JP2015116781A - Laser welding apparatus and method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a laser welding apparatus and method that can selectively weld optically-transparent resin members together.SOLUTION: A laser welding apparatus comprises: a laser oscillator 12b that emits a laser beam 121b; a laser oscillator 12a that emits a laser beam 121a for roughening the surface of an optical transparent object 2 to be welded allowing the laser beam 121b to transmit therethrough; and a control part 10 that controls the laser oscillators 12a, 12b so that, after the surface of the object 2 to be welded is roughened by emitting the laser beam 121a to the surface of the object 2 to be welded, the surface roughened part is melted by emitting the laser beam 121b to the surface roughened part.

Description

  Embodiments described herein relate generally to a laser welding apparatus and a laser welding method for welding a resin member with laser light.

  Conventionally, when joining light-transmitting resin members such as acrylic that transmit light, a method of bonding the members with an adhesive or a method of welding light-transmitting resin members using laser light has been attempted. ing. In the case of welding light-transmitting resin members using laser light, generally, a method of applying a liquid laser absorbent (for example, Clearweld (registered trademark)) to the bonding surface is used. This laser absorbent is opaque before the laser irradiation, but becomes transparent after the laser irradiation and can realize high-quality welding. However, the laser absorber is obtained by adding an additive to an organic solvent, and is not allowed to be used for medical or electronic parts related to avoiding the inclusion of impurities. The same applies to the adhesive described above. Furthermore, the high cost of laser absorbers is often a problem.

  On the other hand, a technique of welding light transmitting resin members without using an adhesive or a laser adsorbent has been devised. Specifically, the surface of one of the light transmissive resin members is roughened using sand paper, sand blasting, or the like to make it an opaque state capable of absorbing laser light. After the surface is irradiated with laser light to generate heat and melt, the surface and the other light-transmitting resin member are brought into contact with each other to enable welding of the light-transmitting resin members. ing.

  As a related technique, a technique is known in which a transparent resin member that transmits laser light by laser light irradiation and a non-transparent resin member that does not transmit laser light are welded (for example, see Patent Document 1).

JP 2011-126237 A

  However, when the method of roughening the surface of the light-transmitting resin member as described above with sandpaper or sandblasting is used, the entire surface of the light-transmitting resin member is roughened and the entire surface becomes opaque. Therefore, there is a problem that selective welding such as welding only a part of the surface is difficult.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a laser welding apparatus and a laser welding method that enable selective welding of light transmitting resin members.

  In order to solve the above-described problems, according to one embodiment of the present invention, a first laser oscillator that irradiates a first laser beam and a light-transmitting deposition target surface that transmits the first laser beam are roughened. A second laser oscillator that irradiates the second laser light, and the surface of the object to be welded is irradiated with the second laser light to roughen the surface, and then the roughened portion is subjected to the first laser light. And a control unit that controls the first laser oscillator and the second laser oscillator so as to melt the roughened portion by irradiating one laser beam.

  Further, according to one embodiment of the present invention, the surface of the object to be welded emitted from the second laser oscillator is roughened against the surface of the light-transmitted object to be transmitted that transmits the first laser light emitted from the first laser oscillator. After the surface of the object to be welded is irradiated with a second laser beam for surfaceizing and the surface is roughened, the surface of the roughened portion is irradiated with the first laser light. Melt.

  According to the present invention, selective welding of light transmissive resin members can be realized.

It is a block diagram which shows the structure of the laser welding apparatus which concerns on this Embodiment. It is a figure for demonstrating a dichroic mirror. It is a figure for demonstrating a dichroic mirror. It is a flowchart which shows the laser welding method which concerns on this Embodiment. It is a figure for demonstrating the method of roughening the to-be-welded material surface. It is a figure for demonstrating the method to weld to-be-welded objects. It is a schematic diagram which shows the state which the to-be-welded objects welded. It is a schematic diagram which shows the state which the to-be-welded objects welded.

  Embodiments of the present invention will be described below with reference to the drawings.

