KR101169981B1 - Laser working method, and oil ring wire rod - Google Patents

Abstract

The present invention discloses a method for laser processing a member having an edge. In this method, a laser beam is irradiated to one side and the edge region of one side of the member having an edge and interposed by interposing the edge of the member having a projection formed in the edge region. The melt formed by melting the protrusion and the edge region is moved to the other side. The laser processing method of the present invention can be preferably applied to an oil ring. The oil ring has left and right rail portions and a web portion connecting the rail portions. The web portion has a plurality of through holes formed by melting, and the remelt solidified product is attached to the wall surface of the through hole, and the protrusions as the molten solidified products do not exist on the outer surface of the web portion.

Description

LASER WORKING METHOD, AND OIL RING WIRE ROD}

This invention relates to the laser processing method of a member which removes the protrusion formed in the member with a laser beam, and the wire rod for oil rings processed accordingly.

When the member is processed, a part of the removed member may remain in a projection shape in an edge region where the edge region refers to a portion including the edge and its vicinity. For example, when a through-hole is drilled by irradiating a laser beam to a flat member, an assist gas is ejected to remove the melt or evaporated gas, but the melt is a sputter until the hole penetrates the laser beam. It scatters to the irradiation surface (surface) side, and after penetration, flows out as a dross to the laser beam passing surface (back surface) side and adheres to the periphery of the opening of the through hole. By optimizing the injection pressure of the assist gas, adhesion of the sputter or dross can be prevented to a considerable level, but this pressure is not necessarily the optimal pressure for the through hole processing, and also depends on the material and the thickness of the member. It is not easy to define an appropriate gas pressure, and it is not easy not to completely adhere. In addition, the application of a sputtering or dross anti-sticking agent to the surface of the member is effective, but can not be completely prevented.

Therefore, the technique is disclosed in Patent Documents 1, 2, and 3, for example, in consideration of allowing the sputter or the dross to adhere during the through hole processing and then removing the sputter or dross.

The laser processing method in patent document 1 is shown to FIG. 9A and 9B. As shown in FIG. 9A, Patent Document 1 discloses a processing step of irradiating a laser beam and an assist gas to a processing location of a processing target object, and removing dross at the processing location as shown in FIG. 9B. In order to solve the above problem, a technical idea including a dross removal step of irradiating the laser beam and the assist gas to the processing location to remove dross is disclosed. Since the purpose of this technique is to improve the precision of a processed shape, a technical characteristic is the point which blows and removes the dross adhering to the process surface, ie, the side wall of a hole.

Moreover, the laser cutting method in patent document 2 performs a laser cutting from this hole after a piercing by irradiating a laser beam, and adheres to the circumference | surroundings of a hole at the time of piercing before laser cutting. It has technical characteristics to remove the slag from the surface of the steel sheet by blowing the laser to the range including the periphery of the hole by melting the laser, and by blowing a gas having a low oxidizing property while having a high pressure. .

In addition, in the laser processing method in Patent Document 3, after irradiating a laser beam to a workpiece to be processed, the laser beam is irradiated to a peripheral region including the portion to be heated and heated near the workpiece. It is considered to be effective for cutting glass by melting the deposit made of the attached sublimation and integrating it with the raw material of the workpiece.

[Patent Document 1] Japanese Patent Application Publication No. 2003-285191 (Paragraph No. 0021 to 0022)

[Patent Document 2] Japanese Patent Application Laid-Open No. 2001-321975 (paragraphs 0008 to 0009)

[Patent Document 3] Japanese Patent Application Publication No. 2004-25228 (Paragraph No. 0010 to 0011)

[Problems to be solved by the invention]

When using the member after a process, for example, by overlapping, you should make sure that a protrusion does not remain on the surface on which the member overlapped. In Patent Document 1, although the dross attached to the side wall of the hole can be removed, the dross attached to the rear surface opposite to the laser incident surface side cannot be removed. Although it is removed by polishing, a completely different work step is required, which is not efficient, and may be undesirable because the entire back surface is removed by the polished portion.

