JP7212467B2 - Component mounter - Google Patents

Description

The technology disclosed in this specification relates to a component mounting apparatus.

Patent Literature 1 discloses a component mounting apparatus. This component mounting apparatus includes a rotary head having a plurality of suction nozzles for sucking components, and an imaging device for capturing images of the components sucked by the suction nozzles.

JP 2017-73474 A

2. Description of the Related Art In a component mounting apparatus, there are some components that are picked up by a suction nozzle for which a plurality of images are captured under different imaging conditions. In the component mounting apparatus of Patent Literature 1, in order to perform a plurality of imaging operations while changing the imaging conditions, it takes time to switch the imaging conditions. That is, when imaging a component under the first imaging condition and the second imaging condition, first, the component is imaged under the first imaging condition, and then the imaging condition is changed from the first imaging condition to the second imaging condition. , and then the part must be imaged under the second imaging condition. In the component mounting apparatus of Patent Literature 1, the driving of the component mounting apparatus must be stopped while the imaging conditions are changed, which may reduce production efficiency. This specification provides a technique for suppressing a decrease in production efficiency caused by switching imaging conditions.

This specification discloses a component mounting apparatus that mounts a component on a substrate. This component mounting apparatus includes a rotary head having a plurality of suction nozzles for sucking components, and an imaging device for capturing images of the components sucked by the suction nozzles. The plurality of suction nozzles are arranged on the first circumference at intervals in the circumferential direction, and are movable on the first circumference. The imaging device is capable of imaging the component sucked by the suction nozzle under a plurality of different imaging conditions at a plurality of imaging positions provided on the first circle.

Since the component mounting apparatus described above has a plurality of imaging positions on the first circle, different imaging conditions can be set for each of the plurality of imaging positions. Therefore, the component sucked by the suction nozzle can be imaged under a plurality of imaging conditions simply by moving the suction nozzle to a plurality of imaging positions. Since it is not necessary to switch the imaging conditions at each imaging position, it is possible to suppress a decrease in production efficiency caused by switching the imaging conditions.

1 is a schematic diagram showing the configuration of a component mounter 10 of an embodiment; FIG. FIG. 2 is a side view schematically showing a rotary head 20 of the component mounter 10; FIG. 2 is a bottom view schematically showing the rotary head 20; 4 is a flowchart showing a mounting procedure of the component mounter 10; The schematic diagram of the lower surface of the rotary head 20 which concerns on a modification.

In an embodiment of the present technology, the plurality of imaging positions may include a first imaging position and a second imaging position different from the first imaging position. Further, the imaging device may include a first camera that images the component at the first imaging position and a second camera that images the component at the second imaging position. In that case, the imaging conditions at the first imaging position may be the imaging conditions of the first camera, and the imaging conditions at the second imaging position may be the imaging conditions of the second camera. The imaging conditions of the first camera may differ from the imaging conditions of the second camera. By equipping the first camera and the second camera, different imaging conditions can be set for the first camera and the second camera.

In an embodiment of the present technology, the plurality of imaging positions may include a first imaging position and a second imaging position different from the first imaging position. The imaging device may comprise a first illuminator for illuminating the component at the first imaging position and a second illuminator for illuminating the component at the second imaging position. The imaging conditions at the first imaging position may be illumination conditions by the first illuminator, and the imaging conditions at the second imaging position may be illumination conditions by the second illuminator. The lighting conditions provided by the first illuminator may differ from the lighting conditions provided by the second illuminator. By equipping the first illuminator and the second illuminator, the part can be illuminated under two illumination conditions without changing the illumination conditions of each illuminator.

In an embodiment of the present technology, the component sucked by the suction nozzle causes the first camera to image the component when positioned at the first imaging position, and the component sucked by the suction nozzle is captured by the second camera. A control device may be further provided that causes the second camera to image the component when positioned at the imaging position of the second camera.