(Device configuration)
The configuration of the laser welding apparatus according to the present embodiment will be described. FIG. 1 is a block diagram showing the configuration of the laser welding apparatus according to the present embodiment. As shown in FIG. 1, the laser welding apparatus 1 includes a control unit 10, laser drivers 11a and 11b, laser oscillators 12a (second laser oscillator) and 12b (first laser oscillator), an optical fiber 13, A propagation optical system 14 (second optical system), an adjustment holder 15 (support portion), a dichroic mirror 16 (first optical system), and a laser scanning device 17 (reflector, drive portion) are provided. Reference numeral 2 denotes a workpiece to be processed by the laser welding apparatus 1. The adherend 2 is a light-transmitting resin member that transmits light (including laser lights 121a and 121b described later), and is, for example, organic glass such as acrylic or polycarbonate. The material is not limited to this, and any material that can be roughened and melted by two kinds of lasers described later may be used. For example, inorganic glass may be used.

  The control unit 10 controls the emission timing and intensity of laser light emitted from the laser oscillators 12a and 12b via the laser drivers 11a and 11b, controls a cooling mechanism (not shown) provided in the laser oscillators 12a and 12b, and an adjustment holder 15, and the laser beam irradiation position control in the laser scanning device 17 are performed. For example, as the control unit 10, an information processing apparatus having a CPU (Central Processing Unit), a memory, an HDD (Hard disk drive), and the like is used.

  The laser driver 11a is for operating a laser oscillator 12a that emits a laser beam 121a (second laser beam) indicated by a dotted line in FIG. 1, and the laser driver 11b is a laser indicated by a one-dot chain line in FIG. This is for operating the laser oscillator 12b that emits the light 121b (first laser light).

  Even if the laser oscillator 12a is a light-transmitting resin member through which the object to be welded 2 transmits light, the condensing position of the laser oscillator 12a is in an opaque state capable of absorbing the laser beam 121b, that is, the light is scattered. The laser beam 121a that can be roughened (hereinafter referred to as roughening) is emitted. In other words, if the condensing position is set inside the object to be welded 2 by the control unit 10 and the laser scanning device 17, the laser light 121 a can be roughened inside. Examples of such laser light 121a include solid lasers such as a green laser and a short pulse laser, and the wavelength is preferably set as appropriate depending on the material of the object to be welded 2. For example, if the material to be welded 2 is acrylic, the wavelength of the laser beam 121a is preferably 532 nm.

  On the other hand, the laser oscillator 12b has an intensity capable of melting the condensing portion of the resin member, and irradiates the laser beam 121b having a wavelength different from that of the laser beam 121a. Examples of such laser light 121b include a semiconductor laser and a fiber laser, and the wavelength thereof is preferably set as appropriate depending on the material of the object to be welded 2 as with the laser light 121a. For example, when the welding object 2 is acrylic, the wavelength is preferably 808 nm or 940 nm if a semiconductor laser is used, and the wavelength is preferably 1064 nm or 1070 nm if a fiber laser is used.

  In the present embodiment, since the object to be welded 2 is a light-transmitting resin member, the laser beam 121b is transmitted without being able to melt the object to be welded 2 in a normal state that is not roughened. Therefore, the laser welding apparatus 1 includes a laser oscillator 12a that can irradiate the laser beam 121a described above, in addition to the laser oscillator 12b. The surface of the object to be welded 2 is melted by irradiating the laser beam 121b after preliminarily roughening the object to be welded 2 with the laser beam 121a, thereby enabling welding with another object to be welded.

  As shown in FIG. 1, the optical path of the laser beam 121a emitted from the laser oscillator 12a travels toward the dichroic mirror 16, passes through the dichroic mirror 16, and travels to the laser scanning device 17. ing. On the other hand, the optical path of the laser beam 121b emitted from the laser oscillator 12b travels to the dichroic mirror 16 through the propagation optical system 14 connected to the optical fiber 13 after propagating through the optical fiber 13 as shown in FIG. Then, the laser beam travels from the dichroic mirror 16 to the laser scanning device 17. The laser beams 121a and 121b incident on the laser scanning device 17 are irradiated onto the object to be welded 2 as shown in FIG.