In addition, in Patent Document 2, the slag attached to the surface is melted and blown with a high-pressure gas, but the slag is removed from the periphery of the slag, but the slag is reattached to another place on the surface or attached to the back through the hole. Since there is a concern, reliability is insufficient in that projections are removed from the surface or the back surface. In addition, in Patent Document 3, although the deposit is dissolved in the base material with respect to the microstructure, like the sublimate, the action on the protrusion formed in the edge region such as burr and dross is considered. Not.

Accordingly, an object of the present invention is to provide a laser processing method for forming projections formed on one side of the edge region in a member having an edge into a melt by laser light and moving them to the other side, and thus processed oil. It is to provide a wire for the ring.

[Means for solving the problem]

According to the main aspect of this invention, the following laser processing methods are provided.

Among the two surfaces of the member having an edge and the projections present in the edge regions, the laser beam is irradiated on one side where the projections exist and the edge region among the two surfaces intersecting the edges. A method for laser processing a member having an edge is provided by melting the edge region to move the resulting melt to the other side.

The melt can be moved by gravity.

The melt may be moved by the kinetic energy of the assist gas.

In the laser processing method of this invention, it is preferable to obtain the member which has an edge and the protrusion is formed in the edge area by the through-hole drilling step which irradiates a laser beam toward one surface of a member, and forms a through-hole.

It is preferable that the energy density of the laser beam irradiated to form the melt is smaller than the energy density of the laser beam irradiated in the through hole drilling step.

The set pressure of the assist gas used to move the melt is preferably 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 this invention can be used suitably for the process of the oil ring wire rod. The wire rod for oil rings has left and right rail portions and a web portion connecting the rail portions, and through the application of the method of the present invention, through holes are formed in the web portion in the through hole drilling step.

According to another aspect of the present invention, the following oil ring wire rod is provided.

An oil ring wire having a left and right rail part and a web part connecting the rail part, wherein the web part has a plurality of through holes formed by melting and remelt solidified material in which a melt is solidified on the wall surface of the through holes. Is attached, and the protrusion part by a molten body does not exist in the outer surface of the said web part.

According to one suitable form of the oil ring wire rod according to the present invention, the edge region on the side where the melt moves to the through hole wall surface is formed in a concave shape or a chamfered shape.

[Effects of the Invention]

According to the present invention, the projections formed on one surface of the edge region can be moved to the other surface without being attached to the back surface of the member on the side opposite to the laser beam irradiation surface of the member. The influence of the formed protrusions can be reduced.

1: A is a schematic diagram which shows one Embodiment of this invention, and is sectional drawing along the axis of the through hole of the metal plate which has a through hole (Example 1).

FIG. 1B is a schematic plan view of the metal plate shown in FIG. 1A (Example 1).

FIG. 2 is a schematic cross-sectional view showing the flow of protrusions present in the inlet portion of the through hole in FIGS. 1A and 1B (Example 1).

Fig. 3 is a schematic diagram showing an embodiment of the present invention, which is a schematic cross-sectional view of a metal flat plate having a through hole along the axis of the through hole (Example 2).

It is typical sectional drawing explaining the formation example of the through hole which has a protrusion in Examples 1 and 2. FIG.

FIG. 5A is a schematic diagram showing an embodiment of the present invention in which a plurality of through holes are formed in a workpiece, and is a cross-sectional view along the axis of the through holes (Example 3). FIG.

FIG. 5B is a schematic cross-sectional view showing a state in which an assist gas is used to flow projections present in the inlet portion of the through hole in FIG. 5A by laser light irradiation (Example 3).

FIG. 6A is a schematic cross-sectional view showing an alternative example to the example shown in FIG. 5A (Example 3).

FIG. 6B is a schematic cross-sectional view showing a state in which an assist gas is used to flow projections present in the inlet portion of the through hole in FIG. 6A by laser light irradiation (Example 3).

7A is a schematic plan view showing a state in which a groove or a cutout is formed in a workpiece by laser light irradiation as an example of the present invention.

