JP4915062B2 - Laser processing equipment - Google Patents

Description

  The present invention relates to a laser processing apparatus having a configuration in which a traveling direction of laser light from a laser oscillator is changed by an optical component and a correction method thereof.

  An example of a laser processing apparatus having a configuration in which the traveling direction of laser light from a conventional laser oscillator is changed by an optical component will be described below using a printed circuit board drilling laser processing apparatus (see, for example, Patent Document 1).

  In FIG. 4, a laser beam 2 emitted from a laser oscillator 1 is changed in direction by a reflecting mirror 3a and branched into two by a beam splitter (branching means) 10, and an XY biaxial galvanometer 4 and 5 and respective galvanometer mirrors. Guided to two sets of laser irradiators A and B having 4a and 5a and an fθ lens 6.

  The optical path lengths at which the laser beams 2a and 2b branched by the beam splitter 10 reach the focusing points by the fθ lenses 6 of the laser irradiation portions A and B are set to be the same distance.

  That is, the laser beam 2a branched by the beam splitter 10 is reflected by the reflecting mirrors 3b and 3c and incident on the galvano mirror 4a, and the laser beam 2b branched by the beam splitter 10 is reflected by the reflecting mirrors 3d, 3e and 3f. The optical path length incident on the galvano mirror 4a is the same length.

  By matching the optical path lengths in this way, the focused states of the laser beams 2a and 2b in the laser irradiation portions A and B are the same, and simultaneous processing on the two substrates 17 can be performed with high accuracy.

  The substrate 17 processed by the laser irradiation structure is held at a predetermined position of the XY table 19.

Since the processing range of the substrate 17 is wider than the scanning area of each laser irradiation part A, B, the processing range is divided into a plurality of parts as shown by the broken lines, and one processing range is obtained by scanning with each laser irradiation part A, B. When the processing is completed, the next processing range is moved below the laser irradiation units A and B by the XY table 19.
JP 11-192571 A

  In the configuration in which the traveling direction of the laser beam is changed by the optical component as in the conventional configuration described above, the optical component that transmits or reflects after the laser beam is incident cannot have 100% reflection or transmission. Some energy is consumed by optical components.

  In many cases, the reflecting optical component is coated to increase the reflectance in accordance with the wavelength of the laser beam, but it is damaged over time.

  If the optical parts are damaged in this way, the intensity of the laser beam on the workpiece decreases, and the desired processing result cannot be obtained. Therefore, the optical parts must be replaced, and the laser There was a problem that it took time to reset the optical parts such as adjusting the position of the light, and the line was stopped during that time, the cost of the optical parts and the work cost were high.

  In view of the above problems, the present invention provides a laser processing apparatus that can reduce replacement of optical components.

In order to solve the above problems, a laser processing apparatus of the present invention includes a laser oscillator, a plurality of optical means for changing the traveling direction of laser light emitted from the laser oscillator, and a laser beam whose traveling direction has been changed by the optical means. Positioning means for entering and positioning the laser beam to a processing position on the workpiece, and a holding unit for holding at least one of the optical means includes an optical axis of the laser light incident on the optical means and the optical Positioning means for positioning so as to be movable in a direction perpendicular to a plane determined by the optical axis of the laser beam whose traveling direction has been changed by the means, and a rotation mechanism for rotatably holding the optical means Is.

Since the laser processing apparatus of the present invention is configured as described above, when the laser light incident portion of the optical component is damaged, the optical component is rotated to immediately rotate the optical component without requiring resetting of the optical component. The parts that are not damaged can be used, and the frequency and work time for exchanging optical components can be reduced as compared with conventional ones.
In addition, since the laser processing apparatus of the present invention provides the correction method as described above, the optical means can be rotated in consideration of the output reduction of the laser oscillator and the presence / absence of the positional deviation between the optical axis of the laser beam and the mask. It can be determined whether or not it is necessary.

  As described above, according to the present invention, at least one of the optical means is rotatably held, and the optical means is disposed at a position shifted from the rotation axis of the rotation with respect to the incident position of the laser beam. By providing the above, it is possible to reduce the frequency of exchanging optical components compared to the conventional one.

(Embodiment 1)
FIG. 1A is a diagram showing a part (not including positioning means) of an optical system arrangement of a laser processing apparatus (for example, a UV laser processing apparatus) in the first embodiment.