  The propagation optical system 14 connected to the optical fiber 13 is an optical system for guiding the laser light 121 b propagated in the optical fiber 13 to the dichroic mirror 16, and is fixedly supported by the adjustment holder 15. The adjustment holder 15 has an XYZ axis adjustment mechanism that can freely move the position of the propagation optical system 14. It should be noted that a drive mechanism controlled by the control unit 10 and capable of arbitrarily moving the propagation optical system 14 may be further provided. The propagation optical system 14 may be changed at regular intervals so that the position of the propagation optical system 14 can be manually changed. You may provide the guide for engaging. In the present embodiment, since various types of laser light are irradiated onto the object to be welded 2 using the laser scanning device 17, it is preferable that the optical axes of the various types of laser light traveling to the laser scanning device 17 are coaxially aligned. By adjusting the position of the propagation optical system 14 using the adjustment holder 15 described above, the optical axes of various laser beams can be aligned on the same axis.

  The laser scanning device 17 includes therein two mirrors and a drive mechanism that rotationally drives the mirrors, and the incident laser beams 121a and 121b are reflected by the two mirrors while being driven to rotate. The light is condensed at an arbitrary position of the welded object 2 and an arbitrary trajectory is drawn on the welded object 2. Specifically, based on the locus data of laser beams 121a and 121b (drawing data indicating which part of the object to be welded 2 is roughened or melted), the drawing speed, and the like input from the user of this apparatus. The control unit 10 controls the mirror angle and drive. By this control, the laser scanning device 17 roughens or melts an arbitrary portion of the workpiece 2 using the incident laser beams 121a and 121b. According to such a laser scanning device 17, for example, characters and figures can be drawn on the object to be welded 2. In the present embodiment, by using this laser scanning device 17, it is possible to rapidly roughen or melt any part of the surface of the object to be welded 2, and to form the object to be welded 2 having various shapes. Welding is possible.

  In the present embodiment, the wavelengths of the laser beams 121a and 121b are different from each other. Therefore, as a mirror that reflects these laser beams in the laser scanning device 17, it is preferable to use a mirror having a two-wavelength coating that can reflect these laser beams. For example, when the laser beam 121a is 532 nm and the laser beam 121b is 808 nm, a coating combination of 532 nm / 808 nm is used, and when the laser beam 121a is 532 nm and the laser beam 121b is 940 nm, a coating combination of 532 nm / 940 nm is used. It is done. As the laser scanning device 17 as described above, for example, a galvano scanner in which a two-wavelength coating is applied to a mirror can be cited.

  Next, details of the dichroic mirror 16 will be described with reference to FIGS. 2 and 3 are diagrams for explaining the dichroic mirror. The dichroic mirror 16 is an optical element that transmits light of a specific wavelength and reflects light of a specific wavelength. In the present embodiment, the dichroic mirror 16 transmits laser light 121a as shown in FIG. As shown in FIG. 4, a mirror coating for reflecting the laser beam 121b is applied. For example, when the laser beam 121a is 532 nm and the laser beam 121b is 808 nm, a 532 nm / 808 nm coating combination that transmits a wavelength of 532 nm and reflects a wavelength of 808 nm is used. When the laser beam 121a is 532 nm and the laser beam 121b is 940 nm, a coating combination of 532 nm / 940 nm that transmits a wavelength of 532 nm and reflects a wavelength of 940 nm is used. Further, the dichroic mirror 16 has a predetermined angle with respect to the propagation optical system 14 in order to align the optical axis of the reflected laser beam 121b with the optical axis of the transmitted laser beam 121a. The optical axes of the laser beams 121a and 121b are matched with each other in combination with the position adjustment of the propagation optical system 14 according to the above.

  The operation of the laser welding apparatus 1 configured as described above will be described with reference to FIGS. FIG. 4 is a flowchart showing the laser welding method according to the present embodiment. FIG. 5 is a diagram for explaining a method for roughening the surface of the objects to be welded, and FIG. 6 is a diagram for explaining a method for welding the objects to be welded together. FIG. 7 is a schematic diagram illustrating a state in which the objects to be welded are welded to each other, and FIG. 8 is a schematic diagram illustrating a state in which the objects to be welded are welded to each other. In the present embodiment, the case where two welded objects 2a and 2b are stacked and welded between these welded objects will be described as an example. In FIG. 7 and FIG. 8, 4 indicated by hatching indicates a contact surface of the welding object 2 b that is not roughened with the welding object 2 a.

