JP6428450B2 - Method and apparatus for remote laser cutting of thin steel sheet - Google Patents

Description

  The present invention relates to a method and apparatus for cutting a thin steel sheet, and more particularly to a method and apparatus for cutting a thin steel sheet using a remote laser that cannot use assist gas.

  A plate-like material such as a steel plate is formed into a pressed product of a predetermined shape by performing a process such as bending or drawing using a press processing device such as a press machine. For example, a skeleton constituting an automobile, etc. To be molded. The press product subjected to the press work has a non-product portion area attached to the peripheral portion of the product portion region, and the non-product portion region is cut (trimmed) along the outer shape of the periphery of the product portion region. Moreover, an opening part may be formed in a product part area | region.

  On the other hand, parts for automobiles are required to have high strength due to the need for weight reduction of automobiles originated from global environmental problems. High-strength steel sheets for automobiles with a tensile strength exceeding 980 MPa have high yield strength. When trimming a press product of such high-strength steel sheets by shear cutting with a press, the residual stress at the cut end is high. Therefore, hydrogen embrittlement (sometimes referred to as crazing or delayed fracture) is likely to occur.

  On the other hand, if trimming of a high-strength steel sheet press product is performed using a laser beam, problems such as hydrogen embrittlement do not occur. In the conventional laser cutting method, an assist gas is injected from a gas nozzle installed so as to be coaxial with the laser beam at the cutting point, and the molten metal or oxide (dross) heated and melted by the laser beam is generated by the dynamic pressure. Excluded on the back of the workpiece. Therefore, the condensing head provided with the gas nozzle for ejecting the assist gas is moved to the cutting point so that the assist gas can be injected to the cutting point. In this case, the moving time of the condensing head on the part where the workpiece is not cut becomes idle time, and it takes a lot of time for cutting, resulting in high cost.

  On the other hand, in remote laser cutting, a laser beam can be freely operated within a certain range by a galvano scanner and cut. If the next cutting is started using the galvano scanner while moving the remote head after one cutting is completed, the idle time for moving only the remote head is not necessary. However, in remote laser cutting, the gas nozzle is installed so as to be coaxial with the laser beam and the assist gas cannot be injected, so that molten metal or the like cannot be excluded. Therefore, for ultra-thin workpieces such as foil, it is possible to perform remote laser cutting by increasing the power density of the laser beam, but a high-strength steel sheet for automobiles having a thickness of about 1 to 2 mm. In some cases, cutting was difficult even though welding was possible.

  Under such circumstances, in Patent Document 1, in remote laser cutting, the front and back sides of the cut region of the workpiece are covered with a box, the front side (laser beam irradiation side) is set to positive pressure, and the back side is set to negative pressure. A technique is disclosed in which a pressure difference is provided and molten metal or the like is scattered on the back surface of the workpiece by the pressure difference. However, in the technique disclosed in Patent Document 1, the installation of the box is large, the front side box that can transmit the laser beam is fouled by spatter and fumes, and the laser beam transmission is not stable, and The laser beam was absorbed in the contaminated portion, and thereby heat was generated, and the front box was sometimes damaged.

  In addition, as one of the techniques for scattering molten metal that has been heated and melted in normal laser cutting that is not remote laser cutting, Patent Document 2 discloses that a vibration synchronized with a laser oscillation pulse is processed in a laser cutting device. A technique including a vibrating means applied to a member is disclosed. In the technique disclosed in Patent Document 2, when the assist gas is not injected together with the laser beam, the laser beam pulse is oscillated and melted by the heat of the laser beam when the downward acceleration of the workpiece to be vibrated up and down is maximum. At the same time that metal or the like is generated, the upward inertia force applied to the molten metal or the like by vibration is maximized, and the molten metal or the like is scattered upward from the workpiece and removed.

  Therefore, when the technique disclosed in Patent Document 2 is applied to a remote laser cutting device, molten metal or the like scattered upward from the workpiece is attached to the protective glass of the remote head located above the workpiece. In some cases, the attached matter prevents the laser beam from passing through the protective glass, the laser beam transmission is not stable, and it is difficult to continue the remote laser cutting. The pulse laser is a laser that intermittently emits light with high instantaneous power, and is effective for fine cutting and fine surface processing. For trimming of high-strength steel sheet press products for automobiles, etc. Therefore, a continuous wave laser capable of cutting at a higher speed has been desired.

