Surface mounter

Abstract

A surface mounter 10 comprises a raising / lowering member 41, a component holder 45, a camera 56, and controllers 65, 120. The component holder 45 comprises a base part 46 that is attached to the raising / lowering member 41, a nozzle part 47 that can move up and down relative to the base part 46 and suctions and holds an electronic component E at the tip, and an elastic member 48 that is positioned across the base part 46 and the nozzle part 47 and elastically deforms when the electronic component E is mounted on a substrate 150 to reduce the impact on the electronic component E. The camera 56 is positioned to the side of the component holder 45 and captures images of the nozzle part 47 as the component holder 45 descends toward the substrate 150 when the electronic component E is mounted on the substrate 150. The controllers 65, 120 recognize the relative displacement between the base part 46 and the nozzle part 47 caused by elastic deformation of the elastic member 48 on the basis of the images of the nozzle part 47 captured by the camera 56 and determine that the electronic component E as held at the tip of the nozzle part 47 has contacted and been mounted on the substrate 150 when the amount of displacement is at or above a threshold value.

Description

Surface mount machine

[0001] This specification relates to a technique for mounting components onto a substrate.

[0002] Surface mount machines use a mounting head to pick up components from a feeder and mount them onto a circuit board. One document disclosing this type of technology is Patent Document 1, shown below.

[0003] Patent No. 7177915

[0004] If the circuit board is warped, component mounting defects may occur. This invention aims to suppress component mounting defects on the circuit board.

[0005] (1) The surface mount machine disclosed herein comprises a lifting member, a component holder, a camera, and a control unit. The component holder comprises a base portion attached to the lifting member, a nozzle portion that is vertically movable relative to the base portion and holds an electronic component by adsorption at its tip, and an elastic member positioned across the base portion and the nozzle portion and elastically deforms during mounting of the electronic component to the substrate to reduce the impact applied to the electronic component. The camera is positioned to the side of the component holder and photographs the nozzle portion of the component holder as it descends toward the substrate during mounting of the electronic component to the substrate. Based on the image of the nozzle portion taken by the camera, the control unit recognizes the relative displacement between the base portion and the nozzle portion due to the elastic deformation of the elastic member, and if the amount of displacement is greater than or equal to a threshold, it determines that the electronic component held at the tip of the nozzle portion has come into contact with the substrate and been mounted. In the surface mount machine described in (1), any configuration other than the above is arbitrary and may be used.

[0006] In configuration (1), contact of components with the substrate is detected from the relative displacement of the base and nozzle due to the elastic deformation of the elastic member. This makes it possible to make the mounting height of electronic components follow the irregularities of the substrate surface, thereby suppressing mounting defects of components on the substrate.

[0007] (2) In the surface mount machine described in (1), the control unit performs, when mounting an electronic component, a first descent control that lowers the electronic component held by the component holder to a first height position above the substrate at a first speed, and a second descent control that lowers the electronic component held by the component holder from the first height position above the substrate to the substrate surface at a second speed slower than the first speed, and the camera may capture an image of the nozzle portion of the component holder when the component holder is descending at the second speed due to the second descent control. According to (2), the descent time of the electronic component (the time it takes to descend to the first height position above the substrate) can be shortened. As a result, it is possible to mount electronic components in a short time, which is effective in shortening the cycle time.

[0008] (3) In the surface mount machine described in (2), the control unit may include a mounting control unit that performs the first descent control and the second descent control, and a determination unit that recognizes the relative change between the base portion and the nozzle portion due to the elastic deformation of the elastic member and determines whether the electronic component held by the component holder has come into contact with the substrate and been mounted. The determination unit may be built into the camera. According to (3), by performing the contact determination of the electronic component with respect to the substrate on the camera side, the contact determination can be made faster. Specifically, compared to the case where image data is transferred to another device and contact determination is made, data transfer time can be reduced.

[0009] (4) In the surface mount machine described in any one of (1) to (3), the control unit may recognize the relative displacement between the base portion and the nozzle portion due to the elastic deformation of the elastic member based on the difference ΔPQ of equation (1).

[0010] ΔPQ = (P Ｎ -P Ｎ－１ ) - (Q Ｎ -Q Ｎ－１ )・・・・(1) P Ｎ This is the vertical axis position of the mounted head at the time of the Nth trigger output. Ｎ－１ This is the vertical axis position of the mounted head at the time of the N-1th trigger output. Ｎ Q is the Z-direction position of the nozzle feature point recognized from the Nth image capture. Ｎ－１This represents the Z-direction position of the nozzle feature point recognized from the N-1 image capture.

[0011] According to (4), by using a comparison with the previous value, it is possible to determine the contact of electronic components with the substrate while suppressing the effects of time lag and individual differences.

