JP4988168B2 - Laser processing equipment - Google Patents

Description

  The present invention relates to a laser processing apparatus that processes a workpiece such as a multilayer printed board or a ceramic plate (green sheet), and more particularly to a laser processing apparatus that repeatedly processes a plurality of workpieces of one lot.

  As a conventional laser processing apparatus, a holder holding a workpiece, a first drive mechanism for driving the holder in a planar XY direction, a laser oscillator, and a laser beam output from the laser oscillator are converged. An optical system that irradiates the workpiece, a second drive mechanism that drives the optical system to change the focal position of the laser beam with respect to the upper surface of the workpiece, and a plurality of at least a central portion and a peripheral portion of the upper surface of the workpiece A sensor for detecting the height of the part and a control unit for calculating the height of the entire upper surface of the workpiece by a detection signal from the sensor and driving the second drive mechanism based on the calculated value; And the laser processing can be performed by quickly correcting the shift of the focal position of the laser beam due to the warping of the workpiece (for example, see Patent Document 1).

  In addition, as another conventional laser processing apparatus, a galvano scanner for scanning laser light from a laser light source in a desired direction and an fθ lens for condensing the laser light from the galvano scanner on a predetermined same plane are provided. A laser head, means for supporting the laser head so as to be able to approach / separate the workpiece surface and move along the workpiece surface, and an interval between the laser head and the workpiece surface. A sensor for detecting the position of the laser processing head while controlling the position of the laser processing head based on the detection result of the sensor so that the laser processing head and the processing surface are at a predetermined interval. Laser processing, and the laser processing is performed while constantly monitoring the distance between the laser head and the processing surface with a sensor. Even if warpage or waviness, there is to precisely control the intensity of the laser beam irradiated on the processed surface, the spot diameter and the like (e.g., see Patent Document 2).

Japanese Patent Laid-Open No. 03-128186 Japanese Patent Laid-Open No. 06-262383

  However, in the conventional laser processing apparatus, the distance between each workpiece and the laser processing head is detected by a sensor, and the focal position of the laser beam or the position of the laser processing head is controlled based on the detected value. . Therefore, it takes time to detect the interval by the sensor, and there is a problem that the tact time of the entire laser processing becomes long.

  The present invention has been made in view of the above, and an object of the present invention is to obtain a laser processing apparatus that processes a plurality of workpieces of one lot that can shorten the tact time.

In order to solve the above-described problems and achieve the object, the laser processing apparatus of the present invention condenses the laser beam from the laser oscillator on a predetermined condensing scanning plane by a processing head that can be displaced in the Z-axis direction. , adsorbed is placed the light-concentrating scan plane XY table, a multilayer printed circuit board or ceramic board to match the processed surface of the same lot of work is identical concave convex surface to be processed workpiece In the laser processing apparatus that performs the processing, the distance sensor that measures the deviation in the Z-axis direction between the condensing scanning plane and the processing surface due to the unevenness of the processing surface, and the XY table are controlled to control the processing Measurement control means for performing deviation measurement processing for obtaining deviation measurement values of the distance sensor at a plurality of positions on the surface and storing the obtained deviation measurement values in a memory, and the work carried into the XY table When the first of the workpieces of the same lot is loaded, the measurement control means is instructed to perform the deviation measurement process, and then based on the deviation measurement value stored in the memory The first work is processed by controlling the processing head and the XY table so that the condensing scanning plane coincides with the processing surface, and the second and subsequent workpieces in the same lot are loaded. In some cases, the second head is controlled by controlling the processing head and the XY table so as to make the condensing scanning plane coincide with the processing surface based on the measured deviation value of the first workpiece stored in the memory. And an operation control means for performing subsequent machining of the workpiece.

  According to the present invention, when the second and subsequent workpieces of the same lot are loaded, the condensing scanning plane is made to coincide with the processing surface based on the measured deviation value of the first workpiece stored in the memory. Since the processing head and the XY table are controlled to process the second and subsequent workpieces, there is no need to measure the deviation between the processing surface and the condensing scanning plane at a plurality of locations of the second and subsequent workpieces. There is an effect that a laser processing apparatus capable of reducing the overall tact time can be obtained.

