Electronics Forum | Fri Mar 26 15:48:31 EDT 2021 | grahamcooper22
Leaded HASL on small pads can be quite difficult to print on...the HASL tends to be domed rather than flat..and that can affect print quality...you really need a perfectly flat pcb pad to print paste on when you are assembling 0.5mm QFPs. If the pcb
Electronics Forum | Thu Jul 03 18:14:03 EDT 2003 | russ
Kris, I don't know what I HAVEN'T SEEN yet cuz I haven't seen it. (HAHAHA) It is kind of like when you are looking for something and you always say after you found it that it was the last place you looked (Why would anyone keep looking for something
Electronics Forum | Thu Mar 25 23:23:00 EDT 2021 | llawrence
The QFP pitch is 0.5mm. Pad size is 1.475 x 0.3mm, and the new aperture size is 1.32 x 0.22mm. I'm not sure about whether or not it is lasered, but on the newly ordered stencil I selected the polishing option. Looks like the pad width is already 2/3
Electronics Forum | Thu Mar 25 20:50:50 EDT 2021 | stephendo
A couple more things. The PCB. What size are the pads? One time a board shop had difficulty putting masking between the pads of a QFP and the pads suffered as a result. When I told them they didn't have to have masking between the pads, the pads w
Electronics Forum | Tue Jun 30 08:17:53 EDT 2009 | davef
How do you specify HASL to your fabricator? We talked about issues with HASL previously here on SMTnet. Search the fine SMTnet Archives to find them. Here is a GREAT article on HASL written by an old friend Earl Moon: http://www.smtnet.com/express/1
Electronics Forum | Sun Jun 14 03:02:14 EDT 2020 | kylehunter
We did a batch of boards with lead free HASL that we thought was leaded. Using standard leaded paste worked, but we did have some wetting issues. The issues were resolved when switching back to leaded HASL. Can't speak to your specific fiducial issu
Electronics Forum | Wed May 03 16:37:10 EDT 2017 | charliedci
I don't believe there should be any issues with the HASL finish. The issue is how long on the shelf and is a bake out required to remove moisture from PCB, as in any FR4 PCB's that may have had time to absorb moisture.
Electronics Forum | Wed Dec 22 12:36:36 EST 2004 | rlackey
Hi Mark, Look on the bright side, if you want to change from HASL you've got the lead free issue which will allow you to evaluate all other finishes, and find the best one for you. Dave, have you seen any unleaded HASL finishes & any issues arising
Electronics Forum | Tue Oct 03 17:11:42 EDT 2006 | cuculi54986@yahoo.com
Our board suppliers tell us, there is no specification they use for HASL thickness, other than "coverage". They also say they have very little control over the HASL thickness. This was not an issue for us in the past, until we started using Pb-fr
Electronics Forum | Mon May 15 12:36:12 EDT 2017 | edhare
I don't believe there should be any issues with > the HASL finish. The issue is how long on the > shelf and is a bake out required to remove > moisture from PCB, as in any FR4 PCB's that may > have had time to absorb moisture. > I don't believe
