off by injecting a gas having high pressure and low oxidizability, and is excluded from the surface of the steel plate. ing.
Further, in the laser processing method in Patent Document 3, after processing a target portion of a target object by irradiating a laser beam, the peripheral region including the target portion is irradiated with a laser beam and heated, so that the vicinity of the target portion is processed. It has a technical feature in that an adhering substance made of an attached sublimate is melted and integrated with a workpiece base material, and is said to be effective for cutting glass.
JP 2003-285191 A (paragraph numbers 0021 to 0022) JP 2001-321975 A (paragraph numbers 0008 to 0009) JP 2004-25228 A (paragraph numbers 0010 to 0011)

When the processed members are used, for example, in an overlapping manner, no protrusions must remain on the overlapping surface of the members. In Patent Document 1, even if the dross attached to the hole sidewall can be removed, the dross attached to the back surface opposite to the laser incident surface cannot be removed. Although it is supposed to be removed by polishing, it is not preferable because it requires a separate process, which is not efficient, and the entire back surface is removed by the amount of polishing.
Further, in Patent Document 2, the noro attached to the surface is melted and blown away with a high-pressure gas, but even if the noro is excluded from the periphery of the hole, it reattaches to another place on the surface, There is a risk of passing through the hole and adhering to the back surface, and it is not reliable in terms of removing protrusions from the surface or back surface. Moreover, in patent document 3, although the deposit | attachment like the sublimation uses the effect | action which melt | dissolves in a base material with respect to a microscopic object, with respect to the protrusion formed in edge areas like a burr | flash or dross. All effects are not considered.

  Thus, an object of the present invention is to provide a laser processing method in which a protrusion formed on one surface of an edge region of a member having an edge is melted by laser light and moved to the other surface, and processing is thereby performed. An oil ring wire is provided.

According to the main viewpoint of this invention, the following laser processing methods are provided.
Of the two surfaces that have an edge and have protrusions in the edge region, and intersect the surface across the edge, irradiate one surface where the protrusion exists and the edge region with laser light, A laser processing method for a member having an edge, wherein the protrusion and the edge region are melted, and the resulting melt is moved to the other surface.
The melt can be moved by gravity.
The melt can also be moved by the kinetic energy of the assist gas.

In the laser processing method of the present invention, it is preferable to obtain a member having an edge and a protrusion formed in the edge region by a through-hole drilling step in which a laser beam is irradiated toward one surface of the member to form a through-hole. .
It is preferable that the energy density of the laser beam irradiated in forming the melt is smaller than the energy density of the laser beam irradiated in the through hole drilling step.
It is preferable that the set pressure of the assist gas used for moving the melt is lower than the set pressure of the assist gas used in the through hole drilling step.
As an application example, the laser processing method of the present invention can be suitably used for processing an oil ring wire. The oil ring wire has left and right rail portions and a web portion connecting the rail portions, and through holes are formed in the web portion in the through hole drilling step by applying the method of the present invention.

According to another aspect of the present invention, the following oil ring wire is provided.
An oil ring wire having left and right rail portions and a web portion connecting the rail portions, wherein the web portion has a plurality of through holes formed by melting, and a melt is formed on a wall surface of the through holes. The remelted solidified product solidified is adhered, and no protrusions due to the melt are present on the outer surface of the web portion.
According to a preferred embodiment of the oil ring wire according to the present invention, the edge region on the side where the melt moves to the wall surface of the through hole is formed in a hollow shape or a chamfered shape.

  According to the present invention, the protrusion formed on one surface of the edge region is moved to the other surface without adhering to the rear surface of the workpiece opposite to the laser beam irradiation surface of the workpiece. Therefore, it is possible to reduce the influence of the projection formed on the workpiece.

Example 1
In the present embodiment, a member in which an edge is formed in a workpiece and a projection is generated in the edge region by processing such as hole processing, groove processing, cutting processing, etc. Among them, the protrusions generated on one surface are melted by irradiating laser light and moved to the other surface. The protrusion is a dross if the processing is laser processing, and a burr (also called a burr) if the processing is cutting. Hereinafter, the case where the burr | flash produced when the through-hole was processed by cutting is removed is demonstrated to an example.