[0012] (5) In the surface mount machine described in any one of (2) to (4), the control unit may lower the electronic component held by the component holder at a constant speed in the second descent control. According to the configuration of (5), it is possible to suppress the impact when the electronic component comes into contact with the substrate to a certain level or less.

[0013] (6) In the surface mount machine described in any one of (2) to (5), the control unit may set the first height position above the substrate based on the maximum amount of warpage of the substrate. According to the configuration of (6), the first height position at which the descending speed of the component switches from the first speed to the second speed is set in relation to the maximum amount of warpage of the substrate, so that the descending component does not collide with the substrate surface while remaining at the first speed.

[0014] (7) In the surface mount machine described in any one of (2) to (6), the control unit may estimate the substrate surface height of the mounting point on which the next electronic component will be mounted based on the estimated substrate surface height on the substrate, and set the first height position above the substrate based on the estimation result. According to the configuration of (7), the first height position at which the descent speed of the electronic component switches from the first speed to the second speed is set in relation to the substrate surface height of the mounting point, so that the descending component does not collide with the substrate surface while still at the first speed.

[0015] (8) In the surface mount machine described in any one of (1) to (7), the control unit may estimate the substrate surface height of the mounting point on which the next electronic component will be mounted based on the estimated substrate surface height on the substrate, and based on the estimation result, decide whether or not to perform mounting confirmation of the electronic component based on the relative displacement between the base part and the nozzle part. According to the configuration of (8), flexible decision-making is possible, such as selecting whether or not to perform mounting confirmation according to the substrate surface height (level of unevenness) of the mounting point.

[0016] (9) In the surface mount machine described in any one of (2) to (8), if the control unit has confirmed the mounting of an electronic component and there is an electronic component that has been mounted in the vicinity of the mounting point to be mounted next, the control unit may lower the electronic component from above to the substrate surface at the first speed and may omit taking a photograph with the camera. According to the configuration of (9), if there is a mounting point in the vicinity that has already been confirmed for mounting, the mounting time can be shortened by omitting the mounting confirmation of that electronic component.

[0017] (10) In the surface mount machine described in any one of items (1) to (8), the control unit may, for specific electronic components that have been registered in advance, photograph the nozzle portion of the component holder with the camera and perform mounting verification of the electronic component based on the relative displacement between the base portion and the nozzle portion. According to the configuration of (10), mounting verification can be performed for electronic components that have been registered in advance.

[0018] (11) In the surface mount machine described in any one of items (1) to (10), the control unit may calculate the mounting load of the electronic component on the substrate from the amount of contraction of the elastic member during component mounting, and save the data or notify the user of the data.

[0019] This invention makes it possible to adjust the mounting height of electronic components to conform to the irregularities on the substrate surface, thereby suppressing component mounting defects on the substrate.

[0020] Plan view of the surface mount machine Side view of the head unit Cross view of the mounting head Diagram showing the operation of the suction nozzle by camera Diagram showing the relationship between the warp of the substrate and the mounting height of the components Diagram showing the compression of the spring due to component contact Diagram showing the relationship between the warp of the substrate and the mounting height of the components Diagram showing the correlation between the lifting axis position of the mounting head during shooting and the Z-direction position of the nozzle feature points based on the image Diagram showing the correlation between the lifting axis position of the mounting head during shooting and the Z-direction position of the nozzle feature points based on the image Diagram showing the time lag of the camera shooting operation Diagram showing the error due to individual differences in the suction nozzle Diagram showing the deviation in correlation due to replacement of the suction nozzle Diagram showing the relationship between the trigger interval and the shooting completion interval Diagram showing the height of the substrate surface Diagram showing the speed characteristics of the mounting head Plan view of the printed circuit board Diagram showing the amount of deviation of the mounting points Control block for the part related to contact judgment Control block for the part related to contact judgment Flowchart of the mounting process Flowchart of the mounting process

[0021] <Embodiment 1> 1. Structural Explanation Diagram 1 of the Surface Mount Machine 10 is a plan view of the surface mount machine 10. The surface mount machine 10 comprises a base 31, a transport conveyor 32, a head unit 33, a drive unit 34, and a feeder 35. The transport conveyor 32 transports the printed circuit board 150 on the base 31 in the X direction. In the following description, the direction perpendicular to the X direction, which is the transport direction of the printed circuit board 150, will be referred to as the Y direction, and the vertical direction (also called the lifting direction) will be referred to as the Z direction.

[0022] The drive unit 34 is a device that moves the head unit 33 on the base 31 in a planar direction (XY direction).

[0023] Examples of the drive unit 34 include a two-axis or three-axis ball screw mechanism driven by a motor. The feeder 35 is a device that supplies electronic components E to be mounted on the printed circuit board 150.

[0024] As shown in Figure 2, the head unit 33 is supported by a support member 38 so as to be slidable in the X direction and is equipped with multiple mounting heads 40. The mounting heads 40 are supported by the head unit 33 so as to be movable up and down and move up and down (up and down in the Z direction) by the drive of a lifting shaft motor 70.