JP 2011-125877 A JP 06-047573 A

  In view of such a situation, an object of the present invention is to provide a method for stably performing laser cutting without enlarging the apparatus in remote laser cutting.

  Therefore, the present inventors diligently studied a method for solving the above problems. A method of mechanically applying a driving force to the workpiece and detaching the molten metal generated by remote laser cutting from the workpiece was investigated. As a result, when the workpiece is vibrated in the direction approaching and away from the remote head, the maximum acceleration in the direction in which the workpiece approaches the remote head is made larger than the maximum acceleration in the direction away from the molten metal, etc. Has been found to be scattered below the workpiece, that is, in a direction away from the remote head.

The present invention has been made based on the above findings, and the gist thereof is as follows.
(1) In a remote laser cutting method of performing laser cutting by irradiating a laser beam continuously oscillated along a cutting line of a workpiece, the laser beam irradiation portion of the workpiece is accelerated in a direction approaching a remote head. Oscillating in the direction approaching and moving away from the remote head so that the acceleration is larger than the acceleration in the direction moving away from the remote head, and the molten metal melted by the laser beam of the workpiece is scattered in the direction moving away from the remote head. A featured remote laser cutting method.
(2) The maximum acceleration acting on the molten metal is such that the maximum acceleration in the direction approaching the remote head is at least twice the maximum acceleration in the direction away from the remote head and at least twice the gravitational acceleration. The remote laser cutting method according to (1) above.
(3) The frequency according to (1) or (2), wherein the frequency (Hz) of the vibration is 10 × v or more and 100 × v or less, where v is a cutting speed (m / min). Laser cutting method.
(4) The value obtained by adding half (mm) of the plate thickness of the workpiece and the amplitude (mm) of the vibration is 2% or less of the focal length of the remote head (1) The remote laser cutting method according to any one of to (3).
(5) A remote laser cutting device for executing the remote laser cutting method according to any one of (1) to (4), including a remote laser device and a vibration device for a workpiece. Remote laser cutting device.

  According to the present invention, it is possible to eliminate idle time of the condensing head and reduce the cutting cost.

It is a figure which shows the outline of the method of cut | disconnecting a to-be-processed member, vibrating. It is a figure which shows operation | movement of a vibration means. It is a figure which shows the speed and acceleration of the to-be-processed member oscillated with a cam and a spring. It is a figure which shows the outline of the other example of the method cut | disconnected while vibrating a to-be-processed member. It is a figure which shows the speed and acceleration of the to-be-processed member oscillated with an electromagnet and a spring. It is a figure which shows the mode of laser cutting. (A) shows a state of laser cutting with a vibration frequency less than 10 × v (Hz), and (b) shows a state of laser cutting with a vibration frequency exceeding 100 × v (Hz). It is a figure which shows the outline which cut | disconnects the high strength steel plate press goods for motor vehicles.

The remote laser cutting method of the present invention (hereinafter referred to as “the cutting method of the present invention”) is a method of performing remote laser cutting by irradiating a workpiece with a laser beam continuously oscillated. By the inertial force acting on the molten metal melted by the laser beam, the part is vibrated in the direction approaching and away from the remote head so that the acceleration in the direction approaching the remote head is larger than the acceleration in the direction away from the remote head. The molten metal is scattered in a direction away from the remote head.
As a result, the workpiece can be cut using a remote laser, so that the free running time of the condensing head can be eliminated, and the laser cutting can be performed without using a large-scale laser cutting device. The molten metal generated by the above can be scattered in the direction away from the remote head below the workpiece.

Hereinafter, the background of the study that led to the cutting method of the present invention will be described.
In remote laser cutting, the assist gas cannot be injected coaxially with the laser beam. Therefore, in the trimming of high-strength steel sheets for automobiles, molten metal generated by cutting cannot be excluded, and in conventional remote laser cutting, Has been desired to improve the removal of the molten metal generated by cutting the workpiece by using a large-scale apparatus.

  Accordingly, the present inventors have studied a method of scattering the molten metal generated by laser cutting downward, that is, in a direction away from the remote head, using continuously oscillated laser light. As a result, when oscillating at least the laser beam irradiation part of the workpiece in a direction away from the laser oscillation source and away from it, the acceleration in the direction approaching the remote head is made larger than the acceleration in the direction away from the remote head. did.