  As shown in FIG. 4, for example, when a drill is fed at a right angle to the A surface of the metal flat plate 10 and the through hole 11 is machined, the burrs are formed on the B surface in the vicinity of the edge 12 opened to the opposite B surface. 13 is formed to expand. If the burr 13 protrudes on the B side, the operator may cut his hand, which is not only dangerous, but also when the flat plate 10 is used as a member of an assembly or a member of a laminated product. In this case, correct assembly cannot be performed. If the number of through-holes 11 is small, the burr 13 may be removed manually with a file. However, if the number of through-holes is large, the present invention which is not efficient and can be automated should be applied. .

In this embodiment, as shown in FIGS. 1 and 2, a flat metal plate (hereinafter referred to as a base material) 10 is irradiated with a laser beam 15 directed toward the B surface with the B surface side from which the burr 13 protrudes facing upward. Thus, the burr 13 protruding from the B surface is used as the melt 13 a and is moved to the wall surface C of the through hole 11. The laser beam 15 has a spot diameter including a range where the burr 13 is spread, and is irradiated around the through hole 11. The laser beam 15 is irradiated with an energy density and time so that the burr 13 is melted. Since the burr 13 has a small heat capacity, the burr 13 is heated in a short time to become a melt 13a having fluidity.
When the edge 12 is heated to a high temperature and the surface layer is melted by the irradiation of the laser beam 15, the melt 13a is absorbed by the melt in the edge region and is integrated into the wall C of the through-hole 11 thinly. spread. The integrated melt has high fluidity, moves along the wall surface C of the through hole 11 as shown in FIG. 2, is cooled according to the temperature gradient, and is firmly bonded to the wall surface C. That is, the burr 13 becomes a melt 13a and moves to the wall surface C of the through hole 11, so that it looks as if the protrusions disappeared from the B surface. In addition, since a part of melt of the edge 12 moves to the wall surface C together, the edge region becomes indented or chamfered.
The laser processing method of the present invention is simple because it suffices to irradiate the laser light to the one surface where the protrusion is formed and the region including the edge region. In addition, according to the present invention, after performing hole processing, groove processing, cutting processing, and the like by laser processing, protrusions can be removed by laser processing, and efficient processing is possible.

Example 2
Example 1 is an example in which the molten burr is integrated with the melt of the edge 12 and is moved to the wall surface of the through hole by gravity, and no special assist gas is used. Can be used to move the melted burr to the wall surface of the through hole. In the second embodiment, as shown in FIG. 3, the laser beam 15 is irradiated toward the B surface of the base material 10 and the assist gas 16 is injected toward the B surface. Here, the laser beam 15 is irradiated with an energy density and a time such that at least the burr 13 is melted, as in the case of the first embodiment. In the second embodiment, the melt in the vicinity of the edge 12 including at least the projection melt moves so as to be pushed away to the other surface by the assist gas, so that the projection is removed from one surface.

As shown in FIG. 3, the assist gas 16 is irradiated along the through hole 11 including the range where the burr 13 is formed. The assist gas 16 is at a pressure that is low enough to allow the melt 13a to move on the base material surface B by the laser beam 15, and moves the melt 13a thinly and widely, but it is preferable not to blow off the melt 13a. . When the melt 13a is blown off, it is scattered on the B surface side of the base material 10 and adheres to other places, or alternatively, it passes through the through holes 11 and is scattered and attached to the A surface side of the base material 10. It is not preferable.
For example, the assist gas 16 is preferably irradiated from a tapered nozzle toward the through hole 11 at a pressure or speed set in accordance with the size, material, size, length, and the like of the burr. Further, in the present invention, the kinetic energy of the assist gas is used, and the melt is swept away but moved so that the members can be arranged freely. Further, the edge 12 does not necessarily have to be melted as long as the protrusion is melted.

  When the burr 13 is melted by the laser beam 15 to the extent that it has fluidity, the melt 13a moves in the direction of the wall surface C of the through hole 11 and moves while spreading toward the wall surface C of the through hole through the edge 12. It is cooled and solidified according to the temperature gradient of C, and is firmly bonded to the wall surface C. At this time, if the edge region is also melted, it is preferable that the melt 13a is absorbed by the edge region melt to increase fluidity and diffuse widely as in the first embodiment. If the temperature of the edge region is high enough to wet the melt 13a, the melt 13a can move in the direction of the through hole 11 on the edge 12, so the edge 12 does not necessarily have to be melted. In this case, the “sag” of the edge 12 can be reduced by reducing the output of the laser beam 15 or shortening the irradiation time.

