JP7752575B2 - How to search for component mounting equipment and backup pins - Google Patents

Description

This invention relates to technology for searching for backup pins.

Component mounting devices that automatically mount components on boards such as printed circuit boards are well known. The component mounting device is equipped with a backup plate on which multiple backup pins are arranged, and the board undergoes component mounting while supported from the back side by the backup pins. Patent Document 1 below discloses using the image recognition results of the backup plate to search for backup pins arranged on the backup plate.

Patent No. 6823156

Generally, the field of view of a camera is narrower than that of the backup plate. Therefore, to search for backup pins over the entire area of the backup plate, the camera must take multiple images. To efficiently search for backup pins, it is preferable to reduce the number of times the camera takes images. Similar problems arise when using search means other than a camera.
An object of the present invention is to efficiently search for backup pins by reducing the number of times and the search time for backup pins.

The component mounting device includes a backup plate, backup pins arranged on the backup plate, a head unit, a search device attached to the head unit for searching for the backup pins on the backup plate, and a control unit.

The control unit uses the search device to search for the backup pin within a specified search area on the backup plate, and if the backup pin is found, it excludes the pin-free area around the found pin and sets the next search area.

This configuration reduces the number of searches and search time for backup pins, allowing for efficient backup pin searches.

In one embodiment of the component mounting device, the search device may be a photography device. In this configuration, backup pins can be searched for using the photography device that is standardly equipped on the component mounting device.

The technology disclosed in this specification can reduce the number of searches and search time for backup pins, making the backup pin search process more efficient.

FIG. 2 is a plan view of the component mounting device. FIG. 2 is a diagram showing a support structure for a head unit. FIG. 2 is a diagram illustrating an electrical configuration of the component mounting apparatus. Plan view of the backup plate Diagram showing pin shape Diagram showing the relationship between pins and pin holes Diagram showing the relationship between pinholes and shooting areas Diagram showing pin-free area (invention applied) A diagram showing an example of pin search (comparison example) FIG. 1 shows a comparative example Pin search process flowchart Pin layout diagram Figure showing an example of pin search (invention application) A diagram showing an example of pin search (comparison example)

1. Overall configuration of component mounting device 1 Figure 1 is a plan view of the component mounting device 1 according to the present invention, and Figure 2 is a diagram showing the support structure of the head unit. In this figure, XYZ rectangular coordinate axes are appropriately shown, with the Z axis direction being the vertical direction.

The component mounting device 1 is a device that automatically mounts electronic components on a substrate S, such as a printed wiring board. The component mounting device 1 is equipped with a base 2, a substrate transport mechanism 4, a component supply unit 8, a head unit 10 that performs component mounting work, and a camera 14 for component recognition.

The base 2 is a table-like structure. The central portion of the base 2 in the front-to-back direction (Y-axis direction) is the work area where components are mounted on the board S, and the board transport mechanism 4 is located in this work area. In Figure 1, the lower side is the front side of the device, and the upper side is the rear side of the device.

The substrate transport mechanism 4 includes a pair of front and rear conveyors 5 and a substrate support mechanism 6 that fixes the substrate S transported by these conveyors 5 at a predetermined working position (the position shown in the figure).

Conveyor 5 is a belt conveyor that extends in the X-axis direction. Boards S are carried into the device from the left side (left side in Figure 1), undergo component mounting work at the work position, and then are carried out of the device from the right side.

The substrate support mechanism 6 lifts the substrate S from the belt of the conveyor 5 and presses it against a fixed backup plate portion attached to the conveyor frame, thereby fixing the substrate S in the working position. More specifically, the substrate support mechanism 6 is equipped with a backup plate 20 that is raised and lowered by an actuator such as an air cylinder. By raising this backup plate 20, backup pins 22 inserted into its upper surface support the substrate S from the rear (bottom) side. The position of the backup pins 22 can be changed manually or automatically depending on the type of substrate S.

Component supply units 8 are provided on both the front and rear sides of the board transport mechanism 4. Each component supply unit 8 has multiple tape feeders 9 arranged along the conveyor 5. The tape feeders 9 use tape as a carrier to supply components for mounting. The tape feeders 9 supply, for example, small chip components such as ICs, transistors, and capacitors, as well as small packaged components such as SOPs (Small Outline Packages).

A head unit 10 is movably mounted above the base 2. The head unit 10 picks up components from the tape feeder 9 and mounts them on the substrate S, and is driven to be movable forward, backward, left, right (X and Y directions) by a head unit drive mechanism using a servo motor as its drive source. Specifically, a head unit support member 16 extending left and right (X-axis direction) and movable forward and backward (Y-axis direction) is disposed above the work area, and the head unit 10 is movably supported on this head unit support member 16.

