JP5579532B2 - Manufacturing method of resin molded products - Google Patents

Description

  The present invention relates to a method for producing a resin molded product.

  For example, a vehicle lamp has a resin molded product in which a housing made of a light-absorbing resin such as acrylonitrile styrene acrylate (ASA) and a lens made of a translucent resin such as polymethyl methacrylate (PMMA) or polycarbonate are welded. There are many cases.

  A resin composition for a housing capable of suppressing the stringing phenomenon in hot plate welding in which a hot plate is sandwiched between a lens and a housing, the lens and the housing are heated and melted by the hot plate, and the hot plate is removed to weld the lens and the housing. It is known (see, for example, Patent Document 1).

  In addition, including a case where the surface of the lens combined with the housing is a curved surface, an elastic light guide capable of accommodating the lens shape and a flat transparent base material are disposed on the lens surface, and a compression load is applied to the elastic light guide and There has been proposed a method in which a lens is brought into close contact, a laser beam is incident from the transparent substrate side, a contact portion between the lens and the housing is heated and melted through the elastic light guide and the lens, and the housing and the lens are welded (for example, , See Patent Document 2).

  In the case of a vehicle lamp, an aluminum film is often deposited on the inner surface of the housing as a light reflecting film. If there is a light reflection film on the welded portion (seal surface) of the housing, the laser beam is reflected under normal laser welding conditions, resulting in poor welding. For this reason, it is known that masking is performed on the welded surface of the housing during vapor deposition so that a light reflecting film is not formed on the welded surface.

JP-A-10-310676 JP 2004-349123 A

  If masking is performed on the welded surface of the housing when forming the light reflecting film, one additional process is required, which increases the manufacturing cost. It is also conceivable that aluminum is scattered on the welding surface due to a mask defect or the like.

  The objective of this invention is providing the manufacturing method of the resin molded product which can weld with a laser beam, even when a light reflection film exists in a welding surface.

  According to one aspect of the present invention, a method for producing a resin molded product includes: (a) a light-absorbing resin member having a welding region; and a light-transmitting resin member having a welding region corresponding to the welding region of the light-absorbing resin member. And (b) a step of forming a light reflecting film on the light-absorbing resin member; and (c) a first focused state where a beam spot diameter is 1.0 mm or less; Repeatedly irradiating the welded region of the light-absorbing resin member to remove the light reflecting film formed on the welded region; (d) the welded region of the light-absorbing resin member and the welded region of the translucent resin member; In a second contact state where the beam spot diameter is 1.5 mm or more and 3.5 mm or less, the laser beam is repeatedly irradiated to the welding region of the light absorbing resin member, and the light absorbing resin Welding the member and the translucent resin member And a degree.

  ADVANTAGE OF THE INVENTION According to this invention, even when a light reflection film exists in a welding surface, the manufacturing method of the resin molded product which can weld with a laser beam can be provided.

It is a diagram which shows roughly the structure of the laser beam welding apparatus using a galvano scanner. It is a figure which shows the positional relationship of the focus of the laser beam 12s. It is a schematic sectional drawing of the processed object for demonstrating the light reflection film peeling process and welding process by the Example of this invention.

  When a light-transmitting (transparent) resin member and a light-absorbing (light-absorbing, opaque) resin member are opposed to and brought into contact with each other in a pressurized state, and the laser beam is irradiated from the light-transmitting resin member side, the laser beam is translucent resin It penetrates the member and reaches the light absorbing resin member. When the laser beam is absorbed by the light absorbing resin member, the light absorbing resin member is heated, softened, and further melted. Since the translucent resin member is in contact with the light-absorbing resin member under pressure, the heat of the light-absorbing resin member is also transmitted to the translucent resin member. Accordingly, the translucent resin member is also softened, the contact area is increased, and the translucent resin member is eventually melted. Both members are in a molten state and are welded.

  In the above welding process, if an aluminum film (Al film) is deposited as a light reflecting film on the welding surface of a light absorbing (light absorbing, opaque) resin member, the laser beam is reflected under normal laser welding conditions. It cannot be welded.

  Therefore, the present inventors welded a light-absorbing (light-absorbing, opaque) resin member and a light-transmitting (transparent) resin member having a light-reflecting film such as an aluminum film (Al film) deposited on the surface. Before the welding process of both members, it was examined that the peeling process for peeling off the Al film was performed with the same equipment as the welding process.

  FIG. 1 is a diagram schematically showing the configuration of a laser beam welding apparatus using a galvano scanner. A laser beam 12 emitted from the laser oscillator 10 is introduced into the scan head 31 via the optical fiber 11. The scan head 31 includes a focus adjustment optical system 13, a first galvano mirror 14, a second galvano mirror 15, and a control device 16.

  A focus adjusting optical system 13 is arranged for the laser beam 12 emitted from the tip of the optical fiber 11 connected to the laser oscillator 10. The focus adjustment optical system 13 includes a movable lens and can adjust the focus position on the optical path. A first galvano mirror 14 is arranged for the laser beam emitted from the focus adjustment optical system 13 and performs, for example, x-direction scanning within the processing surface. A second galvano mirror 15 is arranged with respect to the laser beam reflected by the first galvano mirror 14 and performs, for example, a y-direction scan within the processing surface.

