JP5305223B2 - Method for stripping insulated conductors - Google Patents

Description

  The present invention relates to a method for stripping an insulated conductor, and more particularly to a method for stripping an insulated conductor using a laser beam.

  Conventionally, an insulated conductor is used as a conductor in an electronic device. As an example, this insulated conducting wire uses a copper wire as a core wire and a polyurethane coating as an insulating coating covering the core wire. Polyurethane coating does not have high heat resistance, so when connecting conductors using polyurethane coating to the electrodes of electronic equipment, the coating should be applied simultaneously with the connection by heat at the time of connection without peeling off the coating beforehand. It was peeling.

In addition, depending on the type of electronic equipment in which the insulated conductor is used, the conductor may be required to have high durability, specifically, high heat resistance. In this case, polyamideimide may be used as the insulation coating. is there. Since polyamide imide has a higher melting point than polyurethane, it is not easy to peel the polyamide imide coating by heat at the time of connection. Therefore, it is necessary to peel the coating before connecting, and a method of mechanically peeling with a rotary blade or the like, and a method of melting and peeling the coating with a laser as shown in Patent Document 1, have been proposed.
Special table 2007-516083

  Since the above-described insulated conductor coated with polyamideimide is wound around a coil component or the like, it is required to have flexibility and elasticity, and thus the coating also has flexibility and elasticity. On the other hand, with the conventional coating peeling method using a laser, the coating can be broken and peeled off. However, because the coating has flexibility and elasticity, everything remains on the core without breaking. There was a case. When the connection is performed in this state, a covering is caught in the connection portion, and a connection failure occurs. Then, an object of this invention is to provide the coating peeling method which removes a coating | cover reliably from a connection location.

In order to solve the above-described problems, the present invention provides a peeling method for peeling a coating of an insulated conductor composed of a core wire and a coating covering the core wire, and heating the insulated conductor or irradiating ultraviolet rays to the coating. An embrittlement step of embrittlement of the coating at a temperature lower than the melting point and the coating becomes brittle, and irradiating the embrittled coating of the insulated conductor with a short pulse laser to generate bubbles at the interface between the core wire and the coating, And a coating stripping step of rupturing and scattering the coating embrittled by expanding bubbles and removing the coating from the surface of the core wire.

  According to such a method, since the coating becomes brittle by heating or ultraviolet irradiation, brittle fracture is likely to occur. In this state, when the laser is irradiated to generate bubbles at the interface and the coating is peeled off, the coating is brittle. Therefore, the coating can be easily subdivided, broken and scattered, and the coating can be reliably removed from the surface of the core wire.

  In the above method, it is preferable that the embrittlement step includes a selective embrittlement step of embrittlement only at a portion where the coating is to be peeled off.

  According to such a method, it is possible to reliably remove the coating from the surface of the core wire only at a portion where the coating is to be peeled off, and to keep the core wire covered at other portions.

  According to the coating peeling method of this invention, a coating | cover can be reliably removed in a connection location.

  A method for coating and stripping an insulated conductor according to an embodiment of the present invention will be described with reference to FIGS. A laser peeling machine 1 shown in FIG. 1 mainly includes a laser oscillator 2, an expander 3, a mask 4, a transfer lens 5, a dichroic mirror 6, a holding table 7, and an observation device 8. Yes.

The laser oscillator 2 is a YAG laser irradiation apparatus that irradiates a pulse laser, and the wavelength of the irradiated pulse laser is 1064 nm, the pulse width is 100 nsec or less, preferably 40 nsec or less, the frequency is 20 Hz, and the irradiation energy amount is 230 mJ /. It is an apparatus that has a cm ² ± 10%.

  The expander 3 is disposed on the optical path of the laser light emitted from the laser oscillator 2. The expander 3 includes a convex lens and a concave lens inside. When the laser light is input from one side and output from the other side, the expander 3 It is a device that outputs a light beam with a reduced diameter.

