GB2326980A

GB2326980A - Chip components mounting apparatus

Info

Publication number: GB2326980A
Application number: GB9810318A
Authority: GB
Inventors: Shuichi Munakata; Yoshikazu Inamura
Original assignee: Alps Electric Co Ltd
Current assignee: Alps Alpine Co Ltd
Priority date: 1997-07-01
Filing date: 1998-05-15
Publication date: 1999-01-06
Anticipated expiration: 2018-05-15
Also published as: KR100300837B1; CN1104833C; JP3512598B2; MY121750A; GB2326980B; GB9810318D0; CN1208323A; KR19990013480A; JPH1126989A

Description

CHIP COMPONENTS MOUNTING APPARATUS The present invention relates to a chip components mounting apparatus for mounting lead wire-free chip components such as resistors and capacitors onto a printed circuit board at predetermined positions. Particularly, the invention is concerned with a chip components mounting apparatus called a multi-mounter capable of mounting a large number of chip components onto a printed circuit board by a single operation.

FIGS. 7 and 8 illustrate a conventional chip components mounting apparatus of this type, which is disclosed in Japanese Patent Publication No. Hei 3-15835.

As shown in FIG. 7, a plurality of hoppers 1 are disposed on a components supply stage of the apparatus, with a large number of chip components 2 being received respectively in the hoppers 1. The hoppers 1 are connected to an aligning plate 4 respectively through guide pipes 3. Under the aligning plate 4 is disposed a template 5. The template 5 comprises a guide plate 5a and a base plate 5b which are integral with each other. The guide plate 5a, as an upper plate, is formed with a large number of retaining holes 6.

The template 5 can be moved vertically by means of a drive source (not shown) and is conveyed up to a mounting stage by means of a feed belt (not shown). On the mounting stage is disposed a suction unit having a plurality of suction nozzles 7, as shown in FIG. 8.

In the chip components mounting apparatus thus constructed, first the template 5 is raised into alignment with the aligning plate 4 at the components supply stage by means of the drive source, and in this state the chip components 2 are allowed to drop from the hoppers 1 into the retaining holes 6 through the guide pipes 3 and further through the aligning plate 4. After the chip components 2 have thus dropped into the retaining holes 6 of the template 5, the template is put onto a feed belt (not shown) and is conveyed thereby up to the mounting stage.

During this conveyance, the template 5 is oscillated, thereby causing the chip components 2 to fall sideways within the retaining holes 6. Next, at the mounting stage, the chip components 2 are sucked up from the retaining holes 6 of the template 5 by means of the suction nozzles 7.

Thereafter, as shown in FIG. 8, a printed circuit board 8 is fed just under the suction nozzles 7, and the chip components 2 are fixed temporarily onto pasty solders 9 applied beforehand to predetermined positions of the printed circuit board 8. The chip components 2 are thus transferred from the template 5 onto the printed circuit board 8. Subsequently, the printed circuit board 8 is heated in a reflow oven, resulting in that the pasty solders 9 become melted and electrodes of the chip components 2 are soldered to land portions of the printed circuit board.

Therefore, according to the chip components mounting apparatus constructed as above, the chip components 2, at the components supply stage, are dropped into the retaining holes 6 of the template 5, then the template 5 is conveyed up to the mounting stage by the feed belt, where by the chip components 2 can be transferred from the retaining holes 6 of the template 5 onto the printed circuit board 8.

Thus, if only the retaining holes 6 are formed in the template 5 correspondingly to the number and positions of the chip components 2 to be mounted onto the printed circuit board 8, a single operation permits a large number of chip components 2 to be mounted simultaneously onto the printed circuit board.

In the conventional chip components mounting apparatus described above, the chip components 2 mounted on the printed circuit board 8 and the retaining holes 6 formed in the template 5 positionally correspond to each other, therefore, as the mounted state of the chip components 2 on the printed circuit board 8 becomes denser, not only it is necessary to form in the template 5 a large number of retaining holes 5 in a closely spaced relation to one another, but also it is necessary that suction nozzles 7 for sucking the chip components 2 be also be arranged closely to one another. Thus, there arises the problem that it is impossible to meet the demand for high density mounting of the chip components 2.

According to the present invention, the positions of chip components to be mounted onto a printed circuit board are divided into plural groups, and retaining holes corresponding to those groups are formed for each of the groups beforehand in a template so as to be distributed in two-dimensional directions. Further, the chip components held in the retaining holes are sucked by suction nozzles of a suction unit and are then mounted on the printed circuit board at predetermined positions while the board is moved in two-dimensional directions. With this construction, not only the retaining holes of the template can be formed coarse in comparison with the mounting density of the chip components on the printed circuit board, but also the suction nozzles of the suction unit can be arranged coarse. Thus, it becomes possible to easily satisfy the demand for high density mounting of chip components.

