JPH03203297A - Mounting apparatus for electronic component - Google Patents

Abstract

PURPOSE:To mount a component by using a mounting movement body on the other side while a mounting movement body on one side recognizes an image by a method wherein image-recognizing means which pick up an image of a component-holding state and which detect the dislocation of a holding position on the basis of the image are installed respectively in movement regions of the individual mounting movement bodies. CONSTITUTION:A head unit Uh which has sucked an object component in order to detect the dislocation of a suction position is moved above a camera 27A for image processing use; an image of a component suction state is recognized; a suction position data detected by recognizing the image is sent to a central control part while the head unit Uh on the back side recognizes the image of the component suction state, a head unit Uh on the front side picks up two electronic components to be mounted from a component supply cassette 26B on the front side in the same operation as the head unit Uh on the back side. While a mounting position is being corrected by using an image recognition system, the electronic components are mounted on one printed-circuit board Pb alternately from both sides by using the two head units Uh, Uh. Thereby, the mounting time can be shortened.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an electronic component mounting apparatus for mounting chip-shaped electronic components on a substrate.

[Prior art and its problems]

Conventionally, as an electronic component mounting device designed to automatically mount a large number of chip components such as ICs, resistors, capacitors, etc. on a printed circuit board at high speed and with high precision, the following X-Y movement type mounting device has been commonly used. Are known.

A pair of guide rails is laid across a work station where components are mounted, and a support for supporting a mounting head is slidably installed between the guide rails. The mounting head includes a suction nozzle that suctions and holds electronic components using, for example, an air suction method. Each support supports the mounting head slidably in a direction perpendicular to the guide rail. That is, the mounting head is supported so as to be freely movable in two dimensions: the direction along the support body (referred to as the X direction) and the direction along the guide rail (referred to as the Y direction).

When mounting components, the mounting head picks up the components to be mounted from the component supply section with a suction nozzle, and then
- Move quickly in the Y two-dimensional direction to advance to the component mounting position on the printed circuit board positioned at the work station - 2- and place the picked up electronic component. After placing the electronic components,
Return to the component supply position again and move on to picking up the next electronic component to be mounted. By repeating this series of operations, various types of electronic components are mounted on the printed circuit board.

In the series of operations described above, when picking up the electronic component, the suction position of the suction nozzle relative to the electronic component may shift. Conventionally, a mechanical method using chuck claws has been adopted as a method for correcting the deviation of the suction position. In this method, chuck claws are arranged on all sides around the suction nozzle, and the electronic component is evenly gripped by the four chuck claws to correct the suction position, and there is a drawback in the correction accuracy. In recent years, in order to correct the suction position of electronic components with high precision, optical methods using double image recognition are often employed. In this method, a camera captures an image of a component being sucked by a suction nozzle, and a computer performs arithmetic processing on both images to detect a deviation in the suction position, and corrects the mounting position based on this. Although this mounting position correction method using both image processing allows parts to be mounted with extremely high precision, it has the disadvantage that it takes a relatively long time to process both images. Furthermore, if a dual-image processing device with a high processing speed is employed, the equipment cost will increase significantly.

[Purpose of the invention]

The present invention has been made in view of the problems of the prior art described above, and an object of the present invention is to provide an electronic component mounting device that can accurately correct the holding position of many types of electronic components and mount them in a short time and with high precision. purpose.

[Key points of the invention]

In order to achieve the above object, the present invention provides a working head that removably holds an electronic component, a head driving means for slidably supporting the working head and reciprocating the working head, and the working head and the head driving means. In an electronic component mounting apparatus, the electronic component mounting apparatus includes a head support that integrally supports the work head and a support drive means that moves the head support body forward and backward with respect to a component mounting work area, the work head and the head drive means. , the mounting moving body consisting of the head support body is 2
The key point of the present invention is that image recognition means for detecting the holding position by taking an image of the electronic component holding state of the work head are installed in each moving area of the mounting moving body.

[Embodiments of the invention]

Embodiments of the present invention will be described in detail below with reference to FIGS. 1 and 2.