A component mounter 10 of an embodiment will be described with reference to the drawings. A component mounter 10 of this embodiment is an example of a component mounter in the technology disclosed in this specification, and is a device that mounts a component 12 on a board 14 . The component 12 is configured by a system such as BGA (Ball Grid Array) or CSP (Chip Scale Package). As shown in FIG. 2, the component 12 has, on a mounting surface (lower surface) 12a to the substrate 14, for example, a plurality of convex electrodes (bumps, pillars, etc.) 12b (only one is shown in the figure for simplicity); A planar mark (not shown) is provided to indicate the orientation of the electrodes 12b (that is, the orientation of the component 12 when mounted on the substrate 14). When mounting the component 12 on the board 14, it is necessary to accurately detect the position and direction of the electrode 12b of the component 12 with respect to the board 14, and position and mount the component 12 with respect to the board 14 based on the detection result. be. Therefore, in this embodiment, the same component 12 is imaged under a plurality of imaging conditions, and the position and direction of the component 12 with respect to the board 14 are adjusted.

The component mounter 10 is also called a surface mounter or a chip mounter. The component mounter 10 is usually installed together with a solder printer, other component mounters, and board inspection machines to form a series of mounting lines. As shown in FIG. 1, the component mounter 10 of this embodiment includes a rotary head 20, a first imaging device 37 and a second imaging device 39 (imaging device unit 30), a moving device 40, and a control device. 50 , a plurality of component feeders 62 and a substrate transport apparatus 64 .

Each of the multiple component feeders 62 accommodates multiple components 12 . A component feeder 62 supplies components 12 to the rotary head 20 .

The moving device 40 is a device that moves the rotary head 20 with respect to the substrate 14 and is driven by the control device 50 . The moving device 40 includes an xy robot mechanism that drives the rotary head 20 in xy directions. The moving device 40 includes a guide rail that guides the rotary head 20, a moving mechanism that moves the rotary head 20 along the guide rail, a motor that drives the moving mechanism, and the like. By moving the rotary head 20 with the moving device 40, the rotary head 20 can move between the position where the component 12 is supplied by the component feeder 62 and the substrate 14 on which the component 12 is mounted. Here, the x direction and the y direction of the "xy direction" are substantially perpendicular to each other (see FIGS. 2 and 3).

The substrate transfer device 64 is a device that carries the substrate 14 into the component mounter 10 , positions it in the component mounter 10 , and carries it out from the component mounter 10 . The substrate conveying device 64 of this embodiment includes, for example, a pair of belt conveyors (not shown), a supporting device (not shown) attached to the belt conveyors and supporting the substrate 14 from below, and a driving device for driving the belt conveyors. It can be configured by The board 14 is positioned at a mounting position within the component mounter 10 , and when the component 12 is mounted at the mounting position, the board 14 is transported from the mounting position to the outside of the component mounter 10 .

As shown in FIGS. 2 and 3 , the rotary head 20 includes a base 27 , a rotating portion 26 , multiple nozzle holders 24 , and multiple suction nozzles 22 . The base 27 is attached to the moving device 40 and is movable in the xy directions by the moving device 40 . The rotating part 26 is rotatably attached to the base 27 . The rotating portion 26 protrudes downward from the lower surface of the base 27 . The rotating part 26 rotates around the axis R with respect to the base 27 by an actuator (not shown).

A plurality of nozzle holders 24 are attached to the rotating portion 26 . More specifically, the plurality of nozzle holders 24 are arranged on the lower surface of the rotating part 26 on a circumference C (an example of a first circumference) at a constant distance from the axis R at equal intervals in the circumferential direction. are placed. As described above, since the rotating portion 26 can rotate about the axis R with respect to the base 27, when the rotating portion 26 rotates about the axis R, the plurality of nozzle holders 24 are separated from each other by the adjacent nozzle holders 24. It moves on the circumference C while maintaining it. Further, each of the plurality of nozzle holders 24 is configured to be movable in the z direction (vertical direction) by an actuator (not shown) housed in the rotary head 20 . A suction nozzle 22 is detachably held in each of the plurality of nozzle holders 24 . The suction nozzle 22 is a nozzle that sucks the component 12 . Since the nozzle holder 24 can move on the circumference C, the suction nozzle 22 can also move on the circumference C. As shown in FIG. A suction position A1 is set on the circumference C, and a first imaging position B1 and a second imaging position B2 are also set. The component 12 can be sucked by the suction nozzle 22 when the suction nozzle 22 is positioned at the suction position A1. Also, when the suction nozzle 22 is positioned at the first imaging position B1 and the second imaging position B2, the component 12 sucked by the suction nozzle 22 can be imaged.

