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does not require removal after soldering takes place. This
process, however, requires a controlled soldering atmosphere and
tight process controls to prevent defects.
Compaq U.S. also used "paste-in-hole" technology and wave
soldering of bottom-side small outline integrated circuits
(SOIC's). These processes used different methods of soldering
components to printed circuit boards, adding to the manufacturing
complexity of PCA's used by Compaq U.S. due to the extensive
engineering support and tight manufacturing controls required to
use these processes.
In addition, Compaq U.S. used U-shaped continuous flow
manufacturing lines rather than the more common "batch
processing". Continuous flow manufacturing reduces the time
required to manufacture a PCA because a bare printed circuit
board starts at the beginning of a manufacturing line and flows
through the manufacturing process nonstop until both sides of the
board are populated with components and tested for defects. The
U-shaped lines used by Compaq U.S. and Compaq Asia featured a
layout of lines in a U shape so that testing took place in front
of the beginning of the assembly process. With short cycle time
and in-circuit testers located in front of the pick-and-place
machines (due to the U shape of the line), process controls and
immediate corrective actions could be implemented based on test
data to ensure quality. In contrast, the batch processing used
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Last modified: May 25, 2011