Peter wrote:
>> Results: the 286x markers have a "pump" that you prime, and dispense the
>> paint when you press on the ball point. The paint is thick, which means 
>> it
>> doesn't spread as much and produces nice crisp dots. Unfortunately, the 
>> high
>> viscosity is a disadvantage when you're marking chips in a tray: they 
>> stick
>> to the pen.
>
> Thanks for sharing this. I make it a habit to hold down any SMD part with 
> a
> plastic needle before doing anything near or on it, as long as it is not
> soldered. A wooden toothpick also works in a pinch.

When marking 1000 chips at a time, you want to make the process the least 
cumbersome. :)


>> Both types of paint pass through the RoHS reflow process with flying 
>> colors.
>
> I am curious if you use any conformal coating(s) or organic solvent washes
> or organic solvent based flux, and what any of those things would do to 
> the
> markings. In my experience only resin (epoxy) paint passed those tests. 
> One
> kind of paint that is known to withstand such abuse is the white ink used
> to print (stencil) the text and placement layers on boards. But it is
> impossible to buy it other than by the liter and it is very expensive.
>
> I am also curious whether the marker paint is resin based and polymerizes 
> in
> place or otherwise becomes permanent, perhaps when heated.

Excellent point, I did not think of that. Will definitely check with the CM, 
thank you.

Vitaliy 

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