JP2009234070A - Welding method using laser beam and laser beam welded body - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin member welding method using a laser beam capable of facilitating visual confirmation of a welded part between resin members by the laser beam and facilitating determination of the welding quality, and a laser beam welded body obtained by using the welding method. <P>SOLUTION: Melting resin of a laser beam absorbing resin member flowing out by irradiation of the laser beam appearing as burrs 15 can be visually confirmed from a bonding face between a housing 1 composed of the laser beam absorbing resin member and a cover 2 composed of a laser beam transmissible resin member through a viewing part 14 for observation formed in the cover 2 which is a resin member. By observing a portion of the resins melting from the bonding face, it can be easily confirmed that the resins have melted at a welding part of both resins, and both resin members are welded. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for welding a resin member using a laser beam and a laser beam welded body obtained using the method.

  Conventionally, ultrasonic welding, high frequency welding, thermal welding, laser welding, and the like are known as resin welding methods. Among these, the laser welding method has good workability at the time of welding, such as a small amount of burrs, low vibration and noise, and local heating, and has an excellent appearance after welding. These welding methods have been attracting attention in recent years.

  The laser welding method is a method in which laser light is irradiated to the interface between the abutting resins and melted and welded with energy absorbed at the interface. Since it is necessary to absorb the energy of the laser beam, the laser welding method requires a combination of a light-transmitting resin material and a light-absorbing resin material, and various proposals have been conventionally made. For example, there is a method in which a predetermined laser beam is irradiated to a contact surface and the contact surfaces are immediately pressed by a predetermined pressure bonding means when the contact surfaces are in a molten state. In the laser welding method, a wavelength of 780 to 1200 nm such as a semiconductor laser or a YAG laser is used.

  As an application example of the laser welding method, there is welding of a resin member, for example, a thermoplastic resin housing that houses a sensor, a circuit board, and the like, and a resin cover that closes an opening of the housing.

  7A and 7B are diagrams showing an example of a conventional welding method between a housing and a cover using laser light, where FIG. 7A is a top view, FIG. 7B is a front view, and FIG. 7C is a side view. The housing 71 is a box-shaped member in which a space 73 for accommodating a sensor, a circuit board, and the like is formed. The space 73 is open in one direction, and the internal space of the housing 71 is closed by welding a cover 72 that covers the opening 75 to the housing 71. The housing 71 is formed of a thermoplastic resin having absorption characteristics with respect to laser light L having a predetermined wavelength irradiated from a laser head (not shown), and the cover 72 is heat having transmission characteristics with respect to the laser light L. It is formed of a plastic resin.

  At the time of welding, the laser beam L is irradiated from the side of the cover 72 having transmission characteristics while the side wall end 74 of the housing 71 and the cover 72 are in contact with each other. The laser beam L transmitted through the cover 72 heats the contact surface on the side wall end portion 74 side to melt the side wall end portion 74, and the side wall end portion 74 and the cover 72 are welded when solidified. The laser head circulates above the cover 72 along the side wall end portion 74 surrounding the opening 75 of the housing 71 while irradiating the laser beam L. The side wall end 74 and the cover 72 can be welded over the entire circumference of the opening of the housing 71 by laser light irradiation that makes a round.

  On the other hand, since the welded portion is usually covered with the resin member itself, the welded portion cannot be visually observed. When both the resin housing and cover are welded by laser irradiation, if you want to check the melting condition of the resin, you must peel off the cover that is one of the parts. As a result, visual confirmation of the welded portion is virtually impossible. 7D, the side wall end portion 74 of the housing 71 is formed in the stepped portion 76 so that the welding width d is about 1 mm so that the area of the welding surface can be reduced. However, a part of the laser beam may be directly applied to the exposed end surface 77 of the stepped portion 76. In such a case, a phenomenon such as melting and deformation / degeneration of the end face 77 or ignition may occur, and the appearance may deteriorate and the yield may be reduced.

  As described above, in the laser welding in which the resin is welded by the laser transmissive resin and the laser absorbing resin, the interface of the joint portion is melted, so that the welding state cannot be visually confirmed. For this reason, in products that require hermetic sealing, troubles during welding occur, and if it is not successfully welded, it is difficult to ensure airtightness. In addition, there is a problem that even if the resin melted without being sufficiently welded flows incorrectly.

