JP2011143420A - Laser machining device and machining method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To project a laser beam in a ring-like pattern to a material to be machined by a mechanical method by using ordinary condensing members such as a convex lens and a prism. <P>SOLUTION: By providing a condensing member 18 having a converged point 19 in a position which is deviated from the optical axis Lo of a projecting part in a side direction and a rotating mechanism for rotating the condensing member 18 around the optical axis Lo of the projecting part in a projecting part 11 for projecting a laser beam as the laser beam Bp the beam diameter of which is reduced gradually. The machining device is constituted so that a material to be worked is machined while rotating a spot Bs by the projecting beam Bp around the optical axis Lo of the projecting part by rotating the condensing member 18 by the rotating mechanism. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a laser-type processing technique that uses a laser beam to perform soldering, welding, or other processing of a workpiece, and more specifically, a laser beam spot projected on a workpiece is optically illuminated. The present invention relates to a processing technique for processing a workpiece while rotating around an axis.

  A technique for converting a laser beam into a ring shape with an optical lens and projecting the ring-shaped laser beam onto a workpiece is conventionally known as disclosed in, for example, Patent Document 1 and Patent Document 2. It is known. These techniques can be applied to soldering, especially when the object to be soldered is an annular terminal provided on a board and a rod-shaped terminal of an electronic component inserted therein. By projecting the laser beam onto the annular terminal portion, the laser beam is not projected onto the electronic component through the gap between the annular terminal and the rod-shaped terminal, thereby avoiding the problem that a part of the electronic component is burnt and deteriorated. can do.

  However, the conventional technique described in the above document uses one or more expensive lenses having a special shape such as a cone lens, and optically converts a circular laser beam into a ring-shaped laser beam. Therefore, the structure of the optical system is inevitably complicated and expensive.

JP 2005-28428 A JP 2006-229075 A

  The object of the present invention is to use an ordinary condensing member such as a convex lens or a prism, and to project a laser beam onto a workpiece in a ring pattern by a mechanical method. To provide an apparatus.

  In order to achieve the above object, according to the present invention, an incident portion into which a laser beam from a laser oscillator is incident, and a laser beam from the incident portion is converted into a projection beam having a gradually reduced beam diameter to be processed. A condensing member having a condensing point for condensing the projection beam at a position shifted laterally from the optical axis of the projection unit, and A rotation mechanism that rotates the projection unit optical axis around the projection unit optical axis, and the rotation mechanism rotates the condensing member so that the spot due to the projection beam on the workpiece is projected onto the projection unit light. A laser processing apparatus is provided that is configured to rotate about an axis.

  In the present invention, an adapter is disposed in the projection unit so as to be rotatable about the optical axis of the projection unit, and the condensing member is attached to the inside of the adapter, and the adapter is disposed on a side portion of the projection unit. A drive source for rotating the is disposed.

According to one configuration aspect of the present invention, the condensing member is a condensing lens, and the condensing lens is disposed in a state of being decentered with respect to the projection unit optical axis.
In this case, the projection unit includes a first lens that converts the laser beam from the incident unit into a parallel beam before the condensing lens, and the parallel beam from the first lens is converted into the condensing lens. It is comprised so that it may inject into.

According to another aspect of the present invention, the light collecting member is formed of a prism having a short cylindrical shape, and the prism is disposed in a posture in which an axis is inclined with respect to the optical axis of the projection unit. .
In this case, the projection unit includes a first lens that converts the laser beam from the incident unit into a parallel beam before the prism, and a reduced beam that gradually reduces the beam diameter of the parallel beam from the first lens. And a reduced beam from the second lens is incident on the prism.

  Further, according to the present invention, the condensing member that projects the laser beam onto the workpiece as a projection beam whose beam diameter is gradually reduced is covered at a position where the projection beam is shifted laterally from the optical axis of the soldering apparatus. It is arranged so as to be projected onto the workpiece in the form of a spot, and the condensing member is driven and rotated around the optical axis by a driving source, so that the spot by the projection beam is rotated around the optical axis. There is provided a laser processing method characterized by processing the workpiece.