FIG. 1 is a plan view showing an electronic component mounting apparatus as an embodiment of the present invention, and FIG. 2 is an elevational view thereof. In Figure 1,
A substrate conveyor 2 for conveying printed circuit boards is laid horizontally extending from the center of the device base 1 in the lateral direction (hereinafter referred to as the X direction) in the figure. The substrate conveyor 2 has a pair of rails 2a, 2a laid in parallel on both sides, and a pair of conveyor bells 2b, 2b each stretched so as to run on each rail 2a. These conveyance belts 2b, 2b are driven by a substrate conveyance motor 3 placed at an appropriate location. The printed circuit board pb on which components are to be mounted is supported by conveyor bells 2b and 2b on both sides, and as it rotates, the printed circuit board pb is
It is guided by a+2a and is conveyed along the direction of arrow T from the right side in the figure.

A work stage WS on which electronic components are mounted is set up approximately at the center of the device base 1 on the travel path of the substrate conveyor 2. This work station Ws is defined by rails 2a+2a on both sides and positioning bins 4a+4b at the front end and rear end with respect to the substrate transport direction A, respectively. Both positioning pins 4a and 4b are rotatably supported, respectively, and are rotated by a driving means such as an air cylinder (not shown) to advance their tips into the substrate transport path and are transported by transport belts 2b and 2b. Stop the printed circuit board pb that has come.

Fixing tables 5a and 5b are installed at the front and rear ends of the work stage Ron Ws, respectively, so as to straddle the substrate conveyor 2. Each of the fixing stands 5a and 5b is fixed and extends in a direction (hereinafter referred to as the Y direction) perpendicular to the substrate transport direction (X direction). These fixed bases 5a+5
A pair of guide rails 6at8b are laid on the rails 6a and 8b. 5-6- These guide rails 6a and 6b are arranged inside the fixed bases 5al and 5b (work stage date Ws) so as to extend in the Y direction.
Side) It is laid along the side.

Between the pair of guide rails 6a and 6b, there are two moving platforms 7.
A and 7B are installed so that they can slide freely. As will be described later, each of these movable tables 7A and 7B reciprocates between predetermined areas on the back side (upper side in the figure) and the front side (lower side in the figure) of the apparatus.

Each movable platform 7A+7B has both ends thereof slidably fitted onto each guide rail 6a, 6b via a pair of slide bearings 8, 8, respectively. In this case, each moving platform 7A, 7
Regarding the spacing between each pair of sliding bearings it8.8 interposed at the ends of B, one spacing DI is set larger than the other spacing D2. The reason for this is mobile platform 7A.

The rear crosspiece will be explained in relation to each drive means of 7B. Each moving platform 7
1.7B, X-axis ball screws 9, 9 are installed along its longitudinal direction (X direction), respectively.

A servo motor 11 is connected to one end of each X-axis ball screw 9 via a coupling 10.

Further, a guide rod 12 is installed parallel to each X-axis ball screw 9. This Gaitro Sodo 12 is 2 in this example.
Head unit Uh with 13.13 mounted heads
is slidably supported.

As shown in FIG. 2, each mounting head 13 is equipped with a suction nozzle 13a facing vertically for sucking electronic components with air. Each mounting head 13.13 is connected movably together with a plate 14, and this mounting is done by slidingly inserting the plate 14 onto the guide rod 12. . The mounting plate 14 is an X-axis ball screw 9
It is connected to a feed stand 15 installed so that it can move back and forth in a straight line. The feed base 15 and the X-axis ball screw 9 are connected via a nut member 1e screwed onto the X-axis ball screw 9.

By operating the servo motor 11 and rotating the X-axis ball screw 9 in both forward and reverse directions, the feed table 15 and head unit U are rotated.
h can be integrally moved in a reciprocating straight line along the Gytro-Sodo 12. In this case, since the ball screw has the characteristics that the frictional resistance between the screw and the nut is small and backlash can be easily removed, the mounting head 13
This enables high-speed movement and high-precision positioning.