  Laser light emitted from a laser oscillator 101 (for example, a UV laser oscillator using a YAG laser) passes through a bend mirror 102, a bend mirror 103, a set of collimator lenses 104, a mask 105, and a half-wave plate 106. Then, the beam is split by the beam splitter 107. One of the branched laser beams is guided to the bend mirror 110 through the bend mirror 108 and the bend mirror 109. The remaining laser light is guided to the bend mirror 112 through the bend mirror 111.

FIG. 1B is a diagram showing a part (including positioning means) of the optical system arrangement of the laser processing apparatus in the first embodiment.
The optical paths are lowered downward by the bend mirrors 110 and 112 and guided to the processing table 115 via the Z1 axis and Z2 axis units 113 and 114 which are positioning means incorporating the galvanometer mirror and the fθ lens, respectively.
The processing apparatus operates under numerical control by a control unit (not shown). Data from the control unit is displayed on a processing device touch panel (not shown) provided outside the case. The operator inputs data to the processing apparatus touch panel according to the display content.
The bend mirrors 102 and 103 are both rotatably held and bend mirrors (hereinafter abbreviated as mirrors) that serve as optical means for changing the traveling direction of the laser light provided with a holding portion that shifts the rotation axis from the laser optical axis. The bend mirrors 108 to 112 are ordinary mirrors and have no mechanism for shifting the position.

  The bend mirrors 102 and 103 receive the light receiving position by rotation and linear movement according to a command from the control unit when it is recognized that the laser beam incident position (light receiving position) may be damaged as a result of the processing point output measurement. Can be shifted.

  As described above, the vent mirrors 102 and 103 can be rotated when the light receiving portion is damaged, and light can be received at a new position deviated from the rotation axis. Therefore, as long as an undamaged portion remains, It is unnecessary to replace the optical means with a new one.

  During automatic operation by the processing apparatus, the processing point output of the beam (with mask) used for processing is automatically measured about every 2 hours (at the end of processing of the workpiece being processed). When the measured value is 90% or less of the normal output, an alarm message “Processing point output is reduced. Processing of the remaining workpiece will be stopped.” Is displayed on the processing device touch panel, which is the display means. Stops the execution of the machining program automatically. The remaining unprocessed workpiece is not processed.

  Furthermore, since a soft key “processing point output measurement without mask (beam No. 8)” appears, the output is measured by pressing this soft key. When the ratio of the processing point output to the laser oscillator output (remaining in the history) has decreased by 10% or more from a certain point in the past, “optical component is dirty or damaged → mirror position movement” is displayed on the processing device touch panel. Note that the measurement time interval can be changed to another value.

  As described above, when the ratio of the intensity of the laser beam (the beam in use) on the workpiece to the laser oscillator output is equal to or less than a predetermined value, a message is displayed on the processing device touch panel, and the light receiving position of the optical means Can prompt change.

  Note that the processing device touch panel displays a message when the intensity of the laser beam on the workpiece is less than a predetermined value, not the ratio of the intensity of the laser beam (beam in use) on the workpiece to the laser oscillator output. It is also possible to prompt the user to change the light receiving position of the optical means.

  At the time of machining point output measurement, the measured value and the internal power monitor value of the laser oscillator (laser oscillator output) remain in the storage unit in the control unit as a history. At this time, the ratio of the machining point output to the laser oscillator output is calculated and remains in the history at the same time. When this ratio is reduced by 10% or more from a certain point in the past, “optical component is dirty or damaged → mirror position movement” is displayed on the processing device touch panel. A certain point in the past means a point in time when the processing point output shows a normal output at the beginning of delivery of the processing apparatus or cleaning / replacement of optical parts.

  When the laser oscillator output is reduced by 10% or more, “laser oscillator output reduced” is displayed on the processing device touch panel. When the processing point output of the beam in use (with mask) has decreased by more than 10% compared to a past point in time even though the laser oscillator output and the processing point output decrease without mask are not recognized, the “optical axis” -Relative positional deviation between masks "is displayed on the processing device touch panel.

  As described above, the measured values of the laser oscillator output and the machining point output with and without the mask remain in the history, and the cause of the decrease is estimated from the items that have been reduced and the items that have not been reduced when the output is reduced. It is possible to determine whether or not rotation is necessary.

