JP5731939B2 - Laser processing equipment - Google Patents

Description

  The present invention relates to a laser processing apparatus for processing printed circuit boards.

  When laser processing is performed by the laser processing apparatus, heat of 1% or less of the energy of the laser beam is absorbed by the scan lens. For this reason, the heat absorbed by the scan lens is accumulated while the laser irradiation is continued in the processing operation, and the temperature of the scan lens rises. When the temperature of the scan lens rises, the refractive index changes and the processing hole position accuracy decreases. The deviation of the hole position varies depending on the material and structure of the scan lens, but is recognized to be about 10 tens μm per 1 ° C., for example. Therefore, in order to suppress the degradation of machining accuracy due to heat storage and stabilize the machining accuracy, the laser processing device is warmed up while irradiating the laser beam to the scan lens before laser machining the workpiece. The laser processing position accuracy is stabilized.

  However, sufficient machining position accuracy cannot be obtained simply by performing the disconnection operation. Therefore, for example, in Patent Document 1, a group of collimating lenses provided on the optical axis of a laser beam emitted from a laser oscillator, a driving device for adjusting a collimator lens interval, an fθ lens, and a processing table are mounted. A Z-axis slider that adjusts the work distance with the workpiece being placed, and a temperature sensor that measures the representative temperature of the optical system, and adjusts the collimator lens spacing and work distance according to the measured value of the temperature sensor. Techniques to do this are disclosed. Specifically, prior to processing, the temperature of the fθ lens is measured, and the NC control device calculates a work distance correction amount and a processing focal length correction amount from the fθ lens temperature. At this time, the work distance is adjusted so as to cancel the shift of the processing position due to the change in the optical characteristic of the fθ lens, and the interval between the collimator lenses is adjusted so that the processing focus is aligned with the surface of the printed circuit board.

JP 2010-274267 A

  In the technique described in Patent Document 1, the condensing lens is deformed due to a temperature change of the condensing lens due to laser oscillation conditions, the beam irradiation position is shifted, and the processing position accuracy becomes unstable. A temperature sensor for measuring the representative temperature is provided, and this is dealt with by adjusting the distance between the collimator lens and the work distance corresponding to the measured value by the temperature sensor. However, it is necessary to adjust the distance between the collimator lens and the distance between the scan lens and the workpiece according to the measurement temperature, and the work associated with the correction is very complicated.

  Therefore, the problem to be solved by the present invention is to reduce the time required for warm-up operation and to stabilize the machining accuracy without complicated work.

In order to solve the above-described problem, the first means is a laser processing apparatus that makes a laser beam emitted from a laser oscillator incident on a workpiece via a processing optical system and laser-processes the workpiece, wherein the processing optical system Is a scan lens for making the laser beam incident and focused perpendicularly to the workpiece, and a heating means for heating the scan lens, and is provided so as to be able to approach and separate from the outer periphery of the scan lens. It is characterized by being provided with.

The second means is the laser processing apparatus according to claim 1, wherein when the temperature of the scan lens is lower than a target temperature, the processing optical system brings the heating means close to the scan lens, When the temperature of the scan lens is higher than a target temperature, the scan lens is provided with a drive unit that separates the heating unit from the scan lens .

  ADVANTAGE OF THE INVENTION According to this invention, while shortening the time required for warm-up operation, machining accuracy can be stabilized without complicated work.

It is a figure which shows the outline of the whole structure of the laser processing apparatus which concerns on embodiment of this invention. It is a cross-sectional view which shows the structure of the scan lens of the laser processing apparatus which concerns on embodiment of this invention, and its attaching part. FIG. 2 is a sectional view taken along line AA in FIG. It is a functional block diagram which shows the control system which performs control which concerns on embodiment of this invention.

  In the present invention, a heating unit for heating the scan lens is provided, and the position and / or temperature of the heating unit is controlled to shorten the warm-up operation time. Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a diagram showing an outline of the entire configuration of a laser processing apparatus according to the present embodiment.
In the figure, the XY table 2 of the laser processing apparatus main body is provided so as to be movable on the bed 1 in the X and Y directions in the horizontal orthogonal biaxial direction. On the XY table 2, a plurality of holes are formed on the surface so as to be connected to an internal hollow portion, and a sub table 3 having a vacuum suction function is fixed by connecting the hollow portion to a vacuum source. A workpiece 4 is held by suction on the sub-table 3.