  Regarding the laser welding method and the welding apparatus, by joining the contact surface between the housing member and the lid member inside the opening of the housing member with a laser beam, the central portion of the lid member is prevented from being greatly lifted, Thereafter, there is provided a resin welding method and welding apparatus using laser light in which a contact surface between a side wall portion of a housing member and a lid member is welded so that a gap is hardly generated on the contact surface (Patent Document 1). This method and apparatus are intended to prevent the contact area between the side wall portion and the lid member from decreasing and the molten resin from flowing out of the contact surface along the gap, and as a result, prevent deterioration in weldability. Yes. Further, since the contact pressure jig presses the outer edge of the lid member, interference between the laser irradiation device and the support mechanism of the contact pressure jig does not occur, and the welding apparatus is prevented from becoming complicated.

  Holes are made in the four corners of the circuit board attached to the circuit case, and the fitting part is fitted in the hole so as to be in contact with the joint part at the tip of the pressing part. While the circuit board is sandwiched between the protrusion and the pedestal, the part where the fitting part and the joint part are in contact is welded by laser light irradiation from the lid side, and the outer peripheral part of the lid and the upper part of the main body It is proposed that the circuit board and the lid are attached to the main body by the same welding process by welding the part in contact with the laser beam, and the circuit board is easily attached to the housing at a low cost ( Patent Document 2).

In addition, the present applicant adheres the rim portion of the silicon sensor chip to the ceramic substrate through the ceramic adhesive layer, or adheres to the resin substrate or the metal substrate using the filler-containing rubber adhesive. A semiconductor acceleration sensor and a method for manufacturing the same have been proposed in which a spacer is provided below the spacer and the spacer is removed after bonding to improve thermal hysteresis characteristics and yield (see Patent Document 3).
JP 2007-210165 A JP 2006-165351 A JP 7-20146 A

  Then, in the method of welding resin members using a laser beam, and the laser beam welded body obtained using the same, there is a problem to be solved in terms of facilitating confirmation of the welding of the resin members by the laser beam. . In addition, even when the resin parts are welded together, the resin parts are welded even if they are covered so that the laser beam is not directly applied to the parts that may be deformed, altered, or ignited. There is a problem to be solved in that it can be confirmed.

  The object of the present invention is to facilitate the visual confirmation of the welded portion between the resin members by the laser beam, and to easily determine the quality of the welding, and to use the resin member welding method using the laser beam and the same It is to provide the obtained laser beam welded body.

  In order to solve the above-described problems, the resin member welding method using laser light according to the present invention irradiates the laser light absorbing resin member with laser light transmitted through the laser light transmissive resin member, and the laser light is A welding method using laser light for welding the laser light-absorbing resin member that has been irradiated and melted to the laser-light-transmitting resin member, wherein the laser is passed through a peeping visual part formed on the resin member. It is possible to confirm whether or not the melted laser light absorbing resin member flows out from the joint surface between the light absorbing resin member and the laser light transmitting resin member and appears as burrs.

  According to this method of welding a resin member using laser light, resin melted from the joint surface by laser light irradiation partially flows out of the joint surface through a peeping visual part formed on the resin member to form burrs. By confirming the presence of the burrs, it can be easily confirmed that the resin is surely melted at the welded portion and the two resin members are welded.

  Further, the laser beam welded body according to the present invention is the laser beam absorbing resin member that is irradiated with the laser beam that has been transmitted through the laser beam transmitting resin member and melted by being irradiated with the laser beam. Is a laser beam welded body that is welded to the laser light transmissive resin member, and the resin member faces the joint surface between the laser light absorptive resin member and the laser light transmissive resin member. It has a peeping visual part formed in the aspect, and it is possible to confirm whether or not the melted laser light absorbing resin member flows out of the joining surface and appears as a burr.

  According to this laser beam welded body, the laser beam absorption melted by the irradiation of the laser beam from the bonding surface between the laser beam absorbing resin member and the laser beam transmitting resin member through the viewing portion formed on the resin member. It can be seen that part of the conductive resin member flows out and appears as burrs. Therefore, it can be easily confirmed that the laser beam welded body is a welded body in which the resin at the welded portion is surely melted by the irradiation of the laser light and the both resin members are securely welded.

