JP3338501B2 - Best point pick method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a best point picking method for sucking and holding an optimum position of two kinds of chip-shaped electronic components.

[0002]

2. Description of the Related Art Conventionally, a production line for producing a printed circuit board unit is composed of devices such as a substrate supply device, a dispenser, a component mounting device, and a reflow furnace. Among these apparatuses, the component mounting apparatus has an I.S.P. on a printed circuit board which is supplied with solder from a preceding dispenser and sent out.
A large number of chip-shaped electronic components such as C, resistors, capacitors, etc. are automatically mounted and sent to a reflow furnace at a later stage. This component mounting apparatus is provided with a work head that can freely move in three dimensions, that is, in a vertical, horizontal, and vertical direction, and a chip-shaped electronic component (hereinafter, referred to as a component) is supplied from a component supply unit by a suction nozzle mounted on the work head. , Simply called electronic components) and automatically mounts the electronic components on a printed circuit board.

Each time the mounting operation is performed, two suction nozzles are attached to the operation head in order to shorten the total time required for the operation head to reciprocate between the printed circuit board (hereinafter simply referred to as the substrate) and the component supply unit and to increase the operation efficiency. In some cases, two electronic components are simultaneously attached and held.

[0004] By the way, the process of simultaneously picking up two electronic components involves moving the work head to a predetermined component supply unit position based on the positional relationship between the two suction nozzles and the two component supply units calculated in advance by a program. Go and run. However, when the two suction nozzles do not suck the two electronic components at the correct positions due to the arrangement error of the work head based on the mechanical assembly error with respect to the main unit or the mounting error of the component supply unit, etc. There are many.

[0005] In this case, the center of one of two types of electronic components housed in two adjacent component supply units is:
The two electronic components are simultaneously sucked so that the center of one of the two suction nozzles coincides.

[0006]

However, for example, FIG.
As shown in FIG. 5, when two kinds of large and small electronic components 54a and 54b are to be simultaneously sucked, when the center of the suction nozzle 52A is aligned with the center of the small electronic component 54a, as shown in FIG. , 54b and the center distance L2 between the two suction nozzles, the error x
Therefore, even if the center of the suction nozzle 52B is displaced from the center of the electronic component 54b, the distance ε from the center of the electronic component 54b to the limit of the suckable range (the hatched portion in the drawing).
If b is larger than the error x, the two electronic components 54a and 54b can be easily sucked without any problem.
Can be adsorbed simultaneously.

However, if the reference nozzle designated by the component mounting program is the suction nozzle 52B shown in the figure, the work head moves its moving position to the left as indicated by the arrow D in the figure to indicate the error. The center of the suction nozzle 52B is made to match the center of the electronic component 54b by correcting the distance x. Then, since the distance εa from the center of the electronic component 54a to the limit of the adsorbable range and the error x are almost the same, the electronic component 54a is adsorbed at the adsorbable limit point, and a suction error occurs. The problem that it is easy occurs.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and an object thereof is to realize a best point picking method for always picking up both electronic components to be picked up at an appropriate picking position. It is.

[0009]

SUMMARY OF THE INVENTION According to the present invention, two types of chip-shaped electronic components having different dimensions are simultaneously suction-held by a first and a second suction portion interlocked on a working head and mounted on a printed circuit board. Therefore, the present invention is applied to the best point picking method for sucking and holding the optimal positions of the above two types of chip-shaped electronic components.

[0010] The best point picking method according to the present invention is provided when the center of the first suction portion and the center of one of the two types of chip-like electronic components corresponding to the first suction portion coincide with each other. A suction error distance between the center of the second suction portion and the center of the other two types of chip-shaped electronic components is detected, and the detected suction error distance is determined by a predetermined ratio.
It is divided and this division point is sucked at the center of the second suction part.

According to a second aspect of the present invention, the distance between the center of one of the two types of chip-type electronic components and the limit of the effective range of the chip-type electronic components is determined by dividing the suction error distance into two. And the distance between the center of the other two types of chip-shaped electronic components and the distance to the limit of the effective suction range of the chip-shaped electronic components.