  First, after the position of the propagation optical system 14 and the angle of the dichroic mirror 16 are adjusted to the above-described appropriate positions, the control unit 10 prompts the user to input various data such as the above-described trajectory data and the like. Obtain (step S101). After the acquisition, the control unit 10 activates the laser oscillator 12a via the laser driver 11a and emits the laser beam 121a. The control unit 10 controls the laser scanning device 17 together with the emission of the laser beam 121a, and roughens the surface of the object to be welded 2b installed below the object to be welded 2a as shown in FIG. 5 (step S102). ). Here, 3a indicated by hatching in FIG. 5 is a rough surface roughened by the laser beam 121a on the contact surface on the welded object 2b side among the contact surfaces of the welded material 2a and the welded material 2b. The surface area is shown.

  After the roughening, the control unit 10 stops the laser oscillator 12a, starts the laser oscillator 12b via the laser driver 11b, and emits the laser beam 121b. The control unit 10 controls the laser scanning device 17 together with the emission of the laser beam 121b to melt the surface of the object to be welded 2b as shown in FIG. 6 (step S103), and this flow ends. Here, 3b indicated by hatching in FIG. 6 is a melted portion melted by the laser beam 121b on the contact surface on the welded object 2b side of the contact surface between the welded object 2a and the welded material 2b. Indicates. In addition, although it demonstrated that the contact surface by the side of the to-be-welded material 2b was roughened and melted, you may roughen and melt the contact surface by the side of the to-be-welded material 2b. Needless to say, the laser beams 121a and 121b may be irradiated from any side of the stacked objects to be welded (the object to be welded 2a side or the 2b side).

  According to the present embodiment, even in the case of an object to be welded that transmits the laser beam 121b, the surface of the object to be welded is roughened by the laser beam 121a as a pretreatment so that the laser beam 121b can be absorbed. can do. Therefore, by irradiating the roughened portion with the laser beam 121b, the roughened portion can be melted so that it can be welded to other objects to be welded, and light transmission is possible without using an adhesive or a laser adsorbent. Weldable materials can be easily and inexpensively welded together. That is, the welded material created according to the present embodiment can satisfy environmentally conscious standards and strict standards for hygiene such as medical care. Further, since the roughened portion 3a is formed by using the laser beam 121a, as shown in FIGS. 7 and 8, the contact surface 4 has a portion other than the portion where the molten portion 3b is desired to be formed (the portion where welding is desired). The roughened portion 3a is not formed. That is, the roughened portion 3a can be formed locally with high accuracy. Therefore, it becomes possible to make the welding part of the upper welding thing 2a and the lower welding thing 2b into arbitrary shapes. Moreover, since the welding can be performed in a state in which the material to be welded 2 is laminated, a pretreatment for roughening the surface in advance is not required. Furthermore, it is possible to reduce noise in the roughening process as compared with the case of using sandblasting.

(Application examples)
In the present embodiment, it has been described that the surface of the object to be welded 2b is roughened by the laser beam 121a, and then the irradiation of the laser beam 121a is stopped and the laser beam 121b is irradiated. However, the laser beams 121a and 121b are simultaneously applied. Irradiation and continuous irradiation may be performed so that the surface roughening and the melting proceed simultaneously. Since the optical axes of the laser beams 121a and 121b are on the same axis, the laser beam 121a and 121b are simultaneously irradiated on the same portion of the object to be welded 2b. Therefore, although the laser beam 121b is transmitted until the surface is roughened, the laser beam 121b is melted after the surface is roughened. By comprising in this way, the welding process time can be reduced significantly and the tact time can be improved. Alternatively, only the laser beam 121b may be continuously irradiated, and the laser beam 121a may be irradiated to that portion. Also in this case, as in the case where the laser beams 121a and 121b are simultaneously irradiated, the roughening and the melting can be performed simultaneously, and the same effect can be obtained.

