Printing machine, surface mounter, and method for measuring warpage of substrate

Abstract

To reduce the time required to measure the warpage of a substrate.SOLUTION: A printing machine 11 includes a squeegee 39 that is movable in the Y direction, and a control device 50 that controls the squeegee 39. The control device 50 moves the squeegee 39 in the Y direction with the tip of the squeegee 39 in contact with the surface of the substrate or the surface of the mask, measures the warpage of the substrate, and outputs the result to a surface mounter 12.SELECTED DRAWING: Figure 16

Description

[Technical Field]

[0001] The present invention relates to a technique for measuring the warpage of a substrate. [Background technology]

[0002] In the mounting line, a printer prints solder paste on a board, then the board is transported to a surface mounter, which then mounts components on the printed board. The following Patent Documents 1 and 2 disclose technologies related to this mounting line. [Patent Document 1] JP 2014-19132 A [Patent Document 2] Japanese Patent Application Publication No. 9-70951 DISCLOSURE OF THE INVENTION [Problem to be solved by the invention]

[0003] If the board is warped, the mounting height of the components will change, so it is desirable to measure the warpage of the board using a surface mounter before mounting the components. Also, from the perspective of production efficiency, there is a demand to shorten the time required to measure the warpage.

[0004] An object of the present invention is to measure the warpage of a board using a printing machine and to utilize the results in a surface mount machine, thereby shortening the time required for warpage measurement. [Means for solving the problem]

[0005] (1) A printing machine of the present invention includes a squeegee that can move in the Y direction and a control device that controls the squeegee. The control device moves the squeegee in the Y direction with the tip of the squeegee in contact with the surface of the substrate or the surface of the mask, measures the warpage of the substrate, and outputs the results to a surface mounter. In the printing machine described in (1), any configuration other than the above is optional and may be used.

[0006] The configuration (1) measures the warpage of the board using a printing machine and the results can be used in the surface mount machine, which contributes to shortening the time required to measure the warpage of the board using a surface mount machine.

[0007] (2) In the printing press described in (1), the control device may measure the warpage of the substrate during the printing cycle for one substrate. The configuration of (2) can measure the warpage for each substrate, thereby obtaining highly accurate results.

[0008] (3) In the printing press described in (1), the control device may measure the warpage of the substrate during setup work associated with changing the type of the substrate. The configuration of (3) is less affected by takt time. In addition, measurement can be performed without a mask, which has the advantage of allowing accurate measurement of warpage without being affected by pressure from a mask.

[0009] (4) In the printing press described in any one of (1) to (3), the control device may measure the warpage of the substrate based on measurement data of the squeegee, which changes depending on the warpage of the substrate.

[0010] (5) In the printing press described in (4), the measurement data of the squeegee may be the contact pressure of the squeegee. The contact pressure of the squeegee can be measured by a pressure measuring device such as a load cell. The contact pressure of the squeegee can also be substituted by the motor current of a motor that controls the position in the Z direction. The motor current can be measured by a current sensor or the like.

[0011] (6) In the printing press described in (5), the control device may fix the position of the squeegee in the Z direction when moving the squeegee in the Y direction. Fixing the position of the squeegee in the Z direction makes it easier to detect changes in squeegee contact pressure and changes in motor current. Note that even if the position of the squeegee in the Z direction is not fixed, the position of the squeegee in the Z direction does not necessarily have to be fixed as long as changes in squeegee contact pressure and changes in motor current corresponding to warpage of the substrate can be detected.

[0012] (7) In the printing press described in (4) or (5), the control device may reciprocate the squeegee in the Y direction and measure the maximum point at which the change in the measurement data of the squeegee is greatest for each of the forward and backward passes. The Y coordinate of the midpoint between the maximum points of displacement on the forward and backward passes may be set as the Y coordinate at which the warpage of the substrate is maximum. The configuration of (7) can accurately determine the Y coordinate (Y position) of the substrate at which the warpage is maximum.

[0013] (8) In the printing press described in (4) or (5), the control device may move the squeegee only in the forward direction in the Y direction to measure the maximum point where the change in the measurement data of the squeegee is greatest. A predetermined offset value may be added to the Y coordinate of the measured maximum point to determine the Y coordinate where the warpage of the substrate is maximum. The predetermined offset value may be a design value or a measured value measured in advance by moving the squeegee back and forth. The configuration of (8) can shorten the warpage measurement time in the printing press and suppress the impact on the takt time.

[0014] (9) A surface mounter located downstream of any of the printers described in (1) to (8) includes a head unit and a control device. The head unit includes a laser measuring device that measures the height of measurement points on the substrate, and a mounting head that mounts components on the substrate. The control device reduces some of the measurement points on the substrate measured by the laser measuring device based on the warpage of the substrate measured by the printer. In the surface mounter described in (9), any configuration other than the above is optional and may be used. The configuration of (9) can shorten the warpage measurement time and cycle time of the surface mounter by reducing some of the measurement points.