  That is, when acceleration in a direction approaching the remote head or away from the remote head is applied to the workpiece, an inertial force acts on the molten metal melted by the laser beam in the direction opposite to the acceleration direction. Therefore, in order to disperse the molten metal away from the remote head, the molten metal is separated from the workpiece while the acceleration is acting in the direction approaching the remote head with respect to the workpiece, and the remote head This is achieved by allowing the molten metal to remain on the workpiece while the acceleration is moving away from the workpiece.

  To achieve this, when the workpiece is vibrated in the direction approaching and away from the remote head, if the difference between the acceleration in the direction approaching the remote head and the acceleration in the direction away from the remote head is provided, the molten metal The downward inertial force is greater than the upward inertial force, and the molten metal can be scattered and removed preferentially.

  Therefore, the present inventors use a vibration means for the workpiece to be processed, in which the laser beam irradiation portion of the workpiece to be described below has an acceleration in a direction approaching the remote head greater than an acceleration in a direction away from the remote head. The idea was to perform laser cutting.

  FIG. 1 shows an outline of a method of cutting a workpiece while vibrating it. A remote head 3 attached to a robot 2 of a remote laser cutting device is disposed facing the workpiece 1. Hereinafter, the direction from the workpiece 1 to the remote head 3 is referred to as “upward”, and the opposite direction is sometimes referred to as “downward”. An optical fiber 4 that transmits laser light from a laser oscillator (not shown) is connected to the remote head 3. The laser beam transmitted to the remote head 3 by the optical fiber 4 is reflected by a mirror 5 (only one is shown) that changes the irradiation direction, and a future cutting position on the workpiece 1 as a long-focus laser beam 6 7a and 7b are irradiated. And the already cut part 8 is formed by scanning the laser beam 6 along the future cutting position 7a.

  In this remote laser cutting device, the laser beam 6 can be freely operated by a mirror 5 within a certain range and cut. For example, after the cutting at the future cutting position 7a is finished, the remote head 3 can be moved by the robot 2 and the cutting at the future cutting position 7b can be started by using the mirror 5, so that only the remote head 3 is moved. Time is not required.

  When the laser beam 6 scans the future cutting positions 7a and 7b on the workpiece 1, the workpiece 1 is moved in the vertical direction indicated by the white arrow by the vibration means including the spring 9 and the cam 10. Vibrate. The cam 10 has a disc-shaped portion and a protruding portion that protrudes in the outer peripheral direction from the center of the disc. When the cam 10 is rotated by the cam rotation shaft 11, the workpiece 1 does not substantially move in the vertical direction while being in contact with the disk-shaped portion, but is in contact with the protruding portion (struck by the protruding portion). Then, it is pushed upward and acceleration is applied in the direction toward the remote head 3. Thereafter, the workpiece 1 is pushed back downward by the spring 9. By continuing the series of operations of the spring 9 and the cam 10, the workpiece 1 moves up and down (vibrates).

  Next, the operation of the vibration means composed of the spring 9 and the cam 10 will be described in detail. FIG. 2 is a diagram illustrating the operation of the vibration means. 2 (a) to 2 (e) are enlarged views of the spring 9 and the cam 10 shown in FIG. 1, and as shown by white arrows, FIG. 2 (a) to FIG. Toward e), changes with time in the rotational position of the cam 10 and the position of the workpiece 1 are shown. Note that the rotational position of the cam 10 and the position of the workpiece 1 return from the state shown in FIG. 2E to the state shown in FIG. FIG. 3 is a diagram showing the speed and acceleration of a workpiece to be vibrated by a cam and a spring. 3A to 3E show the speed and acceleration of the workpiece 1 corresponding to the rotational position of the cam 10 shown in FIGS. 2A to 2E.

  In FIG. 2, the end of the spring 9 opposite to the side in contact with the workpiece 1 is supported by a spring support 12 (not shown in FIG. 1). In this state, the cam rotation shaft position 11 is fixed vertically and horizontally, and the cam rotation shaft 11 is rotated in the direction of the black arrow in FIG. In FIG. 2A, the workpiece 1 is in contact with the disc-shaped portion of the cam 9, and shows the state immediately before contacting the protruding portion. Then, in FIG.2 (b), the to-be-processed member 1 contacts the protrusion part, or is hit by the protrusion part, and is protruded rapidly. At this time, the molten metal melted by the laser beam 6 is given an inertial force from the remote head 3 in the direction of the cam 10 (downward), and the molten metal scatters downward together with the effect of gravity.

