Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

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Wave Profile

John

#26032

Wave Profile | 13 October, 2003

Anyone ever noticed a difference in measuring the temperature on a soldered board vs. using an unsoldered mole in their wave? I've been looking at the temperature of a specific part, and it reads much higher on an unsoldered mole vs. a soldered mole. I assume it is heatsinking through the solder/other parts if its connected. The unsoldered mole more closely represents the actual production part. Can anyone recommend a good article/book on general profiling practices? Thanks John

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MA/NY DDave

#26034

Wave Profile | 13 October, 2003

Hi

The answer is yes,

These moles, as you called them, are designed more as process control test instruments than true representations of the products that you will process.

By The Way, Most don't know this so I congratulate you.

Many get schnokered.

YiEngr, MA/NY Dave

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#26035

Wave Profile | 13 October, 2003

IPC-7530 "Guidelines for Temperature Profiling for Mass Soldering Processes (Reflow & Wave)"

As you observe, the temperature you measure will depend on what you are measuring. For instance: * Hottest temperature in the oven - air in the oven * Hottest spot on the board - PCB laminate * Coldest spot on the board - largest component or a ground plane.

R Prasad talks about "Bandwidth of Profile". Where in addition to meeting the shape of the profile, the oven settings must also show a narrow band width (5*C to 10*C). The band width is defined as the total temperature difference across the board in any given zone. The tighter the bandwidth, the more consistent is the yield. If the shape of the profile does not meet the desired shape or if the bandwidth is too wide (more than 10*C), adjust the panel settings.

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Precision Auger Dispense Pump

 Reflow System