  The control device 16 controls the galvano mirrors 14 and 15 and the focus adjustment optical system 13. The emitted laser beam 12 s can be two-dimensionally scanned in the xy plane by the galvano mirrors 14 and 15, and can be moved in the z direction by controlling the focal length by adjusting the focus adjusting optical system 13. . That is, the focusing position of the laser beam can be scanned three-dimensionally. Galvanomira is lightweight and can be scanned at high speed.

  As the laser oscillator, for example, a YAG second to third harmonic laser oscillator, a semiconductor laser, a fiber laser, or the like can be used. If only two-dimensional scanning is used, a scan head having an fθ lens can be used instead of the focus adjustment optical system.

  FIG. 2 is a diagram showing the positional relationship of the focal points of the laser beam 12s.

  By defocusing toward the scan head 31 (in-focus) side from the focal position of the converging laser beam 12s, the beam diameter is set to φ1.5 to 3.5 mm to cause melting in a wide area of the welding region. , A strong bond can be obtained. The defocus point DF may be in the direction opposite to the scan head 31 (out focus) from the focal position.

  In the method of manufacturing a resin molded product according to an embodiment of the present invention, first, a housing 21 having a desired shape (for example, a container shape) made of a light-absorbing resin such as acrylonitrile styrene acrylate (ASA), and polymethyl methacrylate (PMMA). ) And a lens 23 having a desired shape made of a translucent resin such as polycarbonate, and an aluminum vapor deposition film is formed on the inner surface of the housing 21 by a known vapor deposition method or the like. Thereafter, the light reflecting film peeling step and the welding step described later are performed with the same equipment. In the present embodiment, when aluminum (light reflecting film) is deposited on the inner surface of the housing 21, masking of the welding surface of the housing 21 is not necessary.

  FIG. 3A is a schematic cross-sectional view of an object to be processed for explaining a light reflecting film peeling step according to an embodiment of the present invention.

  In the embodiment of the present invention, since the light reflecting film peeling step and the welding step are continuously performed with the same equipment, a container formed of a light-absorbing resin at the stage of the light reflecting film peeling step performed prior to the welding step. A lens 23, which is formed of a light-transmitting resin and closes the opening of the housing 21, is fixed to an upper jig (light-transmitting pressure plate) 25 and is opposed to the upper portion of the shaped housing 21. The case where the welding rib 23a is formed on the lower surface of the lens 23 is shown. The rib 23a is not an essential constituent requirement. In this embodiment, the housing 21 is made of PET-PBT, and the lens 23 is made of PMMA.

  On the inner surface and the welding surface 27a of the container-shaped housing 21 formed of a light-absorbing resin, a light reflection film 22 made of, for example, an Al vapor deposition film is formed. The housing 21 is fixed to a lower jig 24 that can move in the vertical direction.

  In the state where the housing 21 and the lens 23 are combined, even if the Al film 22 is peeled off, the peeled Al cannot be sucked. Therefore, as shown by the black arrow in the figure, the lower jig 24 is lowered to move the housing. 21 and the lens 23 are separated to secure a space for suction.

  The laser beam 12s passes through the upper jig (translucent pressure plate) 25 and the lens 23, and irradiates the upper surface of the Al film 22 on the welding surface 27a of the housing 21 positioned below. The scan head 31 scans the laser beam 12s along the welding region and repeatedly irradiates it. The position in the two-dimensional xy plane is controlled by the galvano mirrors 14 and 15, and the focal length in the z direction is controlled by the focus adjustment optical system 13, thereby maintaining the focus state for peeling off the Al film (first focus state).

  In the first in-focus state in the light reflecting film peeling step, the focal position is in the vicinity of the peeling target. That is, as shown in FIG. 3A, the peeling target Al film 22 is located in the vicinity of the focal position. In this specification, the state of “having a focal position near the peeling target” is a state where the beam spot diameter of the laser beam 12s is 1.0 mm or less on the surface of the peeling target.

  In the light reflecting film peeling process of the present embodiment, for example, peeling (removal) is performed by sublimating 22 on the welding surface 27a at a laser output of 300 W, a scanning speed of 1000 mm / sec, and a number of rotations of 100 or less. In addition, since the Al film after peeling sublimates, for example, it sucks with a suction machine to prevent reattachment.

  FIG. 3B is a schematic cross-sectional view of an object to be processed for explaining a welding process according to an embodiment of the present invention.