  In the present invention, by rotating a condensing member such as a convex lens or a prism with a rotation mechanism, a spot by a laser beam can be rotated around an optical axis and projected onto a workpiece with a ring-shaped projection pattern. Because it uses a mechanical method to obtain a ring-shaped projection pattern and does not use an expensive lens with a special shape such as a cone lens, the configuration of the optical system is simple and very inexpensive. There is an advantage.

It is a side view which shows 1st Example at the time of applying this invention to a soldering apparatus. It is a longitudinal cross-sectional view of FIG. FIG. 3 is a cross-sectional view of a main part of FIG. 2. It is explanatory drawing explaining the principle in which a ring-shaped projection pattern is formed by rotation of a condensing lens. It is a top view of the projection pattern in FIG. It is sectional drawing which shows an example of the soldering object. It is a top view which shows the other example of the soldering object. It is a top view of a mask. It is a top view in the case of soldering the soldering object of FIG. 6 using the mask of FIG. It is a top view which shows the other example of the soldering object. It is sectional drawing which shows 2nd Example at the time of applying this invention to a soldering apparatus. It is explanatory drawing explaining the principle in which a ring-shaped projection pattern is formed by rotation of a prism. It is a top view of the projection pattern in FIG. It is explanatory drawing explaining the principle in which a ring-shaped and dot-shaped projection pattern is formed by rotation of the prism which has a center hole. It is a top view of the projection pattern in FIG.

  FIG. 1 shows a soldering apparatus as an example of a processing apparatus according to the present invention, and FIGS. 1 and 2 show a first embodiment of the soldering apparatus. Reference numeral 1 in the figure denotes a soldering head attached to an articulated arm of a soldering robot (not shown), 2 a laser oscillator that outputs a laser beam, and 3 a laser beam from the laser oscillator 2 to the soldering head 1. An optical fiber 4 for guiding leads a solder supply nozzle for supplying the wire solder 5 to the soldering object 6 which is a workpiece. The solder supply nozzle 4 is connected to a solder supply source (not shown).

  The soldering head 1 includes an incident unit 10 through which the laser beam B1 output from the laser oscillator 2 is incident through the optical fiber 3, and a projection unit 11 that projects the incident laser beam toward the soldering target 6. Have. The incident part 10 and the projection part 11 are arranged in a state where their optical axes, that is, the incident part optical axis Li and the projection part optical axis Lo intersect each other by 90 degrees.

A housing 12 of the projection unit 11 includes a first housing part 12a connected to the incident part 10, a second housing part 12b connected to a tip part of the first housing part 12a via a diaphragm plate 13, and the first housing part 12a. 2 includes a projection nozzle portion 12c connected to the tip of the housing portion 12b.
A semi-transparent mirror 16 and a convex first lens 17 are disposed in the first housing portion 12a along the projection portion optical axis Lo.

  The semi-transparent mirror 16 reflects all the laser beam B1 from the laser oscillator 2 without transmitting it, but transmits other light (visible light). The incident light axis Li and the projection light Each of the circular laser beams B1 incident from the incident portion 10 is reflected in a direction along the projection portion optical axis Lo, and the beam diameter is gradually enlarged. Is incident on the first lens 17 as the expanding beam B2.

  The first lens 17 converts the expanded beam B2 from the semi-transparent mirror 16 into a parallel beam B3, and the parallel beam B3 emitted from the first lens 17 is necessary at the aperture hole 13a of the aperture plate 13. After being narrowed down to a small beam diameter, it is incident on the condensing member 18 mounted in the second housing portion 12b, and is converted into a projection beam Bp whose beam diameter is gradually reduced by the condensing member 18 to be soldered. 6 is projected in a spot shape.

  A cylindrical adapter 22 is provided inside the second housing portion 12b so as to be rotatable about the projection portion optical axis Lo via a bearing 23. The optical member 18 is mounted in an eccentric state with respect to the projection unit optical axis Lo via an annular holder ring 24.

