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Pure Tin Quandry

Andrea

#34732

Pure Tin Quandry | 3 June, 2005

I have a customer who has put a restriction against pure tin finish components. We have gotten our BOMs compliant with all but 5 parts. Fairchild p/n FDD6512A, FQD12N20C, IRLM120A Bournes 3214G-1-501E Sprague 10TS-D10

I am looking for a standard practice or process for tinning or changing the dynamics of the pure tin. Or does anyone know of a company that can get the components compliant. We have looked for crosses for these to no avail. Any ideas on how to make our customer happy TIA, Andrea

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#34733

Pure Tin Quandry | 3 June, 2005

Your customer is being smart. When we look at the evaluation that some component suppliers do in assessing the potential of the pure tin solderability protection they've chosen to produce tin whiskers, we just shake our heads. Essentally they say, we ran this evironmental test and saw no evidence of tin whiskers. So we're good to go. Yewooo!!

Contract, lead tinning * XL Addenda; 708.971.8843 f8846; Gene Binkowski * Six Sigma; 1940 Concourse Dr San Jose, CA 95131; (408) 526-1350 Fax (408) 943-0447 sales@solderquik.com

* Corfin Industries; 7B Raymond Ave, Unit 7 Salem, NH 03079; 603-893-9900 fax 6800 http://www.corfin.net admin@corfin.net; Thomas Hamel * Chip Pro; 10390 E. Lakeview Dr #206 Scottsdale, AZ 85258; 480-860-5790 Fax 8366 Processing Facility 1610 No. Freeway 35E #214 Carrollton, TX 75006 972-242-9455 fax 8497 http://www.chipro.com

* Tintronics Industries; 2122 Metro Circle, Suite A, Huntsville, AL 35801; 256-650-0220 Fax 0230 http://www.tintronics.com; KC Ogata [sales]

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#34737

Pure Tin Quandry | 4 June, 2005

It would appear that pure tin is backward compatible with leaded processes. This makes it a great finish, as if you migrate all your parts over time there is no issue mixing them. I am not aware of any finish that eliminates the possibility of tin whiskers. Please enlighten me. What finish are you looking for? What are you getting besides pure tin? Anything that still reflows at 215C?

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#34738

Pure Tin Quandry | 4 June, 2005

Sn60/Pb40 works

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#34745

Pure Tin Quandry | 4 June, 2005

Sorry Dave, I meant lead free finishes.

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#34747

Pure Tin Quandry | 5 June, 2005

There is none. That's why aerospace is exempt.

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KEN

#34750

Pure Tin Quandry | 5 June, 2005

bright tin has demonstrated remarkable reduction in wisker formation.

Organic inoculations and plating thickness are two very important characteristics in wisker formation.

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#34809

Pure Tin Quandry | 7 June, 2005

Most component fabricators don't properly understand the impact of soldering with pure tin solderability protection on components. Here's one that does: "The Effects of Board Attachment Processing on Sn Whisker Formation on Electroplated Matte-Sn on Copper Alloy Lead Frames", IPC/JEDEC 5th International Conference on Lead-Free Electronic Components & Assemblies, San Jose, March 2004. http://www.agere.com/ehs/leadfree/docs/Tin_Whisker_Matte_Tin_on_Cu.pdf

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