  The injection timing of the assist gas 16 is not necessarily matched with the irradiation timing of the laser beam 15, and may be set individually. For example, the assist gas injection may be started when the burr 13 is melted, and may be allowed to flow for a further time after the irradiation of the laser beam 15 is stopped. In this embodiment, since the melt is moved by the kinetic energy of the fluid, it is not always necessary to set the base material 10 so that the B surface is upward, and the B surface is downward, lateral, or inclined. May be. The irradiation direction of the laser and the injection direction of the assist gas may be set to a direction that is substantially perpendicular to the B surface. Moreover, the burr | attachment area | region in the through-hole 11 is controllable by adjusting the pressure or speed | velocity | rate, etc. of assist gas in the range in which the molten burr | flash 13a is not blown away.

Example 3
In the third embodiment, a through hole drilling process is performed in which a through hole of a workpiece is drilled by laser processing, and a protrusion generated thereby is further moved to the through hole wall surface by laser processing. Here, the projection is suitable for an automated system that targets dross and, for example, processes a large number of small-diameter through holes and removes the dross from the surface of the workpiece.

As shown in FIG. 5A, the laser processing method of the present invention uses a through-hole drilling process in which a through-hole 21 is formed by irradiating and injecting laser light 25 and an assist gas 26 onto the A surface (lower surface) of the workpiece 20. Then, a member having an edge and a protrusion formed in the edge region is obtained. As shown in FIG. 5B, a laser beam 35 and an assist gas 36 are irradiated and jetted onto a region including the edge 22 of the through hole 21 opened on the B surface (upper surface) of the workpiece 20, and the edge 22 of the through hole 21. It is preferable to move the dross 23 formed on the B surface in the vicinity to the wall surface C.
In the through-hole drilling step, the laser beam 25 has a spot diameter that is substantially the same as the diameter of the through-hole 21 to be drilled, and has an energy density that melts the workpiece 20 in the spot region, and is directed toward the A surface of the workpiece. Is irradiated. The assist gas 26 is jetted toward the surface A of the workpiece 20 in a range substantially the same as the spot diameter of the laser beam 25, and has kinetic energy that blows away the melt. As a result, the melt until the through-hole 21 is formed is spattered to the surface A side of the workpiece 20 as a sputter. However, a spatter adhesion preventing agent is applied to the surface of the workpiece 20 in advance, or the laser head is sputtered. Adhesion of the workpiece 20 to the A surface side can be prevented by providing a collection hood or performing vacuum suction or the like.
When the through hole 21 is formed, the melt is discharged to the B surface side through the through hole 21 and adheres to the edge 22 as dross.

For the formation of the melt, the same technique as in Example 2 described above is used. That is, the laser beam 35 has a spot diameter having a size including the adhesion region of the dross 23 attached to the B surface, and is irradiated toward the B surface of the workpiece 20 with heat energy that melts the dross 23 on the B surface. The Here, the energy density on the irradiation surface of the workpiece 20 is preferably lower than the energy density in the through-hole drilling step. In order to reduce the amount of sag of the edge 22, the energy density of the laser light 35 may be lowered.
The assist gas 36 has such kinetic energy that the molten dross 23 can move on the B surface, and irradiates the through hole 21 from a range including the dross adhesion region on the B surface.
Further, the kinetic energy of the assist gas 36 is preferably smaller than the kinetic energy in the through-hole drilling step. For example, the kinetic energy can be reduced by setting the set pressure lower than the set pressure in the through-hole drilling step. . When the dross 23 attached to the B surface is melted, the dross attached to the wall surface C of the through hole is usually melted and the surface of the edge 22 is melted or at least at a temperature sufficient to wet the molten dross. Since it is raised, the melted B-side dross 23 easily moves to the wall surface C and is cooled and solidified.