  The gate-shaped column 5 is fixed on the bed 1. A laser oscillator 6 is installed above the column 5, and the laser beam 6 a output from the laser oscillator 6 is deflected in the optical path by the mirror 7 and positioned by the galvano scanner 8. On the other hand, a Z-axis saddle 19 movable in the Z-axis direction is provided by the Z-axis drive unit 10, and a scan lens 9 such as an fθ lens and the above-described galvano scanner 8 are mounted on the Z-axis saddle 19. . The Z-axis drive saddle 19 moves in the vertical direction with respect to the focal position of the scan lens 9, irradiates the focal position with laser light, and processes the workpiece 4.

  FIG. 2 is a cross-sectional view of the scan lens and its mounting portion. In the figure, a heater 11 divided into four parts is disposed on the outer periphery of the scan lens 9. The heater 11 is provided so as to advance and retreat with respect to the outermost cooling unit 12 by a guide spring 14. When the heater 11 is provided in this manner, the heater 11 can be brought close to the scan lens 9 as shown in FIG. 2A, and the heat radiated from the heater 11 can be transferred to the scan lens 9 side. Due to this heat transfer, the amount of heat stored in the scan lens 9 increases, and the temperature of the scan lens 9 increases.

  In this way, when the heater 11 is divided into four parts and each is provided so as to be able to advance and retreat with respect to the scan lens 9 by the guide spring 14, when the temperature is to be raised, the heater 11 is brought close to the scan lens 9 and the temperature is to be maintained. 2 moves the heater 11 away from the scan lens 9 as shown in FIG. With this configuration, the same temperature as the thermal equilibrium state of the scan lens 9 during the warm-up operation under a certain processing condition can be obtained.

  A cooling unit 12 is provided around the heater 11 so as to absorb the heat of the heater 11. The cooling unit 12 cools the lens that has been overheated by the heater 11, and when the heater 11 is moved to the maximum distance in the direction away from the scan lens 9 by the spring 14 with guide as shown in FIG. The heater 11 and the cooling unit 14 come into contact with each other to cool the heater 11. When the heater 11 is cooled, an increase in the temperature of the scan lens 9 due to an increase in the ambient temperature due to the overheating state of the heater 11 can be prevented.

  FIG. 3 is a view showing a heater moving mechanism and its operation, and is a cross-sectional view taken along line AA in FIG. 3A shows a state in which the heater 11 is close to the scan lens 9, which corresponds to a cross-sectional view taken along line AA in FIG. 2A, and FIG. 3B shows an A-line in FIG. This corresponds to a cross-sectional view taken along line A. In the present embodiment, the heater 11 is always given elastic force to the scan lens 9 side by a guide spring 14, and the heater 11 is moved closer to and away from the scan lens 9 by the movement of the heat insulating member 13. Yes.

  That is, the heater 11 is supported movably along the guide in the horizontal direction by the guide of the spring 14 with guide attached to the cooling unit 12. The cooling unit 12 is attached to an attachment plate 15 provided outside the scan lens 9, and a cylinder 16 is further attached to the outside of the attachment plate 15. The cylinder 16 includes a rod 17 that expands and contracts downward in the figure, and a support plate 18 of the heat insulating member 13 is attached to the tip (lower end) of the rod 17. The heat insulating member 13 is supported on the upper surface of the support plate 18, and the heat insulating member 13 performs the lowering and raising operations according to the expansion and contraction operation of the rod 17.

  The lower surface 11a of the heater 11 is formed in an inclined surface (wedge shape in cross section) such that the side far from the scan lens 9 is the lower side and the near side is the upper side. On the other hand, as can be seen from FIG. 3, the upper surface 13a of the heat insulating member 13 is formed in an inclined surface (cross-sectional wedge shape) such that the side far from the scan lens 9 is the lower side and the near side is the upper side. Are inclined at angles parallel to each other. When the heater 11 is in the position closest to the scan lens 9, the heat insulating material 13 is positioned directly below the heater 11, and the lower surface 11a and the upper surface 13a are separated by a predetermined amount. The heat insulating member 13 is disposed so as to surround the scan lens 9 in a plan view. In the present embodiment, a donut shape in plan view is formed in accordance with the outer shape of the scan lens 9.

  With this configuration, when the scan lens 9 is heated, the rod 17 is extended by the cylinder 16 as shown in FIG. In order to eliminate the overheated state of the scan lens 9, the rod 17 is contracted. In other words, the rod 17 is pulled up. Thereby, the heat insulation member 13 moves upward, the inclined upper surface 13a of the heat insulation member 13 hits the lower surface 11a inclined at the same inclination angle of the heater, and pushes up the heater 11. By this pushing-up operation, the heater 11 moves horizontally to the cooling unit 12 side by the horizontal component force generated on the inclined surface 11a. When the horizontal movement is completed, the heat insulating member 13 rises along the side surface of the heater 11 and is positioned between the heater 11 and the scan lens 9.