  Since the resin member welding method and laser beam welded body using laser light according to the present invention are configured as described above, after welding, by visually observing the bonding surface from the viewing portion for peeping and confirming burrs. The presence or absence of welding and the degree of welding can be confirmed instantaneously. Therefore, it is possible to prevent the defect from flowing to the subsequent process. Moreover, since the edge part provided in the cover so that a peephole is formed covers the step part currently formed in the side wall edge part of a housing, the laser beam is the side wall edge part of the housing which is the absorber Therefore, it is possible to avoid scorching the housing during laser irradiation.

  Hereinafter, based on the attached drawings, embodiments of a resin member welding method and a laser beam welded body using a laser beam according to the present invention will be described. FIG. 1 is a view showing an embodiment of a laser beam welded body according to the present invention, and FIG. 2 is an explanatory view showing a main part in section for explaining the welding method according to the present invention.

  First, referring to FIG. 2, FIG. 2 (a) is a diagram showing a state of a housing and a cover, which are two resin members before being welded by a laser beam, and FIG. 2 (b) is a view showing welding of the housing and the cover. The state after being done is shown. The housing 1 is made of a laser light absorbing resin material, and the cover 2 is made of a laser light transmissive resin material. The resin material is PP (polypropylene), PC (polycarbonate), ABS (acrylonitrile butadiene styrene polymer), PBT (polybutylene terephthalate), PPS (polyphenylene sulfide), etc., and laser by adding auxiliary materials such as carbon black Light absorptivity can be provided. The entire shape of the opening 4 of the side wall 3 to be welded of the housing 1 is substantially rectangular when the opening 4 is viewed from the front. The description of this material is common to each embodiment according to the present invention.

  An end portion 5 surrounding the periphery of the opening 4 is formed into a stepped portion 6 having an end surface 7 whose outer side is lowered about half of its width and an end surface 8 which is left high. The cover 2 is formed in a shape having a shape complementary to the stepped portion 6 at the peripheral edge portion 10 which is a portion corresponding to the end portion 5 of the housing 1. That is, the peripheral edge portion 10 is formed with a groove 11 that accommodates a portion formed on the high end surface 8 of the step portion 6 of the housing 1, and the bottom surface 12 of the groove 11 is formed by laser light as described later. It is a joint surface welded to the end face 8. On the outside of the groove 11, a peripheral surface 13 corresponding to the lower end surface 7 of the step portion 6 is formed. On the peripheral edge portion 10 of the cover 2, a viewing window 14 as a viewing portion is formed at a position where the bottom surface 12 of the groove 11 faces in a slicing shape. That is, the position of the viewing window 14 is set so that the viewing direction through the viewing window 14 matches the in-plane direction of the bottom surface 12.

  The laser heads that irradiate the laser beam L are arranged on the right side in FIGS. 2A and 2B, and are irradiated toward the end surface 8 of the step portion 6 of the housing 1 through the cover 2. The irradiated laser light L passes through the transparent cover 2 and is irradiated to and absorbed by the end surface 8 that remains high in the step portion 6 of the housing 1, and the end surface 8 of the housing 1 and its vicinity are melted. The molten resin material adheres to the bottom surface 12 of the groove 11 and is cooled and solidified in this state, whereby the housing 1 and the cover 2 are welded. In the welded state between the end surface 8 and the bottom surface 12, a gap may be left between the end surface 7 and the peripheral surface 13.

  When welding is performed, the molten resin flows along the bottom surface 12 of the groove 11, and the molten resin that has flowed appears on the side of the viewing window 14 as burrs 15. It can confirm visually that it has welded, and can judge the quality of welding. A rib 16 that fits into the opening 4 is formed on the inner surface of the cover 2. Since the rib 16 generates a distance from the inner peripheral edge of the end surface 8 and the bottom surface 12 to the inside of the housing 1, the burr is prevented from flowing out into the housing 1.

  FIG. 1 shows a laser beam welded body P in which a housing 1 and a cover 2 are joined by a welding method using a laser beam L. FIG. 1A is a top view of the laser beam welded body P, FIG. 1B is a front view, FIG. 1C is a side view, and FIG. 1D is a cross-sectional view taken along the plane AA shown in FIG. . The observation window 14 is formed at a predetermined interval over the entire periphery of the peripheral edge 10 of the cover 2 that covers the opening 4 of the housing 1. Therefore, the quality of welding by the laser beam L can be confirmed over the entire circumference of the peripheral edge portion 10 of the cover 2. The laser beam welded body P is fixed to the frame at a fixing portion 18 by a fixing tool such as a screw or a screw. In addition, signal transmission / reception and power supply between the sensor and circuit board housed in the housing 1 and the outside are performed through a connector 19 connected thereto.