  The adapter 22 is made of an aluminum alloy, has an upper half small diameter portion and a lower half large diameter portion, and is interposed between the outer periphery of the small diameter portion and the inner periphery of the second housing portion 12b. The condensing member 18 is attached to the second housing portion 12b by the bearing 23, and is attached to the attachment hole 22a formed in the large diameter portion via the holder ring 24. In the figure, reference numeral 25 denotes a fixing screw for fixing the holder ring 24 in the mounting hole 22a.

  As shown in FIG. 3, the mounting hole 22 a inside the adapter 22 is eccentric with respect to the center of the adapter 22 (projection part optical axis Lo), and the holding hole 24 a inside the holder ring 24 is also The center of the holder ring 24 is eccentric in the same direction as the eccentric direction of the mounting hole 22a. Accordingly, the condensing member 18 held in the holding hole 24a is also eccentric in the same direction as the eccentric direction of the mounting hole 22a and the holding hole 24a with respect to the projection portion optical axis Lo, and the condensing member An 18 axis (optical axis) L extends parallel to the projection optical axis Lo at a position shifted from the projection optical axis Lo.

  As described above, the condensing member 18 converts the parallel beam B3 from the first lens 17 into the projection beam Bp whose beam diameter is gradually reduced, and condenses it at the focal point, that is, the condensing point 19. It is formed by a glass condensing lens 18A having a shape. As can be seen from FIG. 4, since the condensing point 19 is on the axis L, the condensing lens 18A has the condensing point 19 at a position shifted laterally from the projection unit optical axis Lo. is there. And since the said soldering object 6 is arrange | positioned a little in front (this condensing member 18 side) from this condensing point 19, of the spot Bs formed on the soldering object 6 by projection of the said projection beam Bp. The diameter is larger than when the soldering object 6 is on the condensing point 19. The diameter of the spot Bs can be changed by changing the distance between the light collecting member 18 and the soldering object 6.

A driven pulley 27 is formed on the outer periphery of the large-diameter portion of the adapter 22, and the driven pulley 27 is connected to a drive pulley 29 attached to a drive shaft of an electric motor 28 by a belt 30. The electric motor 28 is connected to a drive source. The adapter 22 is driven and rotated together with the condenser lens 18A. Therefore, the electric motor 28, the drive pulley 29, the driven pulley 27, and the belt 30 constitute a rotation mechanism for rotating the adapter 22 and the condenser lens 18A.
The electric motor 28 is placed on a motor support base 31 fixed to the side surface of the second housing portion 12b.

  When the adapter 22 rotates about the projection unit optical axis Lo, the condenser lens 18A rotates eccentrically around the projection unit optical axis Lo, and the weight balance around the rotation center at that time. Therefore, by decentering the mounting hole 22a of the adapter 22 and the holding hole 24a of the holder ring 24 as described above, the adapter 22 and the holder ring 24 are opposite to the side where the condenser lens 18A is eccentric. The weight on the side is increased, thereby maintaining a weight balance between the adapter 22 and the holder ring 24 and the condenser lens 18A.

The housing 12 of the projection unit 11 has a dust-proof glass 34 that protects the light collecting member 18 from solder smoke, solder balls, or the like during soldering at a position between the second housing unit 12b and the projection nozzle unit 12c. A gas supply nozzle 35 for supplying an inert gas such as nitrogen to the soldering target 6 is connected to the projection nozzle portion 12c.
The dust-proof glass 34 is attached to a glass holding frame 36 that is detachably attached to the housing, and is detachable from the housing 12 together with the glass holding frame 36. Therefore, when the dust-proof glass 34 becomes dirty, the glass holding frame 36 can be removed, and the dust-proof glass 34 can be removed and attached again.

  In the soldering apparatus having the above configuration, when the soldering object 6 is soldered, the laser beam is passed through the condensing lens 18A while rotating the condensing lens 18A by rotating the adapter 22 with the electric motor 28. It projects on the soldering object 6 and melts and solders the line solder 5 supplied from the solder supply nozzle 4. At this time, the condensing lens 18A is continuously driven and rotated at a speed of, for example, 5 revolutions per second or more. However, the rotational speed and the rotational speed of the condenser lens 18A are not limited to this.

