28 Reflow Temperature Profiles REFLOW TRACKER
performance of your process, potential problems can be identified and dealt
with before they occur. (Not available with all versions of Insight.)
The Datapaq Surveyor system (p. 43) is an alternative means of assessing oven
performance which requires you to use specific hardware first to quantify and then
to run checks on the system to ensure it is still operating within limits. Using SPC on
normal Insight paqfiles, on the other hand, requires only the analysis of your routine
profile runs to assess trends in the oven’s performance. Both systems have benefits
and limitations, as shown below.
Pro Con
SPC on
normal
paqfiles
• Measures temperatures of the
actual PCB assembly during the
process.
• Comprehensive report shows data
from each probe separately.
• Can monitor wave, vapor-phase
and rework soldering processes, as
well as reflow.
• Good thermocouple sensor connection
is essential for best results.
• If used on data obtained with standard
test PCBs (‘golden boards’) and their
associated thermocouples, these will
degrade with repeated use, producing
less reliable results.
• Placing logger/PCB assembly on the
conveyor requires care to ensure that
thermocouple wires will not be trapped
in the oven.
• Need to ensure details of data-collection
are standardized for all profiles.
Surveyor • Unskilled operator can conduct
routine profile runs to assess
oven’s performance.
• Only one item to place on the
oven conveyor.
• Logger is reset, and results are
saved, automatically.
• Immediate confirmation of whether
the oven is operating within
specification for a given process.
• Helps to ensure details of data-
collection are standardized.
• Measures only the performance of the
process, not the temperatures
experienced by the actual product.
• For reflow processes only.
Using SPC
Note that, for SPC results to be meaningful, the paqfiles analyzed must be
consistent, i.e. they must relate to the same process (the same oven with the same
recipe settings) and must have used the same test-piece with probes in the same
positions. It is important that the test-piece is maintained in good condition.
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