FIG. 7B is a schematic plan view showing a state in which projections present in the grooves or the cutting edges shown in FIG. 7A are moved by moving laser light irradiation. FIG.

8A is a cross-sectional view showing the cross-sectional shape of the oil ring wire used in the test.

FIG. 8B is a plan view of the oil ring wire rod shown in FIG. 8A. FIG.

9A is a schematic cross-sectional view showing the prior art disclosed in Patent Document 1 in which a through hole is formed by irradiating a workpiece with a laser beam.

FIG. 9B is a schematic cross-sectional view showing a state in which protrusions existing around the end of the through hole formed by the technique shown in FIG. 9A are flowed by laser light irradiation according to the prior art. FIG.

10 is an external photograph showing an example of an oil ring wire rod after the through-hole drilling step in Example 3. FIG.

FIG. 11 is an external photograph showing an example of an oil ring wire rod of the present invention in Example 3. FIG.

FIG. 12 is an external photograph showing an example of an oil ring wire rod of the present invention in Example 3. FIG.

13 is a microstructure photograph showing an example of a cross section of a through hole of an oil ring wire rod of the present invention in Example 3. FIG.

[Description of Symbols]

10, 20: workpiece 15, 35, 45: laser light for melting projections

25: Laser Light for Through Hole Formation

16, 36, 46: assist gas for molten protrusion flow

26: assist gas for through hole formation

13: version 23: dross

11, 21, 31: through hole 37: groove

12, 22, 42: edge A: non-projection surface

B: Protrusion Formation Side (Protrusion Removal Surface)

C: through-hole wall surface 51: thickness of web portion

52: width of through hole 53: length of through hole

54: pitch of through hole 55: width of wire rod for oil ring

56: thickness of the oil ring wire 57: flat surface width of the web portion

58: through hole

Example  One

In this embodiment, the edges are formed on the workpiece by processing such as hole processing, grooving, cutting, and the like, and on one of two surfaces where the edges are sandwiched with respect to the member having projections formed in the edge region. The formed protrusion is made into a melt by irradiating a laser beam, and is moved to the other surface. The projections are dross if the processing is laser processing, and burrs if the processing is cutting. Hereinafter, the case where the burr which arises when processing a through hole by cutting is removed is demonstrated as an example.

As shown in FIG. 4, for example, when the drill is placed at a right angle with respect to the A plane of the metal flat plate 10 and the through hole 11 is machined, the edge 12 opened to the B plane, which is the opposite plane, is opened. It is formed so that the burr 13 may spread on the B surface of () vicinity. If the burr 13 protrudes on the B surface, the operator's hand may be cut, and not only is it dangerous, but also when the flat plate 10 is used as a member of an assembly or a member of a laminated product, It becomes impossible to assemble. If the number of through holes 11 is small, the bobbin 13 may be removed by hand, but when the number of through holes is large, it is not efficient, and therefore, it is preferable to apply the present invention that can be automated.

In the present embodiment, as shown in Figs. 1 and 2, the metal flat plate (hereinafter referred to as a base material) 10 is placed on the B surface side where the burr 13 protrudes, and the laser beam 15 is the B surface. By irradiating toward, the burr 13 protruding from the B surface is made into the molten body 13a and moved to the wall surface C of the through hole 11. The laser beam 15 becomes a spot diameter including the range in which the burr 13 is spread, and is irradiated around the through hole 11. The laser beam 15 is irradiated at an energy density and time at which the burr 13 is melted. Since the burr 13 has a small heat capacity, the burr 13 is heated in a short time to be a melt 13a having fluidity.

Moreover, when the edge 12 becomes high temperature by irradiation of the laser beam 15, and when a surface layer part melts, the molten body 13a will be absorbed by the molten body of an edge area | region, and will be integrated, and the wall surface C of the through-hole 11 Spreads thinly. This integrated melt has high fluidity, moves along the wall surface C of the through hole 11 as shown in FIG. 2, cools according to the temperature gradient, and is firmly bonded to the wall surface C. As shown in FIG. That is, since the burr 13 becomes the melt 13a and moves to the wall surface C of the through hole 11, the projections seem to have disappeared from the B surface. And since a part of melt of edge 12 moves to wall surface C together, an edge area becomes a concave shape or a chamfer shape.