[0015] (10) In the surface mounter described in (9), the control device may determine the number of rows of measurement points to be deleted depending on the level of warpage of the board measured by the printing machine. The configuration of (10) makes it possible to achieve both a long warpage measurement time and high measurement accuracy.

[0016] (11) In the surface mounter according to (9) or (10), the control device may correct the mounting height of the component on the board based on the measurement results of the measurement points that were not deleted. The configuration of (11) can improve the accuracy of mounting components on the board.

[0017] (12) A surface mounter located downstream of any of the printers described in (1) to (8) includes a head unit and a control device. The head unit includes a mounting head that mounts components on the board. The control device corrects the mounting height of the components relative to the board based on the warpage of the board measured by the printer. In the surface mounter described in (12), any configuration other than the above is optional and may be any configuration. The configuration of (12) can correct the mounting height of the components due to the warpage of the board even if the surface mounter does not include a laser measuring device.

[0018] The above series of techniques can be applied to categories of methods. [Effects of the Invention]

[0019] According to the present invention, the warpage of the board can be measured by the printing machine. The results can also be used in the subsequent surface mounting machine, thereby shortening the takt time. [Brief explanation of the drawings]

[0020] [Figure 1] Mounting line configuration diagram [Figure 2] Perspective view of a printing press [Figure 3] Perspective view of a printing press [Figure 4] Diagram showing the structure of the squeegee unit [Figure 5] Diagram showing the structure of the print table [Figure 6] Printing operation diagram [Figure 7] Block showing the electrical configuration of the mounting line [Figure 8] Plan view of surface mounter [Figure 9]Diagram showing the head unit support structure [Figure 10] Diagram showing how a laser measuring device measures the warpage of a board [Figure 11] Diagram showing the relationship between board warpage and component mounting height [Figure 12] Print Cycle Flowchart [Figure 13] Flowchart of setup work for product changeover [Figure 14] Diagram showing the operation of measuring the warpage of a board on a printing press [Figure 15] Diagram showing the operation of measuring the warpage of a board on a printing press [Figure 16] Graph showing pressure changes in the load cell [Figure 17] Graph showing pressure changes in the load cell [Figure 18] Graph showing pressure changes in the load cell [Figure 19] Graph showing pressure changes in the load cell [Figure 20] Graph showing pressure changes in the load cell [Figure 21] Graph showing pressure changes in the load cell [Figure 22] Plan view of the substrate PX [Figure 23] Diagram showing the relationship between the amount of warping and the number of rows to be removed [Figure 24] Flowchart for warpage measurement [Figure 25] Diagram showing S64 processing BEST MODE FOR CARRYING OUT THE INVENTION

[0021] <Embodiment> 1. Mounting line description 1 is a line configuration diagram of a mounting line 10. The mounting line 10 is a line that mounts components E on boards PX. A production management device 15 is a management device for the mounting line 10.

[0022] The mounting line 10 is equipped with a printing machine 11, a surface mounter 12, an inspection machine 13, and a reflow machine 14. The machines 11 to 14 are connected in series via conveyors, and the board PX is transported between the machines in the X direction (the left-right direction in FIG. 1) in order, while performing predetermined operations (printing ⇒ component mounting ⇒ inspection ⇒ reflow).

[0023] The devices 11 to 14 on the mounting line 10 are connected to each other via a LAN (local area network), allowing communication between the devices. The production management device 15 is also connected to the LAN, allowing communication with the devices 11 to 14.

[0024] Hereinafter, the transport direction of the substrate PX is referred to as the X direction, and the direction perpendicular to that (the movement direction of the squeegee 39) is referred to as the Y direction. The up-down direction is referred to as the Z direction. Furthermore, upstream and downstream refer to the flow of the substrate PX on the mounting line 10, and in this embodiment, the right side of FIG. 1 is upstream and the left side of FIG. 1 is downstream. As an example, the substrate PX is a rectangle with two sides in the X direction and Y direction.

[0025] 2. Description of the printing machine The printer 11 is a device that prints solder paste onto the substrate PX.

[0026] As shown in FIG. 2, the printing machine 11 includes a base (not shown), a pair of support walls 21 and 22, a mask holder 23, a mask clamp 24, a mask 25, a slide base 26, a squeegee unit 27, a linear guide 28, and a Y-axis moving device 29.

[0027] The pair of support walls 21, 22 are located on both sides of a base (not shown) in the X direction and extend parallel to the Y direction.

