Tech Briefs Magazine - June 2021 - MD-2

Automated
X-Ray Inspection
I
n the circuit board industry, an computed tomography (CT) X-ray autoincreasing
number of parts and
boards are proving to be difficult to
inspect with automated optical
inspection (AOI) because the solder is
invisible. Furthermore, high-quality re -
quirements such as bonding strength of
the automobile industry and full surface
inspection of the solder are increasing.
To address these needs, Omron has
introduced new technology for accomplishing
inspections within the required
inline takt time (the rate at which a
product must be completed to meet customer
demand). This has been one of
the most challenging requirements for
matic inspection equipment. For continuous
imaging technology, highly ac -
curate positioning control and highspeed
image sensing are required.
The Case for a New
Inspection Method
In recent years, remarkable technological
advancements have been made
in electric vehicles (EVs), advanced driver-assistance
systems (ADASs) and
even automated driving. For the world
of circuit board mounting, this means a
move towards further densification,
while an increasing number of parts and
PCBs have visually inaccessible soldered
joints that cause difficulties in visual
inspection. Typical examples of these
include fillet-less chips and ball grid ar -
rays (BGAs) with solder joints ar ranged
on the underside of the package.
The automotive industry imposes particularly
stringent quality assurance
requirements to protect consumers, and
suppliers are often required to perform
inline full-surface circuit board inspections
(rather than sampling inspections)
and measure solder shapes and inspect
down to bonding strength. Com -
pounding this is the problem of line
worker shortages, which is partly
responsible for the current rapid
increase in demand for high-precision,
high-quality automated in -
spections.
Hence, events in the mounting
industry like circuit board quality issues
and production line stoppages can pose
serious risks to customers. An outflow of
defective circuit boards would immediately
lead to a crisis that could threaten
the safety of people and society. For this
reason, it is more important than ever to
provide a mechanism that prevents any
outflow of defective circuit boards to the
market.
In response to these trends, Omron
developed its AXI (automated X-ray
inspection) system, which has become
widely used in surface mount technology
(SMT) production lines thanks to its
ability to inspect visually inaccessible
items like solder joints on the underside
of parts. Because of the problem with
takt time, however, a conventional
model has been used mainly for offline
sampling inspections or for inline
inspections of key parts only.
Figure 1. The VT-X750.
2
Cov
ToC
This article presents an outline of the
technologies employed for the VT-X750
Series automated inline CT X-ray inspection
system (Figure 1) to improve this
problem and achieve speeds sufficient
for inline use in automotive circuit
Motion Design, June 2021
http://www.abpi.net/ntbpdfclicks/l.php?202106TBNAV
Tech Briefs Magazine - June 2021

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