Since the laser processing method of this invention only needs to irradiate a laser beam to the area | region containing one side and the said edge area | region in which a projection is formed, it is concise. Moreover, according to this invention, after performing a hole process, a grooving process, a cutting process, etc. by laser processing, a projection can be removed continuously by laser processing, and efficient processing is possible.

Example  2

Example 1 is an example of integrating a molten bur with the melt of the edge 12 and moving it to the wall surface of the through hole by gravity, and using no special assist gas, but using the kinetic energy of the fluid, The molten burr may be moved to the wall surface of the through hole. In the present Example 2, as shown in FIG. 3, the laser beam 15 is irradiated toward B surface of the base material 10, and the means which injects the assist gas 16 toward B surface is taken. Here, the laser beam 15 is irradiated at an energy density and time for melting the burr 13 at least, substantially the same as in the first embodiment. In the present Example 2, since at least the melt near the edge 12 including the protrusion melt is pushed to the other face by the assist gas and flows, the protrusion is removed from one face.

As shown in FIG. 3, the assist gas 16 is irradiated along the through hole 11 including the range in which the burr 13 is formed. The assist gas 16 is formed at a pressure low enough that the melt 13a by the laser beam 15 can move the base material surface B phase, and moves the melt 13a thinly and broadly. It is desirable not to blow it. When the molten body 13a blows and blows, it is unpreferable because it scatters to the B surface side of the base material 10, and attaches to another place and also scatters and adheres to the A surface side of the base material 10 through the through-hole 11.

The assist gas 16 is preferably irradiated toward the through hole 11 at a pressure or a speed set according to, for example, the size, material of the burr, the size, length of the through hole, etc. from a nozzle having a sharp tip. Do. Moreover, in this invention, arrangement | positioning of a member is made free by moving so that a melt may flow by using the kinetic energy of an assist gas. In addition, if the projections are molten, the edge 12 does not necessarily have to be melted.

When the burr 13 is melted to the extent of fluidity by the laser light 15, the molten body 13a moves in the direction of the through hole 11 wall surface C, and spreads through the edge 12 to the through hole wall surface C. It cools and solidifies according to the temperature gradient of the wall surface C, and is firmly combined with the wall surface C. At this time, if the edge region is also melted, the melt 13a is preferably absorbed by the edge region melt and high in fluidity and diffused widely, similarly to the first embodiment. If the temperature of the edge region is high enough that the melt 13a is wet, the melt 13a can move on the edge 12 in the direction of the through hole 11, so that the edge 12 does not necessarily need to be melted. In this case, the "sag" of the edge 12 can be made small by reducing the output of the laser beam 15 or shortening an irradiation time.

The injection timing of the assist gas 16 does not necessarily have to match the irradiation timing of the laser beam 15, and may be set individually. For example, when the burr 13 is melted, injection of assist gas may be started, and may flow slightly further in time even after the irradiation stop of the laser beam 15 is carried out. In this embodiment, by moving the melt with the kinetic energy of the fluid, it is not necessary to set the base material 10 so that the B surface is upward, and the B surface may be in the downward direction, the lateral direction, or the inclined posture. . The irradiation direction of the laser and the injection direction of the assist gas may be aligned in a direction substantially perpendicular to the B plane. In addition, the burr attachment region in the through hole 11 can be controlled by adjusting the pressure or speed of the assist gas and the like within the range in which the molten bur 13a is not blown off.

Example  3

In the third embodiment, a through hole drilling step of drilling a through hole of a workpiece by laser processing is carried out, and the resulting projection is further moved to the through hole wall surface by laser processing. Here, the protrusions are targeted for dross, and are suitable for, for example, an automated system which processes a large number of small through holes and removes the dross from the workpiece surface.