[0025] As shown in Figure 3, the mounting head 40 comprises a nozzle shaft 41 and a suction nozzle 45. The nozzle shaft 41 has an air supply path 42 at its axial center. The nozzle shaft 41 has a shaft holder 43 on its outer circumference. The suction nozzle 45 is attached to the tip of the nozzle shaft 41.

[0026] By supplying negative pressure from the negative pressure generator 53 to the supply path 42, a suction force is generated at the tip of the suction nozzle 45, allowing it to adsorb and hold the electronic component E. Conversely, by stopping the supply of negative pressure, the electronic component E can be released. The nozzle shaft 41 is an example of the "lifting member" of the present invention, and the suction nozzle 45 is an example of the "component holder" of the present invention.

[0027] As shown in Figure 3, the suction nozzle 45 is a so-called buffing nozzle and comprises a base portion 46, a nozzle portion 47, and a spring 48. The base portion 46 is attached to the lower part 41A of the nozzle shaft 41.

[0028] The nozzle portion 47 is supported so as to be able to move up and down relative to the base portion 46, and has an opening at its tip for adsorbing and holding an electronic component E. The spring 48 is attached across the base portion 46 and the nozzle portion 47, and elastically deforms when the electronic component E is mounted on the printed circuit board 150, reducing the impact applied to the electronic component E. The spring 48 is an example of the "elastic member" of the present invention.

[0029] Furthermore, the head unit 33 is equipped with a camera unit 55. The camera unit 55 consists of multiple cameras 56 arranged in the X direction. A camera 56 is provided for each mounting head 40 and is located to the side of the mounting head 40. The camera 56 photographs the nozzle portion 47 of the suction nozzle 45 that descends toward the mounting point M on the printed circuit board 150 during component mounting (see Figure 4).

[0030] 2. Contact determination of components and suppression of mounting defects As shown in FIG. 5, the printed circuit board 150 may warp upward (hereinafter referred to as upward warping) or downward (hereinafter referred to as downward warping). When upward warping occurs, the electronic component E may collide with the printed circuit board 150 at high speed and may be damaged. When downward warping occurs, there may be an in-air mounting with poor accuracy. Even if the printed circuit board 150 has upward or downward warping, it is expected that the electronic component E will be mounted at a height following the warp (concavity and convexity) of the board 150. Note that mounting means mounting the electronic component E on the board 15050.

[0031] In this specification, by recognizing the relative displacement between the base portion 46 and the nozzle portion 47 due to the contraction of the spring 48, the contact (landing) between the printed circuit board 150 and the electronic component E is confirmed, and then the lowering of the suction nozzle 45 is stopped, so that the mounting height of the electronic component E is made to correspond to the concavity and convexity of the board surface 150a of the printed circuit board 150.

[0032] Specifically, as shown in FIG. 4, when the mounting head 40 descends toward the mounting point M of the printed circuit board 150, the nozzle portion 47 of the suction nozzle 45 is photographed by the camera 56 fixed to the head unit 33.

[0033] Then, the following two nozzle tip positions are compared. (A) The nozzle tip position predicted from the elevation axis position at the time of photographing by the mounting head 40 (B) The nozzle tip position based on the image photographed by the camera 56

[0034] Comparing the case where the electronic component E is in contact with the printed circuit board 150 and the case where it is not in contact, as shown in FIG. 6, due to the contraction of the spring 48, a difference Δ occurs in the nozzle tip position. Therefore, it is possible to recognize the contact of the component with respect to the printed circuit board 150 based on the difference Δ.

[0035] In this configuration, when the difference Δ is less than the threshold value, the lowering of the mounting head 40 and the photographing of the nozzle portion 47 by the camera 56 are continued. When the difference Δ is greater than or equal to the threshold value, it is determined that there is component contact, and the lowering of the mounting head 40 is stopped.

[0036] In this configuration, after confirming the presence or absence of component contact, the lowering of the mounting head 40 is stopped. As shown in FIG. 7, it is possible to make the mounting height of the electronic component E follow the unevenness of the substrate surface 150a, and it is possible to suppress excessive pushing-in during the upward warping of the printed circuit board 150 and mid-air mounting during the downward warping.

[0037] Hereinafter, the contact determination method will be described separately for stop shooting and continuous shooting. Note that stop shooting is a shooting method in which the mounting head 40 descending toward the mounting point M of the substrate 150 is stopped at the shooting position and the nozzle portion 47 is shot. Continuous shooting is a shooting method in which the mounting head 40 during descent is continuously shot without stopping at the shooting position.