As is clear from the above description, by moving the base 27 in the xy directions, the suction nozzle 22 held by the nozzle holder 24 can move in the xy directions. It moves on the circumference C by rotating around, and moves in the z direction by moving the nozzle holder 24 in the z direction. Therefore, by moving the suction nozzle 22 in various directions, the component 12 can be sucked by the suction nozzle 22 and the component 12 sucked by the suction nozzle 22 can be mounted on the substrate 14 . Therefore, in order to mount the component 12 on the substrate 14 by the rotary head 20, first, the suction nozzle 22 is positioned in the xy direction with respect to the component 12 supplied from the component feeder 62, and the suction surface (lower surface) of the suction nozzle 22 is positioned. ) is brought into contact with the suction nozzle 22 . When the suction surface of the suction nozzle 22 abuts on the component 12, the suction nozzle 22 suctions the component 12 and moves the suction nozzle 22 upward. Next, the component 12 sucked by the suction nozzle 22 is positioned with respect to the substrate 14 by the moving device 40 . At this time, the position and orientation of the component 12 in the xy direction are adjusted so that the plurality of electrodes 12b of the component 12 are positioned at predetermined positions on the substrate 14. FIG. Next, the component 12 is attached to the substrate 14 by moving the suction nozzle 22 downward until the component 12 contacts the substrate 14 . Note that FIG. 3 omits illustration of the component 12 sucked by the suction nozzle 22 .

The imaging device unit 30 includes a first imaging device 37 and a second imaging device 39, and the imaging devices 37 and 39 are attached to the base 27 of the rotary head 20 (see FIG. 2). The imaging devices 37 and 39 are devices for capturing an image of the component 12 sucked by the suction nozzle 22 , and captures an image of the mounting surface (lower surface) 12 a of the component 12 . Since the imaging devices 37 and 39 are attached to the base 27 of the rotary head 20, the imaging devices 37 and 39 do not rotate even if the rotary section 26 rotates. Therefore, the imaging devices 37 and 39 are fixed in position to image, and when the suction nozzle 22 is positioned at a predetermined imaging position, the component 12 sucked by the suction nozzle 22 is imaged. Specifically, when the suction nozzle 22 is positioned at the first imaging position B<b>1 , the component 12 sucked by the suction nozzle 22 is imaged by the first imaging device 37 . Also, when the suction nozzle 22 is positioned at the second imaging position B2, the component 12 sucked by the suction nozzle 22 is imaged by the second imaging device 39 . The first imaging position B1 and the second imaging position B2 are provided at different positions on the circumference C, and the illumination by the first imaging device 37 and the illumination by the second imaging device 39 are They are placed far enough apart that they do not interfere.

The first imaging device 37 includes a first component camera 32 , a first illuminator 36 and a first reflecting mirror unit 33 . The first component camera 32 uses the first illuminator 36 and the first reflecting mirror unit 33 to image the component 12 under the first imaging conditions. Specifically, the first illuminator 36 is configured to irradiate the mounting surface 12a of the component 12 with light obliquely downward (side lighting) via the first reflecting mirror unit 33. there is That is, the first illuminator 36 emits light that forms an acute angle (less than 90°) between the mounting surface 12a and the optical axis of the first illuminator 36 . The first reflecting mirror unit 33 is composed of, for example, a pair of reflecting mirrors, and is arranged on the optical axis of the first component camera 32 . The first component camera 32 images the mounting surface 12a of the component 12 illuminated by the first illuminator 36 via the first reflecting mirror unit 33 (see FIG. 2).

Similarly, the second imaging device 39 includes a second component camera 34, a second illuminator 38, and a second reflecting mirror unit (not shown). The second component camera 34 uses a second illuminator 38 and a second reflecting mirror unit to capture an image of the component 12 under a second imaging condition. Specifically, the second illuminator 38 is configured to vertically irradiate the entire mounting surface 12a of the component 12 with light via the second reflecting mirror unit. That is, the second illuminator 38 irradiates the entire mounting surface 12a with parallel light, and the incident angle of the parallel light with respect to the mounting surface 12a is 90°. The second reflector unit has a configuration similar to that of the first reflector unit 33 . Therefore, the second component camera 34 images the mounting surface 12a of the component 12 illuminated by the second illuminator 38 via the second reflecting mirror unit. Here, the first component camera 32 and the second component camera 34 are examples of the first camera and the second camera in the technology disclosed in this specification.

