Automated Optical Inspection (AOI) Analysis

AOI Analysis An automated optical inspection (AOI) is an analysis which canvass the solder joints for their correctness after soldering the board. As it is often the case that the camera cannot detect all the components to be inspected, it is necessary to ensure this beforehand. PCB Investigator‘s automated optical inspection provide an analysis tool for this detection of the missing inspectability.

 

AOI Analysis 2D

By using the 'AOI check' button the following window appears:

 

 

    Open a PCB design first and then start the ‚AOI check‘.
  1. First you have to decide, if you want to analyze your design with a 2D or 3D inspection. However, the following section deals only with 2D inspection. If you need information about the 3D inspection, use the 3D AOI description.
  2. Enter the angle of your future automated optical inspection for the camera angle. Tolerances can be calculated using’ additional distance’. By default, this value is set to 0.00. As 2-pin components often aren´t relevant or, due to their shape, difficult to analyze , they can be excluded here. Occasionally components with very large pins are used. These pins often do not need to be checked due to their size. For this reason, enter an area in the’ Value of an area to hide huge pins’ input field that meets your requirements. You can also select the two options’ Create an aoi check layer’ and’ Color pins’. If you want an additional layer, on which the direction of inspection per pin is marked, activate ’Create an aoi check layer’.With the use of the ’Color pins’ option, the pins in the diagram displayed in color are also colored in the design.
  3. After you have adapted all values to your requirements, you can start the inspection.
  4. The inspected components and their pins are now displayed and can be sorted using the riders. The result list contains one line per pin. It contains the following information:
    • ID: Identification Number
    • Layer: Contains on which side the pin can be found
    • Component: Component name
    • Pin: Pin number
    • Shadow Component: Component that is too close to the pin
    • Distance: Shows the calculated distance
    • Checkdistance: Shows the required distance
    • Shadowcomp. Height: Shadow component height
  5. The diagram illustrates the result of the inspection.
  6. The inspection can now be saved using the ’Export Result’ option. When using the import result, an old inspection result can be loaded.
  7. If you move the mouse over the ’Help’ icon, the following picture will be displayed to explain how 2D inspection works.
  8. Ignore components: At this point you have the option exclude components that are not relevant for the later AOI analysis. Depending on your design, you can do this by using the properties, the package name or by individually selecting the components in the tool itself.

 

 

Example:

Doubleclick an entry shows the component J1 and the corresponding pin 8 (red colored) with too small distance to the component LDR after the 2D inspection.
aoi_2d_list_entry_on_board

AOI Analysis 3D

By using the 'AOI check' button and switching to 3D AOI the following window appears:

Open a PCB design start, then the ‚AOI‘.

  1. First you have to decide,if you want to analyze your design with a 2D or 3D inspection. However, the following section deals only with 3D inspection. If you need information about the 2D inspection, use the 2D AOI description.
  2. First replace the’ laser angle’ arranged between the laser and the camera with its actual laser angle. Since the direction the laser head moves in differs during the 3D inspection, it can also be adjusted with ’horizontal’ and ’vertical’. The colouring of the affected components can be selected as required. It is also possible to graphically display the overlapping of the shadow with other components in separate layers using the’ create shadow layers’ option. So the layers show the shadow of a component in both test directions and are shown as follows.

 

aoi_3d_additional_layer

3. After you have adapted all values and selection options to your requirements, you can start the inspection

4. The inspected components and their pins are now displayed and can be sorted using the riders. The result list contains one line per pin. It contains the following information:

    • ID: Identification Number
    • Layer: Contains on which side the pin can be found
    • Component: Component name
    • Shadow on: Identifier whether the shadow falls on a component body or the corresponding pin
    • Package: Package name
    • Shadow Components: Shows the component names of the components affected by the shadow

5. The diagram illustrates the result of the inspection.

6. The inspection can now be saved using the ’Export Result’ option. When using the import result, a past inspection result can be loaded.

7. If you move the mouse over the ’Help’ icon, the following picture will be displayed to explain how 2D inspection works.

8. Ignore components: At this point you have the option exclude components that are not relevant for the later AOI analysis. Depending on your design, you can do this by using the properties, the package name or by individually selecting the components in the tool itself.

Example:
Doubleclick an entry shows the component J1 and the corresponding pin 8 (red colored) with too small distance to the component LDR after the 2D inspection.
aoi_3d_list_entry_on_board

H-Bridge

By using the 'AOI check' button and switching to 'H-Bridge' the following window appears:

1. If you click on the question mark, you will be redirected to the corresponding page of the manual.

2. ID: Identification Number

   Layer: Contains on which side the pin can be found

   Component: Component name

3. Min. Pin amount: Minimum number of pins to be checked for an H-Bridge

    Max. Pin distance: Maximum distance between two pins up to which a check will be performed

4.  By clicking on the "i" you get a short explanation including an illustration showing how the H-Bridge Inspection works.

    If Copper is found within the marked area, it will be reported during the H-Bridge Inspection. Such areas can cause problems in the later AOI analysis.

5. The inspection can now be saved using the "Export Result" option. When using the "Import Result" option, an old inspection result can be loaded.

6. After you have adapted all values to you requirements, you can start the inspection.

3D-Ray

By using the 'AOI check' button and switching to '3D Ray' the following window appears. A 3D model of the PCB to be inspected will be loaded automatically (assuming that the required information on the components is stored in 3D).

1. Laser angle: Here, you can set the angle at which the lasers should be aligned to the PCB. The changes are also visualized on the model of the PCB.

2. PCB side: Adjustment of the viewing angle (top, bottom, both). Again, you will see the changes of your settings visualized on your 3D model.

3. Direction: Inspection of the PCB in horizontal, vertical (or both) orientation. The new adjustments will be shown on the model.

4. Resolution: Setting of the field size to be considered. The smaller the field, the more accurate the result, but the longer the duration of the simulation (guideline: 200 µm).

5. Ignore components: At this point you have the option exclude components that are not relevant for the later AOI analysis. Depending on your design, you can do this by using the properties, the package name or by individually selecting the components in the tool itself.

6. If you move the mouse over the 'Help' icon, the following picture will be displayed explaining how the 3D Ray inspection works. 

7. By clicking the button "Start 3D Ray Simulation" the simulation starts.

8. You can view the results of simulation in the window on your 3D model (picture 1), in the tool itself (picture 2) or in a list view. The red marked areas show the not inspectable areas. You can then save the results for the top or bottom (or both) side, depending on you default settings. The areas that cannot be inspected will be exactly quantified. Possible changes of the default settings can lead to an improvement (reduction of the not inspectable areas).

In addition to the visualized representation of the findings, you can also display the results of the simulation in a list view. The list then contains all pins that cannot be inspected by the AOI camera. To show the list, just click on the buttom "Result" on the left corner of the window.

 

 

 

AXI Analysis

overview axi analysis

For all AXI machines you can perform the shadow check. This test checks if the material is covered from bottom to top and inverted.

It also supports combination with AOI machines, you have settings for each package type to set the check, e.g. for a chip component it should check only with orthogonal AOI camera, for qfn components with angle camera and for bga all pins checked with AXI analysis.

For each package group you can define the visible pins, hidden pins and material for bodx and or pins:

overview axi analysis