Electronics Forum | Fri Sep 17 03:13:00 EDT 2010 | grahamcooper22
In HASL pcb coating you need to fully coat the pads with solder and then blow off any excess solder to leave a nice coating on each pad. Generally pcb manufacturers try to give you a flat pcb pad to make your solder paste printing more consistent. To
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 | Fri May 13 19:48:28 EDT 2022 | cbeneat
Not completely. We end up increasing the blow off/vacuum break air pressure. The only issue with that is if we go too high, and a small part is close to the light it will blow it out of position. So on occasion there is a balancing act we have to do.
Electronics Forum | Fri Jun 14 14:25:05 EDT 2002 | davef
Good job clarifying things. So, your MELF are just rolling off the pads. So much for the rocket scientist that talked you into those �V� shaped apertures, eh? [Or taking it the other way: Wow, just think how bad it would be if they weren�t worki
Electronics Forum | Mon Aug 07 10:22:13 EDT 2000 | genglish
Ramon, I have had experience in the problems you are witnessing. The problem can relate to a number of factors. Obviously the printing process is the first place to start your investigations, try looking at the stencil apertures for bleed under the
Electronics Forum | Wed Mar 14 11:51:24 EST 2001 | fmonette
Popcorning is the common designation for defects related to the moiture sensitivity of plastic molded components, like PBGAs. The plastic body of these parts will absorb moisture from the ambiant atmosphere on your factory floor. If a critical level
Electronics Forum | Fri Oct 01 10:04:20 EDT 1999 | Andrew William Dalrymple
I am currently in the middle of a company wide war and I'm looking for data (AMMO). Here are the problems: 1) I am looking for anyone who has done or seen any reports on Thermal Shock to smt parts and/or via holes caused by Soldering Irons at rewor
Electronics Forum | Fri Oct 01 16:17:10 EDT 1999 | Dave F
| I am currently in the middle of a company wide war and I'm looking for data (AMMO). Here are the problems: | | 1) I am looking for anyone who has done or seen any reports on Thermal Shock to smt parts and/or via holes caused by Soldering Irons at
Electronics Forum | Fri Jun 18 13:47:33 EDT 1999 | Jason Gregory
| Now don't everyone jump on this at once, but it seems time for me to send out copies of my not even close to being dated copy of an article about HASL. Though it was published in 1992, in Printed Circuit Fabrication Magazine, and it got rave review
Electronics Forum | Thu Jun 17 19:40:11 EDT 1999 | Scott Cook
| first of all what is the technical term for the small amount of solder on a plated pad. we are getting poor screen printing gasketing on a 20 mil qfp due to this solder not being even or too high in spots and not covering the length of the pads. an