[0012]

The best point picking method of the present invention occurs when the center of the first suction part and the center of one of the two kinds of chip-shaped electronic components corresponding to the first suction part coincide with each other. A suction error distance between the center of the second suction portion and the center of the other chip-shaped electronic component is detected, and the detected suction error distance is determined by the center of the one chip-shaped electronic component and the chip-shaped electronic component. The distance between the center of the other chip-shaped electronic component and the distance to the limit of the effective area of the chip-shaped electronic component is divided into two parts by the ratio of the distance to the limit of the effective area of the part to be picked up and the second suction point. Adsorbed at the center of the part.

[0013] This makes it possible to always pick up both of the two electronic components to be picked up at an appropriate picking position, thereby eliminating a pick-up mistake.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a control unit of the electronic component mounting apparatus according to one embodiment. The electronic component mounting apparatus sucks an electronic component using the best point picking method of the present invention and automatically mounts the electronic component on a printed circuit board.

In FIG. 1, the control unit has a CPU (Central Processing Unit) 1 for controlling the entire apparatus. The CPU 1 includes a key input unit 2, a storage unit 3, a display unit 4, a servo motor Control unit 5 and this servo motor control unit 5
Is connected to the servo motor drive unit 6 via
An / o control unit 7, a pulse motor control unit 8, and a pulse motor drive unit 9 are connected via the pulse motor control unit 8.

The key input unit 2 has a keyboard 2a to be described later, and outputs a key input signal input from the keyboard 2a to the CPU 1. The storage unit 3 has a ROM (Read
and a memory such as a random access memory (RAM), which is accessed by the CPU 1 after storing control and processing programs, various processing data, and the like. The display unit 4 includes a display device 4a described later,
Displays key input data and processing details.

The CPU 1 outputs to the servo motor control unit 5 a drive signal for moving a work head, which will be described later, back and forth and left and right. The servo motor control unit 5 decodes the drive signal input from the CPU 1 and outputs the decoded drive signal to the servo motor drive unit 6. The servo motor drive unit 6 includes an input / output port, and an X-axis servo motor 6a to be described later and a Y (not shown)
Connected to the axis servomotor, the servomotor controller 5
Drive signals input from the X-axis servo motors 6a and Y
Assign to axis servo motor.

The CPU 1 outputs to the pulse motor control unit 8 a drive signal for vertically moving or rotating a suction head of the working head, which will be described later. The pulse motor control unit 8 decodes the drive signal input from the CPU 1 and outputs it to the pulse motor drive unit 9. The pulse motor drive unit 9 also has an input / output port, and is connected to a pulse motor for vertical movement and a pulse motor for rotation (not shown).
The drive signal input from the pulse motor control unit 8 is assigned to a pulse motor for vertical movement and a pulse motor for rotation.

The CPU 1 further includes a control signal for controlling a vacuum pump for operating a suction nozzle, which will be described later, of the suction head, a control signal for operating an air cylinder for driving a stopper for stopping the substrate, and a support pin for supporting the substrate from below. A control signal for setting a position is output to the i / o control unit 7. The i / o control unit 7 converts the control signals input from the CPU 1 into a vacuum pump, an air cylinder,
The output is assigned to the plate elevator drive unit and the like.

FIG. 2 is a front view of the electronic component mounting apparatus controlled by the control unit. In FIG. 1, an electronic component mounting device (hereinafter, referred to as a main device) 10 is a device base 1.
A control unit shown in FIG. 1 is provided in the inside 1a of the device 0a, and a printed circuit board (hereinafter, simply referred to as a substrate) is provided in the inside 11a.
Is provided with a support plate device and the like for supporting the device from below. Various devices are arranged on the upper portion of the device base 10a, and a safety cover 10b (shown by a two-dot chain line) that separates the devices from the outside.
The upper part is covered by. The safety cover 10b has an opening at the front center, a display device 4a comprising a liquid crystal display or a CRT (Cathode Ray Tube) display at the upper part of the non-opening wall on the right side, and a keyboard 2a below the display device 4a. . The keyboard 2a has numerical keys and various instruction keys, and key inputs are made by an external operation.