Embodiment.
Embodiments of a laser processing apparatus according to the present invention will be described below in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a schematic view of an embodiment of a laser processing apparatus according to the present invention, FIG. 2 is a flowchart showing a conventional whole-surface processing process of a workpiece, and FIG. 3A is a laser that passes through an fθ lens. FIG. 3B is a diagram illustrating a depth of focus of a laser beam, FIG. 3C is a diagram illustrating a mode of a shallow depth of focus of a laser beam, and FIG. FIG. 4 is a view showing a mode in which the scanning area of the laser beam is narrowed, FIG. 4 is a schematic view showing a control device of the laser processing apparatus, and FIG. 5A is a view showing a deviation measurement position on the workpiece. FIG. 5-2 is a diagram showing a memory storage mode of the deviation measurement position data and the deviation measurement value, and FIG. 5-3 is a diagram showing a mode in which the deviation measurement position is associated with the scanning area. 6-1 shows the relationship between the destination P point of the scanning area movement and the deviation measurement position. FIG. 6-2 is a diagram showing the Z-axis displacement amount of the machining head at the destination point P, FIG. 7 is a control flowchart of the laser machining apparatus of the present embodiment, and FIG. These are the figures which show the movement of the scanning area of a workpiece | work, and the Z-axis displacement of a process head.

  First, a hardware configuration of a laser processing apparatus and a method for drilling a workpiece W will be described with reference to FIG. Laser drilling is a processing method in which a hole is formed by irradiating a pulsed laser beam LB to a plate-like workpiece W such as a multilayer printed board or a ceramic plate (green sheet). The XY table 5 on which the workpiece W is placed / sucked is positioned at a predetermined position on the X axis / Y axis, and the laser beam LB is scanned in the X axis direction and the Y axis direction by a scanner such as the galvano scanner 2. The laser beam LB is irradiated onto the workpiece W whose processing surface is positioned on the condensing scanning surface 3a through the fθ lens 3 that condenses (focuses) the condensing scanning plane 3a in the predetermined scanning area SA. Then, the workpiece W is drilled.

  As shown in FIG. 1, the laser processing apparatus according to the embodiment includes an XY table 5 that places and sucks a workpiece W and moves the workpiece W in the X-axis direction and the Y-axis direction, and in the XY table 5 and the Z-axis direction. A laser oscillator 6 that is installed at a spaced position and oscillates a pulsed laser beam LB in the X-axis direction, a mirror 6a that causes the laser beam LB in the X-axis direction to enter the processing head 1 in the Z-axis direction, and the processing head 1 A galvano mirror 2 a that scans the laser beam LB incident in the Z-axis direction in the X-axis direction, a galvano mirror 2 b that scans the laser beam LB from the galvano mirror 2 a in the Y-axis direction, and the machining head 1. An fθ lens 3 that converges and focuses the laser beam LB from the galvano mirror 2b on the condensing scanning plane 3a, and a work surface of the workpiece W that is installed on the processing head 1 and A distance sensor 4 for measuring the Z axis direction displacement of the optical scanning plane 3a, and a. Galvano mirrors 2 a and 2 b constitute a galvano scanner 2.

  The processing head 1 can be displaced in the Z-axis direction in order to make the condensing scanning plane 3 a coincide with the processing surface of the workpiece W. In FIG. 1, a servo system for displacing the machining head 1 in the Z-axis direction is not shown. The distance sensor 4 is a contact-type distance sensor that measures the distance by extending the contact 4a and bringing it into contact with the workpiece W.

  Non-contact type distance sensors generally measure the distance by reflected laser light from the workpiece surface. However, in the case of multilayer printed boards and ceramic boards (green sheets), the surface is often a resin, and laser A contact-type distance sensor should be used because there is a risk of scratching when exposed to light.

  The scanning area SA is usually □ 50 mm (50 mm × 50 mm). On the other hand, the workpiece W is about 400 mm × 300 mm in the case of a multilayer printed circuit board, a ceramic board (green sheet), etc., and is wider than the scanning area SA. Therefore, in the scanning (scanning) by the galvano scanner 2, the range of the scanning area SA is obtained. Can only be processed inside. Therefore, the entire surface of the workpiece W is processed by moving the XY table 5 on which the workpiece W is placed by the distance (50 mm) of the scanning area SA in the X-axis direction and the Y-axis direction.

