Electronics Forum | Wed Aug 09 10:51:22 EDT 2017 | cbeneat
I have a question for the experts. After a panel is printed, how long is too long for the panel to sit prior to reflow? I understand each paste will be different, wondering if there is a general rule of thumb?
Electronics Forum | Wed Aug 09 11:59:19 EDT 2017 | dleeper
As you already know, it depends on the paste. There isn't really a rule of thumb, but less time exposed it better. The issue is the flux exposure to the air and ambient conditions. The flux can evaporate or absorb moisture from the air. If the paste
Electronics Forum | Wed Aug 09 12:34:54 EDT 2017 | jdengler
It also varies with the types of deposits. Small deposits of paste (as seen on fine pitch parts or small chips) seem to be more affected by exposure. Jerry
Electronics Forum | Thu Aug 10 11:32:34 EDT 2017 | dleeper
You could always take a scrap board, paste it, and let it sit out over night. Reflow it and then you should have a nice visual aid, covered in solder balls and grainy, irregularly shaped solder mounds.
Electronics Forum | Tue Aug 15 07:27:03 EDT 2017 | emeto
Most important factor - temperature. Back in the days I worked for a place without AC, and summer time this paste couldn't make it for more than an hour. In controlled environment you will be safe for hours or even a shift.
Electronics Forum | Mon Aug 14 15:09:14 EDT 2017 | charliedci
In my experience, in a temperature/humidity controlled environment, 1 hour, no big deal. 4 hours still ok. Overnight your pushing the limits but will probably reflow without issues. Any longer, could be a problem. Again, a lot depend on type of past
Electronics Forum | Wed Jan 13 20:44:42 EST 1999 | Steve Gregory
Hello Sanjay! The cheap deal I use that Earl spoke of is called a SMarT Measure. It's a depth measuring microscope that uses the same principle of measuring optical focus that the units from Vision Engineering do ( if you've ever looked at any
Electronics Forum | Thu Jan 14 15:22:14 EST 1999 | Earl Moon
| Steve, | Whoa, take a breath! That was at least a dollar three-eighty answer. I've got to agree that nothing can replace a qualified, concientious operator for assuring quality. When I too worked at a small shop there in SillyCone Valley, my
Electronics Forum | Thu Jan 14 11:08:29 EST 1999 | Mike McMonagle
Steve, Whoa, take a breath! That was at least a dollar three-eighty answer. I've got to agree that nothing can replace a qualified, concientious operator for assuring quality. When I too worked at a small shop there in SillyCone Valley, my seni
Electronics Forum | Sun Aug 25 07:15:55 EDT 2002 | cnoonan
What are the industry standards for eutectic solder-paste in conjunction with the life span of solder-paste. What is the recommended duration of solder-paste on a printed circuit board. Example: You print a board, how long can it sit before runnin
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