  In addition, although it has been described that the optical axes of the two types of laser beams are coaxial using the dichroic mirror 16, the present invention is not limited to this, and the two types of laser beams are applied to the object 2 by the laser scanning device 17. Any optical system that can irradiate may be used. Further, the laser scanning device 17 may be any device having a mirror capable of reflecting two types of laser light and a mechanism for driving the mirror.

  Further, in the present embodiment, it is described that the laser welding apparatus 1 includes the optical fiber 13, the propagation optical system 14, the dichroic mirror 16, and the laser scanning device 17 in order to irradiate the welding object with two types of laser beams. However, the present invention is not limited to this. For example, a drive system in which the laser oscillators 12 a and 12 b can move is constructed, and the laser beam 121 a and 121 b may be directly irradiated to the object 2 to be welded. Any configuration may be used as long as it is irradiated.

  The present invention can be implemented in various other forms without departing from the gist or main features thereof. Therefore, the above-described embodiment is merely an example in all respects and should not be interpreted in a limited manner. The scope of the present invention is shown by the scope of claims, and is not restricted by the text of the specification. Moreover, all modifications, various improvements, substitutions and modifications belonging to the equivalent scope of the claims are all within the scope of the present invention.

DESCRIPTION OF SYMBOLS 1 Laser welding apparatus 2, 2a, 2b To-be-welded object 3a Roughening part 3b Melting part 4 Contact surface 10 Control part 12a, 12b Laser oscillator 14 Propagation optical system 15 Adjustment holder 16 Dichroic mirror 17 Laser scanning device

Claims (8)

A first laser oscillator for irradiating the first laser beam;
A second laser oscillator for irradiating a second laser beam for roughening a surface of a light-transmitting welded material that transmits the first laser beam;
After irradiating the surface of the object to be welded with the second laser light to roughen the surface, the roughened portion is irradiated with the first laser light to melt the roughened portion. A laser welding apparatus comprising: a control unit that controls the first laser oscillator and the second laser oscillator.   The control unit applies the second laser light to a contact surface of one of the objects to be welded with the other object to be welded in a state where a plurality of the objects to be welded are in contact with each other. After the contact surface is roughened, the surface to be roughened is formed from either the welded side on which the roughened portion is formed or the surface to be welded on which the roughened portion is not formed. 2. The laser welding apparatus according to claim 1, wherein the plurality of objects to be welded are welded by irradiating the first laser beam to melt the roughened portion. The first optical system for guiding the optical axis of the first laser light and the optical axis of the second laser light coaxially to the welding object is further provided. The laser welding apparatus according to 2.   The first optical system receives the first laser light and the second laser light, reflects either the first laser light or the second laser light, and transmits the other, thereby allowing the first optical system to transmit the first laser light and the second laser light. 4. The laser welding apparatus according to claim 3, wherein the laser welding apparatus is a dichroic mirror that coaxially aligns the optical axis of one laser beam and the optical axis of the second laser beam. The second laser beam guides either the first laser beam or the second laser beam to the first optical system so that the optical axis of the first laser beam and the optical axis of the second laser beam are coaxially aligned. Optical system,
The laser welding apparatus according to claim 3, further comprising: a support portion that movably supports the position of the second optical system. The first laser light and the second laser light are guided to a rotatable reflector,
The drive part which rotationally drives this reflector so that the 1st laser beam reflected by the said reflector and the said 2nd laser beam may go to the said to-be-welded object is characterized by the above-mentioned. The laser welding apparatus according to any one of the above. The control unit controls the first laser oscillator and the second laser oscillator to continuously irradiate the second laser light together with the first laser light;
The drive unit follows the irradiation of the surface of the object to be welded with the second laser light, and causes the reflector to irradiate the roughened portion on the surface of the object to be welded with the first laser light. The laser welding apparatus according to claim 6, wherein the laser welding apparatus is driven to rotate.   Second laser light for roughening the surface of the object to be welded emitted from the second laser oscillator with respect to the surface of the object to be welded that transmits the first laser light emitted from the first laser oscillator. After the surface is roughened by irradiating the surface of the object to be welded, the roughened portion is irradiated with the first laser beam to melt the roughened portion. Method.

Images