Y-axis drive ball screws 17a, 17b are installed parallel to the guide rails 13a, 3b, respectively, on the pair of front and rear fixed bases 5a, 5b mentioned above. , from the upper area (center area) of each substrate conveyor 2 on the front and rear fixing tables 5a+5b to an area corresponding to approximately 315 mm of one end portion.

In this case, a pair of Y-axis drive ball screws 17a, 1
7b extends from each central region on the front and rear fixed bases 5a+6b to opposite ends. In this example, the Y-axis drive ball screw 17a installed on the front side with respect to the board transport direction T is placed in the back area on the front fixing table 5a, and the Y-axis drive ball screw 17b installed on the rear side is placed on the rear fixing table 5b. They each extend to the front side area. Y-axis drive servo motors 19a and 19b are connected to the central end portions of these Y-axis drive ball screws 17a and 17b, respectively, via couplings 18a and 18b.

On the other hand, Y
Axial drive ball screws 20a and 20b are installed. In this case, the Y-axis drive ball screw 20a installed on the front side faces the Y-axis drive ball screw 17b on the rear side, and the Y-axis drive ball screw 20b installed on the rear side faces the Y-axis drive ball screw 17a on the front side in parallel. This is an extended installation.

Then, the Y-axis drive ball screw 20 facing on the front side of the device
A toothed boob J21a; 21b is fixed to each end of the machine planing side of the Y-axis drive ball screw 17b. Below each of the toothed pulleys 21a and 21b, as shown in FIG. 2, relay pulleys 21c and 21d, which are two toothed pulleys arranged coaxially in parallel, are rotatably installed. And these two toothed pulleys 21a, 21b and 2
A toothed belt 22 between relay pulleys 21c and 2ici
a, 22b.

22c is wound around the ball screws 20a and 17b to connect them so as to rotate synchronously. In this way, both ball screws 20a
By detouring the drive transmission path between , 17b downward, it is possible to easily attach and detach members such as a component supply cassette 26, which will be described later, from the front side of the apparatus. The Y-axis driving ball screw 17a and the Y-axis driven ball screw 20b, which face each other on the back side of the device, are similarly connected to each other via toothed pulleys 23a, 23b and the like by a toothed belt 24c, etc., so that they can rotate synchronously.

Therefore, the Y-axis drive ball screw 17a facing the rear side of the device
The Y-axis drive ball screw 20b and the Y-axis drive ball screw 20b, which face each other in front of the device, are attached to both ends of the back side moving table 7A.
The shaft drive ball screws 17b are threadedly connected to both ends of the front side moving table 7B via nut members 25, respectively. In this case, each Y-axis drive ball screw 17a, 17b
are connected to the end of each of the movable platforms 7A, 7B where the spacing between the sliding bearings 8.8 is set to the large spacing DI.

Therefore, if the Y-axis drive motor 19b connected to the Y-axis drive ball screw 17b is operated, the toothed belts 22a to 2
The Y-axis drive ball screw 17b and the Y-axis drive ball screw 20a connected by 2c rotate synchronously, and a long head moving body HB consists of a moving table 7B on the near side and a pair of mounting heads 13 and 13 supported by this. Gagaidrail i3a, Et
Move in the X direction along b. In this case, the head moving body HB freely reciprocates in the area where the Y-axis drive ball screw 17b and the Y-axis drive ball screw 20a extend oppositely, that is, about 375 areas on the near side including the above-mentioned work station Ws above the base 1. do. On the other hand, the head moving body HA on the back side of the device
Similarly, the Y-axis drive ball screw 17a and the Y-axis drive ball screw 20b rotate synchronously with the operation of the Y-axis drive motor 19a, and freely reciprocate in about 375 areas on the back side including the work stage Ws. Therefore, both head moving bodies HA
.

Each movement area of the HB is located at the work station W in the center of the device.
They overlap in the end region (region above the substrate transport path) including s.

Incidentally, it is also possible to apply a driving force to the head moving bodies HA and HB from only one side to cause them to move back and forth in a straight line.
In the present invention, the driving force is applied from both sides as described above. The reason is as follows.

Each head moving body HA, HB has a pair of mounting heads 13.
13 movably in a predetermined direction (X direction), and various members such as a driving means are mounted on a moving table 7A.