[0028] The mask holder 23 is attached to the inner surface of the pair of support walls 21 and 22. The mask holder 23 is a rail with an L-shaped cross section. The mask 25 can be fixed by setting the mask 25 on the mask holder 23 and clamping it with the mask clamp 24.

[0029] Furthermore, by releasing the mask clamp 24, the mask 25 can be removed from the mask holder 23 and replaced, as shown in FIG.

[0030] The mask 25 includes a frame-shaped mask frame 25A and a thin plate-shaped stencil (mask sheet) 25B. The stencil 25B is attached to the bottom surface of the mask frame 25A via a tensioner made of an elastic material such as rubber. The stencil 25B is made of, for example, stainless steel, and has openings (not shown) formed therein that correspond to the pattern of solder paste to be printed on the substrate PX.

[0031] The slide base 26 is elongated in the X direction, and has a squeegee unit 27 attached to its center in the X direction. The slide base 26 is supported by a pair of support walls 21 and 22 via linear guides 28, and the slide base 26 and the squeegee unit 27 are capable of reciprocating in the Y direction.

[0032] The Y-axis moving device 29 is a device that moves the slide base 26 and the squeegee unit 27 back and forth in the Y direction. In this embodiment, the Y-axis moving device 29 is made up of a ball screw mechanism 31 and a Y-axis motor 32.

[0033] 4, the squeegee unit 27 is made up of a support base 35, an elevator 36, a movable member 37, an arm 38, a squeegee 39, and a load cell 40. The support base 35 supports the movable member 37 so that it can move up and down.

[0034] A squeegee 39 is attached to the movable member 37 via an arm 38. The squeegee 39 is a plate-shaped member that is long in the X direction. To provide the squeegee 39 with appropriate elasticity, it can be made of a polymer material such as urethane rubber, polyacetal, polyethylene, or polyester. The squeegee 39 is not limited to a polymer material and can also be made of metal. The squeegee 39 is rotatable around an axis O and can be rotated in reverse.

[0035] 4, the lifting device 36 is a device that moves a movable member 37, an arm 38, and a squeegee 39 up and down. In this embodiment, the lifting device 36 is configured by a ball screw mechanism 41 and a Z-axis motor 42. The lifting device 36 is not limited to the above configuration, and may be substituted by a linear motor or the like.

[0036] The load cell 40 is a pressure measuring device that measures the contact pressure of the squeegee 39 against the mask 25 when printing. In this example, the load cell 40 is placed between the movable member 37 and the arm 38. The load cell 40 only needs to be able to measure the contact pressure of the squeegee 39, so it may be placed in another location.

[0037] 3, the printing machine 11 has a printing table 43. The printing table 43 is a table that holds the substrate PX to be processed, and is located below the mask.

[0038] As shown in FIG. 5, the printing table 43 has a support base 44, a lifting base 45, a rail guide 46, a clamp plate 47, a push-up unit 48, and the like.

[0039] The lifting base 45 can be raised and lowered relative to the support base 44. The rail guides 46 are located on the lifting base 45 and are positioned facing each other in the Y direction. A conveyor 49 for transporting the substrate PX is installed on the inner surface of the rail guide 46.

[0040] The clamp plate 47 is attached to the upper part of the rail guide 46, and clamps and fixes the substrate PX that has been carried onto the lift base 45 from both sides in the Y direction.

[0041] The push-up unit 48 is located on the lifting base 45 and between the rail guides 46. The push-up unit 48 is a device that supports the lower surface of the substrate PX during printing. In this embodiment, the push-up unit 48 is made up of push-up pins 48A and a push-up base 48B that can be raised and lowered.

[0042] As shown in FIG. 5, by lifting the lift base 45, the substrate PX supported from below by the push-up unit 48 can be lifted and brought into close contact (mounted) with the lower surface of the mask.

[0043] From this state, by moving the squeegee 39 back and forth in the Y direction, as shown in FIG. 6, the solder paste can be printed onto the substrate PX on the printing table.

[0044] 7 is a block diagram showing the electrical configuration of the mounting line 10. The printing machine 11 is equipped with a control device 50, a Y-axis motor 32, a Z-axis motor 42, a load cell 40, an inspection camera, sensors, etc. The sensors include a current sensor that measures the current of the Y-axis motor 32 and a current sensor that measures the current of the Z-axis motor 42. The sensors also include an encoder that detects the rotation of these motors 32, 42. The control device 50 is equipped with a CPU 51 and a memory 52.

[0045] The control device 50 controls the Y-axis motor 32 and the Z-axis motor 42 in accordance with a printing program recorded in the memory 52, and executes a printing process on the substrate PX. In addition, before printing, the control device 50 executes a warpage measurement process on the substrate PX (details of this process will be described later).