The head unit support member 16 is driven in the front-to-rear direction by a screw feed mechanism driven by the Y-axis motor 17, and the head unit 10 is driven in the X-axis direction along the head unit support member 16 by a screw feed mechanism driven by the X-axis motor 18. In other words, the head unit support member 16 and the screw feed mechanism constitute a head unit drive mechanism.

The head unit 10 is equipped with multiple heads 11 for component pickup and two cameras 12 for board recognition (hereinafter referred to as first cameras 12; these correspond to the imaging devices of the present invention). The multiple heads 11 are arranged in a row in the left-right direction. Each head 11 is capable of lifting and rotating, and is driven by a lifting mechanism and a rotation mechanism (not shown) that are driven by a servo motor. Components are picked up by these heads 11 and removed from the tape feeder 9.

The first camera 12 captures an image of the fiducial mark affixed to the board S in order to recognize the exact position of the board S at the work position. The first camera 12 is equipped with a camera body with an imaging element and a lighting device, and is disposed facing downward on both the left and right ends of the head unit 10. As will be described later, the first camera 12 is used not only to recognize the board S, but also to search for the backup pin 22. In this case, one or both of the two first cameras 12 are used. The first camera 12 corresponds to the "imaging device" and "search device" of the present invention.

A component recognition camera 14 (hereinafter referred to as the second camera 14) is provided on the base 2 between each component supply unit 8 and the board transport mechanism 4. The second camera 14 captures an image of the component removed from the tape feeder 9 by each head 11 in order to recognize the suction state of the component, and is positioned facing upward on the base 2. Like the first camera 12, the second camera 14 also comprises a camera body with an image sensor and a lighting device.

The component mounting operation in the component mounting device 1 is generally as follows. First, the head unit 10 moves above the component supply unit 8, and each head 11 picks up a component from the tape feeder 9. The head unit 10 then moves above the second camera 14 and above the board S, and the components picked up by each head 11 are mounted (placed) at the mounting point on the board S. At this time, the position of the head unit 10 is corrected based on the image of the picked-up component acquired by the second camera 14, so that the component is correctly mounted at the mounting point. This completes one cycle of the mounting operation, and this cycle is repeated thereafter to mount the required components on the board S.

The above operations performed by the component mounting device 1 are controlled by a control unit 30 equipped on the component mounting device 1, as shown in Figure 3.

The control unit 30 is a computer composed of a CPU and memory, and has a main control unit 32 that manages the control executed by the control unit 30. The control unit 30 also has a memory unit 33 that stores programs and various data, a camera control unit 34 that controls the imaging operation of the cameras 12 and 14 based on commands from the main control unit 32, an image processing unit 35 that performs predetermined image processing on image data sent from the cameras 12 and 14, a drive control unit 36 that controls the motors 17, 18, etc. based on commands from the main control unit 32, and a bus 31 that connects these units to the main control unit 32.

As described above, in the component mounting device 1, the board S undergoes mounting operations while supported by the backup plate 20 of the board support mechanism 6, more specifically, by a plurality of backup pins 22 (hereinafter referred to as pins 22 as appropriate).

2. Backup Pins The number and arrangement of pins 22 (hereinafter simply referred to as arrangement) suitable for supporting the substrate S differ depending on the type of substrate S. Therefore, when switching between types of substrate S, the arrangement of the pins 22 is changed as necessary. More specifically, as shown in Fig. 4, a plurality of pin holes 21 are provided in the upper surface 20a (referred to as the pin support surface 20a) of the backup plate 20 in a matrix arrangement with equal vertical and horizontal spacing.

In this example, the backup plate 20 has a total of 96 pin holes 21 arranged in a matrix, with 12 evenly spaced in the X-axis direction and 8 evenly spaced in the Y-axis direction. Pins 22 are inserted into the pin holes 21 positioned appropriately for the substrate S, and when the type of substrate S being produced is changed, the arrangement of the pins 22 is changed to suit the new substrate S.

The position of the pins 22 can be changed either manually or automatically. When done automatically, a dedicated tool for transporting the pins 22 is attached to the head 11, and the pins 22 are inserted and removed from the backup plate 20 based on the lifting and lowering movements of the head 11 and the movement of the head unit 10. This changes the position of the pins 22. The component mounting device 1 is also equipped with a pin station ST, which collects unused backup pins 22.

In the component mounting device 1, the arrangement of the backup pins 22 is stored in the memory unit 33. Therefore, for example, when recovering the backup pins 22 to the pin station ST, the current pin arrangement can be confirmed by accessing the memory unit 33 and reading the data, and the pins 22 can be recovered from the backup plate 20 to the pin station ST.

