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Bareco wax on pressfit connectors?

#23563

Bareco wax on pressfit connectors? | 27 February, 2003

Forgive the non-SMT question. That's why I hate through hole boards. Has anyone ever used Bareco wax on pressfit connectors, and how do you produce a consistent process for its application? Any drawbacks? Background: We have found a design issue with an AMP press fit Connector, p/n 553443-4 50 pin Champ-Lok action pin receptacle assembly. It seems that this design arrangement with the correct dimensions in a Fab with gold finish, will be inconsistent during the assembly operation as confirmed by AMP. The leads will randomly crush or kink inside the housing where it is not visible, unless you remove the protective cover and perform a visual inspection. The AMP Engineer offered several alternatives 1. Continue our effort and replace individual pins as required, by pulling off the housing, removing pins that did not successfully insert, and sliding new pins into the housing for another press fit. (may not work here as we have found that some locations will repeat the defect upon a re-insertion) 2. Use Bareco wax on the surface of the pins, which will displace and evaporate during assembly 3. Use an alternative recommended part. 4. Spec out a HASL finish board instead of gold with no other changes. This alone will yield consistent build results according to an AMP engineer. I have opted to use HASL finish on all new orders. The question is how to use the Bareco wax in a controlled manner in order to rework the defective boards in house. Any expertise is appreciated. I'm going back to the SMT world now.

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MA/NY DDave

#23564

Bareco wax on pressfit connectors? | 28 February, 2003

Hi

I don't believe I have ever done this or seen it, yet maybe since there are some other lube processes.

Ask the Amp Guy for any older App Notes. They used to have a lot.

If I got this right you could put it on the board with an applicator that coats the top and pushes down in the hole a bit. Easier and less sloppy than putting in on the pins.

All you are looking for is to reduce friction during insertion which cuts down on the bending forces.

Good Luck

YiE, MA/NY DDave

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#23569

Bareco wax on pressfit connectors? | 28 February, 2003

Never heard of Bareco wax. Check with your press supplier. They'll have the dirt on this carnuba oil stuff.

I do question replacing ENIG with HASL, no other changes. HASL is going to fill that hole alot more than ENIG. Certainly it will displace more, but will the there be enough room in the hole for everything to fit?

What's the finish on the connector?

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#23575

Bareco wax on pressfit connectors? | 28 February, 2003

I had the same concern. The connector pins are gold also. I am waiting for a response from AMP to supply some of this wonder wax. I can inspect the HASL fabs for proper hole diameter, but I do not have a warm feeling I should be getting involved with the wax. Thanks for your inputs.

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MA/NY DDave

#23576

Bareco wax on pressfit connectors? | 28 February, 2003

Hi

http://barecowax.com/About%20Bareco.htm

You will notice they have a lot of products.

After you get from AMP the actual Bareco lubrication product they are recommending for their product application make sure you know what cleaning method removes the product. Water won't remove some of their products.

YiEng, MA/NY DDave

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#23578

Bareco wax on pressfit connectors? | 28 February, 2003

Paul

We don't like to mix metals on press fits. Yano, we do gold on gold or solder on solder, but we don't mix metals [except with imm silver / tin] to avoid electrochemical corrosion. Is that bad information or does AMP think that's not a problem?

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Pauld

#23582

Bareco wax on pressfit connectors? | 28 February, 2003

Dave, I raised this concern also. AMP claims that the tight fit in the wipe zone creates an airless joint that will not corrode despite the dissimiliar metals. DDave, thanks for the link.

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MA/NY DDave

#23589

Bareco wax on pressfit connectors? | 1 March, 2003

Hi

Hey thanks, you are welcome for the link.

Well to be precise dissimilar metals will corrode at some rate and also depends on the environment. Look at a Galvanic Table. Yet maybe for your application and the ones AMP designed this part for, the corrosion is outside of the product's life cycle. You might want to ask them if they have any life cycle data depending on environment. Again just a thought and probably no big deal.

YiEng, MA/NY DDave

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