JP2011023763A - Component mounting method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a component mounting method capable of preventing deterioration in the mounting accuracy of a component, which may be caused by rotary deflection of a holding means such as a suction nozzle. <P>SOLUTION: In the component mounting method for mounting a component on a substrate by a nozzle which is rotatably attached and generates center misalignment in rotation, a previously regulated reference angle is set in the nozzle, the component is held on a position rotated from the reference angle only by a component rotation angle, and after returning the nozzle to the reference angle, the component is mounted on the substrate. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a component mounting apparatus and a component mounting method, and more particularly, to a component mounting method for holding a component by a holding unit and mounting the component at a predetermined position on a workpiece by rotating the holding unit so that a mounting angle is obtained. .

  The electronic circuit is formed on a circuit board made of an insulating material. In other words, the copper foil bonded on the circuit board of the insulating material is selectively etched to form a predetermined wiring pattern, and a component is mounted thereon, and the electrode of the component is soldered to the connection land of the wiring pattern. As a result, the electronic components are connected to each other to form a predetermined electronic circuit.

  An electronic component mounting apparatus is used for mounting components on such a circuit board. The mounting apparatus includes a mount head, and a component is taken out from the parts cassette by a suction nozzle attached to the tip of the mount head, and is mounted on the circuit board by a combination of movements in the X-axis direction, the Y-axis direction, and the Z-axis direction. Is mounted at a predetermined position.

  Here, in order to correctly mount electronic components at a predetermined position on the circuit board, a work recognition camera is attached to the mount head, and the reference mark on the circuit board is image-recognized by this work recognition camera. Based on this, the position of the circuit board is corrected. In accordance with such position correction, the mounting of the component by the mount head is corrected, and the electronic component is correctly mounted at a predetermined position on the circuit board.

  In a conventional component mounting apparatus, the component is picked up by the suction nozzle of the mount head and then rotated so that the mounting angle is obtained, and further, the amount of shift of the component with respect to the suction nozzle is measured by a CCD camera, laser light, etc. It was made to correct and correct. Accordingly, when the component is picked up by the suction nozzle and then rotated to the mounting angle at which the component is mounted, the reference position of the rotation mechanism holding the component is shifted due to the rotational shake. For this reason, even if correction is performed after that, the reference position is shifted, resulting in an incorrect correction amount, and as a result, there is a problem that the mounting accuracy of the mounted component on the workpiece is deteriorated.

  As shown in FIG. 10, since it is necessary to rotate the suction nozzle 1 to rotate the components so that the mounting angle is obtained, the suction nozzle 1 is rotatably supported by the bearings 3 and 4. The component 5 is adsorbed at the tip. In this case, when the suction nozzle 1 rotates so as to coincide with the virtual axis, the center of the tip portion holding the component 5 of the suction nozzle 1 coincides with the virtual center O as shown in FIG.

  Actually, however, the axis of the suction nozzle 1, particularly its tip portion, as shown in FIG. 11, due to the curved axis of the suction nozzle 1 and the misalignment of the bearings 3 and 4, The portion that adsorbs 5 is shifted, and rotational shake occurs as shown in FIG.

  If the reference position of the rotation mechanism portion of the suction nozzle 1 due to such rotational shake is shifted, the rotational shake trajectory is shown in FIG. 11 even if calibration is performed by measuring the relationship between the rotational angle and rotational shake in advance. As shown, it is not a circle or an ellipse, but an irregular center locus 6 is drawn. That is, the combination of the misalignment of the bearings 3 and 4 and the combination of the bending of the suction nozzle 1 places a load on the shaft of the suction nozzle 1. Therefore, an error occurs in the calibration itself. Therefore, if the rotation is performed after the suction nozzle 1 is sucked, the mounting position of the component 5 is displaced due to the above-described rotational shake, which is a limit to improving the mounting accuracy.

  The present invention has been made in view of such problems, and an object of the present invention is to provide a component mounting method that can eliminate deterioration in mounting accuracy of components due to rotational shake of a holding means such as a suction nozzle. To do.

  In order to achieve the above object, the component mounting method of the present invention is provided in a rotatable manner, and in the component mounting method of mounting a component on a substrate by a nozzle that causes runout during rotation, the nozzle is preliminarily defined. A step of holding the component at a position rotated by a component rotation angle from the reference angle, and a step of mounting the component on a substrate after returning the nozzle to the reference angle. , Including.

  The reference angle is an angle at which the amount of runout is known or does not cause runout.

  According to the component mounting method of the present invention, it is possible to mount a component with high accuracy on a workpiece without being affected by the amount of runout of the holding means.

