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PCB cosmetic reject after reflow

Views: 1613


Jim

#35952

PCB cosmetic reject after reflow | 8 August, 2005

Does anyone come across the problem of pcb turns yellowish color after going thru' reflow under ROsH condition?

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#35957

PCB cosmetic reject after reflow | 8 August, 2005

Could the temperature of your reflow recipe be exceeding the limits of the materials used to fabricate your board?

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#35963

PCB cosmetic reject after reflow | 8 August, 2005

Hi Jim,

What type of your PCB finish?

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Jim

#35978

PCB cosmetic reject after reflow | 8 August, 2005

Hi Ktron,

I'm still waiting for my supplier to get back to me on the type of finishing.

Usually what type of finishing is recommended for reflow under ROsH condition?

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Jim

#35979

PCB cosmetic reject after reflow | 8 August, 2005

Hi Davef,

I'm suspecting that too! The recipe we are using is the optimum for good soldering results. I'm checking with our supplier on the type of pcb material.

Do you know the recommended material for pcb undergoing reflow, under ROsH condition?

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#35980

PCB cosmetic reject after reflow | 8 August, 2005

Jim

Can you be more specific? What's going "yellow / beige" on you? * Laminate * Solder mask * Legend

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Jim

#35981

PCB cosmetic reject after reflow | 8 August, 2005

Hi Davef,

After reflow, the pcb board turns yellowish color. However, the board still pass thru' functional test.

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#35983

PCB cosmetic reject after reflow | 8 August, 2005

Jim

Can you be more specific? What's going "yellowish" on you? * Laminate * Solder mask * Legend

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Jim

#35984

PCB cosmetic reject after reflow | 8 August, 2005

Hi Davef,

The whole laminate turns yellowish.

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#35998

PCB cosmetic reject after reflow | 9 August, 2005

Td or Decomposition Temperature (the temperature that the epoxy actualy starts to break down) should be greater than 330*C for lead-free. Search the fine SMTnet Archives for more on Td.

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Jim

#36024

PCB cosmetic reject after reflow | 9 August, 2005

Hi Davef,

I've found it. Very useful info. Thanks a lot.

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