In the center of the apparatus base 10a, a pair of fixed and movable parallel substrate guide rails 11 are disposed so as to extend horizontally in the substrate transport direction (X-axis direction) (not shown). .
The pair of board guide rails 11 guides the transfer of the board and positions the board in the width direction (Y-axis direction). A plurality of not-shown conveyor belts stretched in a loop shape in contact with the lower part of the board guide rails 11 are movably disposed.
Each of these conveyor belts is driven by a belt drive motor (not shown), looking at the side of the belt having a width of several millimeters in the substrate transport path, and traveling in the substrate transport direction from right to left as indicated by arrow A, The substrate is transported while supporting both sides of the back surface of the substrate from below.

Further, on the apparatus base 10a, a pair of left and right sides extending in a direction (Y-axis direction) perpendicular to the substrate transfer direction (X-axis direction) across the pair of substrate guide rails 11 is provided. Fixed bases 12, 12 'are provided. Although not shown, Y-axis rails are respectively laid on the fixed bases 12 and 12 '. On the Y-axis rail, a long moving table 13 is slidably supported in the Y-axis direction by ball bearings provided at the lower portions at both ends in the longitudinal direction. A work head 14 for mounting is suspended.

The moving table 13 has a longitudinal direction (X
An X-axis servo motor 6a for moving the working head 14 forward and backward in the axial direction) is provided. One end of an X-axis drive feed screw 6c is connected to a drive shaft of the X-axis servo motor 6a via a coupling 6b. The X-axis drive feed screw 6c is screwed with a nut member 14a of the working head 14, and The end is fitted to a bearing fixed to the movable base 13. Therefore, the X-axis drive servo motor 6a connected to the X-axis drive feed screw 6c
Rotates forward and backward, the X-axis drive feed screw 6c rotates forward and backward, and the working head 14 screwed with the screw via the nut member 14a moves forward and backward in the X-axis direction.

The working head 14 includes two suction heads 14c for transferring components and a board recognition camera 14d for confirming a component mounting position of the board, and is disposed inside the apparatus base 1a. 1 is connected by a flexible communication cable 14b. Work head 14
Is supplied with power and a control signal from the control unit via the communication cable 14b, and transmits image data indicating a position on the board to be operated to the control unit.

Next, a Y-axis drive servomotor (not shown) for driving the movable table 13 in the Y-axis direction is arranged on the fixed table 12, and the fixed tables 12 and 12 'are respectively provided with the movable table 1
A Y-axis drive feed screw (not shown) and a Y-axis driven feed screw (not shown) for transmitting the drive of the servo motor are arranged at 3. The Y-axis drive feed screw has a toothed pulley (not shown) having the other end supported by a bearing and fixed to the other end.
The above-mentioned toothed pulley to which the toothed pulley is fixed via another toothed pulley which meshes with one end of the toothed pulley and the loop and another toothed pulley which meshes with the other end of the loop of the toothed belt. It is connected to the Y-axis driven feed screw so as to be able to rotate synchronously. Y-axis drive feed screw and Y-axis driven feed screw are
The moving table 13 is connected to both ends in the longitudinal direction of the moving table 13 via nut members (not shown) screwed to the respective feed screws.

Therefore, if the Y-axis drive servo motor connected to the Y-axis drive ball screw is rotated forward and backward, the Y-axis drive feed screw and the Y-axis driven feed screw rotate synchronously, and are screwed together with these via a nut member. The moving table 13 and, therefore, the work head 14 suspended therefrom moves forward and backward in the Y-axis direction.

A component supply corner 15 is provided in front of the apparatus base 10a. A plurality of component supply units for supplying components to the work head 14 are detachably attached to the component supply corner 15.

FIG. 3 is a perspective view showing a state where the work head 14 sucks components from a plurality of component supply units. As shown in the figure, suction nozzles 14e, 14e attached to the tips of two suction heads 14c, 14c rotatably arranged on the work head 14, respectively,
From the two component supply units 15a, 15a mounted in the component supply corner 15, a large number of electronic components 21,
This shows a state in which the pickup 21 is being picked up by suction.

