Electronics Forum | Tue Dec 07 08:01:40 EST 2021 | jineshjpr
Hi DucHoang, Thanks for your response - Understanding that OSP will have more surface resistivity which does not allows the solder to flow on the entire pads. Let me check peak & revert back sooner.
Electronics Forum | Fri Jan 28 13:49:48 EST 2022 | jseewald
That is correct. This looks like a board that was printed then wiped but not washed. Solder spheres left out on an unsolderable surface will just sit there like this or coalesce into solder balls. Nothing in the picture indicates an issue with the
Electronics Forum | Tue Feb 22 02:51:25 EST 2022 | davef
The industry standard for Resistivity of Solvent Extract (ROSE) Testing analysis is IPC-TM-650 Method 2.3.25 – Detection and Measurement of Ionizable Surface Contaminants by Resistivity of Solvent Extract (ROSE).
Electronics Forum | Thu Apr 07 15:42:29 EDT 2022 | SMTA-69080803
@ProcEng1 Yes... something like that. However, how do I ensure that the adhesive will always stay on one material assuming that the surface area is the same?
Electronics Forum | Wed May 11 20:41:53 EDT 2022 | donovan03608
The leads on the FPC are pre-tinned on both sides with SAC305. The receiving leads are AU. We coat all surfaces with Kester 979 no-clean flux dispensed via pen prior to initiating the hotbar cycle.
Electronics Forum | Mon Jan 09 12:34:00 EST 2023 | stephendo
Molten metal has a high surface tension. If the pads are uneven you can have uneven forces. Decades ago if part were not placed exactly right, they would come out of the oven centered. (or tombstoned)
Electronics Forum | Wed Oct 11 05:58:13 EDT 2023 | kojotssss
Hello all, I know there are very skilled guys. Can anyone suggest a stencil design to avoid component displacement during reflow to improve tension of surface forces and selfalignment? There are cases where the inductors are shifted. All parameters
Electronics Forum | Wed Oct 11 18:30:21 EDT 2023 | kojotssss
Thanks for the opinions! You're right, it can't be solved with a stencil. I have made investigation, the problems are related to the quality of the component land surface, one of the terminal is oxidized.
Electronics Forum | Thu Nov 30 19:19:40 EST 2023 | daniel_stanphill
ProcEng1 made a super important point. The packaging needs to be able to survive the temps needed to reflow the paste. There are a number of jobs we have that we either hand or selective solder the connectors after the surface mount is done for that
Electronics Forum | Wed Feb 07 15:03:54 EST 2024 | madisreivik
Also, if you use etching pen, clean the surface first with solvent as grease blocks the etchant. Some rubbing with steel wool should also help.
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