Safe detection of hidden faults
rate under the above named cir- significant advantage in the inspection time direction a few degrees until
cumstances. as e.g. for an SO-IC image capturing from the solder joints are completely
only one direction is necessary. Even for visible. Consequently, a safe
coming from theory to practice— components with four pin rows, there are fault detection is guaranteed.
a consequent way for innovative only two inspections necessary with one 90°
results rotation of the viewing direction. summary
As a basis for the development of a In the final verification of the For assuring highest quality demands
powerful angled-view module, GOEPEL algorithm, with all available real lifted in the production of PCBs, a powerful
electronic has developed a catalogue that
lead samples included, the application angled-view inspection guarantees layout
contains all appearances of lifted leads
in production resulted in a 100% fault
independent and safe fault detection. The
and their combinations. Based on this
detection rate without increase of the false
size of the captured field of view influences
catalogue, all classes of appearances were
call rate.
the inspection speed of the AOI system sig-
backed up by real samples in close coopera-
The application in a critical assembly
nificantly. The free rotation of the viewing
tion with customers. The result is a pool
situation was also considered in the
direction in an area of 360° allows an easy
of thousands of lifted leads in different
development of the angled-view module
inspection of solder joints that might be
appearances. Based on this, a method of
(e.g., covering by higher components)
covered by components in front of them.
image capturing was identified by modify-
along with the inspection of components
A modular integration into in-line and
ing the directions of viewing and illumina-
in any angular position. Due to these
stand-alone AOI systems allows the module
tion, which ensures the detection of all
considerations, the rotatability in 1° steps
to be used for a significant quality increase
catalogued lifted lead variants.
over an area of 360° was integrated in the
even for smallest batches.
According to the requirements of the
module.
image capturing, an angled view module
The benefit for the user is demonstrated
was developed that is distinguished by an
in the following points:
extraordinarily big field of view (42 mm x
42 mm) with superior image quality and
1. For components in different
depth of focus, as well as a resolution of up
angular positions (e.g. 20°) no
to 10.5 µm/pixel.
adjustment of the inspection
On the basis of the images captured in
position or the parameters
this way, an algorithm was developed that
is necessary as the viewing
enables the automatic detection of lifted
direction has only to be
leads under all circumstances.
adjusted to the respective
The solder joint inspection close to
angular position (e.g. 20°), and
IPC was paid special attention to. That
the inspection can be carried
is only possible due to an angled-view
out using a standard library
inspection of the IC pins. This approach,
sample in 0° position.
using an intelligent optical design, allows
2. If the viewing direction is
the simultaneous inspection of two opposite
obstructed by components, it
pin rows of an IC. Hence, there is a
is possible to turn the viewing
Figure 4. Angled-view module “Chameleon“ for the integration in AOI systems of
the OptiCon series.
Figure 5. AOI systems of the OptiCon family, optional available with rotating
angled-view module “Chameleon.“
12 – Global SMT & Packaging – October 2009 www.globalsmt.net
Page 1  |  Page 2  |  Page 3  |  Page 4  |  Page 5  |  Page 6  |  Page 7  |  Page 8  |  Page 9  |  Page 10  |  Page 11  |  Page 12  |  Page 13  |  Page 14  |  Page 15  |  Page 16  |  Page 17  |  Page 18  |  Page 19  |  Page 20  |  Page 21  |  Page 22  |  Page 23  |  Page 24  |  Page 25  |  Page 26  |  Page 27  |  Page 28  |  Page 29  |  Page 30  |  Page 31  |  Page 32  |  Page 33  |  Page 34  |  Page 35  |  Page 36  |  Page 37  |  Page 38  |  Page 39  |  Page 40  |  Page 41  |  Page 42  |  Page 43  |  Page 44  |  Page 45  |  Page 46  |  Page 47  |  Page 48  |  Page 49  |  Page 50  |  Page 51  |  Page 52  |  Page 53  |  Page 54  |  Page 55  |  Page 56