  FIG. 3 is a view showing a second embodiment according to the present invention. In the embodiment shown in FIG. 1, a peeping notch is formed instead of the peeping window formed on the cover. In the embodiment shown in FIG. 3, the same components and parts as those in the embodiment shown in FIG. 1 are denoted by the same reference numerals as those used in FIG. In this example, a plurality of semicircular cutouts 23 are formed in the cover 22 at predetermined intervals instead of the viewing window. The welded portion can be visually confirmed by looking at the burr 15 flowing out from the joint surface through each notch 23.

  4A and 4B are views showing a third embodiment according to the present invention, in which FIG. 4A is a cross-sectional view of the main part, and FIG. 4B is a view as seen from the side of the housing. The third embodiment is an embodiment in which a viewing window as a viewing portion is formed on the housing side. In the third embodiment, the end portion 35 surrounding the opening 34 of the housing 31 is formed as a stepped portion 36 having an end surface 37 whose height is increased by about half of its width and an end surface 38 which is left low. The cover 32 is formed in a shape having a shape complementary to the stepped portion 36 at the peripheral edge portion 40 which is a portion corresponding to the end portion 35 of the housing 31. That is, the peripheral edge portion 40 of the cover 32 corresponds to the stepped portion 36 of the housing 31, the inner surface 41 of the peripheral edge portion 40 corresponds to the lower end surface (becomes a welding surface) 38 of the housing 31, and the peripheral end surface 42 of the cover 32. Corresponds to a vertical step surface 39 between the end surface 37 and the end surface 38 of the stepped portion 36. A rib portion 43 corresponding to the inner peripheral surface of the opening 34 is formed inside the cover 32.

  A viewing window 44 is formed in the end portion 35 of the housing 31 at a position facing a lower end surface (which becomes a welding surface) 38. That is, the viewing window is formed such that the lower end surface 38 of the stepped portion 36 serving as the joint surface faces in a cut-out shape in the hole of the viewing window 44 and the viewing direction through the viewing window 44 coincides with the in-plane direction of the end surface 38. 44 positions are set.

  Laser light L is emitted from the outside of the cover 32 toward the end surface 38 of the housing 31. The laser beam L that has passed through the cover 32 is applied to the end face 38, and the end face 38 and the resin in the vicinity thereof are melted. When the molten resin is cooled and solidified, it is welded to the inner surface 41 of the peripheral edge 40 that is the joint surface of the cover 32. The weld 15 can be visually confirmed by viewing the burr 15 (FIG. 4B) from which the molten resin flows outward along the inner surface 41 through the observation window 44. The rib portion 43 prevents the burr from flowing into the housing 31 in the same manner as in the example shown in FIG.

  As shown in FIG. 4 (b), a plurality of viewing windows 44 are formed at intervals along the joint surface, and the joint portion formed by welding can be seen at every predetermined position.

  FIG. 5 is a sectional view of an essential part showing a fourth embodiment according to the present invention. In this example, the joint surface between the housing 51 and the cover 52 is widened in a tapered manner on the side when viewed in cross section. The tapered portion may be provided so as to go around the opening end of the housing 51, but may be provided partially. The welding surface by the laser beam L is an end surface 53 on the housing 51 side, and is a surface other than the tapered surface 54. A tapered surface 56 is also formed on the cover 52 side so as to face the tapered surface 54. Since the laser beam L deviating from the end surface 53 is changed in the direction of the laser beam by the tapered surface 56, the tapered surface 54 is prevented from being burnt. Since the inner ends of the tapered surfaces 54 and 56 are connected to the joint surface, it is possible to instantaneously determine whether or not the welded portion is welded by visually confirming the molten resin overflowing as a burr 15 from the joint surface. it can.

  FIG. 6 is a sectional view of an essential part showing a fifth embodiment according to the present invention. In this example, the housing 61 and the cover 62 are fitted on an inclined surface. That is, the concave tapered surface 63 of the housing 61 and the convex tapered surface 64 on the cover 62 side are opposed to each other, and the tapered surface 63 of the housing 61 is melted by receiving the laser beam L transmitted through the cover 62. And it welds to the taper surface 64 by the side of the cover 62 which is a joining surface. The irradiation direction of the laser beam L is set to a direction orthogonal to the slope. As in the fourth embodiment, the joint surface between the housing 61 and the cover 62 is further tapered and opened to the outside. Since the housing 61 side is an inclined surface, it is preferable to form a tapered opening by notching the cover 62 side. In the case of the fourth embodiment, the action and effect of the prevention of scorching by changing the direction of the laser beam and the confirmation of the welded part by visually confirming the molten resin as the burr 15 appearing at the back end of the tapered surface are as in the case of the fourth embodiment. It is the same.