  The speed of the workpiece 1 in FIGS. 2 (a) to 2 (b) is determined based on the relationship of the speed (corresponding to the rotational position of the cam 10) with respect to the time in FIG. You can see that it gets pushed up and gets faster. Then, from the diagram of the relationship of acceleration (corresponding to the rotational position of the cam 10) with respect to time in the lower diagram (b) of FIG. 3, the workpiece 1 is pushed up by the cam 10 and the direction of the remote head 3 ( It can be seen that a large acceleration (upward) is given.

  In FIG. 2 (b) to FIG. 2 (c), the upward speed of the workpiece 1 pushed up is gradually suppressed by the spring 9, and the workpiece 1 is about to change its moving direction downward. . 2B to FIG. 2C, the upward speed of the workpiece 1 is gradually suppressed by the spring 9 from the upper stage (A) of FIG. 3 and then slowed down. In FIG. The speed of 1 is zero.

  In FIG. 2C to FIG. 2D, the workpiece 1 is moved downward by the force of pushing back the spring 9. 2C to 2D, the downward speed of the workpiece 1 becomes a predetermined value according to the pushing back force of the spring 9 from the upper diagram (A) of FIG. It is slower than the speed of the workpiece 1 in FIG. And the acceleration of the to-be-processed member 1 in (c)-(d) from the lower stage figure (b) of FIG. 3 is falling gradually.

  In FIG. 2D to FIG. 2E, the workpiece 1 is moved downward by the pushing back force of the spring 9, and contacts the cam 10 in FIG. 2 (d) to 2 (e), the downward speed of the workpiece 1 from FIG. 3 (a) becomes weaker as the pushing back force of the spring 9 becomes weaker and gradually decreases to zero. The movement (vibration) of the workpiece 1 in the vertical direction is temporarily stopped. And the acceleration of the to-be-processed member 1 in (d) to (e) from the lower stage figure (b) of FIG. 3 is falling gradually.

  Thereafter, the workpiece 1 again takes the state of FIG. 2 (e) to FIG. 2 (a) and repeats a series of vertical movements, but in FIG. 2 (e) to FIG. The processing member 1 is in contact with the disc-shaped portion of the cam 9, and during that time, there is no vertical movement, and it can be seen from FIG. 3 that the speed and acceleration of the processing member 1 are zero.

In this manner, a series of vertical movements including movement in which the workpiece 1 is rapidly pushed up by the cam 10, that is, acceleration in a direction in which the workpiece 1 approaches the remote head 2 away from the remote head 2. By oscillating so as to be larger than the acceleration, molten metal or the like generated by laser cutting can be scattered in a direction away from the remote head below the workpiece.

  The present invention has reached the invention described in the above (1) through the examination process as described above, and the necessary and preferred requirements will be further described in order.

  In the cutting method of the present invention, the laser beam irradiation part of the workpiece is vibrated in the direction approaching and away from the remote head, and the acceleration in the direction approaching the remote head is made larger than the acceleration in the direction away from the remote head. Since it has the feature in a point, the vibration method of a to-be-processed member is demonstrated first.

(Vibration to workpiece)
In order to scatter the molten metal from the remote head 3 in the cam direction (downward), the irradiation part of the laser beam 6 of the workpiece 1 is vibrated in a direction away from the remote head 3 and away from the remote head 3, but efficiently downward. In order to disperse the molten metal, it is vibrated so that the vibration direction and the plate thickness direction substantially coincide. That is, the moving distance A from the irradiation part of the laser beam 6 of the workpiece 1 to the remote head 3 side and the other part (for example, the center, the end) of the irradiation surface of the laser beam 6 of the workpiece 1 The moving distance B and moving distance C to the remote head 3 side are the same, for example, the difference between the moving distance A and the moving distance B or moving distance C is 10% or less of the moving distance A.