The conventional whole surface processing step of the workpiece W will be described with reference to the flowchart of FIG. In step S0, the workpiece W is carried in, placed on the XY table 5, and fixed by suction. Next, in step S0-1, a deviation between the work surface of the workpiece W and the condensing scanning plane 3a is measured at one point, and the processing head 1 is displaced in the Z-axis direction based on the measurement result, and the condensing scanning plane 3a Is matched with the work surface of the workpiece W. Next, in step S1-1, the XY table 5 is moved to move the scanning area SA of the workpiece W. Then, the laser drilling of the scan area SA ₁ by scanning the laser beam LB is performed by the galvanometer scanner 2 in step S1-2. By repeating the processing of steps S1-1 and S1-2 up to the final scanning area SAn (steps S2-1, S2-2,... Step Sn-1, Sn-2), the entire surface of the workpiece W is drilled. When the machining is completed, the suction of the workpiece W to the XY table 5 is finally released in step S100, and the workpiece W is carried out.

  As shown in FIG. 1, accurate drilling cannot be performed unless the condensing scanning plane 3 a is matched with the surface to be processed of the workpiece W. This is due to the depth of focus that occurs when the laser beam LB is condensed by the fθ lens 3. Drilling must be performed by matching the focal position (condensing scanning plane 3a) with the work surface of the workpiece W.

  FIG. 3A is a diagram illustrating an aspect of the laser beam LB scanned in the X-axis direction by the galvanometer mirror 2 a and passing through the fθ lens 3. Within the range of the scanning area SA, the focal point of the laser beam LB is focused on the condensing scanning plane 3a. However, as shown by a broken line in FIG. 3-2, a constant focal depth, that is, a range of the focal depth SY. Only the inside is a point where good drilling can be performed, and the focal depth SY becomes shallower as the laser beam LB enters obliquely toward the end of the scanning area SA.

  Note that the depth of focus SY differs depending on the material of the workpiece W. When the depth of focus is shallow, as shown in FIG. 3C, the P portion is out of the range of the depth of focus SY, and good drilling cannot be performed. Thus, when processing a material having a very small depth of focus SY, it is necessary to narrow the range of the scanning area SA as SA ′, as indicated by SA ′ in FIG. 3-4. In addition, since the laser beam LA is obliquely irradiated at the end of the scanning area SA, vertical drilling cannot be performed with a thick material, or the roundness of the processed hole does not satisfy the required value. It is also necessary to narrow the scanning area SA when drilling a thick material.

  Next, with reference to FIG. 4, the outline of the control apparatus of a laser processing apparatus is demonstrated. The control device controls the XY table 5 (and the distance sensor 4) to measure the deviation in the Z-axis direction between the work surface of the workpiece W and the condensing scanning plane 3a at a plurality of positions of the workpiece W, and obtain the deviation measurement value. The measurement control means 8 that performs the displacement measurement process that acquires and stores the acquired displacement measurement value in the memory M, the memory M that stores the displacement measurement position and the displacement measurement value, and the number of workpieces W carried into the XY table 5 When the first workpiece of the same lot is loaded, the measurement control means 9 is instructed to perform the deviation measurement process, and then the light is condensed based on the deviation measurement value stored in the memory M. The machining head 1 and the XY table 5 are controlled so that the scanning plane 3a coincides with the work surface of the workpiece W, the first workpiece W is machined, and the second and subsequent workpieces W of the same lot are loaded. Sometimes memory M Based on the stored displacement measurement value of the first workpiece W, the machining head 1 and the XY table 5 are controlled so that the condensing scanning plane 3a coincides with the workpiece surface of the workpiece W, and the second and subsequent workpieces W are controlled. The operation control means 8 etc. for performing the machining are provided.

  Next, with reference to FIG. 5A, detection of irregularities on the work surface of the workpiece W based on the measurement of the deviation in the Z-axis direction between the work surface of the workpiece W and the condensing scanning plane 3a by the measurement control means 9. A method of storing the Z-axis value ΔZ as a deviation measurement value in the memory M will be described. The measurement control means 9 lowers the contact 4a of the distance sensor 4 to bring the contact 4a into contact with the surface to be processed of the workpiece W, measures the descending amount of the contact 4a, and measures the condensing scanning plane 3a and the workpiece W. The deviation (Z-axis value ΔZ) from the work surface is measured. The XY table 5 is sequentially moved, and the Z-axis value ΔZ is measured at 15 shift measurement positions over the entire area of the workpiece W shown in FIG.