  The mask 4 is made of glass as a base material, and is arranged on the optical path of the laser light that has passed through the expander 3. Further, the mask 4 includes a transparent region 4A that is a transparent portion and can transmit laser light, and a transmission region peripheral portion 4B that is a peripheral portion of the transmission region 4A. Since the transmissive region peripheral portion 4B is polished glass by blasting or the like, the laser light irradiated to the transmissive region peripheral portion 4B is scattered, and only the laser light irradiated to the transmissive region 4A can be transmitted through the mask. It has become. Further, the transmission region 4A has a substantially rectangular cross section orthogonal to the optical path direction so as to correspond to an irradiation region D (FIG. 6) described later.

  A dichroic mirror 6 is disposed on the optical path of the laser light that has passed through the mask 4 to reflect the laser light at an angle of about 90 degrees and guide it to the transfer lens 5. Further, since the dichroic mirror 6 has a feature of reflecting only a specific wavelength (for the dichroic mirror 6 of the present embodiment, a wavelength near 1064 nm), normal visible light can be transmitted.

  The laser light reflected by the dichroic mirror 6 passes through the transfer lens 5. The transfer lens 5 is composed of a convex lens, and allows incident laser light to converge at a position above the holding table 7. Further, the transfer lens 5 can move in the optical path direction (hereinafter referred to as Z-axis direction), and therefore the focal position can also move in the Z-axis direction.

  The holding table 7 holds the pallet 71 that holds the coil component 10 irradiated with the laser beam, and the pallet 71 by a suction mechanism (not shown), and is movable in the X-axis direction and the Y-axis direction orthogonal to the Z-axis direction. The XY stage 72 is mainly configured. An air blow 73 for injecting air is provided above the pallet 71, and a dust collector 74 is disposed below the XY stage 72.

  The coil component 10 held on the pallet 71 is a common mode filter used for a differential signal interface, and has a dimension of about 4 mm in the longitudinal direction. As shown in FIG. And two coated conductors 12 and metal terminals 13 and 13 as electrodes. The core 11 is molded from a magnetic powder such as ferrite through processes such as compression and sintering.

  The core 11 includes a winding core portion 11A having a substantially rectangular cross section perpendicular to the longitudinal direction, and a pair of flange portions 11B and 11B having substantially the same shape, provided at both ends in the longitudinal direction of the winding core portion 11A. Since the flanges 11B and 11B have substantially the same shape, only one side will be described unless otherwise specified.

  The flange portion 11B includes a main body portion 11C that is a portion connected to the winding core portion 11A, and a pair of sub body portions 11D and 11D that extend in opposite directions from the main body portion 11C.

  Metal terminals 13 and 13 are attached to the sub trunk portions 11D and 11D, respectively. Since the pair of sub-body parts 11D and 11D and the metal terminals 13 and 13 are symmetrically configured with the main body part 11C interposed therebetween, only the one sub-body part 11D and the metal terminal 13 will be described below.

  The metal terminals 13 and 13 are formed in a substantially U shape from a pair of leg portions 13A and 13C extending from both ends of the base portion 13B (FIG. 4). The metal terminal 13 is attached to the sub trunk portion 11D with the leg portion 13A and the leg portion 13C sandwiching the sub trunk portion 11D.

  A section 13D extends from the side in the extending direction of the leg 13A. A fixing portion 13F is provided on the free end side of the leg portion 13A of the section 13D, and a melting portion 13E is provided on the fixing base end side of the leg portion 13A. Further, the leg portion 13 </ b> C serves as a mounting portion that is electrically joined to an electrode on the substrate when the coil component 10 is mounted on a substrate (not shown).

