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Carbon Ink vs Immersion Gold for key pads.

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Board House

#41328

Carbon Ink vs Immersion Gold for key pads. | 2 May, 2006

Hi all,

I'm looking for anyone with info in regards to reliability of carbon ink vs. Immersion Gold Key pads.

I have customers that still request Carbon Ink for there Key pads, while the majority have switch to Immersion Gold.

Is there any reading out there on this subject were I can find out the pros and con's of both. I would like to know how they match up against each other when it comes to longevity.

Thanks for your Help,

Mike

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#41347

Carbon Ink vs Immersion Gold for key pads. | 3 May, 2006

It all depends on process, design and environment in which the contacts are used. Both have excellent conductivity characteristics Both don't oxidize over time On the other hand gold is much softer then carbon, and after hitting that contact a gazillion times there is the potential to displace the gold and allow the underlying Ni to oxidize and prevent contact. As in a situation where the contacts have to be protected by either tape or peelable mask in the assembly process, gold will do better because of its flat and dense surface. Carbon has a rough surface and is more difficult to protect effectively.

Cost evidently will also be a factor in your customer's decision to use carbon. I've used both surfaces in the past and both were equally reliable. When we had problems it was due to design or process related contamination. The failure was never related to the fact it was gold or carbon.

Hope this helps

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Board House

#41353

Carbon Ink vs Immersion Gold for key pads. | 3 May, 2006

Hi Patrick,

Thank you for the info, We like to push ENIG, for us being the ENIG line is in house it is cheaper to use than the carbon, plus shelf life of the Carbon is an issue in Storage. Pre-application.

Thanks again,

Mike

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#41358

Carbon Ink vs Immersion Gold for key pads. | 3 May, 2006

We think well done carbon ink and well done ENIG are equally reliable [maybe 1M operations]. If the gold is pourous [not all that an uncommon], ENIG is far less reliable than carbon ink.

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