  As shown in FIG. 5B, the measured Z-axis value ΔZ associates the shift measurement position (# 1: A1 to # 15: C5) with the Z-axis value ΔZ (# 101 to # 115). And stored in the memory M of the control device. The deviation measurement position is stored in the deviation measurement position storage memory M1 of the memory M shown in FIG. 4, and the Z-axis value ΔZ is stored in the Z-axis value storage memory M2. Data A1 to C5 are binary data of (X1, Y1) to (X5, Y5). As shown in FIG. 5C, if the deviation measurement position is set to the center position of each scanning area SA, highly accurate measurement can be performed.

  When drilling the first workpiece W of the same lot, first, the Z-axis value ΔZ obtained by performing the above-described deviation measurement process is stored in the Z-axis value storage memory M2, and this Z-axis value data (deviation) Drilling of the first workpiece W by controlling the machining head 1 and the XY table 5 so that the condensing scanning plane 3a coincides with the workpiece surface of the workpiece W for each scanning area SA based on the measured value). When drilling from the second workpiece W to the last workpiece W in the same lot, each scanning area SA is determined based on the Z-axis value data of the first workpiece W in the Z-axis value storage memory M2. In addition, the machining head 1 and the XY table 5 are controlled so that the condensing scanning plane 3a coincides with the surface to be machined of the workpiece W to perform drilling.

  The reason why precise drilling can be performed as described above is that the workpiece W such as a multilayer printed board or a ceramic plate (green sheet) to be processed in the present embodiment is placed and sucked on the XY table 5. And the phenomenon that the workpiece W floats due to the heat effect at the time of processing hardly occurs, and the workpiece W of the same lot has the same manufacturing conditions and storage conditions. Based on the finding that they are almost identical.

  When the deviation measurement position is the center position of each scanning area SA as shown in FIG. 5C, the Z-axis value ΔZ at the deviation measurement position measured in advance with the first workpiece W of the same lot is the hole punching. Since it coincides with the scanning area movement position of the XY table 5 at the time of machining, the Z-axis value ΔZ may be used for the Z-axis positioning of the machining head 1 as it is.

  As shown in FIG. 5A, when the deviation measurement position does not correspond one-to-one with the scanning area position, the Z-axis value at the scanning area movement position of the XY table 5 is obtained from the Z-axis value data of the plurality of deviation measurement positions. It is necessary to obtain ΔZ.

  A method for obtaining the Z-axis value ΔZ at the scanning area moving position will be described with reference to FIG. FIG. 6A shows that the destination point P of the scanning area movement is located within the grid surrounded by the distance measurement positions B-1, B-2, C-1, and C-2 shown in FIG. FIG.

  First, from the XY coordinate data of the destination P point, it is specified whether the destination P point is located on a lattice point, on a lattice boundary line, or in a lattice. When located on a lattice point, the Z-axis value ΔZ of the lattice point is set as the Z-axis value of the destination P point, and when located on the lattice boundary line, Z of the two lattice points at both ends of the boundary line When the average value of the axis values ΔZ is set as the Z-axis value of the destination P point and is located in the grid as shown in FIG. 6A, the average value of the Z-axis values ΔZ of the four grid points (B-1 , B-2, C-1, and C-2) (average value of Z-axis values ΔZ) may be used as the Z-axis value of the destination P point.

  Assuming that the Z-axis value of the obtained destination P point is ΔZ, when the workpiece W is moved in the scanning area by the XY table 5, the machining head 1 is moved from the predetermined reference value L to the Z-axis value ΔZ as shown in FIG. Position it with only displacement. As a result, the condensing scanning plane 3a at the destination P point coincides with the surface to be processed of the workpiece W, and the scanning area SA in which the machining head 1 scans at the destination P point is within the depth of focus and is a good hole. Drilling can be performed.