[0038] <Stop Shooting> FIG. 8 shows the correlation (hereinafter, correspondence table) between the vertical axis position of the mounting head 40 at the time of shooting and the Z-direction position of the nozzle feature point based on the image when the suction nozzle 45 is stop-shot. The vertical axis position of the mounting head 40 is the axis value (rotation amount) of the vertical axis motor 70 that raises and lowers the mounting head 40. Note that the axis value of the vertical axis motor 70 can be detected by, for example, an encoder 71.

[0039] The nozzle feature point may be set anywhere as long as it is a place where the nozzle portion 47 is easy to recognize. Also, in order to make it easy to discriminate from the image, it may be made discriminable by a mark or color. Note that the square frame G in FIG. 8 shows the image of the nozzle portion 47 shot by the camera 56. Also, J indicates the feature point.

[0040] The above correspondence table can be created by lowering the mounting head 40 to the shooting position and actually shooting the nozzle portion 47 of the suction nozzle 45 with the camera 56 to obtain data. Coordinates that have not been shot can be complemented from the information of other coordinates.

[0041] The correspondence table in FIG. 8 is a downward-sloping straight line, which means that the Z-direction position of the nozzle feature point can be uniquely specified with respect to the vertical axis position of the mounting head 40. For example, the Z-direction position of the nozzle feature point with respect to the vertical axis position A of the mounting head 40 is Pa, and the Z-direction position of the nozzle feature point with respect to the vertical axis position B of the mounting head 40 is Pb.

[0042] As shown in Figure 9, if the electronic component E comes into contact with the printed circuit board 150 near the lifting axis position C as a result of continuing to descend from the lifting axis position A, even if the mounting head 40 descends further from the lifting axis position C, the Z-direction position of the nozzle feature point does not change thereafter, and a difference occurs in the Z-direction position of the nozzle feature point identified from the lifting axis position of the mounting head 40. The black dots shown in Figure 9 represent the movement trajectory of the nozzle feature point.

[0043] For example, if the mounting head 40 is lowered to the lifting axis position B after contacting a component at the lifting axis position C, and the nozzle portion 47 is photographed, the Z-direction position of the nozzle feature point corresponding to the lifting axis position B is Pb, and the Z-direction position of the nozzle feature point identified from the image is Pc, resulting in a positional difference ΔP between the two positions Pb and Pc.

[0044] Therefore, contact of the electronic component E with respect to the printed circuit board 150 can be determined based on this position difference ΔP. In this configuration, the position difference ΔP is compared with a threshold value, and if the position difference ΔP is greater than or equal to the threshold value, it is determined that the electronic component E held by the suction nozzle 45 has come into contact with the printed circuit board 150.

[0045] <Continuous Shooting> When shooting continuously, it is conceivable that the camera control unit 123 (described later) outputs a shooting trigger to the camera 56 at regular intervals, and the nozzle portion 47 of the suction nozzle 45 is photographed at regular intervals. Therefore, it is considered possible to perform contact detection of the electronic component E based on the correlation (correspondence table) between the vertical axis position of the mounting head 40 at the time the shooting trigger is output and the Z-direction position of the nozzle feature points based on the image.

[0046] However, exposure time and other factors are required from the start to the end of shooting, and as shown in Figure 10, a predetermined time lag occurs between the timing of the shooting trigger output and the timing of the camera 56 completing shooting. Since the mounting head 40 moves during this time lag (in Figure 10, the distance moved is shown by Z1), even if we try to uniquely determine the Z-direction position of the nozzle feature point based on the image from the vertical axis position of the mounting head 40 at the time of the shooting trigger output, an error due to the time lag occurs, making it difficult to maintain the accuracy of contact detection.

[0047] Also, as shown in Fig. 11, there is a variation ε in the nozzle tip position due to individual differences in the suction nozzle 45. As shown in Fig. 12, when the suction nozzle 45 is replaced, a deviation occurs in the correlation (corresponding table). In the example of Fig. 12, the deviation of the corresponding table is shown by a broken line, and the Z-direction position of the nozzle feature point with respect to the lift axis position A has shifted from Pa0 to Pa1.

[0048] Therefore, even if an attempt is made to uniquely identify the Z-direction position of the nozzle feature point based on the image from the lift axis position of the mounting head 40 at the output timing of the imaging trigger as in the above case, an error due to individual variation occurs, and it is difficult to maintain the accuracy of the contact determination.

[0049] In this configuration, the contact determination of the electronic component E is performed using the difference ΔPQ in Equation (1). The first term on the right side of (1) is constant regardless of whether the electronic component E is in contact or not. The second term on the right side of Equation (1) becomes smaller when the electronic component E contacts the substrate 150 and the spring 48 contracts. Therefore, it is possible to perform the contact determination of the electronic component E by comparing the difference ΔPQ in Equation (1) with a threshold value..