Under the (first) imaging condition of the first imaging device 37 described above, the mounting surface 12a of the component 12 is obliquely irradiated with light. Therefore, in the captured image obtained by the first component camera 32, the (unevenness) structure of the electrode 12b provided on the mounting surface 12a of the component 12 can be easily recognized. Therefore, when mounting the component 12 on the substrate 14, it becomes easy to position the electrode 12b of the component 12 at a desired position. Under the (second) imaging condition of the second imaging device 39 described above, the entire mounting surface 12a of the component 12 is irradiated with light from the vertical direction. Therefore, in the captured image obtained by the second component camera 34, the (planar) mark for indicating the orientation of the electrode 12b provided on the mounting surface 12a of the component 12 can be easily recognized. Therefore, when the component 12 is mounted on the board 14, it becomes easy to determine the direction of the component 12 with respect to the board 14. FIG.

As described above, the component mounter 10 of the present embodiment picks up an object on the pick-up nozzle 22 under different conditions such as the first imaging condition and the second imaging condition at the first imaging position B1 and the second imaging position B2. It is possible to image the part 12 that has been processed. That is, by moving the suction nozzle 22 on the circumference C, it can move to a plurality of imaging positions B1 and B2. Therefore, by setting different imaging conditions for each imaging position as in this embodiment, there is no need to switch the imaging conditions of the imaging device unit 30, and the component 12 sucked by the suction nozzle 22 can be picked up under different imaging conditions. It can be imaged. Therefore, it is possible to suppress a decrease in production efficiency caused by switching imaging conditions.

The control device 50 is configured using a computer having a CPU, ROM, and RAM. As shown in FIG. 1, the rotary head 20, the moving device 40, the imaging device unit 30, the component feeder 62, and the board transfer device 64 are communicably connected to the control device 50. FIG. The control device 50 drives each connected device 20, 30, 40, 62, 64 by executing a pre-installed program. That is, the control device 50 drives the moving device 40 to move the rotary head 20, and when the suction nozzle 22 of the rotary head 20 is positioned at the suction position A1, moves the suction nozzle 22 in the z direction. By doing so, the component 12 is sucked. Further, the controller 50 mounts the component 12 on the board 14 by moving the suction nozzle 22 in the z direction when the component 12 that has been sucked is positioned at the mounting position (not shown). Further, the control device 50 causes the first component camera 32 to image the component 12 sucked by the suction nozzle 22 when positioned at the first imaging position B1, and positions the component 12 at the second imaging position B2. Then, the second component camera 34 is caused to take an image.

A procedure for mounting the component 12 on the board 14 using the component mounter 10 will be described with reference to FIG. First, in step S<b>12 , the component mounter 10 sucks the component 12 onto the suction nozzle 22 . Specifically, the control device 50 drives the moving device 40 to move the rotary head 20 to a position (component feeder 62) where the component 12 is picked up. The control device 50 drives the rotary movement mechanism (actuator) of the rotary head 20 to rotate the rotating portion 26 and positions the suction nozzle 22 at the suction position A1. Next, the control device 50 drives the z-axis movement mechanism (actuator) of the rotary head 20 to move the suction nozzle 22 positioned at the suction position A1 downward from the reference height. ) to suck the component 12 . After picking up the component 12, the picking nozzle 22 moves upward again and returns to the reference height.

Next, in step S14, the first imaging device 37 images the component 12 under the first imaging condition at the first imaging position B1 (see FIG. 3). Specifically, the control device 50 drives the rotary movement mechanism of the rotary head 20 to rotate the rotating portion 26 and positions the component 12 sucked by the suction nozzle 22 at the first imaging position B1. Next, the control device 50 drives the first imaging device 37 to image the mounting surface 12a of the component 12 positioned at the first imaging position B1. At this time, the first illuminator 36 obliquely irradiates the mounting surface 12a of the component 12 with light. The first imaging device 37 is fixed to the base 27 of the rotary head 20 and is not affected by the rotation of the rotating portion 26 of the rotary head 20 or the like. Therefore, while the imaging process of step S14 is being performed, the rotary head 20 can pick up another component 12 using another pick-up nozzle 22 positioned at the pick-up position A1.

