Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.

SMTnet
»
Electronics Forum
»
OSP PCB Plating

OSP PCB Plating

Subscribe to Thread

I have a small prototype shop and I received a PCB with OSP ... - Jul 16, 2014 by June

Hi June, The biggest issue with an OSP finish is as soon ... - Jul 17, 2014 by mac5

Hello June The following infomationI find from net for yo... - Jul 18, 2014 by skipBruce

Thanks Mac! I have been doing a lot of reading and I think I... - Jul 18, 2014 by June

The good thing for me is I will not have these around for ve... - Jul 18, 2014 by June

Ensure you control the assembly completion. My previous exp... - Jul 21, 2014 by Edri

June

#72424

OSP PCB Plating | 16 July, 2014

I have a small prototype shop and I received a PCB with OSP plating and I have never used it before. The assembly has several BGAs and I have always used the standard gold plating. Can anyone give me any information on OSP??? Does it solder well? What I read it acts very similar to HASL in the reflow but has better print quality.

June

reply »

mac5

#72435

OSP PCB Plating | 17 July, 2014

Hi June,

The biggest issue with an OSP finish is as soon as the PCB sees a heat cycle (reflow or wave) the finish will begin to degrade. If you have a single sided SMT assembly with THT components installed downstream it works pretty good. But a double sided SMT with THT may have issues wetting to the barrels in the wave or hand soldering. My preference for a board with BGA’s is always ENIG, but OSP is a close second. Good luck.

BR, Mac

reply »

skipBruce

#72436

OSP PCB Plating | 18 July, 2014

Hello June

The following infomationI find from net for you reference. OSP (Organic Solderability Preservative)

1)Preserves copper surface from oxidation until asse mbly.

2) Very thin coating (100-4000 Angstroms).

3)Applied in a vertical (dip tank) or conveyorized ch emical process.

4)Flat, planar surface, well suited to tight-pitch pads (BGA, QFP).

5)6 month shelf life (considered poor).

6)Very manufacturable (no concerns).

Issues:

1) Difficult to inspect (transparent and colorless).

2)Sensitive to handling. typically applied as final mfg process.

3) Limited shelf life.

4)Requires relatively aggressive flux at assembly.

--------------------------------------------------------

Bruce from http://www.nexpcb.com

reply »

June

#72440

OSP PCB Plating | 18 July, 2014

Thanks Mac! I have been doing a lot of reading and I think I understand me challenge ahead of me. I do however have a double sided assembly and the BGA's are on the second side. So I know I have to make this a quick build….

June

reply »

June

#72441

OSP PCB Plating | 18 July, 2014

The good thing for me is I will not have these around for very long and they are prototypes.... We build fast and send them on to our EE's! What I have found to be my challenge is the wiping off of the miss prints on the first side... What I have read is we will have to wipe with a dry towel but try not to have any bad prints…..

reply »

Edri

#72447

OSP PCB Plating | 21 July, 2014

Ensure you control the assembly completion. My previous experience, we control the assembly MUST be completed within 72 hrs, since you open the bare PCB seal, until you completed all the soldering process (Reflow & AWS).

We manage to control the above, and never had a concern in solderability both SMT (w/ BGA) & PTH.

reply »