  When the workpiece 1 is moved beyond the amplitude of the vibration means in the direction of approaching and moving away from the remote head 3 during laser cutting, the focal position of the laser beam 6 and the irradiation portion of the workpiece 1 are The relative positions of the laser beam 6 are shifted, and it becomes difficult to maintain the power density of the laser beam 6 necessary for melting the workpiece 1. For this reason, the vertical position of the workpiece 1 is kept from moving during laser cutting. However, even if the workpiece 1 is moved beyond the amplitude of vibration during laser cutting in a direction approaching or moving away from the remote head 3, the focal position correction function of the remote head 3 can provide It is possible to maintain the power density necessary for cutting the workpiece 1, that is, to maintain the workpiece 1 near the focal point.

  In the cutting method of the present invention, the workpiece 1 is vibrated in laser cutting, but the amplitude of vibration is about 1% of the focal length (for example, the amplitude of vibration is about 5 mm), so that the workpiece is processed. The power density of the laser beam 1 necessary for melting the member 1 can be maintained.

  Regarding the vibration method of the workpiece in the cutting method of the present invention, it has been explained using FIG. 1 and FIG. 2 that the workpiece is vibrated by a spring and a cam. An example will be described.

  FIG. 4 is a diagram showing an outline of another example of a method of cutting while vibrating a workpiece. The workpiece 1 is constrained by a pair of springs 9 sandwiching the workpiece 1 and supported by a spring support (not shown) on the opposite end in contact with the workpiece 1. An electromagnet 12 is provided on the side of the workpiece 1 facing the remote head (not shown) (upward) in order to pull up the workpiece 1 with a large acceleration. In FIG. 4, four pairs of springs 9 and electromagnets 12 are arranged in the vicinity of the corner of the member to be processed. However, the present invention is not limited to this, and the mass, shape, The number and arrangement of pairs of springs 9 and electromagnets 12 can be adjusted depending on the dimensions and the like.

  Next, the operation of the method for vibrating the workpiece in FIG. 4 will be described. FIG. 5 is a diagram showing the speed and acceleration of a workpiece to be vibrated by an electromagnet and a spring. As shown in the upper diagram (A) of FIG. 5, when a current is passed through the electromagnet 14 and the workpiece 1 is pulled up by a magnetic force, the workpiece 1 as shown in the middle diagrams (B) and (C) of FIG. Moves upward rapidly, and then, as the workpiece 1 moves, the upper spring 9 is compressed, and the upward acceleration gradually decreases.

  Subsequently, as shown in the upper diagram (A) of FIG. 5, when the current of the electromagnet 12 is stopped, as shown in the middle diagram (C) of FIG. Is pushed back down. When the workpiece 1 is pushed back, the lower spring 9 is compressed, and the force to push the workpiece 1 upward is increased, and the workpiece 1 tries to stop at the neutral position where the upper and lower springs 9 are not stretched or contracted. However, as shown in FIG. 5, the current is again passed through the electromagnet 12 and the workpiece 1 is pulled up again by the magnetic force. Due to this series of movements, a vibration is applied to the workpiece 1 such that the acceleration in the direction approaching the remote head is greater than the acceleration in the direction away from the remote head. Further, it can be seen from FIG. 5 that the upward acceleration with respect to the workpiece 1 at the start of passing an electric current through the electromagnet 14 is larger than the downward acceleration.

  So far, a spring, a cam or an electromagnet has been used as the vibration means, but these are examples of the vibration means and are not limited. The spring can be changed to another elastic body, and the elastic body has an elastic characteristic that can increase the acceleration upward relative to the acceleration downward of the workpiece, the mass, shape of the workpiece, The selection may be made in consideration of the cutting speed and the vertical speed of the workpiece. The shape of the cam is not particularly limited as long as it has a structure that pushes up the workpiece and has a predetermined strength that can repeatedly move the workpiece in the vertical direction during cutting. . Further, the electromagnet is not particularly limited as long as it has an ability to pull up the workpiece by passing an electric current. Furthermore, the workpiece may collide with the stopper, and the downward speed away from the remote head may be rapidly lost.