[0046] 3. Explanation of surface mounter The surface mounter 12 is located downstream of the printer 11. The surface mounter 12 is a device that mounts components E onto the printed board PX. There may be one or more surface mounters 12, and in this embodiment, the line configuration has three surface mounters 12 arranged in series.

[0047] As shown in FIGS. 8 and 9, the surface mounter 12 includes a base 61, a transport conveyor 62, a head unit 63, and a drive device 64.

[0048] The transfer conveyor 62 is disposed in the center of the base 61. The transfer conveyor 62 is provided with a pair of transfer belts 65, and transfers the substrate PX in the X direction.

[0049] A large number of feeders F for supplying components E are arranged side by side on the base 61 so as to surround a work position in the center of the base. The components E are electronic components such as resistors and capacitors.

[0050] At the work position in the center of the base, a mounting process is performed by the head unit 63 to mount the components E supplied by the feeder F onto the substrate PX.

[0051] The driving device 64 is a device that moves the head unit 63 in a planar direction (X and Y directions) on the base 61. The driving device 64 is composed of a Y-axis ball screw 66, a Y-axis motor 67, an X-axis ball screw 68, and an X-axis motor 69.

[0052] By driving the Y-axis motor 67, the X-beam 70 and the head unit 63 can be moved in the Y direction along the guide rails 71 (Y-axis servo mechanism).

[0053] By driving the X-axis motor 69, the head unit 63 can be moved in the X direction relative to the X-beam 70 (X-axis servo mechanism).

[0054] 9, the head unit 63 is equipped with a plurality of mounting heads 78. The mounting heads 78 are configured to be able to move up and down independently of the head unit 63 by a linear motion mechanism (for example, a screw mechanism) using a Z-axis motor 72 as a drive source.

[0055] A negative pressure is supplied to the mounting head 78 from a negative pressure means (not shown), which generates a suction force at the tip of the head. The mounting head 78 can hold the component E by using the negative pressure.

[0056] The head unit 63 is also equipped with a board recognition camera 73 and a laser measurement device 74. The board recognition camera 73 is fixed to the head unit 63 with its imaging surface facing downward. The laser measurement device 74 is also fixed to the head unit 63 with its measurement surface facing downward. As shown in Fig. 10, the laser measurement device 74 measures the distance to the object by emitting laser light to the object and receiving the reflected light.

[0057] The substrate recognition camera 73 and laser measuring device 74 can be moved to any position on the substrate PX together with the head unit 63, making it possible for the substrate recognition camera 73 to photograph the substrate surface and for the laser measuring device 74 to measure the height of the substrate surface.

[0058] 7, the surface mounter 12 includes a control device 75, an X-axis motor 69, a Y-axis motor 67, a Z-axis motor 72, a board recognition camera 73, and a laser measuring device 74. The control device 75 includes a CPU 76 and a memory 77. The control device 75 controls the X-axis motor 69, the Y-axis motor 67, and the Z-axis motor 72 in accordance with a mounting program recorded in the memory 77, and executes the process of mounting a component E on a board PX.

[0059] The inspection machine 13 is located downstream of the surface mounter 12. The inspection machine 13 is a device that inspects the board PX on which the components E are mounted before the board PX is input into the reflow device .

[0060] The reflow device 14 is a device that heats the inspected substrate PX and melts the solder paste, thereby soldering the substrate PX and the component E together.

[0061] 2. Measuring the warpage of the PX board 11 is a diagram showing a support structure for the substrate PX that has been brought into the working position of the base 61. Reference numeral 81 in FIG. 11 denotes a rail guide, and reference numeral 82 denotes a push-up pin that supports the substrate. If there is no warping, the upper surface of the substrate PX will be substantially flush with the upper surface 81A of the rail guide 81.

[0062] If the substrate PX is warped (curved), the height position of the substrate upper surface changes, which in turn changes the mounting height H of the component E. Therefore, the surface mounter 12 performs laser measurement of the warpage of the substrate PX, and adjusts the mounting height H of the component E relative to the substrate PX according to the warpage of the substrate PX.

[0063] However, to identify the warpage of the substrate PX, it is necessary to measure the heights of a plurality of measurement points M on the substrate using a laser, which takes time and leads to tact loss.

[0064] In this embodiment, the printer 11 uses a squeegee 39 to measure the warpage of the substrate PX, and outputs the results to the surface mounter 12 at the subsequent stage.

[0065] The surface mount machine 12 can utilize the measurement results of the printer 11, thereby shortening the time required to measure the warpage of the board PX. Furthermore, although this is not intended to be a restrictive interpretation, when there is a margin in the takt time of the printer 11 in terms of line balance, measuring the warpage on the printer 11 is particularly advantageous because it has little or no effect on the takt time of the entire line.

