Electronics Forum | Fri Jul 08 09:30:35 EDT 2011 | kahrpr
Check that your pick and place machine is not pushing the part too far in the paste and squeezing the paste off the pad. Your profile could need modifying. In the case of the profile the solder paste can slump off the pads before turning into a liqui
Electronics Forum | Sun Jan 07 08:46:08 EST 2018 | spoiltforchoice
Your paste should specify a number of times it is OK for various things to happen. The two you might care about are the "Stencil Time"/"Working life", which is how long the paste can be out of the pot on your stencil while you print PCBs. The othe
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 Mar 24 23:12:48 EDT 2021 | grahamcooper22
0.66 area aspect ratio...so for example...if the device is 0.5mm pitch QFP, the pcb pad may be 12 thou wide..make the aperture 9 to 10 thou wide...and reduce it's length by 10 % overall compared to the pcb pad.... Depending on device pitch, select ap
Electronics Forum | Wed Jan 11 22:47:31 EST 2006 | davef
We didn't intend to light anyone's fur on fire [get anyone's underwear in a knot, roil the waters, have a cow man] about consultants. The Phil Zarrow wrote a useful paper that could help in evaluating paste. Here read it ... Evaluating Solder Paste
Electronics Forum | Thu May 26 08:52:42 EDT 2011 | davef
Phil Zarrow wrote a useful paper that could help in evaluating paste. Here read it ... Evaluating Solder Paste � Not An Option Contributed by Phil Zarrow of ITM an Independent SMT consulting firm With soldering being the dominant source of assembly
Electronics Forum | Thu Aug 10 13:16:17 EDT 2000 | Bob Willis
Here is some thing that I wrote a while back on solder beading. First what is a Solder Bead? The term solder bead is used to differentiate it from solder balls. A solder bead is a solder ball but its location is normally constant unlike solder bal
Electronics Forum | Mon Sep 17 15:27:51 EDT 2001 | jschake
Challenges: The basic defects that impact assembly yield are bridging, satellite solder balls, and opens (i.e. tombstones / draw bridges). There are many variables with the stencil printing process that can impact these; several of them are listed
Electronics Forum | Thu Feb 11 09:45:06 EST 1999 | Dave F
| | | Helo, | | Is it common for actual print height of solder paste to exceed the stencil thickness. For example If the stencil is 6mill thick and the actual height of the print is apx. 10 or 11mill. What causes the paste height to be greater t
Electronics Forum | Wed Oct 14 13:52:59 EDT 1998 | Bill Schreiber
Dear Sanjay, An important issue involved when stencil printing adhesives vs. solder paste is: How do you clean the stencils after printing? Do you need two machines? Two chemistries? Two waste streams? What are the potential environmental impacts an
