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Lead-free PCB: After Effect

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CP

#43463

Lead-free PCB: After Effect | 21 August, 2006

Hi there,

Does anyone know how the assemblers and PCB fabricators cope with lead-free assembly and materials after the ROHS deadline?

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CP

#43464

Lead-free PCB: After Effect | 21 August, 2006

How does it effect the fabricators' manufacturing yields and efficiencies? And reliability of the fabricated PCB?

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Board House

#43482

Lead-free PCB: After Effect | 22 August, 2006

Hi CP,

From a PCB manufacturing side, all of our product is Lead free / RoHs compliant if it has a surface finish other than Hot Air.

To be ROHS compliant and Able to with stand Lead Free Assembly, this is where the board house would need to switch to a Material with a Higher Td. or De-comp.

Standard Material in USA for Lead Free Assembly is Isola IS410 180 Tg. / 350 Td.

This material has a different Resin content that is able to with stand the higher Assembly Temps needed to flow lead free paste.

IS410 Material Looks like ceramic material and has similar draw backs, its fragile, Hole quality after drilling is not as good as standard material, Shelf life on its Pre-Pregs is 3 mos versus 6 mos for std FR406 Material and availability is a Pain.

Manufacturing time is also increased due to longer Desmear time after drill to clean the holes out and press time at Lamination to cure the material. Total add between the two is about 3 1/2 hours.

Material pricing from FR406 to IS410 is higher but not by much and this will change as more shops convert to it.

The typical pricing increase from Lead free to Assembly Capable Lead Free Material is around 10%. And this is to cover the increased cost of the material and the increased Manufacturing time.

When to switch to this new material type is an assembly issue, We have deal with some CM's that feel that Standard FR406 material will work just fine with there lead free assembly and they are not worried about De-lam. Others will tell us that FR406 material will de-lam. Allot depends on the CM's Paste selection and profiling.

As a board shop, we explain to our CM's that we will not Warrantee FR406 product that goes through Lead free assembly.

Hope this Helps,

Regards,

Board House

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CP

#43568

Lead-free PCB: After Effect | 25 August, 2006

Hi Board House,

Thank you for your inputs.

Do you see the similar problems to flex circuits makers?

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CL

#43570

Lead-free PCB: After Effect | 25 August, 2006

Hi CP,

I used to work for a flex circuit manufacturer. I am at a CM now and am we have started building RoHS production status assemblies. I personally think flex circuits will have a difficult time with the required temps for RoHS. I spoke to someone at my former employer about the RoHS requirements and their reply was "Most of our customers are exempt so were not worried" This is probably true as most of thier business was military or medical. It was obvious that they had not put much emphasis on researching the requirements. Under the construction that they were using when I left (about 5 years ago) the flex curcuits would become nacho's under the required temps. I am curious to see what happens.

CL

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Hussman

#43572

Lead-free PCB: After Effect | 25 August, 2006

Board House,

One last question. Could the above changes make the board more ridid? My concern is we insert Pem nuts via a press. Nothing has changed in this process except the board house. Now when ever we insert these Pem nuts the board cracks. Mind you, this only happens on holes near the edge of the board. If we bore the hole out to the upper tolerance, things are fine. My question is, does the new process produce a more rigid board?

Thanks

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Board House

#43629

Lead-free PCB: After Effect | 28 August, 2006

Being the Lead free material would be more fragile it would have more of a tendency to fracture the material. I have had a customer run into this issue, they have not came across a cure yet. Hitting the upper tolerance might be the cure I will suggest this to them if they have not already tried.

Inregards to Flex material I would not be able to answer, we are a Ridged shop only.

Board House

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