(Acceleration toward the remote head)
In the cutting method of the present invention, the maximum acceleration in the direction approaching the remote head is made larger than the maximum acceleration in the direction away from the remote head, and the maximum acceleration in the direction approaching the remote head at that time is the cutting speed or Depending on the properties of the molten metal melted by the laser beam, the acceleration may be set so that the molten metal can be scattered downward. However, the maximum acceleration in the direction approaching the remote head acting on the molten metal is more than twice the maximum acceleration in the direction away from the remote head and more than twice the gravitational acceleration, so that the weld metal can be efficiently removed from the remote head. It can be scattered away. For example, when cutting downward, if an acceleration greater than gravity is applied to the workpiece in the direction approaching the remote head, the molten metal has its own gravity, so this gravity acceleration is combined. The acceleration more than twice the gravitational acceleration acts in the direction away from the remote head. The maximum acceleration to be applied to the workpiece in the direction approaching the remote head is exemplified by 10 to 50 m / s ² .

(Vibration frequency)
The frequency (Hz) of vibration that vibrates in the direction approaching and moving away from the remote head is preferably 10 × v or more and 100 × v or less, where v is the cutting speed (m / min). FIG. 6 shows the state of laser cutting. FIG. 6A shows a state of laser cutting with a vibration frequency less than 10 × v (Hz), and FIG. 6B shows a state of laser cutting with a vibration frequency exceeding 100 × v (Hz). Show. When the laser beam 6 is moved in the cutting progress direction indicated by the arrow while irradiating the laser beam irradiation unit 15 of the workpiece 1 with the laser beam 6, the frequency of vibration to the workpiece 1 is set to 10 × v (Hz. ), The molten metal 16 will not be scattered for a long time, and as shown in FIG. 6A, the molten metal 16 is elongated to the opposite side of the cutting progress direction without being scattered. Therefore, the workpiece may not be cut.

  Further, the molten metal 16 is stuck to the solid wall surface in the cutting progress direction. While irradiating the laser beam 6 to the laser beam irradiation section 15 of the workpiece 1, the laser beam 6 is applied in the cutting progress direction indicated by the arrow. When moving, if the frequency of vibration exceeds 100 × v (Hz), the period is short, so that the amount of molten metal 16 scattered in one vibration is small, as shown in FIG. And the mass of the molten metal 16 will become small for the contact area with a solid wall surface. For this reason, the inertial force (= mass of molten metal × acceleration) is small, and it becomes difficult to peel off the molten metal 16 from the solid wall surface, and the workpiece may not be cut. The frequency of vibration is exemplified by 10 to 200 Hz.

(Amplitude of vibration)
A value obtained by adding 1/2 (mm) of the plate thickness of the workpiece and the amplitude of vibration (mm) may be 0.02 times (2%) or less of the focal length of the remote head used for remote laser cutting. If the cutting is performed in a range exceeding ± 2% of the focal length of the remote head, the beam diameter becomes too wide, and the power density required to melt the workpiece may not be maintained over the entire plate thickness. When a remote head with a focal length of 500 mm is used, the total of the plate thickness of the workpiece and the vibration amplitude is within 10 mm. More preferably, a value obtained by adding half (mm) of the plate thickness of the workpiece and the amplitude (mm) of vibration is 1% or less of the focal length of the remote head used for remote laser cutting.

(Work piece)
In the cutting method of the present invention, the member to be processed is not particularly limited, and bending or pressing may be performed. The shape of the workpiece is not particularly limited, and may be any shape such as a rectangular shape, a circular shape, or an elliptical shape when viewed from the remote head 2 side in FIG. Moreover, it is preferable that the plate | board thickness of the to-be-processed member 1 shall be more than 0.4 mm and less than 5.0 mm. If the plate thickness is 0.4 mm or less, remote laser cutting can be performed without vibrating the workpiece. On the other hand, when the plate thickness is 5.0 mm or more, the cutting speed becomes slow, and the efficiency improvement effect by shortening the idle running time may be reduced. The plate thickness is preferably 0.5 to 2.3 mm. Moreover, the steel type and component composition of the workpiece 1 are not particularly limited. High-strength steel plate presses for automobiles are effective as such workpieces.

(Remote laser device)
The remote laser device that irradiates the workpiece 1 with the laser beam 6 from the remote head 3 is not particularly limited as long as it has an oscillator that can oscillate high-power laser light. Examples of such an oscillator include a fiber laser, a YAG laser, a disk laser, a semiconductor laser, and a carbon dioxide gas laser. What is necessary is just to adjust the output and beam diameter of a laser beam with the material and plate | board thickness of the to-be-processed member 1, and an output is 1-10 kW and a beam diameter is 0.3-1.0 mm.