However, when the pins 22 are retrieved, if the data in the memory unit 33 is erased and the location of the backup pins 22 is unknown (for example, if the data is erased when the component mounting device 1 is turned off), it will be necessary to search for where the backup pins 22 are located on the backup plate.

3. Searching for the backup pin (1) Prerequisite 1
Figure 5 shows a front view and a bottom view of the backup pin 22. The backup pin 22 comprises a pin body 23, a bottom portion 24, and an insertion portion 25. The bottom portion 24 has a larger diameter than the pin body 23. The insertion portion 25 has a smaller diameter than the pin body 23 and is inserted into the pin hole 21. D in Figure 5 indicates the bottom diameter of the pin (the diameter of the bottom portion 24).

Due to the dimensions of the bottom diameter D of the pin 22 and the pitch P of the pin holes 21, when multiple pins are arranged, the pins must be spaced apart at a certain distance (a range where adjacent pins are not permitted). In other words, it is determined that no pins 22 exist within a certain range from the position where a pin 22 exists (if a pin 22 were to be placed, it would interfere with the existing pins 22).

For example, as shown in Figure 6, if a pin 22 is present in pin hole 21A, it is determined that no pin 22 is present in the adjacent range, specifically, pin holes 21B to 21F.

(2) Prerequisite 2
As shown in FIG. 7, since there are a plurality of pinholes 21 in the photographing area ER of the first camera 12, the presence or absence of pins 22 in the plurality of pinholes 21 can be recognized by image recognition in one photographing operation.

In this embodiment, the imaging area ER of the first camera 12 is a square with the length of one side approximately equal to twice the pitch P of the pinholes 21 (2 x P). Therefore, up to nine pinholes 21 can be captured simultaneously in one imaging session, with the field of view being the same.

(3) Combination of Preconditions 1 and 2 According to Preconditions 1 and 2, when a pin 22 is found in an image captured by the camera 12, a pin-absent range W (a pin hole where the absence of a pin is confirmed) in which the pin 22 is absent can be identified around the found pin. Assume that an image is captured with the pin hole 21A shown in FIG. 8 as the center of the image capture, and eight adjacent pin holes 21 included in the image capture area ER.

In this case, if a pin 22 is found in the pin hole 21B in the upper left corner, the area surrounding the upper left pin hole 21B is a pin-absent range W where no pins exist. Specifically, the five pin holes 21 (indicated by hatched circles) adjacent to the upper left pin hole 21B do not contain pins 22 and are therefore in a pin-absent range.

Similarly, if a pin 22 is found in the pin hole 21C in the lower right corner, the area surrounding the lower right pin hole 21C is a pin-absent range W where no pins exist. Specifically, the five pin holes 21 adjacent to the lower right pin hole 21C (indicated by hatched circles) do not contain pins 22 and are therefore part of the pin-absent range.

(4) Pin search excluding pin-free area W As described above, since there is a pin-free area W around the pin 22, the pin-free area W is identified from the photographing results (presence or absence of a pin in each pinhole), and the pin-free area W is excluded to determine the next photographing area ER, thereby reducing the number of photographs required for pin search.

For example, as shown in Figure 9, if the pin holes 21 are arranged in a 7x7 array with a pin 22 placed every other pin, by excluding the pin-free area W and determining the next shooting area ER, it is possible to perform a pin search for all pin holes 21 with a total of four shots. Note that in Figure 9, the arrows indicate the search order, and the hatched circles indicate pin holes 21 where it has been confirmed that no pins exist.

In contrast, if the pin-free range W is not excluded, nine shots are required to search for pins, as shown in Figure 10. Using this technology, the number of shots required is significantly reduced from nine to four.

(5) A flowchart of a pin search process.
11, the pin search process is made up of eight steps S10 to S80. The pin search process is executed, for example, as a pre-process when the backup pins 22 are collected in the pin station ST.

First, in S10, the control unit 30 determines whether all pins 22 are stored in the pin station ST. This determination can be made, for example, by photographing the pin station ST with the first camera 12 and judging from the image of the pin station ST.

If all pins 22 are stored in the pin station ST (S10: YES), there are no pins 22 on the backup plate 20, so the pin 22 search process ends.

If there are pins 22 that are not stored in the pin station ST (S10: NO), proceed to S20.

When the process proceeds to S20, the control unit 30 moves the head unit 10 onto the backup plate 20, captures images of the unsearched area on the backup plate 20 using the first camera 12, and detects the presence or absence of pins 22 in each pinhole 21 based on the images obtained.