[0050] ΔPQ=(P Ｎ -P Ｎ－１ )-(Q Ｎ -Q Ｎ－１ ).....(1) P Ｎ is the lift axis position of the mounting head at the output timing of the Nth imaging trigger. P Ｎ－１ is the lift axis position of the mounting head at the output timing of the (N - 1)th imaging trigger. Q Ｎ is the Z-direction position of the nozzle feature point recognized from the image of the Nth imaging. Q Ｎ－１ is the Z-direction position of the nozzle feature point recognized from the image of the (N - 1)th imaging. P Ｎ－１ is the previous value of P Ｎ , Q Ｎ－１ is the previous value of Q Ｎ .

[0051] Incidentally, as shown in Fig. 13, ZP=(P Ｎ -P Ｎ－１ ), ZQ=(Q Ｎ -Q Ｎ－１ ). Also, TP indicates the output interval of the imaging trigger.

[0052] In this way, by using a comparison with the previous value, it is possible to determine contact between the electronic component E and the printed circuit board 150 while suppressing the effects of time lag and individual differences.

[0053] Note that the unit for the vertical axis position is μm (micrometer), while the unit for the Z-direction position of the nozzle feature point is pix (pixel), which are different. Therefore, when calculating ΔPQ, it is possible to use a table to convert pix (pixel) to μm (micrometer) to convert the unit for the Z-direction position of the nozzle feature point from pix (pixel) to μm (micrometer) to make the units consistent.

[0054] 3. Timing of Electronic Component Mounting In this configuration, the mounting head 40 continues to descend when the electronic component E makes contact with the printed circuit board 150. After confirming contact, the determination unit 65 (described later) issues a command to stop the descent of the mounting head 40, and mounts (mounts) the electronic component E at the mounting point M on the printed circuit board 150.

[0055] At this time, the nozzle tip position is calculated from the contact detection image, and the substrate surface height H of the printed circuit board 150 is calculated, taking into account the thickness of the electronic component E. Furthermore, after contact with the substrate, the amount of spring 48 is compressed x is calculated from the nozzle tip position when it actually stops descending and the calculated substrate height H, and the mounting load N when mounting the electronic component e onto the printed circuit board 150 is calculated from the spring constant.

[0056] By doing so, it is possible to stabilize the mounting height and mounting load of the electronic component E on the printed circuit board 150, and to improve the mounting accuracy of the electronic component E on the printed circuit board 150.

[0057] In this embodiment, the calculation result of the mounting load N of the electronic component E is stored in the storage unit 127 of the mounting control unit 120, which will be described later, or notified to the user via the main unit control unit 110.

[0058] Furthermore, the board surface height H of the printed circuit board 150 can be determined from the contact height H1 of the nozzle tip and the component thickness H2, as shown in equation (2) below (see Figure 14). In addition, the contact load of the electronic component E can be determined from the initial load of the spring, the spring constant, and the amount of indentation x after contact, as shown in equation (3) below.

[0059] (2) Substrate surface height H = Nozzle tip contact height H1 + Component thickness H2 .... (3) Mounting load N = Initial load N0 + Spring constant k × Amount of indentation after contact x .... (4)

[0060] 4. The diagram 15 showing the downward movement during contact detection illustrates the speed characteristics (downward movement trajectory) of the mounting head 40 in the Z direction during component mounting, with the horizontal axis representing speed and the vertical axis representing position in the Z direction.

[0061] The Z-direction is divided into a first section F1 and a second section F2. The second section F2 indicates the area in which the printed circuit board 150 exists, and is centered on the height position of the printed circuit board 150 when there is no warping. The upper and lower limits of the section are defined by the upper error limit (upper upper position L1) and the lower error limit (lower lower limit L2) of the board surface 150a, respectively.

[0062] Furthermore, the upper upper limit position L1 on the substrate defines the boundary between the first section F1 and the second section F2, and corresponds to the "first height position above the substrate" in this invention.

[0063] These upper and lower error limits (upper limit position L1 and lower limit position L2) may be determined by considering the maximum warp of the printed circuit board 150. In other words, if the maximum warp is large, the error limit is widened and the upper limit position L1 is moved further away from the board 150, and if the maximum warp is small, the error limit is narrowed and the upper limit position L1 is moved closer to the board 150 (the same applies to the lower limit position L2). Furthermore, the maximum warp can be determined, for example, by using inspection data of the printed circuit board 150.

[0064] The first section F1 is an area where the printed circuit board 150 does not exist and is located above the second section F2. In the first section F1 where the printed circuit board 150 does not exist, the speed characteristic S1 of the mounting head 40 is faster than the speed in the second section F2, exhibiting a full acceleration / deceleration characteristic. The reason for this speed characteristic is to allow the mounting head 40 to pass through the first section F1 in a shorter time.