  In the laser oscillator having no internal power monitoring function as described above for monitoring the laser oscillator output, a power sensor is installed in the vicinity of the beam exit. An air cylinder is provided that operates so as to be taken in and out at right angles to the optical path of the laser light near the laser oscillator. The power sensor is fixed to the air cylinder, and moves to the optical path to receive the laser beam when measuring the output of the laser oscillator. After the measurement is completed, the power sensor is removed from the optical path by the air cylinder. Thereafter, the machining point output without the mask is measured, and the ratio of the machining point output to the laser oscillator output is calculated. When this ratio is reduced by 10% or more from a certain point in the past, “optical component is dirty or damaged → mirror position movement” is displayed on the processing device touch panel.

  2A is a diagram showing rotation of the main body mirror 116 of the mirror 102 or 103 in the laser processing apparatus in the first embodiment, and FIG. 2B is a light receiving position in the laser processing apparatus in the first embodiment. It is a figure which shows a change means. The mirror main body 116 is fixed to a ring 117 with two male screws facing each other. The mirror holder 118 has eight female screws (equally spaced on the circumference) into which the male screws for fixing the mirror are screwed, and can be fixed at eight angles. A stage 119 is provided on the pedestal portion of the mirror holder and can be moved in the vertical direction. The optical axis is initially aligned at the center of the mirror, and then the stage 119 moves the mirror position up and down.

  The holder of the beam splitter 107 is provided with a ring-shaped member having a hollow portion where the laser beam of the beam splitter 107 can be branched as a center of the mat. Using the adjustment knob 120, even if the stage 119 is moved within the range where the optical axis does not deviate from the mirror, the optical axis does not deviate from the center of the mat fixed to the holder of the beam splitter 107 with respect to the vertical direction of the stage moving direction. Fine-tune the misalignment. It should be noted that operability is good when a linear guide with a servomotor is incorporated in the stage.

When the processing apparatus touch panel displays “dirt or damage on optical component → mirror position movement”, the mirror 102 closest to the oscillator is selected from the list of mirrors that can be moved. When the “Move Mirror Position” soft key is pressed, the mirror is linearly moved 3 mm above the stage (in a range where the optical path cannot be removed). (It is also possible to rotate the mirror with the rotation mechanism.)
Thereafter, the machining point output without the mask is measured. If the ratio to the laser oscillator output at this time does not change, the mirror is not soiled or damaged. However, if it shows a recovery tendency, dirt or damage exists at the light receiving position before the mirror movement.

  In this case, the mirror surface (reflection surface) is first cleaned, the mirror 102 is returned to the original position by the stage 119, and the processing point output without the mask is measured again. If the ratio with respect to the laser oscillator output at this time has recovered to the same level as when the mirror is moved, the contamination of the mirror has been removed.

There is damage that cannot be removed by cleaning if it is not much different from before cleaning. In this case, the attachment angle is shifted by 45 °, the damaged part is removed from the optical axis, the machining point output without the mask is measured, and it is confirmed that the ratio is equivalent to the laser oscillator output when the mirror is moved.
For optical components that can move the position without changing the optical axis, the above operations are performed in order from optical components that are highly likely to be damaged (the irradiation beam diameter is narrow or the light intensity is low), and the processing point output is Continue until the original level is restored. If the ratio to the laser oscillator output is within 1% compared to a certain point in the past, “Output has recovered. Workpiece processing can be resumed” is displayed on the processing device touch panel.
If the output is not fully recovered by continuing to the end, there is dirt or damage on other optical components without moving mechanism. In this case, a message “Other optical components are dirty or damaged” and a list of possible optical components are displayed on the processing device touch panel. Since these optical components cannot be used by moving their positions, they must be replaced if the machining point output does not recover even after cleaning.

  If the light receiving positions are damaged at all eight fixed angles of the mirror, the eight light receiving positions that are not damaged can be secured again by sliding the entire holder upward 3 mm (in a range where the optical path cannot be removed).

  The linear movement direction of the mirror by the stage may be within the reflection surface of the mirror (at 45 ° to the optical axis).

  When the mirror can be rotated at an arbitrary angle by the servo motor, the place where the light receiving position can be changed further increases. (Refer to FIG. 3.) Each mirror, which is a replacement part, is assigned a number for identification, and is called “mirror No. 1”. Numerical values are input to “diameter (vertical) direction movement amount” and “circumference (angle) direction movement amount” in “mirror No. 1 movement amount setting” displayed on the processing apparatus touch panel. Since the beam diameter is about 1 mm, it is sufficient that the amount of movement in the diameter (vertical) direction of the mirror is 3 mm. The amount of movement is approximately 3 times the beam diameter. The radial movement is performed within a range where the light receiving position is 80% of the effective diameter of the mirror.

