Printed Circuit Board Assembly & PCB Design SMT Electronics Assembly Manufacturing Forum

Printed Circuit Board Assembly & PCB Design Forum

SMT electronics assembly manufacturing forum.


force between the pad and laminate material

scott

#20309

force between the pad and laminate material | 11 June, 2002

I encounter the problem, it is easy for pad(copper) to drop off from the PCB, which is Ni/Au finish. so my question is whether there is any specification about the force between pad and laminate material, and does the PCB corpoartion test this parameter every lot. thanks.

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#20318

force between the pad and laminate material | 12 June, 2002

Don't sound proper.

There is no specification.

Pad peel strength test methods are: * IPC-TM-650, Method 2.4.21 for multiple solderings * IPC-TM-650, Method 2.4.8 for copper peel with a Instron machine.

Typical requirement for Cu is: 6 lbf/in [106 kgf/m]

Your board supplier should keep some test records on lot control. Tough to say more. So much depends on the lay-up of the bare board during fabrication.

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scott

#20333

force between the pad and laminate material | 12 June, 2002

Thank you very much!

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genny

#20390

force between the pad and laminate material | 17 June, 2002

When the pad comes off, is it leaving behind a "black" area? Your board may be suffering from black pad - a condition that occasionally affects ENIG finish boards. It is a process control issue with your board fabricator. The nickel is oxidising before the gold is added, so there is a very poor bond between them. You'll find lots of questions and answers in the archives about this condition.

If the pad is coming completely off and leaving nothing on laminate material underneath, than black pad is not the case. I defer back to Dave's response, then.

Regards.

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Paul

#20431

force between the pad and laminate material | 20 June, 2002

I've seen a problem recently where there was 2 deposits of Nickle then Gold, The problem is the Nickle will not adhere to Nickle, see if you can scrape the pad away with a scalpel.

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scott

#20434

force between the pad and laminate material | 20 June, 2002

according to the ressult of cross-section and removing the component, I find there is no black area in the left pad, and the IMC is also normal, so the black nickle is less impossible. the PCB material is not common FR4, just some thing like ceramic, so the adhesion is the critical problem. anyway, I appreciated your suggestion and help

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