A component recognition camera 31 as shown in FIG. 4A is arranged between the component supply corner 15 and the fixed board guide rail 11 on the front side of the apparatus base together with a suction nozzle exchanger and the like. ing. The component recognition camera 31 and the suction nozzle exchanger are provided so as to be integrally movable in the X-axis direction by a ball screw and a motor for driving the ball screw.

As shown in the figure, the component recognition camera 31 is provided with a suction head 14 c provided on the working head 14.
The suction nozzle 14e sucks and picks up the electronic component 21 from the component supply unit 15a, and waits while moving above the substrate to wait for the suction nozzle 14 of the suction head 14c.
The electronic component 21 to which e is sucked is imaged from below. The image data obtained by this imaging is transmitted to the control unit shown in FIG. 1, and an image recognition process for centering the electronic component 21 is performed.

The controller recognizes the image of the electronic component 21 obtained in the reference visual field 31a of the component recognition camera 31 shown in FIG. The rotation of the suction head 14c is corrected so as to face the Y-axis direction.

Also, the control unit is provided with the component recognition camera 3.
1, the center of the suction nozzle 14e is recognized by imaging the suction nozzle 14e before electronic component suction, and the suction position is determined by image recognition of the electronic component 21 obtained by imaging the electronic component 21 after the electronic component suction. Identify deviations.

Here, the two suction nozzles 14e of the suction head 14c disposed on the working head 14 cause
An algorithm for calculating the position at which the work head 14 stops in order to attract the electronic components 21 of various types at the optimal position is described below.
This will be described with reference to FIGS.

FIGS. 3A and 3B show two suction nozzles 14e.
(14e-1, 14e-2) and two types of electronic components 21
FIG. 3A schematically shows the positional relationship of (21-1 and 21-2). FIG. 3A shows one of the two suction nozzles, with reference to one of the suction nozzles 14e-1.
When the center of the first suction nozzle 14e-1 matches the center of the electronic component 21-1 corresponding to the suction nozzle 14e-1, the center of the other suction nozzle 14e-2 corresponds to the center of the electron corresponding to the suction nozzle 14e-2. The figure shows a state where it is shifted outward by a distance X from the center of the component 21-2.

The algorithm of the optimum position pickup in the present invention is based on the assumption that the shifted distance X is determined by the two types of electronic components 21-.
1, 21-2. By doing so, the shift of the suction position is corrected as the size of the small electronic component becomes smaller and the size of the larger electronic component becomes larger, so that the shift of the suction position is not biased toward one of the electronic components. Therefore, the danger of causing a suction error by performing suction while a large deviation occurs on the suction side of the small electronic component is eliminated.

Two types of electronic parts 21-1 and 21-2 shown in FIG.
The shaded portions 1-2 indicate the effective suction ranges of both parts. Even if an attempt is made to suck the electronic component 21-1 or 21-2 at a position outside the effective suction range (shown by a white solid color), the electronic component can be sucked well because the left and right balance of the suction position cannot be maintained. Misadsorption occurs.

Not only for these electronic components 21-1 and 21-2, but also for the types of all electronic components to be processed, data of the effective suction range of the electronic components is stored in the storage unit 3 in advance as a table. By reading the corresponding data of the electronic components 21-1 and 21-2 from this table, the distances d1 and d2 from the center of each of the electronic components 21-1 and 21-2 to the limit of the effective suction range are calculated. It is possible. These suction effective ranges, that is, the distances d1 and d2 from the center to the limit of the suction effective range are proportional to the sizes of the respective electronic components 21-1 and 21-2.

The position data of the arrangement positions of the two component supply units 15a accommodating the two types of electronic components 21-1 and 21-2 are described in the processing program, and the position data is read from the processing program. By 2
Storage positions (x, y) of the electronic components 21-1 and 21-2
Coordinates) can be recognized. by this,
The center coordinates of the two types of electronic components 21-1 and 21-2 can be calculated.

The two suction nozzles 14e-1 and 14e-1
The center-to-center distance of each of e-2 is recognized in advance using a component recognition camera 31 shown in FIG. 4A and stored in a predetermined area of the storage unit 3. Thereby, the center of the other suction nozzle 14e-2 with respect to the one suction nozzle 14e-1 and the electronic component 21-
The amount of deviation (error distance) X from the center of 2 can be calculated in advance.