[0066] The warpage measurement of the substrate PX can be performed during a printing cycle or during a product type changeover operation by the printing machine 11. Fig. 12 shows a flow for measuring the warpage of the substrate PX during a printing cycle, and Fig. 13 shows a flow for measuring the warpage of the substrate PX during a product type changeover operation.

[0067] <Print cycle flow> A printing cycle is a cycle in which printing is performed on one substrate PX, and as shown in Fig. 12, it consists of six steps: substrate loading in S11, substrate fixation in S12, warpage measurement operation in S13, printing operation in S14, substrate release in S15, and substrate unloading in S16, with the warpage measurement operation in S13 being performed before the printing operation in S14. This flow has the advantage that warpage can be measured for each substrate PX. The printing cycle from S11 to S16 is an example, and is not necessarily limited to the example embodiment as long as it includes the warpage measurement operation in S13. For example, it may include other steps.

[0068] <Flow during product type changeover> The product type changeover work is a work (setup work) that is performed when changing the product type of the substrate PX, and is composed of six steps, as shown in Fig. 13: the push-up pin replacement work in S21, the conveyor width change work in S22, the substrate PX loading in S23, the substrate PX fixing work in S24, the warpage measurement operation in S25, and the mask clamping operation in S26. In this example, the warpage measurement operation in S25 is performed before the mask clamping in S26.

[0069] This flow has the advantage that the warpage measurement operation of the substrate PX is not performed during the printing cycle, so there is no or only a small decrease in the tact time of the printing machine 11. Another advantage is that, as shown in FIG. 3, the warpage measurement of the substrate PX can be performed without the mask 25. The disadvantage is that after the setup work, the warpage is measured as a representative of the substrate PX to be printed first, and the warpage of the second and subsequent substrates PX is not measured. The setup work of S21 to S26 is one example, and as long as the warpage measurement operation of S25 is included, the process is not necessarily limited to the example of the embodiment. For example, some steps may be omitted, or other steps may be included.

[0070] <Measurement of warpage of substrate PX> The measurement of the warpage of the substrate PX is made up of four steps (1) to (4). Figure 14 shows the movement of the squeegee 39 in each step. The load cell 40 measures the contact pressure of the squeegee 39.

[0071] (1) The control device 75 lowers the squeegee 39 at the position of one of the clamp plates 47A, and stops the lowering of the squeegee 39 when the value of the load cell 40 reaches a designated pressure. The designated pressure is, for example, a pressure slightly weaker than the printing pressure (contact pressure during printing). (2) The control device 75 fixes the position in the Z direction, moves the squeegee 39 in the Y direction while keeping it in contact with the surface of the substrate to be measured, and measures the pressure P of the squeegee 39 with the load cell 40. (3) When the squeegee 39 reaches the other clamp plate 47B, the control device 75 raises the squeegee 39 once and reverses it. After that, the control device 75 lowers the squeegee 39 again at the position of the other clamp plate 47B, and stops the lowering of the squeegee 39 when the load cell 40 reaches the specified pressure. (4) The control device 75 then fixes the position in the Z direction, moves the squeegee 39 in the Y direction while keeping it in contact with the surface of the substrate to be measured, and measures the pressure P of the squeegee 39 with the load cell 40.

[0072] When the mask 25 is attached, the substrate PX to be measured is brought into close contact with the lower surface of the mask as shown in FIG. 15, and measurements (1) to (4) are carried out on the mask 25.

[0073] 16 and 17 are graphs showing the change in pressure of the load cell 40 when the squeegee 39 is moved back and forth. The vertical axis shows the pressure value [N] of the load cell 40, and the horizontal axis shows the Y coordinate of the tip position of the squeegee 39. P1 is the pressure value at the start of squeegee movement, and P2 is the pressure value at the end of squeegee movement. The line connecting P1 and P2 is the reference pressure line K of the load cell 40. P3 is the point farthest from the reference pressure line K, that is, the maximum pressure point of the load cell 40.

[0074] The greater the warp (upward convex warp) of the substrate PX, the stronger the reaction force of the substrate PX against the squeegee 39. Therefore, the greater the warp of the substrate PX, the greater the pressure change of the load cell 40. Therefore, the Y coordinate (position in the Y direction) of the substrate PX where the warp is maximum can be detected from the Y coordinate of the maximum pressure point P3 of the load cell 40. Furthermore, the maximum warp amount ΔZ of the substrate PX can be detected from the distance (pressure change amount ΔP) of the maximum pressure point P3 from the reference pressure line K.

[0075] The amount of warpage ΔZ is the amount of displacement of the substrate surface in the Z direction, with the case where there is no warpage as the reference. In the above example, the measurement is performed with the height of the squeegee 39 fixed, but the height of the squeegee 39 may not be fixed as long as the warpage of the substrate PX can be detected as a pressure change of the load cell 40.