  As described above, the laser beam 35 and the assist gas 36 in forming the melt are different from each other in the energy density of the laser beam, the spot diameter, the injection range of the assist gas, and the kinetic energy compared to the through-hole drilling step. It is preferable to irradiate and inject the workpiece toward the surface opposite to the through-hole drilling step, and laser processing equipment may be constructed according to the form of the workpiece, the specifications of the through-hole, and the like. For example, if the workpiece is a square or circular plate material and a through hole is formed in a predetermined plane area, a general laser processing machine in which a laser head or a work set base is controlled in three axial directions is used. It is preferable. At this time, first, the entire number of through holes is drilled in the through hole drilling step, then the work piece is inverted and set, and the laser beam energy and focus position, and the assist gas pressure and nozzle position are adjusted. The dross can be moved with respect to the total number of through holes in the formation of the melt.

  Further, if the workpiece is a long member and a through hole is formed along the member, the workpiece is moved as indicated by arrows in FIGS. 5A and 5B, and the through hole is moved along the movement path. A system in which a laser beam and assist gas irradiation / injection station for a drilling process and a laser beam and assist gas irradiation / injection station for forming a melt are sequentially provided may be used. In this case, the laser beam and assist gas irradiation and the jetting direction of the through-hole drilling step and the melt formation may be configured as shown in FIGS. 6A and 6B in addition to those shown in FIGS. 5A and 5B. As shown in FIG. 5B, when the laser beam and assist gas irradiation used for forming the melt and the injection direction are directed downward, the action of gravity can also be used for dross removal, so the assist gas pressure can be reduced or the removal time can be shortened. This is preferable because it can be applied, and the technique of Embodiment 1 that does not use a special assist gas can also be applied.

In the first, second, and third embodiments, the description has been given with respect to the through hole having a diameter smaller than the spot diameter of the laser beam that moves the melt to the wall surface of the through hole. It corresponds to what was performed continuously, and the present invention can be applied similarly. For example, in the techniques of Examples 1 and 2 or the melt formation technique in Example 3, as shown in FIG. 7A, the laser beam 35 and the groove 37 having the same width as the diameter of the through hole 31 are used. The assist gas 36 may be applied so as to be irradiated and jetted in a range including the groove width and moved relative to the workpiece in the groove length direction.
Further, as shown in FIG. 7B, the laser beam 45 and the assist gas 46 are irradiated and jetted to a range including the cutting edge 42 to the cutting portion 47 larger than the through-hole diameter, and the workpiece is irradiated. It may be relatively moved along the cutting edge 42. Further, the laser beam for removing the protrusions does not necessarily have to be irradiated in a direction substantially perpendicular to the B surface as described above, and may be irradiated from an oblique direction. In contrast, irradiation in a substantially horizontal direction may be used. Further, the material of the target member is not limited to metal, but may be ceramic, resin, or the like.

A suitable member as a processing object to which the laser processing method of the present invention is applied has a left and right rail part and a web part connecting the rail part, and the web part is formed with a through hole in the through hole drilling step. It is a wire rod for oil ring. In particular, a stainless steel oil ring wire containing 8 to 25% Cr by mass is suitable.
When the member in the present invention is applied to an oil ring wire, the shape is as shown in FIGS. 8A and 8B, for example. At this time, typical dimensions are, for example, that the thickness 51 of the web portion is 0.5 mm or less, the width 52 of the through hole formed in the web portion is 0.3 mm to 0.7 mm, and the length 53 of the through hole is 0.00. 5 to 1.2 mm, and the pitch 54 of the through holes is 3 to 10 mm.

Based on the test Example 3, first, continuously running, mass%, C: 0.5%, Si: 0.2%, Mn: 0.3%, Cr: 10%, the balance A stainless steel oil ring wire having a composition composed of Fe and inevitable impurities was continuously drilled with a large number of oval through holes for oil circulation by laser processing. Subsequently, the process which moves a melt to a through-hole wall surface by laser processing was performed. As shown in FIG. 8A, the target oil ring wire has a substantially H-shaped cross section, a width 55 between the left and right rails is 1.5 mm, a thickness 56 is 1.5 mm, and a web portion connecting the rail portions. This flat wire has a flat surface width 57 of 1 mm and a thickness 51 of 0.4 mm. Further, as shown in FIG. 8B, laser processing was performed so that long hole-shaped through holes 58 having a width 52 of 0.5 mm and a length 53 of 0.8 mm were formed in series at a pitch 54 of 10 mm in the web portion.