This shift amount (error distance) X is divided by a ratio proportional to the size of both electronic components 21-1 and 21-2, and is used as a shift amount of each suction position after suction position correction described later. Allocated to the electronic components 21-1 and 21-2. As described above, the distances d1 and d2 from the centers of the electronic components 21-1 and 21-2 to the limit of the effective suction range are proportional to the sizes of the respective electronic components 21-1 and 21-2. Therefore, instead of the size of the electronic component, these distances d1,
The displacement amount (error distance) X is divided and distributed according to d2.

For this purpose, first, the shift amount X is subdivided into amounts corresponding to the distances d1 and d2. This is represented by the equation “Δd = X ÷
(D1 + d2) ". Next, this Δd is
The distribution is performed according to the magnitudes of the distances d1 and d2. this is,
It is obtained by the expressions “x1 = Δd × d1” and “x2 = Δd × d2”. Here, x2 can also be obtained by the expression “x2 = X−x1”.

As is clear from FIGS. 5A and 5B and the above equation, the stop position of the working head 14 is shifted rightward by the displacement x1 to be distributed to the electronic component 21-1 obtained by the above calculation. If the correction (X-x1) is performed, the suction nozzle 14e-1 becomes x1
The suction nozzle 14e-2 moves toward the center of the electronic component 21-2 by x1, leaving a displacement of "X-x1" (= x2). As a result, the shift amounts x1 and x2 to be distributed to the electronic components 21-1 and 21-2 can be distributed to the two types of electronic components 21-1 and 21-2, respectively.

That is, “x1” obtained from the above equations
= (X ÷ (d1 + d2)) × d1 ”, and the stop position of the work head 14 may be corrected to the right by x1 (minus correction). The same figure
The shift amount X shown in (a) is outside the center of the electronic component 21-2, but when the shift amount X is inside the center of the electronic component 21-2, it is corrected to the left by the calculated x1. (Plus correction).

FIG. 6 shows a processing operation of correcting the stop position of the work head 14 based on such an algorithm and sucking an electronic component in the electronic component mounting apparatus having the above-described configuration of the present embodiment. This will be described with reference to a flowchart. This processing is performed by the CPU of the control unit shown in FIG.
1 is based on the electronic component mounting processing program stored in the storage unit 3 to position the board to be carried into the main unit, and to suck the electronic component.
This is a process performed in a process in which a series of processing operations of mounting the electronic component on a substrate and unloading the substrate are repeated, and mounting the electronic component on a predetermined number of substrates. In this process, registers A, B, X, and Y built in the CPU 1 are used to temporarily store data.

In the flowchart shown in the figure, first, initial settings are made (step S1). In this process, data such as the type of electronic component that is predetermined in accordance with the type of board processed by the electronic component mounting processing program and the mounting position of the component supply unit in which the electronic component is stored are shown in FIG. 1 from the storage unit 3 shown in FIG.
In this process, the values of the center coordinates (x, y) of the pick-up position of the electronic component to be picked up are set in the registers X and Y based on the read data.

Next, the suction range of the chip A (electronic component) is determined (step S2). In this process, in order to recognize a range in which one of the two electronic components to be simultaneously sucked (chip A) can be sucked (effective), a table is prepared in advance corresponding to each type of electronic component. The effective range data of the electronic component (chip A) is read from the table indicating the effective suction range registered in the storage unit 3, and the effective suction data is read from the center of the electronic component 21-1 shown in FIGS. 5 (a) and 5 (b). This is a process of calculating the distance d1 to the limit of the range and storing it in the register A.

Subsequently, a suction range of the chip B (electronic component) is determined (step S3). This processing is performed for the other electronic component (chip B) of the two electronic components that are simultaneously sucked.
The data of the electronic component (chip B) is read from the table indicating the effective suction range in the same manner as described above in order to recognize the range in which the electronic component 2 can be sucked, and the electronic component 2 shown in FIGS.
This is a process of calculating the distance d2 from the center of 1-2 to the limit of the effective suction range and storing it in the register A.