In FIG. 2, a circular laser beam B1 incident from the incident part 10 is reflected by the semi-transparent mirror 16 and is incident on the first lens 17 as an expanded beam B2. Then, after being converted into a parallel beam B3 by the first lens 17, it is incident on the condensing lens 18A and is converted into a projection beam Bp whose beam diameter is gradually reduced by the condensing lens 18A. It is projected as a spot Bs on the soldering target 6 at a position deviating from the optical axis Lo.
At this time, since the condensing lens 18A rotates eccentrically around the projection unit optical axis Lo, the spot Bs also rotates around the projection unit optical axis Lo as shown in FIGS. As a result, the laser beam is projected onto the soldering object 6 in a ring-shaped projection pattern.

  The diameter of the ring 37 drawn by the spot Bs can be changed by changing the amount of eccentricity of the condenser lens 18A. The distance between the condenser lens 18A and the soldering object 6 can be adjusted by exchanging the condenser lens 18A with one having a different focal length.

  Here, when the soldering object 6 is, for example, as shown in FIG. 6, when the rod-shaped terminal 42 of the electronic component 41 is inserted into the annular terminal 40 formed on the substrate, the spot Bs is It is made to rotate in a ring shape along the annular terminal 40. As a result, the laser beam is prevented from being projected onto the electronic component 41 through the gap between the annular terminal 40 and the rod-shaped terminal 42, and a part of the electronic component 41 is burned by the laser beam and deteriorated. It can be avoided.

  Further, as shown in FIG. 7, the terminals 44 on the substrate and the terminals 46 of the electronic component 45 are arranged along the circumference, and the cream solder previously applied to these terminals 44 and 46 is applied with a laser beam. In the case of melting and soldering (reflow soldering), the diameter of the spot Bs is set to a size that can surround at least one pair of terminals 44 and 46, and the spot Bs is rotated at high speed. Thus, the reflow soldering can be performed. In this case, since only the terminals 44 and 46 and their surroundings are locally heated by the spot Bs, even when the heat-sensitive electronic component 45 is mounted, there is a problem of “burn” due to the projection of the laser beam. Hard to occur.

However, a mask 48 as shown in FIG. 8 may be used if it is desired to completely avoid the “burn” problem. This mask 48 has a through hole 49 in a portion corresponding to the terminals 44 and 46, and is disposed so as to cover the electronic component 41 as shown in FIG. By rotating, the laser beam can be projected only to the portions of the terminals 44 and 46 through the transmission hole 49.
In addition, when performing the said reflow soldering, installation of the said solder supply nozzle 4 and a solder supply source is abbreviate | omitted.

  Further, when the soldering object 6 is a board and an electronic component 45 provided with a plurality of terminals 44 and 46 facing each other on the left and right as shown in FIG. By reciprocally rotating 180 degrees at a time, the left and right terminals 44, 44 of the electronic component 45 can be soldered together one by one in the order of the terminals 46, 46 on the board. In this case, even if the solder supply nozzles 4 are provided on both sides of the soldering head 1 and the line solder is supplied to the left and right terminals, cream solder is pre-applied to each terminal to perform reflow soldering. Anyway.

  When soldering the electronic component 45 as shown in FIG. 10, conventionally, after all the terminals 44 of the electronic component 45 are soldered, the other terminal 44 is soldered. When the terminal is soldered, the electronic component 45 may be displaced or tilted with the solidification of the solder. If the other terminal is soldered in this state, connection failure is likely to occur. However, when the soldering apparatus of the present invention is used, the left and right terminals 44, 44 can be soldered instantaneously before the solder is solidified, so that such a problem does not occur.

  FIG. 11 shows a second embodiment of the soldering apparatus. The main difference between the soldering apparatus of the second embodiment and the soldering apparatus of the first embodiment shown in FIG. 2 is that the prism 18B is used as the light condensing member 18, and that the stage before the prism 18B is used. A convex second lens 52 is provided. Since the other configuration is substantially the same as that of the first embodiment, the same components as those of the first embodiment are denoted by the same reference numerals as those of the first embodiment, the description thereof is omitted, and the configuration is different. The part will be described below.