It is a perspective view which shows the whole structure of a component mounting apparatus. It is the front view which fractured | ruptured a part which shows a mount head. It is a side view of the mount head. It is a side view of a mount head when a mirror is retracted. It is a side view of a mount head when a suction nozzle is lowered. It is a block diagram which shows the system configuration | structure of a control part. It is a flowchart which shows mounting | wearing operation | movement of components. It is the front view and top view which show the state to which the front-end | tip part of an adsorption nozzle moves by core blurring. It is a flowchart which shows another mounting | wearing operation | movement. It is a longitudinal cross-sectional view which shows the support of the adsorption nozzle of an ideal state. It is a longitudinal cross-sectional view which shows the state in which the front-end | tip part of the suction nozzle was eccentric by the runout.

  The present invention will be described below with reference to the drawings. First, the entire configuration of the component mounting apparatus that prevents the runout when rotated to the mounting angle will be described with reference to FIGS.

  As shown in FIG. 1, the component mounting apparatus includes a base 10, and a frame 11 is mounted on the base 10. A parts cassette mounting table 12 is provided on one side surface, and the parts cassette 13 is arranged and mounted on the mounting table 12. Although only a single parts cassette 13 is shown in FIG. 1, in practice, a large number of parts cassettes 13 each holding a tape holding different types of parts by a reel are arranged in a line. A transport conveyor 14 extending in the lateral direction is provided in front of the arrangement position of the parts cassette 13, and the circuit board 15 is supplied by the transport conveyor 14.

  On the other hand, an X-axis unit 17 is attached to the lower part of the frame 11, and a Y-axis unit 18 that can be moved in the X-axis direction by the X-axis unit 17 is provided. A mount head 19 is attached to be freely movable. As shown in FIG. 2, the mount head 19 is provided with a suction nozzle 20 at its tip side, and the suction nozzle 20 sucks and holds components and mounts it at a predetermined position on the circuit board 15.

  Next, the configuration of the mount head 19 will be described with reference to FIGS. The mount head 19 includes a frame 23, and a ball nut 24 is rotatably supported on the frame 23. The ball nut 24 is screwed with a ball screw 25 arranged vertically. Moreover, a pulley 26 is attached to the ball nut 24. A pulley 30 is attached to the output shaft 29 of the motor 28 on the frame 23. A timing belt 31 is stretched between the pulley 26 of the ball nut 24 and the pulley 30 of the output shaft 29 of the motor 28.

  The ball screw 25 having the suction nozzle 20 at the tip is further engaged with a spline nut 34. The spline nut 34 is located on the lower side of the ball nut 24 and further includes a pulley 35 on the outer periphery thereof. On the other hand, a pulley 37 is fixed to the output shaft of the motor 36 shown in FIG. A timing belt 38 is stretched between the pulley 35 of the spline nut 34 and the pulley 37 of the motor 36.

  A work recognition camera 42 is supported on the frame 23 via a bracket 41. The workpiece recognition camera 42 is for recognizing the circuit board 15 (see FIG. 1) sent by the conveyor 14 from above.

  A bracket 45 is fixed to the frame 23, and a linear guide 46 is attached to the front end side of the bracket 45 so as to extend in the lateral direction. A ball screw 47 is also supported by the bracket 45 in parallel with the linear guide 46. An arm 48 is fixed to a ball nut 49 that is screwed into the ball screw 47. A mirror 50 is attached to the tip side of the arm 48. A pulley 52 is fixed to the ball screw 47. A pulley 56 is fixed to the output shaft 55 of the motor 54 arranged in the horizontal direction. A timing belt 57 is stretched between the pulley 52 of the ball nut 49 and the pulley 56 of the motor 54. Further, a mirror 61 is supported on the side of the bracket 45 via another bracket 60, and a component recognition camera 62 is attached to the upper portion of the mirror 61. The component recognition camera 62 is for performing image recognition by reflecting the image of the lower surface of the component sucked by the suction nozzle 20 by the mirrors 50 and 61.

  The workpiece recognition camera 42 and the component recognition camera 62 are connected to a controller 63 as shown in FIG. The controller 63 includes a computer that performs image processing performed by the cameras 42 and 62 and performs calculations. The controller 63 controls the X-axis unit 17, the Y-axis unit 18, the motors 28, 36 and 54, and the transport conveyor 14.