Then, the optimum position is determined (step S
4). This process corrects the suction stop position of the working head 14 by plus or minus x1 based on the algorithm shown in FIGS. 5 (a) and 5 (b).

Subsequently, it is moved to the optimum position (step S
5). In this processing, the X-axis servo motor 6a and the Y-axis servo motor (not shown) shown in FIG.
4 is a process for moving the position No. 4 to the optimum position obtained by the above correction.

Then, adsorption is started (step S).
6). This process is a process of controlling the vacuum pump to operate the two suction nozzles 14e-1 and 14e-2 to simultaneously suction two types of electronic components.

According to the present embodiment, the suction nozzle 14e-1
Although only one of the two suction nozzles is used as the reference suction nozzle for calculating the position, any one of the two suction nozzles may be set as the reference suction nozzle.

[0052]

According to the present invention, the amount of deviation between the centers of the two suction nozzles and the centers of the two electronic components can be distributed in proportion to the sizes of the two electronic components.
Both of the two electronic components to be picked up can always be picked up at the appropriate picking position, and therefore, the risk that a shift in the picking position is biased toward one electronic component to cause a picking error in a small electronic component is eliminated. You.

[Brief description of the drawings]

FIG. 1 is a block diagram of a control unit of an electronic component mounting apparatus according to one embodiment.

FIG. 2 is a front view of the electronic component mounting apparatus controlled by a control unit.

FIG. 3 is a perspective view showing a state in which a work head sucks components from a plurality of component supply units.

FIGS. 4A and 4B are diagrams illustrating image pickup by a component recognition camera, and FIG. 4B is a diagram illustrating image recognition by image pickup by a component recognition camera;

FIGS. 5A and 5B are diagrams illustrating an algorithm for calculating a position for sucking two kinds of electronic components at an optimum position by two suction nozzles.

FIG. 6 is a flowchart illustrating a processing operation for sucking an electronic component at an optimum position.

FIG. 7 is a diagram illustrating a conventional state in which two types of electronic components, large and small, are simultaneously attracted.

[Description of Signs] 1 CPU 1a Inside of device base 2 Key input unit 2a Keyboard 3 Storage unit 4 Display unit 4a Display unit 5 Servo motor control unit 6 Servo motor drive unit 6a X-axis servo motor 6b Coupling 6c X-axis drive Feed screw 7 i / o control unit 8 pulse motor control unit 9 pulse motor drive unit 10 main unit 10a device base 10b safety cover 11 board guide rail 11a inside of device base 12, 12 'fixed base 13 movable base 14 work head 14a Nut member 14b Communication cable 14c Suction head 14d Substrate recognition camera 14e Suction nozzle 15 Component supply corner 15a Component supply unit 21 Chip-shaped electronic component

Continuation of front page (58) Fields investigated (Int.Cl. ⁷ , DB name) B25J 9/10 B25J 15/06 H01L 21/68 H05K 13/02

Claims (2)

(57) [Claims] The two types of chips are mounted in such a manner that two types of chip-shaped electronic components having different dimensions are simultaneously suction-held and mounted on a printed circuit board by first and second suction portions interlocked on a work head. In the best point picking method for sucking and holding an optimal position of a chip-shaped electronic component, the center of the first suction part and the center of one of the two kinds of chip-shaped electronic parts corresponding to the first suction part are set. detecting a suction error distance between the center of the second the two with the center of the suction portion of the other kinds of electronic chip components generated when matched, the adsorption error distance the detected
A best point picking method, comprising: dividing the chip-shaped electronic component into two parts at a ratio proportional to the size of the chip-shaped electronic part, and adsorbing the division point at the center of the second adsorption part. 2. The distance between the center of the one of the two types of chip-shaped electronic components, the distance to the limit of the effective suction range of the chip-type electronic components, and the center of the other two types of chip-shaped electronic components. 2. The best point picking method according to claim 1, wherein the detected suction error distance is divided into two by a ratio of a distance to a limit of a suction effective range of the chip-shaped electronic component.