Since it is supported on 7B, it is naturally long and heavy as a whole. Such a head moving body HA.

If you move the HB by applying driving force only from one end,
Since the moment of inertia is large, vibrations at the non-drive side ends of each head moving body HA and HB become intense, especially when starting or stopping. Therefore, not only the positioning accuracy of the head moving body HA itself, for example, decreases, but also its vibrations cause damage to the guide rail ea.

It is also transmitted to the other head moving body HB via eb.
It also reduces the positioning accuracy.

Therefore, in the present invention, as described above, ball screws 17a, 20b and ball screws 17b, 20a as driving means are connected to both ends of the head moving bodies HA, HH, respectively, and linear driving force is applied approximately equally from each end. to act. As a result, even the long and heavy head moving bodies HA and HB can be smoothly moved in the X direction without vibration and accurately positioned.

In addition, in order to more stably suppress the occurrence of vibration in each of the head moving bodies HA and HB, in this example, sliding bearings 8 and 8 on the driving side are used.
The distance DI is set larger than the distance D2 for the sliding bearing on the driven side. Thereby, the ball screws 17a, 20b and 17b, 2 on both sides that drive the head moving bodies HA, HB.
Even when the timings of the operations 0a are shifted, vibrations of the head moving bodies HA and HB can be effectively suppressed.

As a result, the head moving bodies HA and HB can be stably positioned with high precision.

Furthermore, for example, if we explain using the head moving body HB on the near side,
Each ball screw 20a, 17b is connected to a pair of guide rails ea, E3b that support both ends of the head moving body HB.
Since both are laid close to each other on the same rear side (with respect to the substrate transport direction T), the bending moment applied by the linear driving force acting on the head moving body HB is reduced.

Thereby, the rigidity 3-4- of the movable table 7B etc. in the head moving body HB can be reduced, and the size and weight of the apparatus can be reduced.

On the base 1, component supply units FA and F are located near the ends of the base on the back and front sides of the board conveyor 2.
B is set respectively. Each parts supply department FA, FB has
A large number of component supply cassettes 2E3A and 26B are set in parallel, respectively. The component supply cassettes 26A and 26B both contain a supply tape in which rectangular parallelepiped chip components are embedded at regular intervals, wound around a reel. Each component supply cassette 28A, 26B stores the same electronic component, and a large number of component supply cassettes 26
By arranging A and 26n in parallel, it is possible to prepare a large amount of various types of electronic components. In this case, the permutations and combinations of the types of electronic components (component supply cassettes) are optimally set so that components can be supplied efficiently in as short a time as possible. In this example, the component supply cassette 26B that stores large electronic components is placed in the component supply position FB on the front side, and the component supply cassette 26B that stores small electronic components is placed in the component supply position FA on the back side.
I set it to 8A. When parts are to be supplied, the supply tape is intermittently fed out from the reel by the provided feeding mechanism, and is picked up by the suction nozzle 13a (FIG. 2) of the mounting head 13 that has descended at the pick-up position Pp.

Between each component supply position FA, FB on the back side and front side of the device and the substrate transport conveyor 2, there are a pair of double-image recognition cameras 27A, 27A and 27B, 27B, and suction nozzle exchangers 28A, 28B, respectively. It is installed.

Each of the two-image recognition cameras 27A to 27B is mounted on the mounting head 13.
An image of the electronic component suctioned by the suction nozzle 13a is taken, and both images are processed by a computer to detect a deviation in the suction position. This detection data is sent to a central control unit (not shown) and is used for position correction when mounting the electronic component on the printed circuit board pb. In this example, each head moving body HA
, since two mounting heads 13 and 13 are installed in parallel on each HB, correspondingly two cameras 2 for both image processing are installed.
7A, 27A and 27B, 27B are arranged in parallel at each predetermined position.

Each of the suction nozzle exchangers 28A and 28B has a large number of storage pits formed in parallel, and holds various types of suction nozzles 13a in these storage pits in a freely insertable and removable manner in preparation for replacement. Both image recognition cameras 27A to 27B and suction nozzle exchanger 28A described above.