[0065] In the second section F2 where the printed circuit board 150 is located, the speed characteristic S2 of the mounting head 40 is a constant speed characteristic. The reason for the constant speed characteristic is to ensure that the impact value (proportional to the speed) when the electronic component E comes into contact with the printed circuit board 150 is below the standard value, thereby preventing damage to the electronic component E. The downward speed of the mounting head 40 in the first section F1, as defined by the speed characteristic S1, corresponds to the first speed of the present invention, and the downward speed of the mounting head 40 in the second section, as defined by the speed characteristic S2, corresponds to the second speed of the present invention.

[0066] 5. Whether or not to perform contact detection operation Performing contact detection operation (an operation to detect whether or not an electronic component E has made contact with the printed circuit board 150) may increase the mounting cycle time. For this reason, the possibility of performing contact detection operation may be set for each electronic component E.

[0067] Figure 16 is a plan view of the printed circuit board 150, showing the mounting points Ma and Mb and the surrounding measurement points 1 to 5. Measurement points 1 to 5 are points where the board surface height is known, such as the edge of the board or mounting points where components have already been mounted. Note that the board surface height at the edge of the board can be considered zero (a flat surface without irregularities). This is because the top surface is held down by the clamping device, and the edge of the board does not warp.

[0068] <Substrate surface height of mounting point M> Figure 17 shows the positional relationship between mounting point M and measurement points 1 to 3. The deviation amount Z of mounting point M can be estimated from the Z coordinates, Y coordinates, and Z coordinates of the three measurement points 1 to 3 located around mounting point M. The deviation amount Z is the Z coordinate (substrate surface height) of mounting point M, with height zero as the reference.

[0069] The deviation Z at the implementation point M increases as the distance from measurement points 1 to 3 increases, and also increases as the difference between the maximum deviation and the minimum deviation between measurement points 1 to 3 increases.

[0070] Therefore, as shown in Figure 16, the deviation amount Z tends to be larger at the implementation point Mb where there are no surrounding measurement points than at the implementation point Ma where there are surrounding measurement points.

[0071] If the deviation amount Z of the mounting point M is less than the threshold, the contact detection operation may be omitted and normal mounting may be performed. If the deviation amount Z of the mounting point M is greater than or equal to the threshold, the contact detection operation may be performed to confirm contact of the components and then mounting may be performed.

[0072] Furthermore, when the deviation amount Z of the mounting point M is calculated, the range of the second section F2 is changed based on that value. If the deviation amount Z is large, the upper limit position L1 on the upper side of the substrate is moved away from the substrate 150, thereby preventing the mounting head 40, which is descending rapidly in the first section F1, from colliding with the printed circuit board 150.

[0073] 6. The control block diagram 18 for contact detection shows the control block of the contact detection portion of the surface mount machine 10. The surface mount machine 10 includes a main unit control unit 110, a mounting control unit 120, and a camera 56. The main unit control unit 110 includes a control unit 111 and a storage unit 113, and controls the surface mount machine body (the entire surface mount machine 10 excluding the head unit 33). The main unit control unit 110 is mounted on the surface mount machine body.

[0074] The mounting control unit 120 comprises a motor control unit 121, a camera control unit 123, an information processing unit 125, and a storage unit 127. The mounting control unit 120 primarily controls the raising and lowering of the mounting head 40 and performs the mounting operation of electronic components E onto the printed circuit board 150. The mounting control unit 120 is mounted on the head unit 33 together with the camera 56.

[0075] The camera 56 includes an imaging unit 61, an illumination unit 63, a determination unit 65, and a storage unit 67. The storage unit 67 stores the image of the suction nozzle 45 that has been captured. The determination unit 65 determines whether the electronic component E is in contact with the printed circuit board 150 based on the image of the suction nozzle 45.

[0076] In this configuration, the camera 56 stores the image of the suction nozzle 45 in its memory unit 67, and the camera 56 performs contact detection of the electronic component E with respect to the printed circuit board 150. As shown by the dotted line in Figure 19, compared to the case where these processes are performed in the main control unit 110, it is possible to eliminate the time required to transfer image data from the camera 56 to the main control unit 110, and the contact detection of the electronic component E and the control of the lifting axis of the mounting head 40 can be performed at high speed.

[0077] In this embodiment, the functions of the control unit of the present invention are divided between the camera (contact detection) 56 and the implementation control unit (Z-axis control) 120.

[0078] 7. Explanation of the Implementation Process Figures 20 and 21 are flowcharts of the implementation process. The implementation process consists of steps S10 to S130. Figure 20 shows the first half of the implementation process (S10 to S40), and Figure 21 shows the second half of the implementation process (S50 to S130). As a preliminary step, it is assumed that the data for the correspondence table in Figure 8 has been created and is stored in the storage unit 67 of the camera 56.

[0079] First, in S10, the mounting control unit 120 determines whether contact detection is necessary for the electronic component E to be mounted. Whether or not contact detection is necessary may be set by the user.

[0080] Enabling the contact detection function may slow down the cycle time. Therefore, if cycle time is a priority, it may be advisable to disable contact detection.