  When the heat insulating member 13 is located at this position, the radiant heat from the heater 11 is shielded by the heat insulating member 13 and is not transmitted to the scan lens 9 side. This state is the state shown in FIG. 2B, and the planar side surface 11 b outside the heater 11 contacts the planar inner surface of the cooling unit 12 to absorb the heat of the heater 11 and cool the heater 11. To do. Since the heat insulating member 13 and the cooling unit 12 have such a function, as the heat insulating member 13, for example, a ceramic or resin-based heat insulating material is suitable. Further, when the heat insulating member 13 is warmed by the heater 11 before the heater 11 is stopped when the heat insulating member 13 is positioned at the heat insulating position (the position shown in FIG. 2B and FIG. 3B), Since the desired heat insulating effect may not be obtained, it is desirable that the heat capacity of the heat insulating member 13 is large.

  Further, even if the cooling unit 12 moves the heater 11 to a position away from the scan lens 9 or inserts a heat insulating member 13 therebetween so that the heat of the heater 11 is not directly transmitted to the scan lens 9, the heater There is a possibility that the scan lens 9 is thermally affected by the heat radiation of the eleventh. Therefore, the cooling unit 12 uses, for example, a heat sink using an aluminum material or a heat sink in which cooling water is passed through an aluminum material in order to quickly transfer the remaining heat of the heater 11.

  Thus, in this embodiment, as shown in FIG. 3B, when the heat insulating member 13 is moved upward by the cylinder 16, the heater 11 is guided by the inclined surfaces 11a and 13a of the heater 11 and the heat insulating member 13. The spring 14 moves backward in the direction away from the scan lens 9 against the resilient force of the spring 14. In this state, since the heat insulating member 13 is interposed between the scan lens 9 and the heater 11, even when the heater 11 is in an overheated state, the heat is not directly transmitted to the scan lens 9. Therefore, an unnecessary temperature rise of the scan lens 9 can be prevented. Further, when the heat insulating member 13 is lowered at the end of laser processing on the workpiece 4 and the heater 11 is in contact with the scan lens 9, the temperature of the scan lens 9 can be kept constant even during processing standby. When the temperature of the scan lens 9 is kept constant, the heat-insulating member 13 may be lifted and lowered as necessary to control the amount of heat supplied to the scan lens 9 side.

  In this embodiment, the raising / lowering operation of the heat insulating member 13 is interlocked with the expansion / contraction operation of the rod 17 operated by the cylinder 16, and the raising / lowering operation of the heat insulating member 13 is interlocked with the approaching / separating operation of the heater 11. It is also possible to drive the movement of the member 13 and the heater 11 independently using different actuators, and to link the approach and separation operation of the heater 11 with respect to the scan lens 9 and the lowering and raising operation of the heat insulating member 13. In this case, since it is not necessary to drive the heater 11 by the heat insulating member 13, it is not always necessary to provide the inclined surfaces 11 a and 13 a on the heater 11 and the heat insulating member 13.

  In addition, any actuator that can be considered in a normal design range such as a motor and a cylinder (hydraulic pressure, pneumatic pressure) can be used as the actuator used for the proximity and separation operation of the heater 1 with respect to the scan lens 9. Moreover, the same thing can be applied also about the raising / lowering operation | movement of the heat insulation member 13. FIG.

  Further, in this embodiment, the heat insulating member 13 and the cylinder 16 that drives the heat insulating member 13 are provided, or the spring 14 with guide is used to drive the heater 11, but these are omitted, and the heater 11 and the heater 11 are omitted. It is also possible to provide a drive mechanism that can execute only the approaching / separating operation with respect to the scan lens 9. In this case, it is possible to control the temperature of the scan lens 9 by combining the proximity / separation operation of the heater 11 or the on / off operation of the heater 11 and the proximity / separation operation of the heater 11.

  In the present embodiment, the heater 11 is disposed so as to face the side surface of the scan lens 9, but the scan lens 9 is generally configured by combining a plurality of lenses and supported by the holder. Directly heats the holder of the scan lens 9, and the scan lens 9 is indirectly heated through the holder. Thereby, unevenness in the temperature distribution is reduced, and the scanning lens 9 is more preferably heated. Further, if the heater 11 is formed on the back side (cooling unit 12 side) of the copper block, the scanning lens 9 can be heated more uniformly and the cooling rate can be increased. Also, the heating state of the scan lens 9 is more preferable.