More specifically, according to the present invention there is provided a chip components mounting apparatus wherein chip components received within a plurality of hoppers are dropped into a large number of retaining holes, which are formed in a template correspondingly to predetermined chip components mounting positions of a printed circuit board, and are arranged in order therein, then the template is conveyed up to the position just under a suction unit, and thereafter the chip components are sucked out of the retaining holes by means of plural suction nozzles of the suction unit and are mounted onto the printed circuit board at the predetermined positions, the chip components mounting positions on the printed circuit board being divided into plural groups, for each of which retaining holes are formed in the template so as to be distributed in two-dimensional directions in corresponding relation to the components mounting positions of that group, and the printed circuit board being moved in two-dimensional directions to mount the chip components sucked by the suction nozzles onto the printed circuit board for each of the groups.

As means for conveying the template up to the position just under the suction unit may be used an XY table which constitutes a stationary portion of a twodimensional linear motor and at least two carriers which constitute a movable portion of the two-dimensional linear motor. By one carrier the template is moved to just under the suction unit, while by the other carrier the printed circuit board is moved in two-dimensional directions, whereby not only it is possible to enhance the degree of freedom of circulation paths along which the template moves, but also a relative position between each suction nozzle and the printed circuit board can be corrected accurately.

Embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings, in which: FIG. 1 is a front view of a chip components mounting apparatus according to an embodiment of the present invention; FIG. 2 is a side view thereof; FIG. 3 is a plan view schematically showing movement paths of carriers provided in the chip components mounting apparatus; FIG. 4 is a sectional view explaining operation principles of the carriers; FIGS. 5A and 5B are explanatory diagrams showing a relation between components mounting positions of a printed circuit board and the positions of retaining holes formed in a template; FIG. 6 is a sectional view showing principal portions of the template and each carrier; FIG. 7 is an explanatory diagram showing in what manner chip components are dropped onto a template provided in a conventional chip components mounting apparatus; and FIG. 8 is an explanatory diagram showing in what manner the chip components are mounted onto a printed circuit board from the template shown in FIG. 7.

An embodiment of the present invention will be described in detail hereinunder with reference to the accompanying drawings, in which FIG. 1 is a front view of a chip components mounting apparatus embodying the invention, FIG. 2 is a side view thereof, FIG. 3 is a plan view schematically showing movement paths of carriers provided in the chip components mounting apparatus, FIG. 4 is a sectional view explaining operation principles of the carriers, FIGS. 5A and 5B are explanatory diagrams showing a relation between components mounting positions of a printed circuit board and the positions of retaining holes formed in a template, and FIG. 6 is a sectional view showing principal portions of the template and each carrier.

As shown in FIGS. 1 to 3, an XY table 11 is fixed onto a base 10 of the chip components mounting apparatus, and first to third carriers 12, 13 and 14 are placed on the XY table 11. A plurality of hoppers 15 are disposed above the XY table 11, and chip components are received within the hoppers 15. The hoppers 15 are connected through guide pipes 16 to an arrangement board 17 mounted on the base 10.

The arrangement board 17 constitutes a components supply means, and just under the arrangement board is positioned a components supply stage S1. On the base 10 are mounted a suction unit 18 and a pair of image pickup cameras 19. A mounting stage S2 is positioned just under the suction unit 18, while just under the cameras 19 are disposed image recognition stages S3. The image recognition stages S3 are in symmetric positions with respect to a straight line joining the components supply stage S1 and the mounting stage S2. In FIG. 1, due to a limited space for illustration, the suction unit 18 is shifted to the righthand side, and the right-hand camera 19 is omitted. On the front side of the XY table 11 are disposed two conveyors 20 for the conveyance of printed circuit boards 21. Between the two conveyors 20 is formed a substrate supply/discharge stage S4.

As shown in FIG. 4, the XY table 11 constitutes a stationary portion of a two-dimensional linear motor, in which a stationary member 22 made of a high permeability material such as pure iron has a large number of convex portions 22a formed in a lattice shape at pitches of 1 mm for example. The surface of the stationary member 22 is covered with a resin coat 23. On the other hand, the first to third carriers 12, 13 and 14 constitute movable portions of the two-dimensional linear motor. The carriers each comprise a movable member 24 formed of a non-magnetic material such as, for example, aluminum and a plurality of magnet cores 25 incorporated in the movable member 24, the magnet cores 25 each having a comb teeth-like end faces, whose end faces are opposed with a slight phase difference respectively to the convex portions 22a of the stationary member 22. A coil 26 is wound round each magnet core 25.