As shown in FIG. 5A, the laser processing method of the present invention irradiates and sprays the laser light 25 and the assist gas 26 on the A surface (lower surface) of the workpiece 20 to form the through holes 21. By the through hole drilling step, a member having an edge and a projection formed in the edge region is obtained. As shown in FIG. 5B, the laser beam 35 and the assist gas 36 are irradiated to a region including the edge 22 of the through hole 21 opened in the B surface (upper surface) of the workpiece 20. It is preferable to spray and to move the dross 23 formed in the B surface near the edge 22 of the through hole 21 to the wall surface C. FIG.

In the through hole drilling step, the laser beam 25 has a spot diameter having a diameter substantially the same as the diameter of the through hole 21 to be drilled, and has an energy density for melting the workpiece 20 in the spot region. It is irradiated toward A side of. The assist gas 26 is sprayed toward the A surface of the workpiece 20 in a range substantially the same as the spot diameter of the laser beam 25 to be kinetic energy blown by blowing the melt. As a result, the melt until the through-holes 21 are formed is scattered to the A surface side of the workpiece 20 as a sputter, but a sputtering-preventing agent is applied to the surface of the workpiece 20 in advance, or sputtered to the laser head. By attaching the accommodation hood and sucking by vacuum, the attachment of the workpiece 20 to the A surface side can be prevented.

When the through hole 21 is formed, the melt is discharged to the B surface side through the through hole 21 and attached to the edge 22 as a dross.

Formation of a melt uses the technique similar to Example 2 mentioned above. That is, the laser beam 35 has a spot diameter of a size including the attachment area of the dross 23 attached to the B surface, and the heat of the work 20 with the thermal energy to melt the dross 23 on the B surface. Irradiated toward B side. Here, the energy density in the irradiation surface of the workpiece 20 is preferably an energy density lower than the energy density in the through hole drilling step. And in order to reduce the sag of the edge 22, you may reduce the energy density of the laser beam 35. FIG.

The assist gas 36 becomes kinetic energy which enables the molten dross 23 to move on the B surface, and irradiates toward the through hole 21 from a range including the dross attachment region of the B surface.

In addition, the kinetic energy of the assist gas 36 is preferably less than the kinetic energy in the through-hole drilling step, and the kinetic energy is reduced by, for example, setting the set pressure lower than the set pressure in the through-hole drilling step. can do. When the dross 23 attached to the B surface is melted, the dross attached to the through hole wall C is also melted, and the surface of the edge 22 is molten, or at least the melted dross is wetted. Since it can raise to sufficient temperature, the molten dross 23 of the B surface easily moves to the wall surface C, and it solidifies by cooling.

As described above, the laser beam 35 and the assist gas 36 in forming the melt have different energy densities, spot diameters, assist ranges of the assist gas, and kinetic energy of the laser beam as compared with the through hole drilling step. In addition, it is preferable to irradiate and spray the workpiece toward the surface opposite to the through hole drilling step, and the laser processing equipment may be constructed in accordance with the shape of the workpiece, the specification of the through hole, and the like. For example, if the workpiece is a square or circular plate and the through hole is formed in a predetermined range of the plane, it is preferable to use a general laser processing machine in which the laser head or the work set stage is controlled in the three axis direction. At this time, first, in the through-hole drilling step, the total number of through-holes is drilled, and then, the workpiece is inverted and set, and the energy and focus position of the laser beam and the pressure and nozzle position of the assist gas are adjusted, and the melt The dross may be moved with respect to the total number of through holes by forming.

In addition, if the workpiece is a long member and a through hole is formed along the member, the workpiece is moved as shown by the arrows in Figs. 5A and 5B, and the laser beam and assist gas for the through-hole drilling step are moved along this movement path. What is necessary is just to make the irradiation and injection station and the melt-forming laser beam and assist gas irradiation and injection station into the system provided sequentially. In this case, the laser beam and assist gas irradiation and injection directions for the through hole drilling step and the melt formation may be the aspects as shown in Figs. 6A and 6B, in addition to those shown in Figs. 5A and 5B. When the laser beam and assist gas irradiation and injection directions used for forming the melt are directed downward as shown in Fig. 5B, the action of gravity can also be used to remove dross, so that the pressure of the assist gas is made smaller or the removal time is shortened. It is also desirable to apply the technique of Example 1, which may or may not use a special assist gas.

