Electronics Forum | Fri Apr 06 10:43:57 EDT 2007 | flipit
Hi, Anyone seeing difficulty is soldering MLFs or QFN with lead free solder? I have an MLF with 3 rows of pads on each of the 4 sides of the part and then the large center ground plane in the middle. The part is 20 mil pitch. Had good luck with l
Electronics Forum | Thu Jul 07 11:52:25 EDT 2016 | proceng1
We just pulled a Speedline Accuflex printer out of storage. After programming a board and stencil, and calibrating the fiducials and everything, we do a test alignment and bring the board to print height. It is off. I've done it now with two diffe
Electronics Forum | Mon Aug 14 14:27:00 EDT 2017 | emeto
Here is some food for thought. Try to answer these questions yourself and I am sure you will see huge improvement. Reasons: - Bad PCB design - Plating-uneven HASL cause more than OSP Au/Ni or Silver - Poor paste and print quality - uneven paste ca
Electronics Forum | Fri Dec 01 14:40:02 EST 2017 | emeto
Very interesting pictures. It shows paste height of 200um - which is at lest 6mil stencil deposit. That on the other hand posts another question. Can you measure the ground pad level in relation to the solder mask level with the SPI? I had assemblies
Electronics Forum | Thu Aug 05 11:51:44 EDT 1999 | Wolfgang Busko
| | | | | | | | | | | | Hello, | | | If you are using no-clean and they are entrapped in the flux it is also IPC accepted but i havent found a customer yet who agrees with that. Im sure you have checked your profile. I had the same problem with chi
Electronics Forum | Thu Dec 24 01:38:36 EST 1998 | Chris Grendler
I need advice on a pad design which several other engineers whom I work with would like to try. I think it is an utterly crazy but I can't seem to convince them differently. My current 0402 chip pad sizes on alumina and FR4 substrates are .022"X.
Electronics Forum | Fri Feb 20 14:16:06 EST 1998 | Dave McFadyen
I've been using metal blades on several brands of printers over the past few years and have to agree with comments in other replies. Contact print is a must or you will tear slits in your stencils at the ends of the blade. Center-mounted (floating) s
Electronics Forum | Thu Oct 17 17:18:48 EDT 2002 | Leandro G. Barajas
Hi everybody, This is a simple posting to initiate a discussion on different ways to troubleshoot, improve, and control the Stencil Printing Process SPP in SMT manufacturing. There are many SPC, ANOVA and other analysis techniques that provide insi
Electronics Forum | Wed Jan 10 20:06:43 EST 2007 | SSS
I've been assembling thousands of boards for dozens of customers over the past 5 years with 0402 chip components. 85% can happen very easily even with newer equipment. Defect challanges with 0402 packages is almost always tombstoning. Capacitors abou
Electronics Forum | Wed Aug 22 19:54:54 EDT 2001 | mkallen
Can anyone point me to a relevant IPC spec that specifies an allowable board stretch, measured between metal features on outer layers (e.g., between fiducials and component pads on the topside of a board)? I've got a non-linear stretch problem that'
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