By controlling the direction and magnitude of an electric current to be fed to the coils 26, the first to third carriers 12, 13 and 14 can be moved freely in twodimensional directions on the XY table 11 at pitches of 0.01 mm for example. High-pressure air is blown off between the stationary member 22 and the movable member 24 to form an air gap, so that the first to third carriers 12, 13 and 14 move smoothly on the XY table 11.

Templates 27 are fixed respectively onto the first and second carriers 12, 13, and a large number of retaining holes 27a for receiving chip components 28 therein are formed in the template 27, as shown in FIG. 6. The first carrier 12 circulates along circulation paths a to d in the left half of FIG. 3, while the second carrier 13 circulates along circulation paths e to h in the right half of FIG. 3.

Thus, the first and second carriers 12, 13 move along different circulation paths from each other. On the other hand, a printed circuit board 21 is put on the third carrier 14. The third carrier 14 reciprocates between the mounting stage S2 and the substrate supply/discharge stage S4 in FIG. 3, and when the chip components 28 are mounted onto the printed circuit board 21 at the mounting stage S2, the third carrier 14 moves in two-dimensional directions, as will be described later.

As shown in FIGS. 5A and 5B, each of the positions on the printed circuit board 21 where the chip components 28 are mounted dose not correspond to each of the positions on the template 27 where the retaining holes 27a are formed.

In such a corresponding relation to the chip components mounting positions, the retaining holes 27a are formed group by group distributedly in two-dimensional directions.

To be more specific, as shown in FIG. 5A, a division is made into plural mounting position groups, four groups A to D for example, so that components mounting positions are spaced as apart as possible from one another, taking into account the density of components mounting positions on the printed circuit board 21. On the other hand, as shown in FIG. 5B, the upper surface of the template 27 is divided into four areas of A to D, and retaining holes 27a corresponding to the mounting position groups A to D are formed respectively in the areas A to D. As a result, the density of retaining holes 27a in each of the areas A to D on the template 27 becomes one fourth of the mounting density of the chip components 28 on the printed circuit board 21. Likewise, the arrangement density of suction nozzles (not shown) of the suction unit 18 also becomes one fourth of the chip components mounting density on the printed circuit board 21.

The following description is now provided about the operation of the chip components mounting apparatus constructed as above. Before the start of operation, the first and second carriers 12, 13 are moved to predetermined positions on the Xy table 11, for example, to left and right upper corners, respectively, in FIG. 3 and are then subjected to positioning with respect to their origins.

Thereafter, the first carrier 12 is moved to the components supply stage S1, where the chip components 28 received in the hoppers 15 are dropped through the guide pipes 16 and the arrangement board 17 into the retaining holes 27a of the template 27 fixed onto the first carrier 12. At this time, the second carrier 13 stands by at the position of its origin mentioned above.

After the chip components 28 are thus dropped onto the template 27 on the first carrier 12, the first carrier is moved from the components supply stage S1 to the image recognition stage S3 through the circulation path a in FIG.

3, then is returned to the components supply stage S1 through the circulation paths b, c, d and is thereafter circulated along the circulation paths a to d. When the first carrier 12 moves from the components supply stage S1 to the image recognition stage S3, the second carrier 13 moves in its turn from the position of the origin to the components supply stage S1, where the chip components 28 received in the hoppers 15 are dropped into the retaining holes 27a of the template 27 fixed onto the second carrier 13. Subsequently, the second carrier 13 circulates along the circulation paths e to h in FIG. 3 while being delayed one to three steps relative to the first carrier 12, and at each stage there is performed a predetermined operation for the templates on the first and second carriers 12, 13.

More specifically, the first carrier 12 moves from the components supply stage S1 to the image recognition stage S3, where it is reciprocated slightly in XY directions, so that the chip components 28 oscillate within the retaining holes 27a of the template 27 placed on the first carrier 12. At this time, by controlling the direction and magnitude of the electric current to be fed to the coil 26, the first carrier 12 can be oscillated in various patterns of different amplitudes and different accelerations. Therefore, within the retaining holes 27a of the template 27, the chip components 28 also oscillate in various patterns and are brought down sideways, whereby a disorderly arrangement of the chip components is almost corrected. Thereafter, at the image recognition stage S3, the presence or absence of the chip components 28 in the retaining holes 27a, as well as the state of arrangement of the chip components such as whether their sideways fallen condition is satisfactory or not, are checked imagewise using the cameras 19.