  As shown in FIG. 4, the two covered conductive wires 12 wound around the winding core portion 11 </ b> A are each composed of a core wire 12 </ b> A that is a copper wire and an insulating coating 12 </ b> B made of polyamideimide. The coated conducting wire 12 has an outer diameter of about 90 μm and a core wire diameter of about 70 μm. A connecting point 12C is defined at both ends of the coated conducting wire 12, and the connecting point 12C becomes a peeling point described later. The insulation coating 12B has flexibility and elasticity at room temperature, and can suitably follow the core portion 11A when the coated conductor 12 is wound around the core portion 11A. When the insulating coating 12B is heated to a temperature close to the melting point, the insulating coating 12B hardens and becomes brittle (embrittlement), so that it is more likely to break than before heating. Therefore, when an impact is applied to the insulating coating 12B in this embrittled state, the insulating coating 12B is easily broken and subdivided.

  An observation device 8 is disposed on the opposite side of the transfer lens 5 with respect to the dichroic mirror 6. The observation device 8 includes a mirror 81, a correction lens 82, a CCD camera lens 83, a rear converter lens 84, a CCD camera 85, an image processing device 86, a monitor 87, and an illumination 88. The mirror 81 is positioned on a straight line (on the Z axis) from the transfer lens 5 to the dichroic mirror 6 and is disposed such that its mirror surface forms about 45 degrees with the Z axis. The CCD camera 85 is arranged such that a straight line from the CCD camera 85 to the mirror 81 is orthogonal to the Z axis, and a straight line from the CCD camera 85 to the mirror 81 and the mirror surface of the mirror 81 form about 45 degrees. . Since the dichroic mirror 6 transmits visible light, a state in which the coil component 10 irradiated with the laser light is reflected on the mirror 81 via the transfer lens 5 and the dichroic mirror 6 can be photographed by the CCD camera 85. . The correction lens 82 is disposed between the CCD camera 85 and the mirror 81 to correct aberrations. The CCD camera lens 83 is a lens for forming an image on the CCD camera, and the rear converter lens 84 is a lens for changing the magnification. The image processing device 86 is a device that processes an image captured by the CCD camera 85 and displays the image on the monitor 87, and the illumination 88 irradiates the coil component 10 with visible light so that it can be easily viewed.

  As shown in FIG. 2, the laser peeling machine 1 includes a CPU 91 that is an arithmetic device and a memory 92 that stores processing performed by the CPU 91. The CPU 91 controls the laser light emitted from the laser oscillator 2 and controls the operation of the transport system controller 93, the air blow 73, and the dust collector 74 that controls the amount of movement of the XY stage 72. A drive system controller 95 that controls the movement of the transfer lens 5 in the z-axis direction and an illumination controller 96 that controls the illumination 88 are provided to perform each control.

  Based on the flowchart shown in FIG. 5, a coating peeling process for peeling the insulating coating 12 </ b> B of the coated conducting wire 12 with the laser peeling machine 1 will be described. First, in step S01, as shown in FIG. 6, with the covered conductor 12 held on the leg portion 13A by the fixing portion 13F, the coil component 10 is placed in a furnace (not shown) and heated (brittle). Process). The heating temperature at this time is lower than the melting point of the insulating coating 12B and is a temperature at which the insulating coating 12B becomes brittle.

  After the heating, in step S02, the coil component 10 is fixed to the pallet 71 and the fixed pallet 71 is placed on the XY stage 72 as shown in FIG. In step S03, a start switch (not shown) is turned on to start the laser peeling machine 1. By turning on a start switch (not shown), the pallet 71 is attracted and fixed on the XY stage 72 (S04). The position of the XY stage 72 in this state is defined as the supply position. Thereafter, the process proceeds to S05, and the XY stage 72 is moved by the transport system control unit 93, and the sub trunk portion 11D portion of the coil component 10 that is the irradiation region D (FIG. 6) is arranged at the irradiation position. After confirming that the movement of the XY stage 72 is completed on the monitor 87 (S06), the process proceeds to S07, where the laser oscillator 2 irradiates the laser beam and heats the insulating coating 12B (coating peeling step).

  The laser light emitted from the laser oscillator 2 enters the expander 3, the light flux of the laser light is reduced, and the reduced laser light is irradiated near the transmission region 4 A of the mask 4. At this time, the reduction rate of the laser light in the expander 3 is preferably set to such a reduction rate that the area is such that at least the transmission region 4A enters the cross section of the reduced laser light. By setting it as such a reduction rate, the energy amount per unit area of the laser beam which permeate | transmits the transmissive area | region 4A can be raised.