Next, in step S16, the second imaging device 39 images the component 12 under the second imaging conditions at the second imaging position B2 (see FIG. 3). Specifically, the control device 50 drives the rotary movement mechanism of the rotary head 20 to rotate the rotating portion 26 and positions the component 12 sucked by the suction nozzle 22 at the second imaging position B2. Next, the control device 50 drives the second imaging device 39 to image the mounting surface 12a of the component 12 positioned at the second imaging position B2. At this time, the second illuminator 38 irradiates the entire mounting surface 12a of the component 12 with light in the vertical direction. In this embodiment, the illumination lights of the first imaging device 37 and the second imaging device 39 do not interfere with each other, and can be photographed simultaneously. Therefore, while the imaging process of step S16 is being performed, the first imaging device 37 can image the mounting surface 12a of the component 12 positioned at the first imaging position B1. 20 can pick up another component 12 using another pick-up nozzle 22 positioned at pick-up position A1.

Next, in step S18, positioning processing for determining the position and direction of the component 12 is executed. Specifically, the control device 50 performs image processing on captured images under two different lighting conditions obtained from the first imaging position B1 and the second imaging position B2, and identifies the positions of the electrodes 12b of the component 12. At the same time, the direction of the component 12 with respect to the suction nozzle 22 is identified. Then, based on the specified position of the electrode 12b and direction of the component 12, the position and direction of positioning the suction nozzle 22 (component 12) with respect to the substrate 14 are determined. Based on the determined positioning direction, the control device 50 drives the rotary movement mechanism of the rotary head 20 to adjust the mounting direction of the component 12 with respect to the board 14 .

Next, in step S20, the component 12 is mounted on the board 14. FIG. Specifically, the control device 50 drives the moving device 40 to adjust the rotary head 20 in the xy direction based on the positioning position determined by the positioning processing in step S18, thereby positioning the component 12 relative to the substrate 14. Adjust position. After positioning, the control device 50 drives the z-axis movement mechanism of the rotary head 20 to move the suction nozzle 22 downward and mount the component 12 on the board 14 .

Through the series of steps described above, the component mounter 10 is used to complete the mounting of the component 12 on the board 14 . Therefore, even if one component 12 performs imaging under a plurality of imaging conditions, it does not take time to switch the imaging conditions. That is, it is possible to suppress a decrease in production efficiency caused by switching imaging conditions.

Although one component 12 has been described in the mounting procedure of the above-described embodiment, the component 12 can be mounted on the board 14 by using a plurality of other suction nozzles 22 at the same time and performing similar steps.

Further, the direction (rotational angle) adjustment of the component 12 in step S18 was performed before the (xy) position adjustment of the component 12 in step S20, but the order is not limited to this order, and the (xy) position adjustment of the component 12 is performed. Orientation (rotation angle) adjustment of the component 12 may be performed later. Alternatively, both may be performed simultaneously. Here, the "rotational angle" is an angle of rotation about an axis substantially perpendicular to the xy plane (substantially horizontal plane consisting of the above-mentioned x and y directions).

Further, in the above-described embodiment, the imaging condition to be changed is the irradiation angle of illumination, but the present invention is not limited to such an example, and can be applied when various imaging conditions are changed. As a modification, the light source colors of the first imaging device 137 and the second imaging device 139 may be different. This is because depending on the form type of the component 12 used in the component mounter 10, the structure (bump, pillar, etc.) for positioning the component 12 can be more clearly recognized by changing the light source color.

For example, as shown in FIG. 5, a first imaging device 137 includes a first component camera 132, a first illuminator 136, and a reflector unit (not shown). It is configured to irradiate the mounting surface 12a of 12 with red light. The first component camera 132 images the mounting surface 12a of the component 12 illuminated in red by the first illuminator 136 . The second imaging device 139 includes a second component camera 134, a second illuminator 138, and a reflector unit (not shown). , for example, to emit blue light. The second component camera 134 images the mounting surface 12 a of the component 12 illuminated in blue by the second illuminator 138 . Note that the first illuminator 136 and the second illuminator 138 can be configured to emit light of specific colors (red and blue light) by using filters that cut off specific wavelengths. .

