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Changing Ni/Au finish to HASL lead free

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#63347

Changing Ni/Au finish to HASL lead free | 20 December, 2010

The buyers in our company like to change the PCB finishing because of reducing costs. The proposed change is going from Ni/Au to HASL lead free, I know that in the beginning of the lead free period there where a lot of problems to use the HASL especially at the fine pitch SMT components. Now at the end of 2010 is there a good HASL lead free finishing which don't have these problems ?

Regards, Johan

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#63354

Changing Ni/Au finish to HASL lead free | 20 December, 2010

When you say Fine Pitch is this .5mm or is it smaller?

I wonder what problems they experienced with HASL, the only problem I recall hearing was the surface was not flat. When applying paste with a stencil I can not see how the flatness is an issue. If soldering proto boards by hand yes, flat is important.

Bob K.

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#63359

Changing Ni/Au finish to HASL lead free | 21 December, 2010

0.5 and 0.4 mm pitch, we think we could get problems with the solderpaste stencil. Also some board have keypads and then we have do do partial gold and I think that will not reduce the costs

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rem

#63361

Changing Ni/Au finish to HASL lead free | 21 December, 2010

1st the buyer shouldn't control the process based on cost. Let them buy stuff and stick to that.

2nd, I do think leveling in th HASL process is important. If you have high spots on pads for fine pitch your wiping away more of that aperture than others. Your inconsistently filling some apertures up more than others with the unlevel pre-soldered finish. On 5mil stencils this is critical.

I switched from HASL to Immersion Silver due to these problems and eliminated most of my screen printer issues concerning fine pitch.

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#63362

Changing Ni/Au finish to HASL lead free | 21 December, 2010

I know when we used them we had problems when one pad is 7 mils tall nest to a flat pad one lead touches the pad the lead next to it isnt touching anything so then have an open I don't see how anybody dosnt have problems with it that use quad flatpacks and an 4 - 6 mil thick stencil just my 2 cents

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#63365

Changing Ni/Au finish to HASL lead free | 22 December, 2010

Hi Johan,

As a Asian board supplier - I would not recommend using Lead free hasl on any product that has BGA, you would be just looking for issues, flatness being the main.

I agree with one of the other replies - Your purchasing dept. should not be the ones make decisions on Custom product like a pcb board. The surface finish alternitive that is a little cheaper that ENIG is Silver but you trade off shelf life and tarnish issues.

I would stick with Enig. pricing for it has not gone up that much do to you are only platting 2-3 micro inches, now if your board has Gold tabs or Select Hard gold keypads or any Deep gold process than yes pricing has gone up considerably due to the current price of gold. The only thing there you can look at is reducing the thickness of the hard gold being put down. Normal thickness on gold tabs and such plating is 30 micro inches. I have had clients lower this down to 10-15 Micro inches of hard gold and save quite a bit do to the total amount of gold being used.

Hope this helped,

Best regards,

Mike Dupont www.activepcb.com Active Sales Associates, Inc.

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#63368

Changing Ni/Au finish to HASL lead free | 22 December, 2010

HI I used both of solder leveling HASL and ENIG, HASL I can recommended for biger pitch is cheaper solder leveling than ENIG but problem with that solder leveling is during the reflow process HASL isn't flat and during reflow process component move on the pad the follows from to not flat surface and too much HASL level in some part of pad, if you would like to use HASL you must answer also on the more question HASL but what type of HASL ?? clean Sn (232degree) or SN100C (227degree) depaend on type of component you use on pcb also you can think about small diameter of solder ball in solder paste that help , I'm sure. You must thinking about also BGA if you have on PCB generally if you have pitch more than 0,8 on bga you can normal solder bga (but rememmber about compatibility of alloy sometimes is solder bga has diffrent alloy than solder paste and solderability on ENIG isn't the same what soldering on HASL)

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#63418

Changing Ni/Au finish to HASL lead free | 4 January, 2011

Hi Mike,

We only are using ENIG not hard gold, we are using edge contacts but the connectors will only be removed if the product is being replaced, normal life time for the equipment where the electronics is build-in is 15 years. Also the electronics is designed for that lifetime. Also for the keypads we don't use hard gold.

Best regards

Johan

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#63419

Changing Ni/Au finish to HASL lead free | 4 January, 2011

Hello Piter,

I don't know which type of HASL we will be using, we decided to do some test and I have to decide together with two other people which material we will try. Searching on the internet i discovered that it's not so easy to find a good solution.

Best regards,

Johan

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#63440

Changing Ni/Au finish to HASL lead free | 6 January, 2011

Hi Johan,

Sounds like you have already gone over your product very well to reduce product cost. Switching away from Deep gold Tabs & carbon ink Key pads can save quite a bit. The only other thing to suggest would be material - Moving away from Isola or Nelco to some Equivalent material like- Grace, Iteq or Nanya could also trim some cost out.

Best Regards,

Mike Dupont Midwest Sales Mgr. Mdupont@activepcb.com www.activepcb.com Active Sales Associates, Inc.

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