  Next, with reference to a control flowchart of the laser processing apparatus by the operation control means 8 shown in FIG. 7, a description will be given of a processing step for repeatedly punching a plurality of workpieces W in the same lot. 7 is different from the flowchart of the conventional machining process of FIG. 2 in that steps S101, S104, S105, and S106 are newly added.

  In step S0, the workpiece W is carried in, placed on the XY table 5, and fixed by suction. Next, the number of workpieces W loaded is counted by a counter in step S0-1. In step S102, it is determined whether or not the work W carried in is first. If the work W is first, the process proceeds to step S103, where the measurement control means 9 is instructed to collect and collect the work surfaces of the work W at a plurality of locations on the work W. The deviation in the Z-axis direction with respect to the optical scanning plane 3a is measured, the deviation measurement value (Z-axis value ΔZ) is stored in the memory M, and the process proceeds to step S1-1 ′.

  In step S1-1 ′, the XY table 5 is moved so that the condensing scanning plane 3a coincides with the first scanning area of the surface to be processed of the workpiece W in step 103, and the deviation measurement value stored in the memory M is obtained. Based on this, the machining head 1 is displaced (Z-axis correction). Proceeding to step S1-2, the galvano scanner 2 scans the laser beam LB to perform drilling in the first scanning area.

  Next, proceeding to step S2-1, the XY table 5 is moved so that the condensing scanning plane 3a coincides with the second scanning area of the surface to be processed of the workpiece W, and the deviation measurement value stored in the memory M is obtained. Based on this, the machining head 1 is displaced (Z-axis correction). Proceeding to step S2-2, the galvano scanner 2 scans the laser beam LB to drill the second scanning area.

  Thus, by repeating the processing of steps S1-1 ′ and S1-2 up to the last scanning area (steps S2-1 ′, S2-2,... Step Sn-1 ′, Sn-2), The entire surface of the first workpiece W is drilled, and when the processing of the first workpiece W is completed, the process proceeds to step S100, and the suction of the first workpiece W to the XY table 5 is released, and the first workpiece W is It is carried out.

  In step S104, it is determined whether or not the processed workpiece W is the last workpiece in one lot. If it is the last workpiece, the process advances to step S105 to determine whether there is a next lot. If not, the processing of one lot of the workpiece W is finished.

  Here, since step S104 is negative, the process returns to step S0, the second workpiece W is carried in, placed on the XY table 5, and fixed by suction. Next, in step S0-1, the number of workpieces W loaded (second) is counted. Since the workpiece W loaded in step S102 is the second, the process proceeds to step S1-1 ′.

  In step S1-1 ′, the XY table 5 is moved so that the condensing scanning plane 3a coincides with the first scanning area of the processing surface of the second workpiece W in step 103, and 1 stored in the memory M is stored. The machining head 1 is displaced based on the measured deviation value of the second workpiece W. Proceeding to step S1-2, the galvano scanner 2 scans the laser beam LB to perform drilling in the first scanning area.

  In this way, the second workpiece of one lot to the last workpiece of one lot are each processed by repeating the processing steps from step S0 to step S100. After the processing of step S100 for the last work of one lot, the process proceeds to step S104. Since this is the last work of one lot, the process proceeds to step S105. If there is a next lot, the process proceeds to step 106, and the counter is counted in step S106. Clear to "0", return to step S0, and repeat the machining steps from step S0 to step S100 to the last workpiece of the next lot. In this way, processing up to the last lot is performed. Since the deviation measurement processing is performed for each lot, even if the lot changes and the unevenness of the workpiece changes, the focal position of the laser beam LB (condensing scanning plane 3a) can be made to coincide with the work surface of the workpiece W. It is possible to perform a good drilling process over all the lots.

  After all, in the present embodiment, as shown in FIG. 8, in the machining process from the first workpiece to the last workpiece in one lot, the Z axis is moved along with the movement of the scanning area SA of the workpiece W by the XY table 5. Based on the Z-axis value ΔZ of the first workpiece W stored in the value storage memory M2, the Z-axis position of the machining head 1 is corrected, and the focal position of the laser beam LB (the condensing scanning plane 3a) is set to that of the workpiece W. A good drilling process can be performed in a short tact time by matching with the surface to be processed.