According to the above configuration, the same component 12 is illuminated with two lights, red and blue, without switching the imaging device. Therefore, even if the optimum light source color for the component 12 to be imaged is not clear in advance, images can be acquired in a plurality of light source colors and an appropriate image can be selected later. That is, it is not necessary to pre-set imaging conditions. In this case, the control device 50 selects from among the plurality of captured images such that the detailed form of the component necessary for positioning the component 12 is clear (for example, the end of the electrode 12b of the component 12 is clearly visible). ) may have a function of automatically discriminating the image.

This modification is advantageous even when a plurality of types of components 12 are attached to the same rotary head 20 . In this case, without switching the imaging conditions, the component 12 can be imaged under appropriate imaging conditions by changing the imaging position for each component according to pre-registered component data.

Also, the imaging conditions to be changed are not limited to the illumination conditions such as the illumination angle or the color of the light source, and the camera resolution and the like may be different. With such a configuration, the same rotary head 20 can be used to image components 12 having different dimensions.

Although the imaging devices 37 and 39 are attached to the base 27 of the rotary head 20 in the above-described embodiment, they may be attached to the main body of the mounter 10 without being limited to such an example. Also in this case, the same effects as in this embodiment can be obtained.

In the imaging device unit 30 of this embodiment, two imaging devices 37 and 39 are illustrated, but the number is not limited, and one or three or more imaging devices may be provided. However, when a plurality of images are captured by one imaging device, the imaging device may be configured to be able to illuminate a plurality of imaging positions by adjusting the angle of the reflecting mirror. According to such a configuration, although it is necessary to adjust the angle of the reflecting mirror to switch the imaging conditions, the number of imaging devices can be reduced, which is advantageous in terms of installation space and cost.

Although several specific examples have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes of the specific examples illustrated above. The technical elements described in this specification or drawings exhibit technical usefulness alone or in various combinations.

10: Component Mounting Machine 12: Component 12a: Component Mounting Surface 12b: Electrode 14: Board 20: Rotary Head 22: Suction Nozzle 24: Nozzle Holder 26: Rotating Part 27: Base 30: Imaging Device Units 32, 132: First Components camera 33: first reflecting mirror units 34, 134: second component cameras 36, 136: first illuminators 37, 137: first imaging devices 38, 138: second illuminators 39, 139 : Second imaging device 40 : Moving device 50 : Control device 62 : Component feeder 64 : Substrate transfer device A1 : Suction position B1 : First imaging position B2 : Second imaging position

Claims (4)

A component mounting apparatus for mounting components on a substrate ,
a rotary head having a plurality of suction nozzles for sucking the component ;
an imaging device that captures an image of the component sucked by the suction nozzle ;
a controller ;
The plurality of suction nozzles are arranged on a first circumference at intervals in the circumferential direction and are movable on the first circumference ,
The imaging device is capable of imaging the component sucked by the suction nozzle under a plurality of different imaging conditions at a plurality of imaging positions provided on the first circle ,
The control device performs image processing on a plurality of captured images of a component sucked by the suction nozzle captured under the plurality of different imaging conditions at the plurality of imaging positions, and the image processing results of the plurality of captured images. determining the position and direction of the suction nozzle that has picked up the component with respect to the substrate, based on
Component mounting equipment. The plurality of imaging positions includes a first imaging position and a second imaging position different from the first imaging position,
The imaging device includes a first camera that images the component at the first imaging position , a second camera that images the component at the second imaging position , and
The imaging condition at the first imaging position is the imaging condition of the first camera ,
the imaging condition at the second imaging position is the imaging condition of the second camera ;
2. The component mounting apparatus according to claim 1, wherein imaging conditions of said first camera are different from imaging conditions of said second camera . The plurality of imaging positions includes a first imaging position and a second imaging position different from the first imaging position,
The imaging device includes a first illuminator that illuminates the component at the first imaging position and a second illuminator that illuminates the component at the second imaging position. ,
The imaging condition at the first imaging position is an illumination condition by the first illuminator,
The imaging condition at the second imaging position is an illumination condition by the second illuminator,
3. The component mounting apparatus according to claim 2, wherein illumination conditions by said first illuminator are different from illumination conditions by said second illuminator. The control device is
When the component sucked by the suction nozzle is positioned at the first imaging position, the first camera is caused to image the component, and the component sucked by the suction nozzle is the 4. The component mounting apparatus according to claim 2, wherein the second camera is caused to image the component when positioned at the second imaging position .

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