  As described above, the electronic component mounting apparatus according to the present embodiment includes a parts cassette 13 that supplies electronic components wound in a tape as shown in FIG. 1, a conveyor 14 that conveys the circuit board 15, and an electronic component. Is mounted from the parts cassette 13 and mounted at a predetermined position on the circuit board 15, and the X-axis unit 17 and the Y-axis unit 18 for moving the mount head 19 to the predetermined position on the circuit board 15. It consists of and.

2 and 3, the mount head 19 includes a suction nozzle 20 for sucking electronic components, a ball screw 25 with a spline for moving and rotating the suction nozzle 20 in the vertical direction, and a spline. Motor 28 for rotating ball nut 24 of ball screw 25 with timing belt 31 via timing belt 31, motor 36 for rotating spline nut 34 of ball screw 25 with spline via timing belt 38, and suction nozzle 20 A first mirror 50, a second mirror 61, and a component recognition camera 62 for detecting the position of the electronic component attracted by the linear guide 46 for retracting the mirror 50 when the suction nozzle 20 moves up and down, The ball screw 47 is rotated via the ball screw 47 and the timing belt 57. Circuit board 1 for mounting because the motor 54, and the electronic component
The board recognition camera 42 that detects the position 5 is configured.

  If the ball nut 24 is rotated by the motor 28 while the spline nut 34 is stopped without driving the motor 36, the ball screw 25 moves up and down without rotating. Accordingly, the suction nozzle 20 can be moved in the Z-axis direction. On the other hand, when the spline nut 34 is rotated by the motor 36 and the ball nut 24 is rotated at the same angle by the motor 28, the ball screw 25 performs only rotational movement without moving up and down. Therefore, the rotation operation of the suction nozzle 20, that is, the θ-axis operation is performed thereby.

  Next, an outline of an electronic component mounting operation by such a mounting apparatus will be described. The circuit board 15 is transported by the transport conveyor 14 and positioned at a predetermined position. Then, this mounting apparatus moves the mount head 19 in the X-axis direction and the Y-axis direction by the X-axis unit 17 and the Y-axis unit 18, and recognizes the fiducial mark on the circuit board 15 as the workpiece provided on the mount head 19. The image is picked up by the camera 42 and its position is detected, thereby prompting the accurate position of the circuit board 15. By such an operation, it is possible to know where the workpiece recognition camera 42 is moved and where the electronic component is to be mounted.

  After that, the mount head 19 moves to the component take-out position of the parts cassette 13 for supplying the electronic components, and lowers the suction nozzle 20 to vacuum-suck the electronic components. At this time, the position of the mirror 50 is at a position retracted from the vertical movement area of the suction nozzle 20 as shown in FIGS. Then, after the suction nozzle 20 picks up the electronic component, it rises to a predetermined height by the rotation of the ball nut 24, and then the mirror 50 moves below the suction nozzle 20 as shown in FIG. Then, the image of the lower surface of the electronic component sucked by the suction nozzle 20 is reflected by the mirrors 50 and 61 and picked up by the component recognition camera 62.

  Using the information regarding the position of the electronic component imaged by the component recognition camera 62, the amount of displacement of the electronic component from the camera image reference position (usually the rotation center position of the suction nozzle 20) at the time of suction is detected. The mount head 19 moves to a predetermined position on the circuit board 15 programmed in advance to a position where the amount of positional deviation at the time of suction is corrected. Thereafter, the mirror 50 is retracted as shown in FIG. 4 and the suction nozzle 20 is lowered as shown in FIG. 5 to mount the electronic component at a predetermined position on the circuit board 15.

  In this embodiment, in order to eliminate an error that occurs in the mounting position due to the rotational deflection of the suction nozzle 20, the nozzle angle for which mechanical accuracy is guaranteed in advance is set as a reference angle, for example, 0 °. The mounting angle of the parts is β °. Here, at the reference angle, or 0 °, it is necessary that the suction nozzle 20 does not run out of core or the amount of out-of-core is known. As shown in FIG. 8, when the nozzle 20 rotates, the center of the nozzle 20 passes through the virtual center O at the reference angle or the angle 0, and thereby the runout becomes 0 at the reference angle.

  As shown in FIG. 7, the suction nozzle 20 is reset to 0 ° in the rotation direction before the component 70 is sucked. Thereafter, the suction nozzle 20 is rotated in the opposite direction by an angle β equal to the mounting angle. Then, the nozzle 20 is lowered to suck the component 70. Then, after the suction, the suction nozzle 20 is raised to a predetermined height, the suction nozzle 20 is rotated by β °, and the electronic component 70 is adjusted to the mounting angle, so that the suction nozzle 20 is brought into a state coincident with the reference angle, that is, 0 °. Become. In the case of this angle shown in FIG. 8, the amount of runout is zero.

