Juhani,

Just out of curiousity are you using Advance Circuits Inc?  Your
vendor may be having problems with there Probimer 52 development
application.  On a slot that is .098x8.66 (2.5mmx220mm) you should
not have a problem in removing mask within the non-plated area,
assuming it is a non-plated through hole.  One way of looking at 
this, is if you have any .093 NPTH on the board are they removing 
the mask within those holes.  Hopefully they are, which should be
representative of other .093 holes or slots.

John Gulley - PE
Compuroute Inc. 
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214-340-0543

> From:          "Lainonen Juhani (NTC/Espoo)" <[log in to unmask]>
> To:            IPC TechNet <[log in to unmask]>
> Subject:       FAB: Curtaincoat Probimer 52 process
> Date:          Wed, 10 Apr 96 10:46:00 eet

> 
> Hello PCB Manufacturers
> 
> Problem, which take place with curtain coated Probimer 52, is Solder Mask
> on a hole walls, where it shouldn't be.
> The hole is routed and plated slot, size 2.5 mm x 220 mm.
> Our PCB supplier said that this is impossible to do with curtain coat 
> method.
> Have anyone any experience on similar cases?
> Any good advices, thanks.
> 
> [log in to unmask]
> 
>