I see no reason why hermetically sealed elcos cannot be conformally
coated. If an elco generates pressure, it is because it is already in a
fault condition and should therefore be changed, anyway.
Brian
Lum Wee Mei wrote:
> Hello,
>
> Since we are on electrolytic cap, how about conformal coating (acrylic) on them?
> We have been coating them since day one as no one has instructed that
> electroltic cap cannot be coated.
>
> Recently, there have been opinion that we cannot coat them as there will be no
> gap for the pressure to escape - similar to the below issue?
>
> What are your opinions?
>
> Regards,
> Wee Mei
>
>
> Quoting Brian Ellis <[log in to unmask]>:
>
>
>>It depends on what cleaning medium you are using. If you are using a
>>halogenated solvent and just a microgram penetrates inside the casing,
>>you will see customers complaining of failures after 6 months to 2
>>years. This is well-known and was publicised by Sprague in the 1960s.
>>This company recommended using only hermetically sealed elcos if
>>cleaning in halogenated solvents. They also tested aqueous cleaning and
>>determined zero effect by aqueous cleaning, including with saponifiers
>>which could cause superficial corrosion of the outer case. However,
>>IMHO, it always makes sense with aqueous cleaning to have each stage
>>slightly warmer (say 5 deg C) than the previous one, so that you always
>>have positive pressure inside the cans while they are wet, to prevent
>>the ingress of contaminated water.
>>
>>Brian
>>
>>Scott Lefebvre wrote:
>>
>>
>>>We have a problem with the plastic disk coming off after being process
>>
>>through our In-Line PCB washer. What concerns if any should I have.
>>
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