  Thereafter, the mirror 50 moves to below the suction nozzle 20 as shown in FIGS. The image of the component 70 sucked by the suction nozzle 20 is reflected by the mirror 50 and the mirror 61 and picked up by the component recognition camera 62. Since the suction nozzle 20 has a reference angle with which mechanical accuracy is guaranteed, a slight positional deviation amount of the electronic component at the time of suction from the position of the electronic component 70 imaged by the component recognition camera 62 regardless of the magnitude of the shaft shake. Can be accurately detected.

  The mount head 19 moves to a position where the minute positional deviation amount at the time of accurate suction detected at a predetermined position on the circuit board 15 programmed in advance is corrected, and the mirror 50 is retracted again as shown in FIGS. As shown in FIG. 5, the electronic component 70 is mounted at a predetermined position on the circuit board 15 in the vicinity of the angle 0 of the suction nozzle 20 in which the suction nozzle 20 is lowered to ensure the mechanical accuracy.

  Accordingly, it is possible to mount in a state where the correction amount is accurately reflected, and the mounting accuracy is improved. At this time, the suction nozzle 20 is mounted at a reference angle that guarantees mechanical accuracy, that is, an angle shifted by a correction amount from 0 °, but the correction amount of the angle component is a very small angle. It is hardly affected by nozzle runout. Therefore, it is possible to mount the component 70 accurately without being affected by the runout.

  Although there is no problem when the correction amount of the angle component as described above is very small, there is a possibility that the center deviation may be affected by the angle due to the correction when the correction amount is small. Therefore, in the correction area that is actually used frequently, the amount of deviation from the reference angle of 0 °, which combines the mechanical accuracy of the suction nozzle 20 with an arbitrary number of points, is measured in advance and interpolated to reflect the mounting accuracy. Can be improved.

  FIG. 9 shows a mount operation using such an interpolated angle. Here, the angle of the nozzle 20 at that time is detected, and the closest reference angle among the reference angles obtained by interpolation is detected. Then, the suction nozzle 20 is reset to the detected reference angle. Thereafter, the suction nozzle 20 is rotated in the reverse direction by an angle equal to the mounting angle. Then, after rotating in the reverse direction, the component 70 is sucked by the suction nozzle 20, and the suction nozzle 20 is rotated in the forward direction by an angle equal to the mounting angle. Then, the image recognition of the component 70 is performed by the component recognition camera 62, and the correction angle suction nozzle 20 is rotated. Thereafter, the component 70 is mounted by the suction nozzle 20.

  As described above, in the component mounting apparatus and the mounting method of the present embodiment, the suction nozzle 20 recognizes the correction amount at an angle at which the mechanical accuracy is guaranteed, reflects the correction, and performs mounting near the guaranteed position. It is a thing. Therefore, the mounting accuracy of the electronic component 70 is improved, and in particular, it is possible to avoid the influence of runout due to the rotation of the suction nozzle 20.

10 ... Base, 11 ... Frame, 12 ... Parts cassette mounting base, 13 ...
Parts cassette, 14 ... Conveyor, 15 ... Circuit board, 17 ... X-axis unit, 18 ... Y-axis unit, 19 ... Mount head, 20 ... Suction nozzle, 23 ... Frame, 24 ... Ball nut, 25 ... Ball screw, 26 ... Pulley, 28 ... Motor, 29 ... Output shaft, 30 ... Pulley, 31 ... Timing belt, 34 ... Spline nut, 35 ... Pulley, 36 ... Motor, 37 ...
Pulley, 38 timing belt, 41 bracket, 42 work recognition camera, 45 bracket, 46 linear guide, 47 ball screw,
48 ... Arm, 49 ... Ball nut, 50 ... Mirror, 52 ... Pulley, 5
4 ... motor, 55 ... output shaft, 56 ... pulley, 57 ... timing belt,
60 ... Bracket, 61 ... Mirror, 62 ... Parts recognition camera, 63 ... Controller, 65, 66 ... Bearing, 67 ... Trajectory, 70 ... Parts

Claims (3)

In a component mounting method in which a component is mounted on a board by a nozzle that is provided so as to be rotatable and a runout occurs when rotating,
A predetermined reference angle is set for the nozzle, and the component is held at a position rotated from the reference angle by a component rotation angle;
Mounting the component on a substrate after returning the nozzle to the reference angle. The component mounting method according to claim 1, wherein the reference angle is an angle in which the amount of runout is known. 2. The component mounting method according to claim 1, wherein the reference angle is an angle that does not cause the runout.

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