Next, the first carrier 12 moves from the image recognition stage S3 to the mounting stage S2, where the chip components 28 on the template 27 are sucked by suction nozzles (not shown) of the suction unit 18 and are thereby taken out from the retaining holes 27a. Since the retaining holes 27a are formed dividedly to four areas A to D on the template 27, the chip components 28 thus sucked by the suction nozzles are not in corresponding relation to the components mounting positions on the printed circuit board 21. Subsequently, the first carrier 12 returns to the image recognition stage S3, where it is checked imagewise whether the chip components 28 have been taken out in a satisfactory condition or not. If the answer is affirmative, that is, if there is no defect, the first carrier 12 returns to the components supply stage S1, where the chip components 28 are again dropped into the retaining holes 27a of the template 27.

On the other hand, the third carrier 14 receives a printed circuit 21 from one conveyor 20 at the substrate supply/discharge stage S4, then moves to the mounting stage S2, where the chip components 28 located on the suction unit 18 side are fixed temporarily to predetermined positions on the printed circuit board 21, using a pasty solder. In this case, as noted previously, the chip components 28 located on the suction unit 18 side do not correspond to the components mounting positions on the printed circuit board 21,respectively, so that when the third carrier 14 is moved in two-dimensional directions at the mounting stage S2, the chip components are fixed temporarily to the predetermined positions on the printed circuit board. For example, when the third carrier 14 is moved in the order of areas A, B, C and D on the template 27, first the chip components 28 corresponding to the area A are temporarily fixed onto the printed circuit board 21 and thereafter the chip components 28 corresponding to the areas B, C and D are successively fixed temporarily onto the printed circuit board. In this way the chip components 28 corresponding to all of the mounting position groups A to D are fixed temporarily onto the printed circuit board 21. Thereafter, the third carrier 14 moves from the mounting stage S2 to the substrate supply/discharge stage S4, where the printed circuit board 21 with the chip components 28 mounted thereon is discharged from the third carrier 14 onto the other conveyor 20.

Also for the template 27 on the second carrier 13 there are performed just the same operations as above at each stage, provided the second carrier 13 reciprocates along the circulation paths e to h different from the circulation paths of the first carrier 12 while being delayed one to three steps relative to the first carrier.

For example, when the first carrier 12 moves along the circulation path d toward the components supply stage S1, the second carrier 13 moves along the circulation path g toward the image recognition stage S3. For example, therefore, in the event a disorderly arrangement of chip components 28 is detected with respect to the template 27 on the second carrier 13, only the second carrier 13 is moved from the image recognition stage S3 to the correction stage S5 (see FIG. 3) on the XY table 11, and while the second carrier 13 is stopped for correction at the correction stage S5, the first carrier 12 and the third carrier 14 are moved in the manner described above, whereby the chip components 28 can be mounted on the printed circuit board 21. Conversely, while the first carrier 12 is stopped, the second carrier 13 and the third carrier 14 are moved in the manner described above, thereby permitting the chip components 28 to be mounted on the printed circuit board 21.

Although in the above embodiment the first and second carriers 12, 13 are moved between the components supply stage S1 and the mounting stage S2 along circulation paths different from each other, either the first carrier or the second carrier and the third carrier 14 may be used to mount the chip components 28 on the printed circuit board 21 although the working efficiency is somewhat deteriorated.

Although in the above embodiment the components mounting positions on the printed circuit board 21 are divided into four groups and retaining holes 27a are formed in the template 27 so as to be distributed group by group, it goes without saying that the number of divided groups of the components mounting position is not limited to four, which number may be a plural number other than four according to the mounting density of the chip components 28 on the printed circuit board 21.

Claims

1. A chip components mounting apparatus in which chip components received in a plurality of hoppers are dropped into a multitude of retaining holes which are formed in a template correspondingly to predetermined chip components mounting positions on a printed circuit board, and are arranged in order in said retaining holes, then said template is conveyed up to the position just under a suction unit, allowing the chip components to be sucked out of said retaining holes by a plurality of suction nozzles of said suction unit and be mounted onto said printed circuit board at the predetermined positions, wherein: the chip components mounting positions on said printed circuit board are divided into a plurality of groups, said retaining holes are formed in the template so as to be distributed in two-dimensional directions group by group and in corresponding relation to the chip components mounting positions, and said printed circuit board is moved in two-dimensional directions, allowing the chip components sucked by said suction nozzles to be mounted group by group onto the printed circuit board.

2. A chip components mounting apparatus according to claim 1, including an XY table which constitutes a stationary portion of a two-dimensional linear motor and at least two carriers which constitute movable portions of the two-dimensional linear motor, and wherein said template and said printed circuit board are moved by said carriers.

3. A chip components mounting apparatus substantially as hereinbefore described with reference to, and as illustrated by, Figures 1 to 6 of the accompanying drawings.