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May 2009

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Subject:
From:
Werner Engelmaier /* <[log in to unmask]>
Reply To:
TechNet E-Mail Forum <[log in to unmask]>, [log in to unmask]
Date:
Fri, 15 May 2009 17:45:31 -0400
Content-Type:
text/plain
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text/plain (175 lines)
 Hi Leif,
This info spells 'trouble.'


 LCP—Liquid Crystal Polymer has some strange properties, including warpage and CTE.
Copper alloy with Au over Ni means that that Cu alloy is likely BeCu which is not solderable hence the Ni/Cu surface treatment.
Your experience is not much of a surprise—change connector source.
Werner


 

-----Original Message-----
From: Leif Erik Laerum <[log in to unmask]>
To: TechNet E-Mail Forum <[log in to unmask]>; [log in to unmask]
Sent: Fri, 15 May 2009 5:42 pm
Subject: Re: [TN] Connector with loose pins









Werner, 
 

The data sheet lists the insulator material as LCP. The pins are stated 
to be a copper Alloy with Gold over Nickel. 
 

Leif Erik Laerum 

Quality Assurance Manager 

Texas Memory Systems 

[log in to unmask] 

Tel: (713) 266-3200 x468 

www.texmemsys.com 
 

 

Werner Engelmaier /* wrote: 

>  Hi Leif 

> You do not say how long that connector is and what the connector body material is. 

> My guess on very skimpy info is that you have a too long connector made with an unsuitable connector body material, with connector pins made of some connector pin metal, like BeCu, that while it is a good connector pin material with good spring characteristcs, it makes for bad solder joints 

> 

> Werner 

> 

> 

>  
> 

> 

>  
> 

> -----Original Message----- 

> From: Leif Erik Laerum <[log in to unmask]
> 

> To: [log in to unmask] 

> Sent: Fri, 15 May 2009 5:16 pm 

> Subject: [TN] Connector with loose pins 

> 

> 

> 

> 

> 

> 

> 

> 

> 

> Technetters,? 

> ? 

> 

> I have a less scientific question, but I hope someone has some 
> experience with a similar problem.? 

> ? 

> 

> We have a .090 think motherboard where one particular part number 
> connector frequently have loose pins. It is 33 cm by 16mm. There are 
> lots of other types of connectors on the board that does not have 
> issues. We only have problem with one part number. These connectors are 
> at the very front of the board. They go in the oven first. This is a 
> leaded solder board and we use SN63/Pb37 solder. The loose pins tend to 
> be at the end of the connector and on power planes. On some boards it 
> appears that the connector sort of twists or bows a little bit.? 

> ? 

> 

> The problem is that this surface mount connector is very hard to fix. 
> The pins frequently short and due to space limitations, it is hard to 
> reach them with the tip of the soldering iron. They also tend to develop 
> shorts easy. This makes it even harder to fix after reflow.? 

> ? 

> 

> We have tried reducing the cooling at the end. We have sent the boards 
> through the oven with the mate installed in order to stiffen up the 
> connector. 
The profile was checked as late as today. Nothing jumped out 
> at me.? 

> ? 

> 

> Does anyone have experience with a similar problem that they managed to 
> solve?? 

> ? 

> 

> Thank you.? 

> ? 

> 

>   


 


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