Since the mirror and the optical axis form an angle of 45 °, the irradiation beam diameter spreads ^20.5 times in the circumferential direction. Therefore, the amount of movement in the circumferential direction (angle) is about 4 mm. When the moving direction of the mirror is horizontal, the moving amount in the horizontal direction is about 4 mm, and the moving amount in the circumferential direction (angle) is about 3 mm. When the radial movement amount is 3 mm and the circumferential movement amount is 4 mm for a mirror having a diameter of 2 inches, 103 light receiving positions including the center can be secured by one mirror.

  Mirror No. 1, the counter number displayed in the “Mirror No. 1 light receiving position” column of the screen increases by 1 each time the light receiving position is moved, and when it reaches 103, “Mirror No. 1 is time to replace” is displayed. To do. This counter is reset when the mirror is replaced. The number and amount of movement of the female screw for fixing the mirror may be set to appropriate values according to the size of the mirror and the beam irradiation diameter.

  As described above, the position where the optical means can receive light is managed by the number, and when the predetermined threshold value is reached, all the light receiving positions are damaged, so that the optical means is not removed from the laser processing apparatus and inspected. However, it becomes possible to prove that the replacement is necessary.

  Also, in the “mirror No. 1 movement amount setting”, the “diameter (vertical) direction movement amount” is not set, and a numerical value is input only in the “circumference (angle) direction movement amount”, and the mirror No. When the light receiving position of 1 is changed, mirror No. 1 is a unit of prime number of 360 ° or less excluding 2 °, 3 °, and 5 °, which is a divisor of 360 °. When 1 is rotated, the light receiving position can be efficiently selected without overlapping.

  The mirror can be rotated at an arbitrary angle by using the end face of the mirror fixing ring 117 as a worm wheel and meshing with the worm gear to rotate the gear side. It is also possible to control the angle by attaching a motor to the worm gear. Further, the mirror may be integrated with the rotor of the servo motor to control the angle.

  The structure for moving the light receiving position of the mirror as described above is mainly used in a portion where the beam diameter on the light receiving surface is thin, and is not necessarily used in a place where the beam diameter is large and the mirror is not damaged.

  This structure may be applied not only to the bend mirrors 102 and 103 but also to the half-wave plate 106 and the beam splitter 107. Since the beam splitter 107 has a wedge, when the mounting angle is changed or the beam splitter 107 is moved in the vertical direction, the optical axis on the transmitted light side of the beam splitter 107 needs to be readjusted.

  In the laser processing apparatus according to the first embodiment, the output of the laser oscillator is adjusted by the control DC current value, and an adjustment knob for adjusting the control DC current value inside the laser oscillator is provided. When “laser oscillator output reduction” is displayed, the control DC current value inside the laser oscillator is gradually increased with the adjustment knob, and adjustment is made so that the machining point output without the mask is restored to a past point in time. If the laser oscillator output is within 1% compared to a certain point in the past, it is judged that it has recovered, and the screen displays “Output has recovered. Workpiece processing can be resumed.”

  When “relative positional deviation between optical axis and mask” is displayed, the mask position is corrected. There are two types of mask position adjustment, the circumferential direction and the radial direction. The circumferential direction is adjusted by the angle of the servo motor of the mask changer. Initially, the machining point output is measured with a beam (beam used for machining) that has passed through the mask while moving in units of 0.1 °. When the machining point output is larger than the previous measurement value, the machining point output is moved by 0.1 ° in the same direction, and when it is smaller, the machining point output is measured and compared with the previous measurement value. This is repeated as long as the increasing trend continues. Measure at least 3 different angles. Since the peak is past when the measured value is lower than the previous measurement value, the relation of the machining point output to the angle is approximated by a quadratic curve, and the angle corresponding to the peak position is calculated from the approximation formula and set.