  The laser light applied to the mask 4 passes through the mask 4 only in a portion where the cross section orthogonal to the optical path direction corresponding to the irradiation region D (FIG. 6) is substantially rectangular. At this time, the transmissive region peripheral portion 4B, which is an irradiation position other than the transmissive region 4A, scatters the laser light and prevents the laser light from passing through the mask 4. Since the luminous flux of the laser light is reduced by the expander 3, the energy per unit area is larger than when irradiated from the laser oscillator 2. However, since the energy of the laser light applied to the mask 4 is much smaller than the energy of the converged laser light in the vicinity of the irradiation position on the pallet 71, it is possible to prevent the transmission region peripheral edge 4B from being deteriorated by the laser light. Thus, the life of the mask 4 can be extended.

  The laser light that has passed through the mask 4 is reflected at a right angle by the dichroic mirror 6 and irradiated onto the transfer lens 5. The transfer lens 5 converges the laser light and irradiates the irradiation area in order to increase the amount of energy per unit area of the laser light. In this case, the size of the irradiation area is as follows. The beam diameter at the mask 4 is φb, the beam diameter at the irradiation area is φd, the distance from the mask 4 to the transfer lens 5 is f0, and the distance from the transfer lens 5 to the irradiation area is: When f1, it is calculated by the formula φb = f0 ÷ f1 × φd. Therefore, the transfer lens 5 is moved in the Z-axis direction by the drive system control unit 95 and adjusted in advance so that a suitable irradiation region is obtained. Although it is assumed that the XY stage 72 itself is moved in the Z-axis direction, the XY stage 72 is already provided with a mechanism that can move in the X-axis direction and the Y-axis direction. If the function of moving in the direction is provided, the configuration becomes complicated, and it becomes difficult to maintain the accuracy of movement. Therefore, by adopting a configuration in which the transfer lens 5 is moved in the Z-axis direction, it is not necessary to adopt a complicated configuration, and control in the X, Y, and Z-axis directions can be performed with high accuracy.

  A laser beam that has been transmitted through the transfer lens 5 and converged is irradiated onto the irradiation region. In this case, since the laser light passes through the insulating coating 12B and is irradiated onto the surface of the core wire 12A, the surface of the core wire 12A absorbs the energy of the laser light, and the interface 12a between the insulating coating 12B and the core wire 12A suddenly changes. The temperature rises. Since this temperature rise (temperature change from room temperature to 1000 ° C. or more) occurs in an extremely short time, the polyamideimide constituting the insulating coating 12B of the interface 12a chemically changes and gasifies without melting. Therefore, as shown in FIG. 7B, countless bubbles 12b are generated at the interface 12a.

  As shown in FIG. 7C, the bubbles 12b rapidly expand in volume along the interface 12a due to the temperature rise at the location irradiated with the laser beam, and the insulating coating 12B is continuously peeled from the surface of the core wire 12A. . As the volume expansion of the bubble 12b proceeds, the insulating coating 12B cannot withstand the stress associated with the volume expansion, and the portion covering the bubble 12b of the insulating coating 12B ruptures as shown in FIG. Since the process from generation of bubble 12b to expansion to burst is performed in an extremely short time, the burst of the portion covering the bubble 12b of the insulating coating 12B is accompanied by an impact. The insulating coating 12B embrittled by this impact breaks in a fragmented state. When the insulating coating 12B is subdivided and fractured, the insulating coating 12B is insulated in a state where a portion that is not peeled off at the boundary of the irradiation region D (outside the irradiation region D) and a portion that is peeled off (the irradiation region D) are clear. The coating 12B is scattered from the surface of the core wire 12A and peeled off. That is, the insulation coating 12B in the irradiation region D does not peel off while attached to the insulation coating 12B outside the irradiation region D, and the insulation of the irradiation region D is securely separated from the insulation coating 12B outside the irradiation region D. The coating 12B peels off. As a result, the insulation coating 12B in the irradiation region D is reliably removed from the core wire 12A after being peeled off, and the core wire 12A can be reliably exposed in the irradiation region D.

