D-MAX DMC-20SEC Manual de usuario descargar pdf (Pagina 30)

Figure 23. Photograph and graphic representation of SMT joint made with lead-free (left) and lead-based (right) sol‐

der

8. Detailed analysis of AOI systems

As can be seen in the previous section, AOI machines handle several tasks. Much literature is

dedicated to the intelligence of these systems, but from a technical point of view we can also

examine other aspects. A large number of these AOIs work on high-mix-high-volume SMT

lines where the most important key factors are the inspection duration and quality. The

attributes of this system relate to the following sections:

1. actuating parts (drives and axes)

2. image acquisition system (sensors, optics, illumination)

3. software processing part

They work in close relationship to each other, so the speed of each has to be in sync. There are

three well-defined mechanical constructions for an AOI system:

• without special moving parts / drives inside

• with PWB positioning table

• with camera-module actuating unit

The simplest case is when the working-process of the system does not include special posi‐

tioning steps. The PWB is positioned/placed in “one step” into the field of camera system, an

image is acquired and the PWB is then taken out for the next process. This could be of great

benefit because the machine does not need to synchronize any movements during the image

acquisition process. The speed affecting factor can thus be ignored. This is used typically in

Automatic Final Inspection (AFI) systems. This does not mean that the system has to only

contain one camera. For more complex applications the number of cameras can be increased.

More cameras mean more complex image transformation and manipulation tasks so it follows

that these systems are only capable of use when looking at pre-defined areas.

Materials Science - Advanced Topics

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D-MAX DMC-20SEC Manual de usuario Pagina 30