Here, the machining point output is measured and compared with the normal output value during machining. If the difference recovers to within 2%, the screen will display “Output is recovered. Machining of the workpiece can be resumed.” If it does not recover, radial adjustment is required. A servo motor that performs positioning in a direction perpendicular to the optical axis is moved horizontally along with the mask changer for adjustment. The movement is performed in units of 100 μm, and the position where the machining point output reaches a peak is determined and set in the same manner as described above. Here, the machining point output is measured, and it is confirmed that it has recovered to the normal output during machining.
When any of the mask positions is adjusted, the same adjustment is required for the remaining other masks. In this case, since the deviation with respect to the optical axis is considered to be substantially equal, adjustment time can be saved by correcting and setting the difference between the set values before and after the previous mask position adjustment (both in the circumferential direction and the radial direction). When the message “Output is restored. Machining of the workpiece can be resumed” appears, the output measurement value at this point can be registered as comparison reference data to be referred to in the subsequent output confirmation. Although the present embodiment is a biaxial machining apparatus, this structure can be adopted even with a uniaxial machining apparatus.

  According to the present invention, it is possible to provide an industrially useful laser processing apparatus and its correction method that can be maintained more easily than conventional ones, and maintenance costs can be reduced.

(A) The figure which shows a part of optical system arrangement | positioning (a positioning means is not included) in the laser processing apparatus in Embodiment 1 of this invention (b) Optical system arrangement | positioning of the laser processing apparatus in Embodiment 1 of this invention Figure showing a part (including positioning means) (A) The figure which shows the mirror main body of the laser processing apparatus in Embodiment 1 of this invention (b) The figure which shows the light-receiving position change means of the mirror of the laser processing apparatus in Embodiment 1 of this invention The figure which shows arrangement | positioning of the change place of the laser receiving position of the mirror in Embodiment 1 of this invention Diagram showing conventional laser processing equipment

Explanation of symbols

101 Laser oscillator 102, 103 Bend mirror (with linear movement mechanism and rotation mechanism)
104 Collimator lens 105 Mask (or mask changer)
106 half-wave plate 107 beam splitter 108-112 bend mirror 113 unit incorporating Z1-axis galvanometer mirror and fθ lens 114 unit incorporating Z2-axis galvanometer mirror and fθ lens 115 processing table 116 mirror body 117 mirror Fixing ring 118 Mirror holder 119 Stage 120 Adjustment knob for moving stage

Claims (9)

A laser oscillator, a plurality of optical means for changing the traveling direction of the laser light emitted from the laser oscillator, and the laser light whose traveling direction has been changed by the optical means is incident to position the laser light at a processing position on the workpiece. Positioning means for
A holding portion that holds at least one of the optical means is a plane determined by the optical axis of the laser light incident on the optical means and the optical axis of the laser light whose traveling direction is changed by the optical means. A laser processing apparatus comprising positioning means for positioning so as to be movable in a vertical direction and a rotating mechanism for holding the optical means rotatably . 2. The laser processing apparatus according to claim 1, further comprising display means for displaying an instruction to rotate the optical means when the intensity of the laser beam on the workpiece is not more than a predetermined value. Storage means for storing the intensity of the laser light emitted from the laser oscillator is provided, and the display means compares the value stored in the storage means with the intensity of the laser light on the workpiece and is a predetermined ratio or less. The laser processing apparatus according to claim 2, wherein an instruction for prompting the rotation of the optical means is displayed at a value of. A motor for rotating the optical means or a speed reducer incorporating the motor is provided in the holding portion, and a rotation angle control means for controlling a rotation angle of the optical means by the motor or the speed reducer incorporating the motor is provided. Item 4. The laser processing apparatus according to any one of Items 1 to 3. The laser processing apparatus according to claim 4, wherein a prime number of 360 ° or less excluding 2 °, 3 °, and 5 ° is selected as a rotation angle of the optical means by the rotation angle control means. 6. The laser processing apparatus according to claim 4, wherein the optical means is rotated by the rotation angle control means when the intensity of the laser beam on the workpiece is not more than a predetermined value. The rotation angle control means when the value stored in the storage means for storing the intensity of the laser light emitted from the laser oscillator and the intensity of the laser light on the workpiece are equal to or less than a predetermined ratio. The laser processing apparatus according to claim 6, wherein the optical means is rotated. A number-of-rotations storage means for storing the number of rotations of the optical means; a comparison section for comparing a value stored in the number-of-rotations storage means with a value of the number of rotations indicating the replacement timing of the optical means; and a signal from the comparison section The laser processing apparatus according to claim 1, further comprising a replacement instruction display unit that instructs replacement of the optical unit. The laser processing apparatus according to claim 8, wherein the display unit is used as the replacement instruction display unit.

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