[0076] Furthermore, the relationship between the pressure change amount ΔP of the load cell 40 and the warpage amount ΔZ of the substrate PX may differ depending on the material, size, and thickness of the substrate PX. In such cases, a table using these as parameters may be created in advance, and the maximum pressure change amount ΔP may be referenced in the table to detect the warpage amount ΔZ of the substrate PX.

[0077] As shown in Figure 18, there are cases where the pressure change on the outbound path (solid line) does not match the pressure change on the return path (dashed line). In this case, the Y coordinate of the substrate PX at which the warpage is maximum can be calculated from the Y coordinate of the midpoint P3C between the maximum pressure points P3A and P3B on the outbound and return paths. In addition, the maximum warpage ΔZ of the substrate PX can be calculated by calculating the distance (pressure change ΔP) of the midpoint P3C from the reference pressure line K.

[0078] Furthermore, when the printing table 43 is tilted, the reference pressure line K is also tilted, as shown in Figure 19. KA is the reference pressure line on the outgoing path, and KB is the reference pressure line on the return path.

[0079] In this case, the points farthest from the reference pressure lines KA and KB on the outbound path (solid line) and return path (dashed line) are set as maximum pressure points P3A and P3B. Then, the Y coordinate of the substrate PX at which the warpage is maximum can be calculated from the Y coordinate P3C(Y) of the midpoint between the two maximum pressure points P3A and P3B.

[0080] Furthermore, the maximum warpage ΔZ of the substrate PX can be calculated from the average value of the pressure change ΔPA at the maximum pressure point P3A on the outward path and the pressure change ΔPB at the maximum pressure point P3B on the backward path.

[0081] 20, when the squeegee 39 moves only on the outward path, the pressure change amount ΔPA at the maximum pressure point P3A on the outward path is used as is, and the maximum warpage amount ΔZ of the substrate PX is found from the pressure change amount ΔPA. In addition, the Y coordinate of the substrate PX where the warpage is maximum can be found by one of the following methods.

[0082] (1) The Y coordinate of the maximum pressure point P3A on the outward path is adopted as it is and is set as the Y coordinate of the substrate PX where the warp is maximum. (2) The maximum pressure points P3A and P3B are measured in advance for the forward and backward passes, and the offset value in the Y direction is calculated from the midpoint P3C between the two maximum pressure points P3A and P3B. The offset value is then added to the Y coordinate of the maximum pressure point P3A on the forward pass, and this coordinate is used as the Y coordinate of the substrate PX where the warpage is maximum. The offset value is the deviation of the maximum pressure point P3A in the Y direction from the midpoint P3C, and is shown as the dimension α in Figure 19.

[0083] The graph in Fig. 21 shows the pressure change (change in contact pressure of the squeegee 39) of the load cell 40 measured when the squeegee 39 was moved back and forth on a transparent mask at a contact pressure of 3 [N] for an upwardly warped substrate PX. LA indicates the pressure change on the outward path, and LB indicates the pressure change on the return path.

[0084] From this result, it was confirmed that warpage of the substrate PX causes a change in pressure of the load cell 40 (a change in the contact pressure of the squeegee 39). The contact pressure of the squeegee 39 is an example of "measurement data of the squeegee" in the present invention.

[0085] 3. Reduction of laser measurement points in surface mounter 12 By using the measurement results (pressure changes of the load cell 40) from the printing machine 11, the tendency of warping of the substrate PX can be grasped, and therefore it is possible to reduce the number of measurement points M by the laser measuring instrument 74. Specifically, what can be detected from the pressure changes of the load cell 40 is the tendency of warping in the Y direction, and it is possible to reduce the number of measurement points M in the Y direction.

[0086] FIG. 22 is a plan view of the substrate PX, where (A) shows the measurement point M before removal, and (B) shows the measurement point M after removal.

[0087] In this example, two rows of measurement points M at both ends in the Y direction and one row (the central row) of measurement points M near the Y coordinate where the warp of the substrate PX is maximum are left, and the other measurement points M are deleted. Specifically, two rows on each side are deleted, with the row near the Y coordinate as the boundary.

[0088] The number N of rows to be removed may be determined according to the level of warpage of the substrate PX, for example, the number may be reduced as the warpage increases (see FIG. 23).

[0089] 24 is a flowchart relating to measurement of warpage of a substrate PX. Here, a case where warpage measurement is performed for each substrate PX will be described.

[0090] <Processing on Printing Machine 11 side> During the printing cycle, the control device 50 uses the squeegee 39 to measure the warpage of the substrate PX (S51). Then, based on the measurement results, the control device 50 calculates the Y coordinate at which the warpage of the substrate PX is maximum (S52), and further calculates the maximum warpage amount ΔZ (S53).