  The insulating coating 12 </ b> B removed by scattering is blown off by the air blow 73 and sucked by the dust collector 74. Therefore, it is suppressed that the insulation coating 12B scattered on the coil component 10 remains, and it is difficult for a poor connection to occur in the subsequent connecting step. Then, as shown in FIG. 7 (e), all the insulation coating 12B of the connecting portion 12C is removed, and the surface of the core wire 12A is exposed as shown in FIG. At this time, since the laser light is irradiated only to the irradiation region D, it is possible to suppress unnecessary laser light from being irradiated to the coated conductive wire 12 and the core 11 outside the irradiation region D. Accordingly, the outside of the irradiation region D is not heated by the laser beam, and the coil component 10 can be prevented from being damaged.

  After the above steps are completed, the process proceeds to step S08, and if there is a coated conductor that has not yet been stripped (S08: NO), the process proceeds to S09, and the XY stage 72 has moved and is still The process returns to S05 to perform the coating peeling of the coated conductor that has not been stripped. If the coating peeling of all the coated conductors has been completed (S08: YES), the process proceeds to S10, and the XY stage 72 is returned to the supply position. Thereafter, the suction of the pallet 71 is stopped (S11), the pallet 71 and the coil component 10 on the pallet 71 are taken out (S12), and the coating peeling process is completed.

  After the coating peeling process is completed, the melted portion 13E (FIG. 4) is bent so as to cover the exposed portion, and then the melted portion 13E and the core wire 12A are formed as shown in FIG. The coil component 10 is completed by welding. At this time, since the insulating coating 12B on the core wire 12A, which becomes the connecting portion, is peeled off and securely removed, the insulating coating 12B is not caught in the connecting portion, and the connection failure can be suppressed.

  The insulated lead coating peeling apparatus and the coating peeling method according to the present invention are not limited to the above-described embodiments, and various modifications and improvements can be made within the scope described in the claims. For example, in the above-described embodiment, the embrittlement process is performed by putting the coil component 10 in a furnace (not shown) as a heating means. However, the other laser is irradiated with the laser light emitted from the laser oscillator 2 as another heating means. A chemical conversion step may be performed. At this time, the output of the laser beam irradiated from the laser oscillator 2 is weakened and the transfer lens 5 is moved so that the laser beam is suitably applied to the insulating coating 12B, thereby adjusting the insulating coating 12B at a temperature lower than the melting point. Can be heated. In addition, when performing the embrittlement process with laser light, a low-power second laser oscillator may be used in addition to the laser oscillator 2. Examples of the second laser oscillator include a transmitter that emits laser light having a far infrared wavelength such as a CO2 laser.

In addition to the laser oscillator, a device that emits heat rays such as a xenon lamp or a halogen lamp may be used as another heating means. By condensing the heat rays irradiated from these lamps with a lens, the insulating coating 12B can be heated and embrittled.
Further, as shown in FIG. 10, a heating element such as a heater chip 99 may be brought into direct contact with the coated conductor 12, and the embrittlement process may be performed by the heat. At this time, the heater chip 99 preferably includes an abutment surface 99A that follows the outer shape of the coated conductor 12. According to such a configuration, the insulating coating 12B can be heated by the entire contact surface 99A, and the embrittlement process can be performed more suitably. Moreover, since the part which does not require peeling of the covering conducting wire 12 is not heated, only the part which needs to be peeled can be preferably peeled off.

  In addition, although polyamideimide is used as the insulating coating 12B, the material is not limited to this, and other materials may be used as long as the material becomes brittle when heated. Further, a UV curable resin may be used. In this case, the embrittlement process can be performed by irradiating with ultraviolet rays instead of the heating means.