  First, the lower jig 24 is indicated by a black arrow from the state in which the lens 23 is fixed to the upper jig (translucent pressure plate) 25 and disposed opposite to the upper side of the housing 21 shown in FIG. 3B, the welding rib 23a on the lower surface of the lens 23 is brought into pressure contact with the welding surface 27a from which the Al film 22 has been peeled off at a pressure P to obtain the state shown in FIG. The laser beam 12s passes through the upper jig 25 and the lens 23 and irradiates the welding surface 27a of the housing 21 that is in contact with the rib 23a. The irradiation position is scanned along the rib (welding region) 23a by driving the galvano mirror. The position in the two-dimensional xy plane is controlled by the galvano mirrors 14 and 15, and the focal length in the z direction is controlled by the focus adjustment optical system 13 to maintain the welding focus state (second focus state).

  In the second in-focus state in this welding process, the laser beam 12s is in the defocus state described with reference to FIG. 2 and has a focal position farther than the workpiece. That is, as shown in FIG. 3B, the defocus point DF is set near the irradiation position (joint region between the rib 23a and the welding surface 27a). That is, by defocusing the laser beam 12 s toward the scan head 31 (in-focus), the beam diameter is set to φ1.5 to 3.5 mm to cause melting in a wide area of the welding region.

  In the welding process of the present embodiment, for example, the irradiation position is scanned at a laser output of about 150 W to 240 W, a scanning speed of 1000 mm / sec to 20000 mm / s, and a number of laps of about 10 to 300. For example, when the housing 21 is ASA and dark gray, the laser output can be 200 W, so that melting can be generated in a wide area of the welding region. Since the absorption of the laser beam 12s varies depending on the color of the housing 21, it is necessary to adjust the laser output accordingly.

  The number of laps is set based on the scanning speed and the circumference of the welding surface 27a (welding line). The ratio of the circumferential length / scanning speed is substantially constant. For example, when the circumferential length is 1200 mm and the scanning speed is 10,000 mm / s, the number of revolutions is preferably about 200. For example, in the case of a circumferential length of 1200 mm and a scanning speed of 1,000 mm / s, the number of laps is preferably about 20 laps.

  The trajectory of the laser beam 12s may follow the same trajectory for each round, or may be gradually shifted outward.

  In the light reflecting film peeling step shown in FIG. 3A described above, the lower jig 24 is lowered and the focal position of the laser beam 12s is the lowered position of the lower jig 24. At the position where the lower jig 24 is raised so that the lower surface (rib 23a) of the lens 23 and the upper surface (welding surface 27a) of the housing 21 are in contact with each other, the laser beam 12s is in the above-described state. 2 is set to be in focus.

  In the embodiment of the present invention, the lower jig 24 can be moved up and down, so that the first in-focus state is in the lowered position of the lower jig 24 and the second in-focus state is in the raised position. Thus, if the focus position can be set in advance, the focus adjustment optical system 13 of the scan head 31 can be omitted.

  As described above, according to the embodiment of the present invention, the focusing state of the laser beam 12s can be changed by moving the lower jig 24 up and down, so that the light reflecting film peeling step and the welding step can be performed with one facility. It can be performed. Therefore, the processing equipment cost of the resin molded product can be reduced.

  Further, according to the embodiment of the present invention, since the Al film 22 on the welding surface 27a can be peeled (removed) by performing the light reflecting film peeling step before the welding step, Al deposition is performed on the housing 21. There is no need to mask or the like when performing. Therefore, the masking process of the welding surface 27a of the housing 21 can be omitted from the manufacturing process of the resin molded product, and the manufacturing cost can be reduced.

  In the above-described embodiment, one lens 23 is welded to the housing 21, but two of the inner lens and the outer lens may be welded to the single housing 21 in the same process.

  Although the embodiments have been described above, the present invention is not limited to these embodiments. For example, the combination of the translucent resin member and the light absorbing resin member is not limited to the lens and the housing. You may make a showcase for small valuables such as jewelry. Various other uses are possible. It will be apparent to those skilled in the art that various modifications, substitutions, improvements, combinations, and the like can be made.

DESCRIPTION OF SYMBOLS 10 ... Laser oscillator, 11 ... Optical fiber, 12 ... Laser beam, 13 ... Optical system for focus adjustment, 14 ... 1st galvano mirror, 15 ... 2nd y galvano mirror, 16 ... Control apparatus, 21 ... Housing, 22 ... Al Membrane, 23 ... lens, 23a ... rib, 24 ... lower jig, 25 ... upper jig (translucent pressure plate), 27a ... welding surface, 31 ... scan head

Claims (1)

(A) preparing a light-absorbing resin member having a welding region and a light-transmitting resin member having a welding region corresponding to the welding region of the light-absorbing resin member;
(B) forming a light reflecting film on the light absorbing resin member;
(C) In the first focusing state where the beam spot diameter is 1.0 mm or less, the laser beam is repeatedly irradiated to the welding region of the light-absorbing resin member, and the light reflecting film formed on the welding region is removed. And a process of
(D) In a second focusing state in which the welded region of the light-absorbing resin member and the welded region of the translucent resin member are in a pressure contact state, and the beam spot diameter is 1.5 mm or more and 3.5 mm or less. A method for producing a resin molded article, comprising: repeatedly irradiating a welding region of the light-absorbing resin member with a laser beam to weld the light-absorbing resin member and the light-transmitting resin member.

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