[0091] Thereafter, the control device 50 outputs the calculated warpage information to the surface mounter 12 by communication via the LAN (S55). The warpage information includes the Y coordinate at which the warpage of the board PX is maximum and the maximum warpage amount ΔZ.

[0092] After outputting the warpage information, the control device 50 prints solder paste on the board PX after the warpage measurement. After printing is completed, the board PX is sent to the surface mounter 12.

[0093] <Processing on the surface mounter 12 side> The control device 75 starts the warpage measurement sequence when the substrate PX is carried in from the printing machine 11. Specifically, the control device 75 calculates measurement points M to be deleted from the warpage information from the printing machine 11 (S61).

[0094] Then, the height of the measurement points M after removal is measured by the laser measuring device 74 (S62). In the example of Fig. 22, the measurement points M in two rows at both ends in the Y direction and in one row in the center are measured.

[0095] After the measurement, the control device 75 determines whether the tendency of the warpage of the substrate PX measured by the laser measuring device 74 matches the measurement result of the printing machine 11 (S63).

[0096] If they match (YES), the measurement results of the printing press 11 can be determined to be highly reliable, and if they do not match (NO), the measurement results of the printing press 11 can be determined to be unreliable.

[0097] If it is determined that the reliability is high, the process proceeds to S64, where a process for selecting a method for calculating the warpage of the board PX is performed. Three patterns (1) to (3) are prepared for calculating the warpage (see FIG. 25). The mounting point is the mounting point of the component E.

[0098] (1) The warpage measurement results (measurement results of S62) by the surface mounter 12 are used, and interpolation or the like is performed to calculate the warpage (surface height) at each mounting point on the board PX.

[0099] (2) The warpage measurement results (measurement results of S51) from the printing machine 11 are used, and interpolation or the like is performed to calculate the warpage (surface height) at each mounting point on the substrate PX.

[0100] (3) The measurement result of the printing machine 11 (measurement result of S51) is corrected with the measurement result of the surface mounter 12 (measurement result of S62), and the warpage (surface height) of each mounting point on the board PX is calculated by interpolation, etc. The correction is, for example, correcting the offset (deviation) of the measurement result of the surface mounter 12 relative to the measurement result of the printing machine 11.

[0101] The user can select the calculation method from (1) to (3). Note that the calculation method (2) is provided in consideration of the case where the surface mounter 12 is not equipped with the laser measuring device 74.

[0102] The control device 75 calculates the warpage (surface height) of each mounting point of the substrate PX using the calculation method selected by the user, and then mounts the component E on the mounting point of the substrate PX.

[0103] At this time, the control device 75 corrects the mounting height H of the component E relative to the board PX based on the warpage (surface height) of each mounting point of the board PX calculated in S64 (see FIG. 11).

[0104] By adjusting the mounting height H in accordance with the warpage of the substrate PX, it is possible to improve the mounting accuracy of the component E. The same applies to the case of S65 described below.

[0105] If the determination in S63 is NO, the process proceeds to S65, where the control device 75 does not adopt the measurement results of the printing machine 11, and measures the deleted measurement points M with the laser measuring device 74. In the example of Fig. 22, the four rows of measurement points M on both sides of the center that were deleted in S61 are measured with the laser measuring device 74. Then, interpolation or the like is performed from the measurement results of all measurement points M measured in S62 and S65 to calculate the warpage of each mounting point on the substrate PX.

[0106] The above processes (S51 to S54 on the printing machine side, S61 to S65 on the mounting machine side) are performed for each board PX to be worked on, so that the accuracy of mounting the components E onto the board PX can be improved regardless of warpage.

[0107] 4.Effects As described above, by using the warpage measurement results of the substrate PX by the printing machine 11, some of the measurement points M of the laser measuring instrument 74 are eliminated, thereby shortening the measurement time of the measurement points M. As a result, the takt time of the surface mounter 12 can be shortened.

[0108] <Other embodiments> The present invention is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments, for example, are also included within the technical scope of the present invention.

[0109] (1) In the above embodiment, the warpage of the substrate PX was determined from the contact pressure of the squeegee 39 (the pressure value of the load cell 40). The greater the warpage of the substrate PX (upward convex warpage), the stronger the reaction force of the substrate PX, and therefore the larger the motor current of the Z-axis motor 42. Therefore, the warpage of the substrate PX may be measured based on the motor current of the Z-axis motor 42 instead of the contact pressure of the squeegee 39.

