Electronics Forum | Wed Jul 22 13:50:49 EDT 1998 | Justin Medernach
| My firm has just begun it's first PCB that will use BGA packaging. I have been reading up on the processes involved with BGAs and was wondering if you need to apply solder paste to the pads prior to applying heat and mounting the part to the board
Electronics Forum | Fri Mar 24 13:02:53 EST 2000 | Ashok Dhawan
Two questions on ESD: 1. What is recommended method ( Air ionizer , grounding strip etc. ) for a board prep ? We Kapton Tape for masking pads or not to be soldered areas. or Is there a wet mask recommended for masking boards campatible with NC Sold
Industry News | 2018-08-16 19:58:50.0
The SMTA Capital Chapter is holding its upcoming Capital Expo and Tech Forum at Johns Hopkins University / Applied Physics Lab, Kossiakoff Center, 11100 Johns Hopkins Road, Laurel, MD 20723, on Thursday, August 23rd.
Technical Library | 2018-09-26 20:33:26.0
Bottom terminated components, or BTCs, have been rapidly incorporated into PCB designs because of their low cost, small footprint and overall reliability. The combination of leadless terminations with underside ground/thermal pads have presented a multitude of challenges to PCB assemblers, including tilting, poor solder fillet formation, difficult inspection and – most notably – center pad voiding. Voids in large SMT solder joints can be difficult to predict and control due to the variety of input variables that can influence their formation. Solder paste chemistries, PCB final finishes, and reflow profiles and atmospheres have all been scrutinized, and their effects well documented. Additionally, many of the published center pad voiding studies have focused on optimizing center pad footprint and stencil aperture designs. This study focuses on I/O pad stencil modifications rather than center pad modifications. It shows a no-cost, easily implemented I/O design guideline that can be deployed to consistently and repeatedly reduce void formation on BTC-style packages.
SMTnet Express, September 27, 2018, Subscribers: 31,354, Companies: 11,055, Users: 25,237 Assessing the Effectiveness of I/O Stencil Aperture Modifications on BTC Void Reduction Carlos Tafoya, Gustavo Ramirez, Timothy O'Neill; AIM Solder Bottom
PCB Libraries, Inc. | https://www.pcblibraries.com/Forum/when-should-a-pad-use-windowpane-paste-mask_topic2600_post10599.html
. Let's say you use a 0.125 mm (5 mil) stencil thickness. If you have a thermal pad that has 100% paste mask coverage, there is no where for the solder to flow and the package ends up sitting on top of
| http://etasmt.com/cc?ID=te_news_industry,24163&url=_print
homothermal period to solder melting and this rapid heating process has a close relationship with such defects as solder balls due to splash down and warped components due to imbalanced wettings on components
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