In the first search, since all areas have not been searched, one of the four corner areas of the backup plate 20 is designated as the photography area ER and a photograph is taken to detect whether or not the pin 22 is present. Then, the process proceeds to S30.

When proceeding to S30, the control unit 30 determines whether or not a pin 22 has been detected in the initial search area (photography area ER). If a pin 22 has been detected (S30: YES), proceed to S40.

When proceeding to S40, the control unit 30 determines the next search area (photography area ER) by excluding the following two:

(A) Searched area (B) Pin-free area W

On the other hand, if no pin 22 is detected in the initial search area (S30: NO), proceed to S50.

When proceeding to S50, the control unit 30 excludes only the searched area (A) and determines the next search area (photography area ER).

Then, the process proceeds to S60, where the control unit 30 takes a camera image of the next search area determined in S40 or the next search area determined in S50, and detects the presence or absence of pins 22 in each pinhole 21 based on the obtained image. Then, the process proceeds to S70.

When proceeding to S70, the control unit 30 determines whether all pins 22 have been discovered. If there are undiscovered pins 22 (S70: NO), the control unit 30 proceeds to S80. When proceeding to S80, the control unit 30 determines whether there are any unsearched areas remaining.

If there are any unsearched areas (S80: NO), the process proceeds to S30 and repeats the same process as already described.

Then, when all pins 22 have been found (S70: YES) or there are no more unsearched areas (S80: YES), the pin 22 search process ends.

Figure 12 shows the arrangement of pin holes 21 and the placement of pins 22. In this example, nine backup pins 22 are arranged on a backup plate 20 having 12 x 8 pin holes 21.

Figure 13 is a diagram showing an example of a search for a pin 22. White circles represent pinholes 21 where no pin is placed, black circles represent pinholes 21 where a pin is placed, and hatched circles represent pinholes 21 where the absence of a pin has been confirmed. In this example, the first row moves the photography area ER from the left corner to the right corner. By excluding the pin-free range W and determining the position of the photography area ER, the pin search is completed in three shots in the first row.

In the second row, the shooting area ER has been moved from the right corner to the left corner. As with the first row, by excluding the pin-free area W and setting up the shooting area ER, the pin search is completed in three shots.

In the third row, the shooting area ER has been moved from the left corner to the right corner. As with the first and second rows, by excluding the pin-free area W and setting up the shooting area ER, the pin search is completed in four shots.

In this way, pin search can be completed for the entire area of the backup plate 20 with a total of 10 shots. In contrast, if the non-existent area W is not excluded, 12 shots are required to search for pins, as shown in Figure 14. Using this technology, the number of shots required is reduced from 12 to 10. One of the features of this technology is that it dynamically changes the position of the next search area depending on the pin search results (presence or absence).

4. Description of Effects With this configuration, the number of times the pin holes 21 need to be photographed can be reduced when searching for pins 22 on the backup plate. In particular, the more pins that have been searched for, the wider the pin-free range W becomes. This reduces the search area ER, making it possible to reduce the number of times the images need to be photographed. Reducing the number of times the images are photographed also reduces the search time, allowing for more efficient pin 22 search work. Furthermore, pins 22 are often arranged densely. In such cases, applying this technology effectively makes it possible to significantly reduce the number of times the images need to be photographed and the search time.

<Other Embodiments>
The technology disclosed in this specification is not limited to the embodiments described above and illustrated in the drawings, and the following embodiments, for example, are also included in the technical scope.

In the above embodiment, a camera 12 was used to search for the backup pin 22, but a laser detector, sensor, etc. may also be used as long as it is capable of detecting the pin 22.

In the above embodiment, an example was described in which this technology was used to search for backup pins, but it can also be applied to checking whether there are any extra backup pins on a backup plate.

1 Component mounting device 10 Head unit 12 First camera (corresponding to the photographing device and search device of the present invention)
20 Backup plate 22 Backup pin 30 Control unit W Pin-free range

Claims (3)

A component mounting device,
A backup plate;
a backup pin disposed on the backup plate;
A head unit and
a search device attached to the head unit and configured to search for the backup pin on the backup plate;
a control unit;
the control unit searches for the backup pin within a predetermined search area on the backup plate using the search device;
When the backup pin is found, the component mounting device excludes a pin-free area around the found pin and sets the next search area. 2. The component mounting apparatus according to claim 1,
The component mounting apparatus, wherein the search device is an imaging device. A method for searching for a backup pin, comprising:
Searching for the backup pin within a predetermined search area on the backup plate;
When the backup pin is found, the search method for the backup pin excludes a pin-free area around the found pin and sets the next search area.