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Subject:	Re: Through-hole Solder Joint inspection and quality criteria
From:	刘常康 <[log in to unmask]>
Reply To:	刘常康 <[log in to unmask]>
Date:	Wed, 1 Nov 2000 09:19:15 +0800
Content-Type:	text/plain
Parts/Attachments:	text/plain (1 lines)

Dear Engelmaier,

 Thank for your help.

 I think perfect fillet shows good wetting, and our product is communication equipment, and I am not sure that which is inportant between wetting and fill ratio.

 Can you give any more advice?

 

Best regards

Liu Changkang



----- Original Message ----- 

From: "Werner Engelmaier" <[log in to unmask]>

To: <[log in to unmask]>

Sent: Wednesday, November 01, 2000 12:55 AM

Subject: Re: [TN] Through-hole Solder Joint inspection and quality criteria





> In a message dated 10/31/0 4:12:07, [log in to unmask] writes:

> > One partly poor wetting component  after wave soldering, through-hole

> >solder joint shows good wetting near top side PCB, but show bad wetting

> >on the bottom side and through-hole is about 70% filled. some suggest good

> >wetting is key to evaluate a SJ reliability. IPC suggest 75% filled is

> >OK, which one I choose?

> >Same situation happen to  paste in hole process, Which type SJ is ok?

> >the key is the fill ratio or the good wetting?

> >If half of through hole SJ is good wetting, half of which is bad, Is it ok?

> 

> Hi Liu,

> Good wetting is by far the more important physical aspect--however, an

> incomplete fill may be a sign of wetting problems. Further, if you have

> "partly poor wetting", how do you know the rest is "good wetting"?

> If you have good wetting, a partial hole fill is only important in a severe

> use environment, e.g. automotive, because of the stress concentration on the

> PTH barrel at the solder/no-solder interface.

> 

> Werner Engelmaier

> Engelmaier Associates, L.C.

> Electronic Packaging, Interconnection and Reliability Consulting

> 7 Jasmine Run

> Ormond Beach, FL  32174  USA

> Phone: 904-437-8747, Fax: 904-437-8737

> E-mail: [log in to unmask], Website: www.engelmaier.com

> 

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