Gold Embrittlement in Lead-free Solder

http://www.smta.org/penang/presentations/s6_p3_chiu_alex.pdf


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Connector Removal and Replacement

This article explains how remove and replace a high density a through hole hole connector using a solder fountain.

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Pin in Paste Technology

ITM PIn in Paste Part 1 - YouTube:

FCI Pin in Paste Guide


Samtec's SSQ design incorporates standoffs between each tail position (.080” apart) as shown below.



The SSQ is a square tail pin which fills the inside of the hole more than a solder tail would. 

SSQ connector bodies are made from Liquid Crystal Polymer (LCP),  they are lead-free compatible. Compliant with the reflow profile parameters detailed in IPC/JEDEC J-STD-020D which requires that components be capable of withstanding a peak temperature of 260°C as well as 30 seconds above 255°C.  The parts can also withstand three reflow passes.

Stencil aperture design should be similar to that shown below, elongating the relatively narrow apertures outward from the plated through hole.  Additionally, it is highly recommended to include a ‘spoke’ emanating from the annular ring, designed to facilitate the migration of the solder paste to the plated through hole during reflow.




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Soldering - Problems with Insufficient Barrel Fill

Problems with Insufficient Barrel Fill: - Circuit Net

"We are seeing insufficient barrel fill (60-75%) during lead free wave soldering. Can you point to some reasons why we may be seeing this insufficient condition and suggest a cure?

R. S"

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Paste Stencil Design Process Flow

Single PCB Design > Single PCB Gerbers > PCB Fabricator > PCB Fabricator Array > Assembly Pallet Array > Paste Stencil Array for Assembly Pallet > Gerbers to Assembly House > Gerbers to Stencil House > Paste Stencil Pallet and Gerbers Back to Assembly House > Paste Stencil Pallet Gerbers Onramp > Company Configuration Control.

The final paste stencil Gerbers (as modified by Assembly House or Stencil House) which have been optimized for yield should be assigned a drawing number and be checked into configuration control.

3D Solder Paste Volume Inspection

50% of assembly defects are solder paste printing related.

Source: http://www.ipcoutlook.org/mart/52922F.shtml

What Paste Stencil Thickness to Use

What is the Ideal Stencil Thickness? - IPC Outlook

SMT Expert - Bob Willis Online

Bob Willis Online

Peelable Solder Mask - Pink Lady

Peelable Solder Mask: RoHS Compliant Peelable Solder Mask