Similarly to the laser processing equipment shown in FIG. 5 described above, the laser processing equipment for the through-hole drilling process and the melt formation were installed in series along the traveling line of the oil ring wire. Hereinafter, similar elements will be described with reference to FIGS. 5A and 5B using the same reference numerals.
The oil ring wire 20 is run in a posture such that the web surface is up and down, and the A and B surfaces in FIGS. 5A and 5B correspond to both sides of the web. In the through-hole drilling step, as in the case described with reference to FIG. 5A, a pulse YAG laser 25 with an output of 4.5 kW is applied from the lower side of the oil ring wire 20 toward the web surface A. In addition, irradiation was performed with a spot diameter of about 0.45 mm so as to focus on, and a nitrogen gas 26 having a pressure of 0.7 MPa was injected as an assist gas to pierce the through hole 21. In the through-hole drilling step, two-stage drilling was performed in which a hole having a predetermined size was formed after a small-diameter hole was drilled. At this time, the through-hole 21 became a shape narrowed from the A surface toward the B surface, and drosses 23 adhered to the edge 22 on the B surface side in several points. FIG. 10 shows an example of the appearance of the through hole of the oil ring wire to which dross is attached after the through hole drilling step.

  In the formation of the melt, as described with reference to FIG. 5B, the pulse YAG laser 35 with an output of 1.5 kW is applied from above the oil ring wire to the web surface B, and the spot diameter is about 0.6 mm on the B surface. The laser beam was irradiated so as to include the through hole and its peripheral portion and the energy density was lowered. Further, as the assist gas 36, nitrogen gas was injected into the laser irradiation range at a pressure lower than the pressure in the through hole drilling step. Specifically, injection was performed while changing the set pressure from 0.01 MPa, 0.03 MPa, 0.05 MPa, and 0.1 MPa, and the removal state of the dross 23 was observed. Note that the assist gas 36 was not injected.

In the oil ring wire 20 on which the melt is formed, the dross 23 formed after the through-hole drilling step moves from almost on the web surface B to the through-hole 21 wall surface C at any assist gas 36 pressure. However, dross was attached over almost the entire circumference of the wall surface C of the through hole 21. When the adhesion state of the solidified body in the through hole 21 is seen, the pressure of the assist gas 36 increases and reaches the lower side of the through hole wall surface C, and the edge region on the B surface side of the through hole 21 increases. There was a tendency to go out. In addition, when the pressure of the assist gas 36 is 0.1 MPa, a slight amount of a solidified body adhering to the web surface A is seen, and the pressure seems to be slightly too high.
When the assist gas 36 was not injected, most of the dross remained in the vicinity of the B surface of the wall surface C of the through hole.

  An application example of the present invention is shown in FIG. As shown in FIG. 11, it was confirmed that the dross attached around the through hole of the oil ring wire was melted and chamfered by laser irradiation, and the dross was not dropped off.

As another application example of the present invention, a pulse YAG laser 35 having an output of 0.7 kW was jetted simultaneously with the assist gas 36 having a pressure of 0.03 MPa to move the dross to the wall surface of the through hole.
FIG. 12 shows an example of an external appearance photograph of the oil ring wire of the present invention. As shown in FIG. 12, the dross adhering to the periphery of the through hole of the wire for the oil ring is melted by the laser irradiation in forming the melt to form a chamfer, and it can be confirmed that the dross does not fall off. It was.
FIG. 13 shows an example of a microstructure photograph of the cross section of the through hole. As shown in FIG. 13, it was confirmed that the dross moved to the wall surface of the melt through hole and the dross did not fall off. Thereby, the optimal wire as an oil ring wire was able to be obtained.

