Supporting niche service needs at a regional level—a case study
Supporting niche service
needs at a regional level—
a case study
by Barry Reece and Ken Russell, Clover Electronics, Atlanta, GA, USA
introduction
Regional electronics Regional EMS providers fill critical niches in
production differences
manufacturing services
their customers’ supply chains by handling
Larger displays, such as those used in high-
(EMS) providers are not
hard-to-outsource programs or highly
way signage, often use through-hole technol-
simply being asked to provide
specialized low-to-medium volume assembly
ogy PCBAs. These larger panels may be 2 ft
a full range of traditional
processes. Clover Electronics (Atlanta, GA)
x 1 ft in overall dimensions. A production
EMS services. Their business
has focused on the market requiring high
challenge in these larger footprint prod-
focus often drives them in
performance displays for applications such
ucts is that wave conveyor speed must be
as communications, gaming, security, traffic
directions not found widely
increased to deal with the heat during wave.
signage, etc.
in higher volume EMS provid-
On one project, the assembly was consistent-
Most LCD manufacturers look for
ly run through the wave at 4X normal speed
ers. One example is Clover
annual production quantities in the
to minimize the heat on the board, resulting
Electronics. It has developed
hundreds of thousands for custom application
in no solder joint quality issues.
strong capabilities in LCD development. Typically, niche applications
The LED strip used in smaller display
backlight design and LCD
have annual quantities in the 5K-30K per
backlights is normally 100% SMT, although
customization to address
year range. To address this issue, this
there may be wire attachment post-SMT.
the needs of customers whose
contractor buys commercial off-the-shelf
The production challenge is that LEDs have
volumes or specific application
LCDs and customizes them for specific
lenses that are sensitive to heat and handling
needs do not align with avail-
customer requirements. Such customizations
damage. As a result, it is important to main-
able off-the-shelf product. This
can include improved optical performance:
tain proper thermal profiles during reflow
most likely an increase in luminance and
article will look at the SMT
and minimize handling during production
reliability. The off-the-shelf unit almost
process control challenges
and any work-in-process movement between
always requires the contractor to disassemble
production areas. The lens that is used on
inherent in manufacturing the
the unit where a number of modifications
ultra bright LEDs is made of a silicon type
printed circuit board assemblies
can be made with the aim of meeting a
material and can easily be knocked off with
(PCBAs) used in these pro- specific customer requirement. CCFL back-
improper handling. In this contractor’s
grams. It will also look at key
lights are generally replaced with a PCBA
case, carriers are used for the strips and
issues in process control in the
strip of ultra bright LEDs manufactured
the process is completely inline from paste
final integration process.
by the contractor. Additionally, in some
deposition through the oven.
applications the diffuser stack is modified
Comparatively, smaller (less bright)
with specialty films to enhance light output.
LEDs use an inverted type lens inside the
In other applications, the exterior of the dis-
Keywords: EMS, LCD
case, and there is no problem with them in
play is ruggedized or otherwise modified to
terms of reflow characteristics for leaded or
Customization, SMT
meet customer requirements. These rugge-
RoHS compliant applications.
LEDs, Process Control
dized displays may have to withstand hostile
Additionally, SMT LEDs don’t have
environmental factors such as blowing sand,
leads outside the body of the component
heat, humidity, altitude and boot kick or
and are similar to QFNs and leadless chip
drop tests. For these requirements the LCDs
carrier (LCC) products. Instead, they have
are modified to include anti-reflective coated
pads under the component with three leads.
films or cover glass, thick kick-plate glass or
One lead is for heat dissipation and the
privacy films.
“The production challenge is that LEDs have lenses
that are sensitive to heat and handling damage.”
32 – Global SMT & Packaging – January 2009 www.globalsmt.net
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