  Further, as described above, when the laser beam, the heat ray, and the ultraviolet ray are irradiated, as shown in FIG. 11, the reflecting mirror 9 may be provided on the opposite side of the light source with the coated conducting wire 12 interposed therebetween. According to such a configuration, it is possible to irradiate substantially the entire surface of the coated conductor 12 by irradiation from one direction, and it is possible to more suitably embrittle the insulating coating 12B. Moreover, when irradiating laser light, heat rays, and ultraviolet rays, as shown in FIG. 6, the irradiation region D may be defined and irradiated by a mask or the like (selective embrittlement step). If it is such a structure, it can suppress that the covering conducting wire 12 outside the irradiation area | region D embrittles.

The conceptual diagram showing the coating peeling apparatus which concerns on embodiment of this invention. The block diagram which concerns on control of the coating peeling apparatus which concerns on embodiment of this invention. The top view of the coil components provided with the insulated lead wire peeled with the coating peeling apparatus which concerns on embodiment of this invention. The fragmentary perspective view of the coil component provided with the insulated lead wire peeled with the coating peeling apparatus which concerns on embodiment of this invention. The chart which concerns on the coating peeling process in the coating peeling apparatus which concerns on embodiment of this invention. The fragmentary top view of the coil component provided with the insulated lead wire peeled with the coating peeling apparatus which concerns on embodiment of this invention. The partial sectional view showing the state of (a) pulse laser irradiation, (b) bubble generation, (c) bubble expansion, (d) bubble rupture, and (e) peeling completion in the coating peeling step according to the embodiment of the present invention. The fragmentary perspective view of the state before the completion of the connection of the coil component provided with the insulated lead wire peeled with the coating peeling apparatus which concerns on embodiment of this invention. The fragmentary perspective view of the state where the insulation conducting wire of the coil component provided with the insulation conducting wire peeled with the coating peeling apparatus which concerns on embodiment of this invention was connected. The figure which shows the state which made the heater chip contact | abut to the covering conducting wire concerning the modification of the coating peeling apparatus which concerns on embodiment of this invention. The figure which shows the irradiation state to the covering conducting wire concerning the example of a change of the coating peeling apparatus which concerns on embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 .... Laser peeling machine 2. Laser oscillator 3. Expander 4. Mask 4A ... Transmission region 4B ... Transmission region peripheral part 5. Transfer lens 6. Dichroic mirror 7 .... Holding stand 8 .... Observation device 9 .. Reflective mirror 10 .. Coil parts 11.. Core 11 A... Core part 11 B .. Collar part 11 C .. Main trunk part 11 D .. Sub trunk part 12 .. Coated conductor 12 A. · Insulation coating 12C · · Connection point 12a · · Interface 12b · · Bubble 13 · · Metal terminal 13A · · Leg portion 13B · · Base 13C · · Leg portion 13D · · 13E · · melting portion 13F · · fixed portion 71..Pallet 72..Stage 73..Air blow 74..Dust collector 81..Mirror 82..Correction lens 83..Camera lens 84..Rear converter lens 85..Camera 86..Image processing 87 ... monitor 88 · Lighting 91 .. CPU 92 · Memory 93 ... conveying system control unit 94 · air blow dust collection controller 95 ... driving system control unit 96 ... illumination control unit

Claims (2)

A stripping method for stripping a coating of an insulated conductor composed of a core wire and a coating covering the core wire,
An embrittlement step of embrittlement of the coating at a temperature lower than the melting point of the coating and embrittlement of the coating by heating the insulated conductor or irradiating with ultraviolet rays;
Irradiating the embrittled coating of the insulated wire with a short pulse laser, generating bubbles at the interface between the core wire and the coating, expanding the bubbles, rupturing and scattering the embrittled coating, and And a coating peeling process for removing from the surface.   2. The coating exfoliation method according to claim 1, wherein the embrittlement step includes a selective embrittlement step of embrittlement only at a portion to be exfoliated.

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