In Examples 1, 2, and 3, the through hole having a diameter smaller than the spot diameter of the laser beam for moving the melt to the through hole wall surface was described. However, the groove processing and the cutting process are performed by continuously performing the through hole drilling operation. The present invention can be applied similarly. For example, as for the technique of Example 1, 2, or the melt formation technique in Example 3, about the groove 37 which has the same width as the diameter of the through-hole 31, as shown in FIG. 7A, The laser beam 35 and the assist gas 36 may be irradiated and injected in the range including the groove width, and moved so as to move in the longitudinal direction of the groove relative to the workpiece.

In addition, as shown in FIG. 7B, with respect to the cut portion 47 larger than the through hole diameter, the laser beam 45 and the assist gas 46 are irradiated and sprayed in the range including the cut edge 42, What is necessary is just to move along the cutting edge 42 relative to a workpiece. In addition, the laser beam for removing a projection does not necessarily need to be irradiated in a substantially perpendicular direction with respect to the B plane as mentioned above, and may be irradiated from an inclination direction, and is substantially horizontal with respect to the cutting edge of a base material edge part. You may irradiate in the direction. In addition, the material of a target member is not limited to a metal, Ceramics, resin, etc. may be sufficient.

A suitable member as a processing object to which the laser processing method of the present invention is applied has an rail portion on the left and a web portion connecting the rail portion, and the web portion is an oil ring wire rod in which a through hole is formed in the through hole drilling step. In particular, wire rods for stainless steel oil rings containing 8-25% Cr by mass are very suitable.

When applying the member in this invention to the oil ring wire rod, it is set as the shape as shown to FIG. 8A, FIG. 8B, for example. At this time, the representative dimension is, for example, 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 0.5 to 0.5 mm. 1.2 mm and the pitch 54 of a through hole are 3-10 mm.

exam

Based on the said Example 3, the stainless steel which has the composition which consists of C: 0.5%, Si: 0.2%, Mn: 0.3%, Cr: 10%, remainder Fe, and an unavoidable impurity at the mass% which is running continuously continuously first. In the steel wire for steel oil ring, many long circular through holes for oil circulation were continuously drilled by laser processing. Next, the process which moves a molten body to a through-hole wall surface by laser processing was performed. As shown in Fig. 8A, the target oil ring wire is substantially H-shaped in cross section, the width 55 between the left and right rails is 1.5 mm, the thickness 56 is 1.5 mm, and the web portion connecting the rail portion. The flat wire width 57 is 1 mm and the thickness 51 is 0.4 mm. In addition, as shown in Fig. 8B, laser processing is performed to form a long hole through-hole 58 having a width 52 of 0.5 mm and a length 53 of 0.8 mm in series at a pitch 54 of 10 mm in the web portion. It was done.

As shown in FIG. 5 mentioned above, the laser processing equipment provided the laser processing equipment for the through-hole drilling step and the formation of a melt in series along the traveling line of the oil ring wire rod. Hereinafter, similar elements will be described with reference to FIGS. 5A and 5B using the same reference numerals.

The oil ring wire 20 is driven in a posture in which the web surface is up and down, and the A and B surfaces in FIGS. 5A and 5B correspond to both surfaces of the web. In the through-hole drilling step, as described with reference to FIG. 5A, the pulsed YAG laser 25 with an output of 4.5 kW is focused from the lower side of the oil ring wire 20 toward the web surface A at the midpoint between the A surface and the B surface. Irradiation was carried out at a spot diameter of about 0.45 mm, and a nitrogen gas 26 with 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 dimension was formed after drilling a hole having a small diameter. At this time, the through hole 21 became a shape narrowing from the A surface toward the B surface, and the dross 23 was attached to the edge 22 on the B surface side in several spots. 10 shows an example of the appearance of the through hole of the oil ring wire rod with the dross after the through hole drilling step.