[0081] Enabling contact detection improves mounting quality, so it may be advisable to enable it for fragile or expensive components. It may also be advisable to enable contact detection for components mounted in areas prone to warping, such as the center of the circuit board.

[0082] If contact detection is not required (S10: NO), the contact detection operation is omitted and the normal implementation operation is performed.

[0083] If contact detection is required (S10: YES), the process proceeds to S20, where the mounting control unit 120 checks for the presence or absence of height information around the mounting point. The surrounding height information is, for example, information on the substrate surface height H of the mounting point M that has already been mounted.

[0084] If there is no height information around the mounting point (S20: YES), the process proceeds to S30, and the mounting control unit 120 determines the upper limit position L1 on the substrate, as shown in Figure 15. If there is no height information around the mounting point, the upper limit position L1 is determined using empirical values ​​or the like.

[0085] If height information around the mounting point is available (S20: NO), the process proceeds to S40, where the mounting control unit 120 calculates the deviation amount Z of the mounting point M on which the electronic component E is mounted from the height information around the mounting point, and checks whether that value is above a threshold.

[0086] If the deviation amount Z of the mounting point M is greater than or equal to the threshold, the process proceeds to S30, where the mounting control unit 120 determines the upper upper position of the substrate based on the deviation amount Z of the mounting point M. In other words, if the deviation amount Z of the mounting point M is greater than the threshold, the curvature of the substrate surface 150a is large, so the upper upper position L1 of the substrate is set further away from the substrate 150 (the distance V in Figure 15 is increased).

[0087] If the deviation amount Z is less than the threshold, the warping of the substrate surface 150a is small, and it can be determined that the risk of mounting failure is small even if the contact detection operation is omitted, so the process proceeds to normal mounting. Also, if the component to be mounted is a component for which normal mounting is not permitted, the process proceeds to S30.

[0088] In this embodiment, specific electronic components for which contact detection is required are linked to electronic component E and their information is registered in advance. By registering that contact detection is necessary, a YES determination is made in both S10 and S40, and contact detection can be performed.

[0089] In S30, when the upper limit position L1 on the substrate is set, the process proceeds to S50 in Figure 21, where the mounting control unit 120 moves the mounting head 40 to its initial position (initial height) above the substrate. In the subsequent S60, the mounting control unit 120 moves the mounting head 40 from its initial position to the upper limit position L1 on the substrate at the fastest permissible speed according to the speed characteristic S1 shown in Figure 15 (corresponding to the "first descent control" of the present invention).

[0090] When the mounting head 40 moves to the upper upper limit position L1 on the substrate, the mounting control unit 120 lowers the mounting head 40 at a constant speed thereafter according to the speed characteristic S2 shown in Figure 15 (corresponding to the "second descent control" of the present invention).

[0091] Subsequently, in S80, the suction nozzle 45, which is descending at a constant speed, is photographed by the camera 56 of the head unit 33. The camera 56 may either take pictures while stopped or continuously.

[0092] In the subsequent step S90, the determination unit 65 of the camera 56 makes a contact determination of the electronic component E based on the image of the suction nozzle 45 captured in S80. The loop from S70 to S90 is repeated until contact of the electronic component E with the printed circuit board 150 is confirmed, at which point the process proceeds to S100.

[0093] When the process moves to S100, the camera 56 sends a command to the mounting control unit 120 to stop the lowering of the mounting head 40. Then, in S110, the mounting control unit 120 calculates the contact height H1 of the nozzle tip, and further calculates the substrate surface height H of the mounting point M using the above equation (2).

[0094] Then, in S120, the lifting shaft motor 70 stops, and the electronic component E held by the suction nozzle 45 is mounted on the mounting point M of the printed circuit board 150.

[0095] Subsequently, the process moves to S130, where the mounting control unit 120 calculates the mounting load N of the electronic component E on the printed circuit board 150 based on equation (3) above. The calculation results of the board surface height H and mounting load N are then stored in the storage unit 127 or notified to the user via the main unit control unit 110.

[0096] 8. Explanation of Effects This configuration allows the mounting height of the electronic component E to follow the unevenness of the board surface 150a, even if the printed circuit board 150 is warped, thereby suppressing mounting defects of the electronic component E on the printed circuit board 150.

[0097] <Other Embodiments> The technology disclosed herein is not limited to the embodiments described above and illustrated in the drawings, but also includes, for example, the following embodiments.

[0098] (1) In the above embodiment, contact detection was performed by the camera 56, but it may also be performed by the main unit control unit 110 or the mounting control unit 120.