  That is, the second lens 52 is disposed at the tip of the first housing portion 12a in the projection unit 11, and the parallel beam B3 from the first lens 17 is reduced by the second lens 52 so that the beam diameter is gradually reduced. After being converted into the beam B4, it is sent to the prism 18B, and is converted into the projection beam Bp by changing the optical path by the prism 18B, and is condensed toward the condensing point 19.

The prism 18B has a short cylindrical shape, and, as can be seen from FIGS. 12 and 13, has an entrance surface 18a and an exit surface 18b on both end faces in the direction of the axis L, and the axis L is used as the optical axis of the projection unit. It is held in the mounting hole 22a inside the adapter 22 in a posture inclined with respect to Lo.
In the prism 18B, in general, incident light incident from the incident surface 18a is refracted in the prism, and then emitted from the output surface 18b as emitted light parallel to the incident light. Accordingly, by tilting the axis L of the prism 18B, the reduced beam B4 is refracted in the prism 18B and then condensed at a position shifted laterally from the projection unit optical axis Lo. Point 19 is obtained. Therefore, the prism 18B has the condensing point 19 at a position shifted laterally from the projection unit optical axis Lo. Reference numeral 53 in FIG. 11 denotes a fixing ring for fixing the prism 18B.

The prism 18B used in the above embodiment has a diameter of 30 mm, an axial length of 20 mm, and an inclination angle θ with respect to the projection unit optical axis Lo of 9.13 degrees. Of course, it may be. For example, the inclination angle θ of the prism 18B can be set to various sizes within a range of 45 degrees or less. In this case, the prism 18B can be attached to the adapter 22 so that the inclination angle θ can be changed.
In addition, a balance weight 54 is attached to a part of the adapter 22 in order to maintain a weight balance around the rotation center when the adapter 22 rotates.

  In the second embodiment, the reduced beam B4 incident on the inclined incident surface 18a of the upper surface of the prism 18B from the second lens 52 is refracted by the prism 18B and emitted from the lower emission surface 18b. The projection is projected onto the soldering object 6 in a spot Bs shape at a position shifted laterally from the projection unit optical axis Lo. At this time, since the prism 18B rotates around the projection unit optical axis Lo in a posture inclined with respect to the projection unit optical axis Lo, the spot Bs is also shown in FIGS. The ring 37 is drawn on the soldering object 6 by rotating around the projection portion optical axis Lo. Accordingly, the soldering object 6 can be soldered in the same manner as in the first embodiment.

  The diameter of the ring 37 drawn by the spot Bs can be changed by changing the inclination angle of the prism 18B, and the position of the condensing point 19 is different from that of the second lens 52 having a different focal length. It can be adjusted by exchanging or by exchanging the prism 18B with one having a different length or refractive index in the direction of the axis L.

As shown in FIG. 14, the prism 18B may be provided with an inner hole 56 that penetrates the central portion thereof. The inner hole 56 is formed concentrically with the projection portion optical axis Lo, and is inclined with respect to the axis L of the prism 18B. However, the inner hole 56 can also be formed concentrically with the axis L of the prism 18B. In this case, the diameter of the inner hole 56 is large enough to allow a part of the reduced beam B4 to pass through. It is necessary to form it.
By providing such an inner hole 56, as shown in FIG. 15, the spot portion 38 can be formed by the projection beam Bp passing through the inner hole 56 at the center of the ring 37 drawn by the spot Bs.

  The soldering apparatus provided with the prism 18B with the inner hole 56 is preferably used when the soldering object 6 is the annular terminal 40 and the rod-shaped terminal 42 as shown in FIG. That is, the annular terminal 40 can be heated by the spot Bs rotating in the ring 37 shape, and the rod-shaped terminal 42 can be heated by the spot portion 38 at the center of the ring 37. This is a problem when the rod-shaped terminal 42 is not heated. The problem that a certain molten solder is rapidly cooled by the low-temperature bar-like terminal 42 to cause a solder failure can be avoided reliably.