In the formation of the melt, as described in FIG. 5B, the pulse YAG laser 35 having an output of 1.5 kW is defocused on the B surface so as to have a spot diameter of about 0.6 mm from the upper side of the oil ring wire rod toward the web surface B. The laser beam was made to include the through-hole and its periphery, and the energy density was reduced and irradiated. In addition, as the assist gas 36, nitrogen gas was lowered than the pressure in the through hole drilling step and injected in the laser irradiation range. Specifically, the spraying was performed while switching the set pressure to 0.01 MPa, 0.03 MPa, 0.05 MPa, 0.1 MPa, and the removal state of the dross 23 was observed. In some cases, the assist gas 36 was not injected.

In the case of the pressure of any assist gas 36, the dross 23 formed after the through hole drilling step is substantially formed of the through-hole 21 from the web surface B. ) And the dross was attached over substantially the entire circumference of the through hole 21 wall surface C). In the attachment state of the coagulated body in the through hole 21, as the pressure of the assist gas 36 increases, the coagulation body is attached to the lower side of the through hole wall surface C, and the B surface side of the through hole 21 is further attached. The edge area of tends to be cut out a lot. And when the pressure of the assist gas 36 is 0.1 Mpa, the coagulated body adhering on the web surface A is observed to be small but the pressure is considered to be slightly high.

When the assist gas 36 was not injected, most of the dross stayed in the vicinity of the B surface of the through hole wall surface C.

An application example of the present invention is shown in Fig. 11 (photograph). As shown in FIG. 11, the dross adhering to the perforation hole of the oil ring wire rod melt | dissolved and formed the chamfer shape by laser irradiation, and it turned out that dross does not fall off.

As another application example of the present invention, a pulse YAG laser 35 having an output of 0.7 kW was sprayed at the same time as the assist gas 36 having a pressure of 0.03 MPa to move the dross to the wall surface of the through hole.

12 shows an example of the appearance photograph of the wire rod for oil ring of the present invention. As shown in FIG. 12, the dross adhering to the perforation hole of the oil ring wire rod melt | dissolved by the laser irradiation in the formation of a melt, and it confirmed that the dross did not fall off.

An example of the micro structure | tissue photograph of a through-hole cross section is shown in FIG. As shown in FIG. 13, it was confirmed that the dross moved to the wall surface of the molten through hole, and the dross did not fall off. Thereby, the optimal wire rod can be obtained as the wire rod for oil ring.

The laser processing method of this invention is a technique which improves the edge state which arises in the various processing of various members containing mechanical components, such as an oil ring for internal combustion engines, and can remove the protrusion which exists in an edge area by laser irradiation. .

Claims (9)

A laser processing method of a member having an edge and a projection in an edge region, the laser beam is irradiated to one surface where the projection is present and the edge region among two surfaces which intersect the edge and intersect the edge. Moving the melt formed by melting the projections and the edge region to the other side, Laser processing method. The method of claim 1, The movement of the said melt is made by gravity, the laser processing method. The method according to claim 1 or 2, The movement of the said melt is made with the assist gas, The laser processing method. The method according to claim 1 or 2, A through hole drilling step of irradiating a laser beam toward one surface of the member to form a through hole, wherein the member having an edge and a projection present in an edge region is created. 5. The method of claim 4, The energy density of the laser light irradiated to form the melt is lower than the energy density of the laser light irradiated in the through hole drilling step. 5. The method of claim 4, The set pressure of the assist gas used to move the melt is lower than the set pressure of the assist gas used in the through hole drilling step. 5. The method of claim 4, And the member is an oil ring wire having a left and right rail part and a web part connecting the rail part, and in the through hole drilling step, the through hole is formed in the web part. An oil ring wire having a rail part on the left and a web part connecting the rail part, The web portion has a plurality of through holes formed by melting, and a remelt solidified product in which a melt is solidified is attached to a wall surface of the through hole, and a protrusion by a melt does not exist on the outer surface of the web portion. Wire rod for oil ring. 9. The method of claim 8, The wire rod for oil rings, wherein the edge region on the side where the melt moves to the through-hole wall surface is concave or chamfered.

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