It is a figure which shows the 1st Example of the welding method of the resin member using the laser beam by this invention, and a laser beam welded body. It is explanatory drawing which shows the principal part of the laser beam welding shown in FIG. It is a figure which shows the 2nd Example of the welding method of the resin member using the laser beam by this invention, and a laser beam welded body. It is a figure which shows the 3rd Example of the welding method of the resin member using the laser beam by this invention, and a laser beam welded body. It is a figure which shows the 4th Example of the welding method of the resin member using the laser beam by this invention, and a laser beam welded body. It is a figure which shows the 5th Example of the welding method of the resin member using the laser beam by this invention, and a laser beam welded body. It is a figure which shows the conventional laser beam welding.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Housing 2 Cover 3 Side wall 4 Opening part 5 End part 6 Step part 7 End face 8 End face 10 Peripheral part 11 Groove 12 Bottom face 13 Peripheral surface 14 Viewing window (viewing part) 15 Burr 16 Rib 18 Adhering part 19 Connector 22 Cover 23 Notch 31 Housing 32 Cover 34 Opening portion 35 End portion 36 Step portion 37 End surface 38 End surface 39 Step surface 40 Peripheral portion 41 Inner surface 41
51 Housing 52 Cover 53 End Surface 54 Tapered Surface 56 Tapered Surface 61 Housing 62 Cover 63 Tapered Surface 64 Tapered Surface L Laser Light P Laser Light Welded Body

Claims (8)

The laser light absorbing resin member is irradiated with laser light transmitted through the laser light transmitting resin member, and the laser light absorbing resin member melted by irradiation with the laser light is welded to the laser light transmitting resin member. In the welding method using laser light,
The melted laser light absorbing resin member flows out from the joint surface between the laser light absorbing resin member and the laser light transmitting resin member through the peeping viewing portion formed on the resin member and appears as a burr. A welding method using a laser beam, characterized in that the presence or absence of this can be confirmed.   The viewing portion is a window formed by penetrating through any one of the laser light absorbing resin member and the laser light transmitting resin member located outside or a notch formed by notching. The welding method using a laser beam according to claim 1, wherein the method is a welding method.   The visual portion includes the laser light absorbing resin member and the laser light transmitting resin member from the abutting surface where the laser light absorbing resin member and the laser light transmitting resin member are abutted and combined. The welding method using laser light according to claim 1, wherein the welding method is a peeping window or notch formed with a tapered surface extending outward.   The laser light absorbing resin member is a housing that has an opening and accommodates a sensor and a circuit board therein, and the laser light transmissive resin material is a cover that closes the opening of the housing. The welding method using the laser beam according to any one of claims 1 to 3. The laser light absorbing resin member is irradiated with laser light transmitted through the laser light transmitting resin member, and the laser light absorbing resin member melted by irradiation with the laser light is welded to the laser light transmitting resin member. In laser light welded body,
The resin member includes a viewing portion for peeping formed in a state in which the joining surface between the laser light absorbing resin member and the laser light transmitting resin member faces in a slicing shape, and the melted laser light It is possible to confirm whether or not the absorbent resin member flows out of the joint surface and appears as a burr.   The viewing portion is a window formed by penetrating through any one of the laser light absorbing resin member and the laser light transmitting resin member located outside or a notch formed by notching. 6. The laser beam welded body according to claim 5, wherein the laser beam welded body is provided.   The visual portion includes the laser light absorbing resin member and the laser light transmitting resin member from the abutting surface where the laser light absorbing resin member and the laser light transmitting resin member are abutted and combined. 6. The laser beam welded body according to claim 5, wherein the laser beam welded body is a peeping window or a notch formed with a tapered surface extending outward.   The laser light absorbing resin member is a housing that has an opening and accommodates a sensor and a circuit board therein, and the laser light transmissive resin material is a cover that closes the opening of the housing. The laser beam welded body according to any one of claims 5 to 7.

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