The installation position of 28B is optimally set so that the total mounting time of electronic components can be shortened as much as possible.

All the drive means in the electronic parts replacement device, i.e.
Axis drive motors 11, 11, Y-axis drive motor 19a+
1'9bz Motor 3 for driving each substrate conveyor, air cylinder for raising and lowering the mounting head 13 and for suction (not shown), feeding mechanism for component supply tape, etc., and camera 27A for processing both images.
27B is connected to a central control unit (not shown) of an electronic component replacement device, and an optimal control signal based on a preset program is output from the central control unit to each drive means, so that the electronic components can be replaced efficiently and in a short time. It is accurately mounted on the printed circuit board PB. The basic pattern of the component mounting operation will be explained below.

First, it is assumed that an electronic component is picked up by the rear mounting head 13, for example. A head unit (equipped with a pair of mounting heads 13.13)Uh is connected to a Y-axis drive motor 19a and an
While operating the shaft drive motor 11 to move in the X direction,
direction, and is stopped above the pickup position Pp of the component to be picked up in the component supply cassette 26A. Next, lower the head unit Uh and
After picking up several target parts at the same time, it is lifted up.

In addition, if two target parts cannot be picked up at the same time due to the arrangement of the parts supply cassette 26A, the head unit) Uh
are moved in the X direction and picked up one by one.

Next, in order to detect a suction position shift, the head unit 1-Uh that has suctioned the target component is moved above the double-image processing camera 27A, and double-image recognition of the component suction state is performed. The suction position data detected by both image recognition is sent to the central control unit.

When the rear head unit (Uh) is performing double-image recognition in the component suction state, the front head unit Uh performs the same operation as the rear head unit UlI from the front component supply cassette 26B. Pick up two electronic components to be mounted.

After the rear head unit 1-Uh has finished recognizing both images of the component, it places the component on the work station Ws.
Move to the place position where you want to perform. At this time, the central control unit corrects the stop position of the head unit )Uh based on the suction position deviation data obtained in the previous step of recognizing both images, and the head unit )Uh accurately stops at the corrected proper place position. The printed circuit board Pb is transported to the work station Ws as the board transport conveyor 2 rotates,
It is positioned in a predetermined position. The head unit Uh, which has finished positioning, immediately descends and touches the printed circuit board pb.
Place two electronic components in the specified positions on the top.

After the part placement by the back head unit Uh is completed, the part placement by the front head unit Uh is then performed. At this time, as mentioned above, since the movement ranges of the head moving bodies HA and HB overlap in the central area including the work stage G6, the head moving bodies HA
, there is a risk that the HBs will collide with each other. In this example, each Y-axis drive motor 19a.

An encoder section is provided in 19b, and pulse signals from the encoder section are counted by a central control section to grasp the position of each head moving body HA, HB. Then, while confirming the relative positions of both head moving bodies HA and HB based on the position data, drive control of each Y-axis drive motor 19a and 19b is performed to prevent a collision between the head moving bodies HA and HB on the work station Ws. It is prevented.

The back head unit Uh, which has finished placing the parts and retreated from the work stage Ws, heads again to the parts supply position FA in order to pick up the electronic parts to be newly mounted. Here, if it is necessary to replace the suction nozzle 13a for the next electronic component to be mounted, move the head unit Uh above the suction nozzle exchanger 28A, and replace the suction nozzle 13a.
exchange. In this case, first, the used suction nozzle 13a is stored in a predetermined storage pit, and then a new suction nozzle is installed. The suction nozzle 13a is automatically attached and detached by raising and lowering the head unit Uh.

The back head unit Uh has returned to the parts supply position FA.
Start picking up new electronic parts. At this time, the front head unit Uh is placing components onto the printed circuit board Pb.

Thereafter, the two head units Uh and Uh repeat the same operation, and the electronic components are mounted on the printed circuit board pb in an orderly and rapid manner.