  Further, when the heater 11 is turned on / off as described above, it is necessary to set the heater 11 on / off timing. In this case, the temperature of the scan lens 9 is detected and the detection result is turned on / off. It is preferable to perform the feedback. Therefore, the temperature detection may be performed by the temperature sensor 110 (see FIG. 4) provided inside or on the outer periphery of the holder of the scan lens 9. In the present embodiment, since the holder is similar to the outer peripheral shape of the scan lens 9, average temperature measurement can be performed at one temperature detection point. However, depending on the shape of the scan lens 9, a plurality of temperature detection points may be provided, and an average value of temperatures detected at a plurality of locations may be taken.

  The feedback control of the heater 11 is performed so that, for example, the thermal equilibrium temperature of the scan lens 9 and the measured temperature of the scan lens 9 during the warm-up operation of the laser processing apparatus become the same temperature. 100 is provided. FIG. 4 is a functional block diagram showing a control system that executes control according to the present embodiment. The control device 100 controls not only the heater temperature but also the driving of the rod 7 of the cylinder 9 described above, and thus also controls the heat transfer state by the heat insulating member 13. That is, the control device 100 turns on the heater power source when the temperature sensor 110 measured temperature is lower than the target temperature and brings the heater 11 closer to the scan lens 9, and when the measured temperature is higher than the target temperature, The power is turned off and the heater 11 is moved away from the scan lens. Therefore, the control device 100 includes a memory 101 that stores the target temperature in a table for each processing condition. In the case of heating control of the heater 11, the target temperature is read from the memory 101 and measured by the temperature sensor 110. The temperature is compared with the temperature, and the temperature control of the heater 11 or the drive control of the cylinder 6 is executed based on the comparison result.

  The cylinder 6 is driven by transmitting a control signal from the control device 100 to the driver 120 that drives the cylinder (actuator) 6, and the ON / OFF control of the heater 11 is also sent to the heater driver 130. It is executed based on the control signal from

  The processing conditions are mainly laser processing conditions, such as a laser frequency, a pulse width, and the number of shots. As described above, the temperature rise characteristics (time-varying characteristics) of the scan lens 9 during warm-up operation under various laser processing conditions are stored in a table in the memory 101, and various feedback control is performed by referring to the table. It is possible to ensure the stability of processing accuracy under various processing conditions. Further, a history of the temperature rise of the scan lens 9 during the warm-up operation is stored in the memory 101, and the temperature at that time and the number of repetitions of laser irradiation until the scan lens 9 reaches the thermal equilibrium temperature and stabilizes without the warm-up operation. Accordingly, each time the temperature of the scan lens 9 is measured, it is also possible to perform control so as to correct the deviation of the optical axis of the laser light generated according to the temperature at that time. Such control can also contribute to stabilization of machining accuracy.

  The control device 100 includes a CPU, a ROM, and a RAM (not shown). The CPU reads a program code stored in the ROM, expands the program code in the RAM, and uses the RAM as a work area and a data buffer. Executes control based on the defined program. Note that the RAM can be used as the memory 101 for storing the target temperature for each processing condition, or a separately provided storage device can be used.

  As described above, according to the present embodiment, the heater 11 and the cooling unit 12 can quickly heat the scan lens 9 and cool the heater 11, thereby shortening or eliminating the warm-up operation time. Moreover, since the heating control of the heater 11 can be performed based on the temperature measured by the temperature sensor, the temperature of the scan lens 9 can be maintained at a predetermined temperature. As a result, stable processing accuracy can be ensured without causing a change in refractive index due to a temperature change of the scan lens 9.

  Furthermore, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention, and all the technical matters included in the technical idea described in the claims are all included. The subject of the present invention. The above embodiment shows a preferable example, but those skilled in the art can realize various alternatives, modifications, variations, and improvements from the contents disclosed in this specification, These are included in the technical scope described in the appended claims.

4 Work 6 Laser Oscillator 6a Laser Beam 7 Mirror 8 Galvano Scanner 9 Scan Lens 11 Heater 12 Cooling Unit 13 Heat Insulating Member 16 Cylinder 17 Rod 18 Support Plate 100 Controller 101 Memory 110 Temperature Sensor

Claims (2)

A laser processing apparatus that laser-emits a laser beam emitted from a laser oscillator and enters the workpiece via a machining optical system, and the machining optical system impinges the laser beam perpendicularly to the workpiece. A scan lens for condensing and a heating means for heating the scan lens provided to be close to and away from the outer peripheral portion of the scan lens, Laser processing equipment. The laser processing apparatus according to claim 1,
When the temperature of the scan lens is lower than the target temperature, the processing optical system brings the heating means close to the scan lens, and when the temperature of the scan lens is higher than the target temperature, the heating means A laser processing apparatus comprising driving means for separating the lens from the scan lens .

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