Electronics Forum | Mon Feb 10 10:23:53 EST 2020 | emeto
Solder paste has stencil life time - if you go over it means you should change it. If you print boards in front and keep them for too long before reflow, the flux is still evaporating, so you are not mitigating the risk. Paste also likes room tempera
Electronics Forum | Thu Feb 27 12:41:21 EST 2020 | duke211
look at the specs of your solder and stencil life. Check the humidity, low humidity dries the paste. Slowing down your swipe speed and frequent wipe cleaning of your stencil can help.
Electronics Forum | Sat Feb 08 04:37:19 EST 2020 | spoiltforchoice
I work with small batches and this is what I do. However I don't do it because of the paste. Instead I do it because I am the sole operator on the line and I want one process finished so I can keep a better eye on the others. I specifically work with
Electronics Forum | Wed Dec 09 09:47:32 EST 2009 | dyoungquist
I am curious as to why you need to mix.... We use a 500g cartridge with air gun. Our process is remove the cartridge from the fridge, allow it to warm up to room temperature before inserting into air gun, then apply bead of paste to the stencil. N
Electronics Forum | Fri Jul 29 10:03:02 EDT 2011 | blnorman
At a previous location we used the Semco cartridges. Occasionally the operator would have to scrape down the stencil and knead the paste back in. That would keep the paste on the edges from drying out. It was just standard procedure.
Electronics Forum | Thu Feb 28 14:32:13 EST 2008 | cyber_wolf
Let me re-state the last part.... The throwing out part is paste dependent.
Electronics Forum | Thu Dec 10 12:53:12 EST 2009 | deanm
Bryan, Dyoungquist is correct. You should not need to mix solder paste. Overmixing solder paste can adversely affect it. Follow these guidelines and you should be fine: 1. Keep unopened containers of paste in the refrigerator. 2. Take one container
Electronics Forum | Wed Jul 27 09:58:05 EDT 2011 | davef
Pressure printing systems Conventional stencil printing techniques have fundamental limitations as regards paste handling: The volume of paste available for printing is limited, so frequent replenishment is necessary Paste is difficult to c
Electronics Forum | Fri Feb 29 07:32:43 EST 2008 | samitokgoz
We have the same problem... We are using water soluable solder paste (Alpha ws609) and it dries out very quick. I don't want to throw out the paste inside the printer, but on the other and I don't want to risk my production by adding flux or alchol o
Electronics Forum | Thu Feb 28 14:27:07 EST 2008 | cyber_wolf
The flux dries out and the paste sticks in the stencil apertures. As the flux dries it also causes the solder to oxidize. Hahaha ! I remember adding flux to paste back in the day to loosen it up. Do not do it ! I have been told by reputable industry