As described above, electronic components are mounted alternately on one printed circuit board Pb using the two head units Uh and Uh from both sides while correcting the mounting position using the dual image recognition method. The installation time is reduced to about half compared to when installing with unit Uh. Therefore, by adopting the mounting position correction method using double image recognition, the time for mounting one electronic component increases, but this increase is almost canceled out in the total mounting time, and the mechanical suction position correction using the conventional chuck jaws If this method is adopted, the result will be -.

Further, since the suction nozzle exchangers 28A and 28B are respectively disposed in the movement area of each head unit Uh, the suction nozzles 13a in each head unit Uh can be exchanged independently from each other.

Therefore, one head unit) Uh is the suction nozzle 13a.
By optimally setting the timing and frequency of replacing the head unit Uh in consideration of the relationship with the mounting operation of the other head unit Uh, the increase in component mounting time due to replacing the suction nozzle can be minimized. can be suppressed to

It should be noted that the present invention is not limited to the specific embodiments described above, and it goes without saying that various modifications can be made within the technical scope of the present invention.

For example, the driving means for moving the head unit (Uh) is not limited to a combination of a motor and a ball screw, but various drive and speed change mechanisms such as a mechanism that converts the rotational force of a motor into linear motion using a pinion and a rack can be adopted. .

Also, guide rail 8a, E! The linear guide means such as b is not necessarily necessary, and can be omitted by increasing the rigidity of the drive elements 21-22- such as ball screws.

In addition, the present invention can also be applied to a method in which printed circuit boards are not continuously conveyed in a straight line by a conveyor, but are intermittently conveyed to a work station by a suction head or the like.

〔Effect of the invention〕

As described above in detail, according to the present invention, two sets of mounting moving bodies are provided, each of which is equipped with a work head capable of holding an electronic component in a detachable manner, and these mounting moving bodies are moved toward a component mounting area. Since the electronic components are advanced and retreated alternately from both sides, a large number of electronic components can be mounted on the board quickly and orderly, and the total time required for component mounting is greatly reduced. Then, since a double-image recognition means is installed in the moving area of each loaded moving body to take an image of the component holding state and detect a deviation in the holding position from both images, one loaded moving body performs double-image recognition. In the meantime, components can be mounted on the other mounting moving body.

Therefore, it is possible to cancel the relatively long recognition time for both images, and it is possible to carry out component mounting in approximately the same amount of time as when mounting components using a conventional mechanical component holding position correction method using one set of moving objects. Become. Therefore, it is possible to mount many types of electronic components at high speed and with high precision while correcting the mounting position using the dual image recognition method.

[Brief explanation of drawings]

FIG. 1 is a plan view showing an electronic component mounting apparatus as an embodiment of the present invention, and FIG. 2 is an elevational view of the electronic component mounting apparatus. 1... Base 2... Board conveyor 5a, 5b... Fixed base 8a, 6b... Guide rail 7A, 7B... Moving platform 8... Sliding bearing 9... X-axis ball screw 11...X-axis drive motor 12...Guide rod 13...Work head 13a...Suction nozzles 17a, 17b...Y-axis drive ball screw 19a,
19 b" 4-axis drive motors 20a, 20b...Y-axis driven ball screws 21a, 21b, 23a, 23b...
Toothed pulleys 21c, 21d... Relay pulleys 22a to 22c+ 24c... Toothed belt 25...
・Nut members 26A, 28B...Parts supply cassettes 27A, 27B
...Both image recognition cameras 28A, 28B...Suction nozzle exchanger Pb...Printed circuit boards HA, HB...Head moving body Uh...Head unit Ws...Work station Pp...Pickup Position 25-

Claims (1)

[Claims] A work head that removably holds an electronic component; a head drive means that slidably supports the work head and moves it back and forth; and a head support that supports the work head and the head drive means so that they can move together. , an electronic component mounting apparatus having a support driving means for moving the head support body forward and backward with respect to a component mounting work area, the mounting moving body comprising the work head, the head driving means, and the head support body; An electronic component mounting apparatus characterized in that two sets of image recognition means are provided in each movement region of the mounting moving body, and each image recognition means is installed in each moving area of the mounting moving body to take an image of the electronic component holding state of the work head and detect the holding position.