  The laser processing method of the present invention is a technique for improving the state of an edge generated by various processing of various members including mechanical parts such as an oil ring for an internal combustion engine, and can remove protrusions existing in the edge region by laser irradiation.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic diagram which shows one Example of this invention, and sectional drawing in alignment with the axis line of a through-hole of the metal flat plate which has a through-hole (Example 1). FIG. 1A is a schematic plan view of a metal flat plate shown in FIG. 1A (Example 1). Typical sectional drawing which shows the flow condition of the protrusion which exists in the entrance part of the through-hole in FIG. 1A and FIG. 1B (Example 1). It is a schematic diagram which shows one Example of this invention, and is typical sectional drawing along the axis of a through-hole of the metal flat plate which has a through-hole (Example 2). FIG. 6 is a schematic cross-sectional view illustrating an example of forming a through hole having a protrusion in Examples 1 and 2. It is a schematic diagram which shows one Example of this invention which forms many through-holes in a to-be-processed object, and is sectional drawing which follows the axis line of a through-hole (Example 3). FIG. 5B is a schematic cross-sectional view (Example 3) showing a state in which an assist gas is used to cause a protrusion existing at the entrance portion of the through hole in FIG. 5A to flow by laser light irradiation. Typical sectional drawing which shows the alternative of the example shown to FIG. 5A (Example 3). FIG. 6A is a schematic cross-sectional view showing a state in which an assist gas is used to flow a protrusion existing at the entrance portion of the through hole in FIG. 6A by laser light irradiation (Example 3). The typical top view which shows the state which forms a groove | channel or a cutting part in a workpiece by laser beam irradiation as an example of this invention. FIG. 7B is a schematic plan view showing a state in which the protrusions present on the edge portion of the groove or the cutting portion shown in FIG. Sectional drawing which shows the cross-sectional shape of the wire for oil rings used by the test. The top view of the wire material for oil rings shown to FIG. 8A. The typical sectional view showing the prior art indicated in patent documents 1 which irradiates a work piece with a laser beam, and forms a penetration hole. FIG. 9B is a schematic cross-sectional view showing a state in which protrusions existing at the edge of the through hole formed by the technique shown in FIG. 9A are made to flow by laser light irradiation according to the prior art. FIG. 6 is an appearance photograph showing an example of an oil ring wire after a through hole drilling step in Example 3. 3 is an appearance photograph showing an example of a wire for an oil ring of the present invention in Example 3. FIG. 3 is an appearance photograph showing an example of a wire for an oil ring of the present invention in Example 3. FIG. 5 is a microstructural photograph showing an example of a cross-section of a through hole of a wire for an oil ring of the present invention in Example 3.

Explanation of symbols

10, 20 Workpiece 15, 35, 45 Protrusion melting laser beam 25 Through hole forming laser beam 16, 36, 46 Molten projection flow assist gas 26 Through hole forming assist gas 13 Burr 23 Dross 11, 21, 31 Through-hole 37 Groove 12, 22, 42 Edge A Projection non-formation surface B Projection formation side (projection removal target surface)
C Through-hole wall surface 51 Web portion thickness 52 Through-hole width 53 Through-hole length 54 Through-hole pitch 55 Oil ring wire width 56 Oil ring wire thickness 57 Web portion flat surface width 58 Through Hole

Claims (9)

  Of the two surfaces that have an edge and have protrusions in the edge region, and intersect the surface across the edge, irradiate one surface where the protrusion exists and the edge region with laser light, A laser processing method for a member having an edge, wherein the protrusion and the edge region are melted, and the resulting melt is moved to the other surface.   The laser processing method for a member having an edge according to claim 1, wherein the melt is moved by gravity.   The laser processing method for a member having an edge according to claim 1 or 2, wherein the melt is moved by an assist gas.   4. The member having an edge and having protrusions in the edge region is formed by a through-hole drilling step in which a laser beam is irradiated toward one surface of the member to form a through-hole. The laser processing method of the member which has an edge described in any one of these.   The laser processing method for a member having an edge according to claim 4, wherein the energy density of the laser beam irradiated to form the melt is lower than the energy density of the laser beam irradiated in the through-hole drilling step. .   The laser of the member having an edge according to claim 4 or 5, wherein a set pressure of the assist gas used for moving the melt is lower than a set pressure of the assist gas used in the through-hole drilling step. Processing method.   The said member is an oil ring wire which has a rail part on either side and a web part which connects this rail part, The said through-hole is formed in the said web part by the said through-hole drilling process. Item 7. A laser processing method for a member having an edge according to any one of Items 6 to 6.   An oil ring wire having left and right rail portions and a web portion connecting the rail portions, wherein the web portion has a plurality of through holes formed by melting, and a melt is formed on a wall surface of the through holes. An oil ring wire in which a remelted solidified product solidified is adhered, and no protrusions due to a melt are present on the outer surface of the web portion.   The wire material for an oil ring according to claim 8, wherein an edge region on a side where the melt moves to the wall surface of the through hole is in a recessed shape or a chamfered shape.

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