  The movement of the laser beam 6 is performed by scanning the mirror 5 in the remote head 3, and the scanning speed (cutting speed) of the laser beam 6 on the workpiece may be selected from a range that can be cut, and is particularly limited. However, 1 to 100 m / min is exemplified. Preferably, it is 5-20 m / min.

  Next, examples of the present invention will be described. The conditions in the examples are one example of conditions used for confirming the feasibility and effects of the present invention, and the present invention is based on this one example of conditions. It is not limited. The present invention can adopt various conditions as long as the object of the present invention is achieved without departing from the gist of the present invention.

  The workpiece was cut as a high-strength steel plate press for automobiles using the cutting method of the present invention. FIG. 7 is a diagram showing an outline of cutting a high-strength steel plate press for automobiles. The high-strength steel plate press 17 for automobiles in FIG. 7 is made of a 1500 to 1800 MPa hot stamp material, and is the one before trimming of the center pillar 18 having a plate thickness of 1.6 mm, so that the center pillar 18 can be obtained. The hatched area of the product 17 is removed.

  A through-hole was formed by irradiating the laser beam 6 from the remote head in the hatched area of the press product 17 on the outer periphery of the center pillar 18. In addition, when the hatched area of the press product 17 is small and the distance from the end of the hatched area to the cutting position is short, the cutting method of the present invention can be applied from the end without forming the through hole.

  After a through-hole is formed in the shaded area of the press product 17, the acceleration in the direction in which the press product 17 approaches the remote head is applied from the remote head using a vibration device composed of a spring 9 and a cam 10 (not shown). The press product 17 was irradiated with the laser beam 6 and cut so as to vibrate in a direction approaching the remote head and a direction away from the remote head so as to be larger than the acceleration in the direction of moving away.

The laser beam was focused to a beam diameter of 0.6 mm with a laser beam output of 5 kW and a focal length of 500 mm. 1.8 mm obtained by adding 0.8 mm which is half of the plate thickness 1.6 mm of the center pillar 18 and 1.0 mm of vibration amplitude is 0.36% of the focal length. The cutting conditions are laser beam scanning speed (cutting speed) 5 m / min, maximum acceleration in the direction approaching the remote head 20 m / s ² , maximum acceleration in the direction away from the remote head 7 m / s ² , and vibration frequency. Was set to 60 Hz.

  Thereby, compared with the case where the cut center pillar 18 cuts the press product 17 by shear cutting, the residual stress at the cut end face is reduced, and hydrogen embrittlement can be suppressed.

  According to the present invention, it is possible to eliminate idle time of the condensing head and reduce the cutting cost. Therefore, the present invention has high industrial applicability.

DESCRIPTION OF SYMBOLS 1 Work piece 2 Robot 3 Remote head 4 Optical fiber 5 Mirror 6 Laser beam 7a Future cutting position 7b Future cutting position 8 Previous cutting part 9 Spring 10 Cam 11 Cam rotating shaft 12 Spring support 13 Cam rotating shaft position 14 Electromagnet 15 Laser beam irradiation Part 16 Molten metal 17 Pressed product 18 Center pillar

Claims (5)

  In a remote laser cutting method of performing laser cutting by irradiating a laser beam continuously oscillated along a cutting line of a workpiece, the acceleration in a direction approaching the remote head is applied to the laser beam irradiation portion of the workpiece. The molten metal is vibrated in a direction away from the remote head by vibrating in a direction approaching and away from the remote head so as to be larger than an acceleration in a direction away from the remote head. Remote laser cutting method.   The maximum acceleration acting on the molten metal is such that the maximum acceleration in the direction approaching the remote head is at least twice the maximum acceleration in the direction away from the remote head and at least twice the gravitational acceleration. Item 2. The remote laser cutting method according to Item 1.   3. The remote laser cutting method according to claim 1, wherein the frequency (Hz) of the vibration is 10 × v or more and 100 × v or less, where v is a cutting speed (m / min). 4.   The numerical value obtained by adding half (mm) of the plate thickness of the workpiece and the amplitude (mm) of the vibration is 2% or less of the focal length of the remote head. The remote laser cutting method according to any one of the above.   A remote laser cutting device for executing the remote laser cutting method according to any one of claims 1 to 4, comprising a remote laser device and a vibrating device for a workpiece to be processed. Cutting device.

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