Also, a CCD camera can be used. That is, as indicated by a chain line in FIG. 11, the CCD camera 57 is disposed at the upper end of the housing 12 of the projection unit 11 with the imaging optical axis aligned with the projection unit optical axis Lo. The soldering target 6 can be imaged through the inner hole 56.
At this time, the image of the soldering object 6 picked up by the CCD camera 57 is displayed on a monitor (not shown). For example, the laser beam for the soldering object 6 is viewed while viewing this image at the teaching stage before soldering. It is used to position the projection position of the projector and to monitor whether or not the soldering is normally performed at the time of soldering.

  As described above, the laser processing apparatus rotates the condensing member 18 such as a convex lens or a prism having the condensing point 19 at a position shifted from the optical axis Lo of the projection unit by a rotation mechanism, thereby the condensing member. The spot Bs by the projection beam Bp from 18 can be rotated around the optical axis Lo of the projection unit and projected onto the work piece in the form of a ring. Since an expensive lens having a special shape such as a cone lens is not used, there is an advantage that the configuration of the optical system is simple and very inexpensive.

  The above embodiment is a case where the present invention is applied to a soldering apparatus. However, the present invention is not limited to a processing apparatus other than the soldering apparatus, for example, welding or drilling of various workpieces such as synthetic resin parts and semiconductor substrates. The present invention can also be applied to a processing apparatus that performs cutting or the like.

2 Laser oscillator 10 Incident part 11 Projection part 17 First lens 18 Condensing member 18A Condensing lens 18B Prism 19 Condensing point 22 Adapter 28 Electric motor 37 Ring 52 Second lens Lo Projection part Optical axis B3 Parallel beam B4 Reduced beam Bp Projection beam Bs Spot

Claims (7)

An incident portion where a laser beam from a laser oscillator is incident, and a projection portion that converts the laser beam from the incident portion into a projection beam with a gradually reduced beam diameter and projects it in a spot shape on a workpiece,
A condensing member having a condensing point where the projection beam condenses at a position shifted laterally from the optical axis of the projection unit, and a rotation for rotating the condensing member around the optical axis of the projection unit And a spot formed by the projection beam on the workpiece is rotated around the optical axis of the projection unit by rotating the light collecting member by the rotation mechanism. This is a laser processing device.   The adapter for holding the condensing member is attached to the housing of the projection unit so as to be rotatable about the optical axis of the projection unit, and a drive source for driving and rotating the adapter is attached. Item 2. The processing apparatus according to Item 1.   The processing apparatus according to claim 1, wherein the condensing member is a condensing lens, and the condensing lens is disposed in a state of being decentered with respect to the optical axis of the projection unit.   The projection unit has a first lens that converts the laser beam from the incident unit into a parallel beam in front of the condensing member, and the parallel beam from the first lens is incident on the condensing lens. The processing apparatus according to claim 3, wherein the processing apparatus is configured as follows.   The said condensing member consists of prisms which have a short cylindrical shape, and this prism is arrange | positioned with the attitude | position which inclined the axis line with respect to the said projection part optical axis, The Claim 1 or 2 characterized by the above-mentioned. Processing equipment.   The projection unit has a first lens that converts the laser beam from the incident unit into a parallel beam before the prism, and a first lens that converts the parallel beam from the first lens into a reduced beam whose beam diameter is gradually reduced. The processing apparatus according to claim 5, further comprising: two lenses, wherein the reduced beam from the second lens is incident on the prism.   A condensing member that projects a laser beam onto a workpiece as a projection beam whose beam diameter gradually decreases, and the projection beam is projected onto the workpiece in a spot shape at a position shifted laterally from the optical axis of the soldering apparatus. The condensing member is driven and rotated around the optical axis by a driving source, whereby the spot by the projection beam is rotated around the optical axis to process the workpiece. A laser processing method characterized by that.

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