[0110] (2) In the above embodiment, when the squeegee 39 was moved in the Y direction, the position of the squeegee 39 in the Z direction was fixed and the contact pressure of the squeegee 39 (pressure value of the load cell 40) was measured. Then, the warpage of the substrate PX was measured based on the pressure change in the contact pressure. When the squeegee 39 was moved in the Y direction, the position of the squeegee 39 in the Z direction may be adjusted so that the contact pressure of the squeegee 39 (pressure of the load cell 40) was constant. Then, the warpage of the substrate PX may be measured based on the amount of change in the position of the squeegee 39 in the Z direction. Note that the amount of change in the position of the squeegee 39 in the Z direction can be measured by an encoder (a detector that detects the rotation of the Z-axis motor). The position of the squeegee 39 in the Z direction is an example of "squeegee measurement data" in the present invention.

[0111] (3) In the above embodiment, two pieces of information, the Y coordinate at which the warpage of the substrate PX is maximum and the maximum warpage amount ΔZ, are transmitted from the printer 11 to the surface mounter 12 as warpage information of the substrate PX (substrate warpage measurement results). The printer 11 is only required to be able to communicate to the surface mounter 12 at least the tendency of warpage in the Y direction, and of the two pieces of information, it may be sufficient to transmit only the Y coordinate at which the warpage of the substrate PX is maximum.

[0112] (4) In the above embodiment, the surface mounter 12 is equipped with the laser measuring device 74, but the surface mounter 12 may not be equipped with the laser measuring device 74. In this case, the surface mounter 12 may correct the mounting height H of the component E relative to the substrate PX based on the warpage of the substrate PX measured by the printing machine 11. [Explanation of symbols]

[0113] 10 Mounting Line 11 Printing machine 12 Surface mount machine 25 Mask 32 Y-axis motor 42 Z-axis motor 39 Squeegee 40 load cells 50 Control device 63 Head Unit 74 Laser Measuring Instrument 75 Control Device 78 Mounting head

Claims

1. 1. A printing press, comprising: a squeegee movable in the Y direction; a control device for controlling the squeegee, The control device moves the squeegee in the Y direction with the tip in contact with the surface of the substrate or the surface of the mask, measures the warpage of the substrate, and outputs the results to a surface mounter.

2. 2. The printing press according to claim 1, The control device measures the warpage of a single substrate during a printing cycle for the substrate.

3. 2. The printing press according to claim 1, The control device measures the warpage of the substrate during setup work associated with changing the type of the substrate.

4. 2. The printing press according to claim 1, The control device measures the warpage of the substrate based on measurement data of the squeegee, which changes depending on the warpage of the substrate.

5. 5. The printing press according to claim 4, The measurement data of the squeegee is a contact pressure of the squeegee.

6. 6. The printing press according to claim 5, The control device fixes the position of the squeegee in the Z direction when moving the squeegee in the Y direction.

7. The printing press according to claim 4 or claim 5, the control device reciprocates the squeegee in the Y direction, and measures a maximum point at which a change in the measurement data of the squeegee is greatest for each of the forward and backward movements; A printing machine in which the Y coordinate of the midpoint between the maximum displacement points on the forward and backward paths is set as the Y coordinate at which the warp of the substrate is maximum.

8. The printing press according to claim 4 or claim 5, the control device moves the squeegee only on the forward path in the Y direction, and measures a maximum point at which a change in measurement data of the squeegee is maximum; A printing machine that adds a predetermined offset value to the Y coordinate of the measured maximum point to determine the Y coordinate at which the warp of the substrate is maximum.

9. A surface mounter located downstream of the printing machine of claim 1 or claim 2, A head unit and a control device are provided. The head unit includes: a laser measuring device for measuring the height of a measurement point on the substrate; a mounting head that mounts components on the board, The control device reduces some of the measurement points of the board by the laser measuring device based on the warpage of the board measured by the printing machine.

10. 10. The surface mounter according to claim 9, The control device determines the number of rows of measurement points to be deleted in accordance with the level of warpage of the board measured by the printing machine.

11. 10. The surface mounter according to claim 9, The control device corrects the mounting height of the component relative to the board based on the measurement results of the measurement points that were not deleted.

12. A surface mounter located downstream of the printing machine according to claim 1 or 2, A head unit and a control device are provided. The head unit includes: a mounting head that mounts components on the board, The control device corrects the mounting height of components relative to the board based on the warpage of the board measured by the printing machine.

13. A method for measuring warpage of a substrate, comprising: A method for measuring warpage of a substrate, in which a squeegee is moved in the Y direction in a printing machine with its tip in contact with the surface of the substrate or the surface of a mask, the warpage of the substrate is measured, and the results are output to a surface mounter.

14. The method for measuring warpage of a substrate according to claim 13, A method for measuring warpage of a substrate, comprising: adjusting a position of the squeegee in the Z direction when moving the squeegee in the Y direction so that the contact pressure of the squeegee is constant; and measuring the warpage of the substrate based on the position of the squeegee in the Z direction.

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