Electronics Forum | Tue Jun 01 10:15:29 EDT 2004 | davef
We agree with John about his comments on the controlable factors relating to your printer, but we'd add that paste formulation and mesh are also contributors to nice looking bricks.
Electronics Forum | Tue Jun 01 07:26:55 EDT 2004 | johnwnz
Alistair, your paste deposit is controlled by a few things: Stencil thickness Squeegee pressure Squeegee speed Print gap in 99 out of 100 applications for paste printing you would have a print gap of 0 i.e. on contact printing where the PCB is in fu
Electronics Forum | Tue Jun 01 12:48:49 EDT 2004 | pjc
AP25 can handle warped boards to a degree. I also depends on the board clamping system on the machine. There are three avbl. First is Universal Vacuum box, second is dedicated tooling with vacuum and third is Y Snugger tooling that does not use vacuu
Electronics Forum | Wed Jan 25 16:18:12 EST 2012 | wrongway
Your uising 6 mil thick screen on 0603 and sot-23 and you think you need more paste? when i use a 6 mil screen on a sot-23 and 0603 it is almost to much paste. 5 mill does just fine on those parts but if you think you need more paste then don't go t
Electronics Forum | Wed Jan 25 14:40:36 EST 2012 | gaz
We are using 6 mil screens, and these boards have 0603,SOT23 and SOD523. Seems like we could use *more* paste, not less on a lot of these components, so does it make sense to get a thinner screen? Wouldn't this mean we'd get less paste?
Electronics Forum | Mon Feb 06 21:24:21 EST 2012 | gaz
By changing paste and making a better profile, it seems like we have enough paste. The process was just not working very well with SN100. So far the 5mil looks good, so thanks for the input!
Electronics Forum | Fri Sep 25 16:47:57 EDT 2009 | esoderberg
0.5mm pitch QFP's are typically mixed with large components on all of my boards. I usually use a 6 mil stencil with a minimum aperture width of 10 mils. Normal aperture size is 10 x 50 which causes shorts about 20% of the time. A recent purchase of
Electronics Forum | Thu Mar 02 17:46:22 EST 2006 | Chris
Go with no greater than 0.005". Pleanty of paste and minimal shorting issues. 0.004" will even work
Electronics Forum | Tue Feb 14 21:05:45 EST 2012 | isd_jwendell
What is the percent solids of the paste you are using?
Electronics Forum | Sun Sep 27 22:39:55 EDT 2009 | rajeshwara
The same issue i faced 2 yrs before , i sugest 1. Use stencil of 4 mils ( Take care of Aspect Ratio and Area Ratio ). 2. Use Solder Paste of Type 4.5 and Viscosity in between 1100 to 1300. ( Try Solder Paste of Cookson or Alpha metals : OM338 T45-L