  In step S101 of the flowchart shown in FIG. 7, a considerable time is required because the distance sensor 4 measures the deviation of the workpiece W at a plurality of locations. When the distance sensor 4 is a contact sensor, it usually takes about 3 seconds to measure, so when measuring 15 points as shown in FIG. 5-1, approximately 3 seconds × 15 locations = about 45 seconds. It takes time. This time is not negligible considering that the processing time of one workpiece W is usually 2 to 3 minutes, but when processing 24 workpieces W per lot, it is the time required for only the first one. Therefore, in terms of the total tact time, the tact time is greatly reduced as compared with the case of measuring all 24 deviations.

  In the present embodiment, the workpiece W is a multilayer printed board or a green sheet, and the number of one lot is very large. The multilayer printed circuit board has a unit of 24 to 48 lots, and the green sheet has a unit of hundreds of lots, and the tact time can be greatly shortened with respect to processing by a conventional laser processing apparatus.

  As described above, in the present embodiment, the drilling process of the workpiece W has been described. However, the laser processing apparatus of the present invention can also be applied to laser precision cutting and the like.

  The laser processing apparatus of the present invention is suitable for drilling a workpiece having a large number of one lot such as a multilayer printed board or a green sheet.

It is the schematic of embodiment of the laser processing apparatus concerning this invention. It is a flowchart which shows the conventional whole surface processing process of a workpiece | work. It is a figure which shows the aspect of the laser beam which passed the f (theta) lens. It is a figure which shows the focal depth of a laser beam. It is a figure which shows an aspect with a shallow focal depth of a laser beam. It is a figure which shows the aspect which narrowed the scanning area of the laser beam. It is the schematic which shows the control apparatus of a laser processing apparatus. It is a figure which shows the shift | offset | difference measurement position on a workpiece | work. It is a figure which shows the memory storage aspect of deviation measurement position data and a Z-axis value. It is a figure which shows the aspect which matched the deviation | shift measurement position with the scanning area. It is a figure which shows the relationship between the destination P point of a scanning area movement, and a shift | offset | difference measurement position. It is a figure which shows the Z-axis displacement amount of the processing head in the destination P point. It is a control flowchart of the laser processing apparatus of this Embodiment. It is a figure which shows the movement of the scanning area of a workpiece | work, and the Z-axis displacement of a process head.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Processing head 2 Galvano scanner 3 f (theta) lens 3a Condensing scanning plane 4 Distance sensor 5 XY table 6 Laser oscillator 8 Operation control means 9 Measurement control means M Memory LB Laser beam W Workpiece

Claims (4)

The laser beam from the laser oscillator, the displaceable machining head in the Z-axis direction is converged to a predetermined light collecting scan plane, the adsorbed been placed on the condenser scan plane XY table, the multilayer printed circuit board or in a ceramic plate to match with the processing surface of the same lot of work is identical concave convex processed surface laser machining apparatus for machining a workpiece,
A distance sensor for measuring a deviation in the Z-axis direction between the condensing scanning plane and the processing surface due to unevenness of the processing surface;
Measurement control means for controlling the XY table to obtain deviation measurement values of the distance sensor at a plurality of locations on the work surface, and performing deviation measurement processing for storing the obtained deviation measurement values in a memory;
Count the number of workpieces that are loaded into the XY table, and when the first workpiece of the same lot is loaded, instruct the measurement control means to perform the deviation measurement process, Based on the stored deviation measurement value, the machining head and the XY table are controlled so that the condensing scanning plane coincides with the workpiece surface, and the first workpiece is machined. When the second and subsequent workpieces are carried in, the processing head and the processing head so as to make the condensing scanning plane coincide with the processing surface based on the deviation measurement value of the first workpiece stored in the memory. Operation control means for controlling the XY table to process the second and subsequent workpieces;
A laser processing apparatus comprising:   The laser processing apparatus according to claim 1, wherein the workpiece is processed for each scanning area by sequentially moving the scanning area.   The laser processing apparatus according to claim 2, wherein a deviation measurement in the Z-axis direction between the condensing scanning plane and the work surface of the workpiece is performed for each scanning area.   The laser processing apparatus according to claim 1, wherein the laser processing apparatus repeatedly processes a plurality of lots of workpieces.

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