[0099] (2) In the above embodiment, the substrate surface height H of the mounting point M can be estimated in conjunction with the contact detection operation. If there is a mounting point M in the vicinity of the next mounting point M for which the substrate surface height H has been estimated, it can be determined that the substrate surface height H of the mounting point M has not changed much from the substrate surface height H of the neighboring mounting point M. For this reason, if there is a mounting point M in the vicinity of the next mounting point M for which the substrate surface height H has been estimated, the contact detection operation may be omitted, and the substrate surface height H of the mounting point M may be used as the substrate surface height H of the neighboring mounting point M, and the electronic component E may be mounted. In this case, the electronic component E is lowered from above to the substrate surface 150a at a first velocity, and is not photographed by the camera 56. Note that the vicinity is the range in which it can be determined that there is no change or only a small change in the substrate surface height H.

[0100] 10 Surface mount machine 33 Head unit 40 Mounting head 41 Nozzle shaft (lifting member) 45 Suction nozzle (component holder) 46 Nozzle holder (base part) 47 Nozzle part 48 Spring (elastic member) 55 Camera unit 56 Camera 65 Judgment unit (control unit) 70 Lifting shaft motor 120 Mounting control unit (control unit) 150 Printed circuit board E Electronic components

Claims

1. A surface mount machine comprising: a lifting member; a component holder; a camera; and a control unit, wherein the component holder comprises: a base portion attached to the lifting member; a nozzle portion that is vertically movable relative to the base portion and holds an electronic component by adsorption at its tip; and an elastic member positioned across the base portion and the nozzle portion, which elastically deforms to reduce the impact applied to the electronic component when the electronic component is mounted on a substrate; the camera is positioned to the side of the component holder and photographs the nozzle portion of the component holder as it descends toward the substrate when the electronic component is mounted on the substrate; and the control unit recognizes the relative displacement between the base portion and the nozzle portion due to the elastic deformation of the elastic member based on the image of the nozzle portion taken by the camera, and determines that the electronic component held at the tip of the nozzle portion has come into contact with the substrate and been mounted if the amount of displacement is greater than or equal to a threshold; 2. A surface mount machine according to claim 1, wherein the control unit performs, during the mounting of an electronic component, a first descent control that lowers the electronic component held by the component holder to a first height position above the substrate at a first velocity, and a second descent control that lowers the electronic component held by the component holder from the first height position above the substrate to the substrate surface at a second velocity slower than the first velocity, and the camera captures an image of the nozzle portion of the component holder when the component holder is descending at the second velocity due to the second descent control.

3. A surface mount machine according to claim 2, wherein the control unit includes a mounting control unit that performs the first descent control and the second descent control, and a determination unit that recognizes the relative change between the base portion and the nozzle portion due to the elastic deformation of the elastic member and determines whether the electronic component held by the component holder has come into contact with the substrate and been mounted, the determination unit being built into the camera.

4. A surface mount machine according to claim 1 or claim 2, wherein the control unit recognizes the relative displacement between the base portion and the nozzle portion due to the elastic deformation of the elastic member based on the difference ΔPQ of equation (1). ΔPQ = (P Ｎ -P Ｎ－１ ) - (Q Ｎ -Q Ｎ－１ )・・・・(1) P Ｎ This is the position of the lifting axis of the component holder at the time of the Nth trigger output. Ｎ－１ This is the position of the lifting axis of the component holder at the time of the N-1th trigger output. Ｎ Q is the Z-direction position of the nozzle feature point recognized from the Nth image capture. Ｎ－１ This represents the Z-direction position of the nozzle feature point recognized from the N-1 image capture.

5. A surface mount machine according to claim 2, wherein the control unit lowers the electronic component held by the component holder at a constant speed in the second descent control.

6. A surface mount machine according to claim 2, wherein the control unit sets the first height position above the substrate based on the maximum amount of warpage of the substrate.

7. A surface mount machine according to claim 2, wherein the control unit estimates the substrate surface height of the mounting point on which to mount the next electronic component based on the estimated substrate surface height on the substrate, and sets the first height position above the substrate based on the estimation result.

8. A surface mount machine according to claim 1 or claim 2, wherein the control unit estimates the substrate surface height of the mounting point on which the next electronic component will be mounted based on the estimated substrate surface height on the substrate, and determines whether or not to perform mounting confirmation of the electronic component based on the relative displacement between the base portion and the nozzle portion based on the estimation result.

9. A surface mount machine according to claim 2, wherein the control unit checks for the mounting of an electronic component near the next mounting point and, if a mounted electronic component exists, lowers the electronic component from above to the substrate surface at the first speed and does not take a photograph of it with the camera.

10. A surface mount machine according to claim 1 or claim 2, wherein the control unit photographs the nozzle portion of the component holder with the camera for a specific electronic component that has been registered in advance, and performs mounting confirmation of the electronic component based on the relative displacement between the base portion and the nozzle portion.

11. A surface mount machine according to claim 1 or claim 2, wherein the control unit calculates the mounting load of the electronic component on the substrate from the amount of contraction of the elastic member during component mounting, and stores or notifies the user of the data.

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