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Subject: Re: [Homebrew_PCBs] Re: setting up the Right Way

From: Stefan Trethan <stefan_trethan@...>
Date: 2010-01-26

Sure is.

The drilled holes will expose the edge there to under-etching, might
want to use mounting hole locations or something. Also, if you raise a
burr it will lift the film there, not ideal. And you need to drill the
holes in just the right place. I haven't found that method to be
particularly practical.

I very rarely do two-sided boards at home, although most of my board
stock would be double sided. So I have never perfected the process and
it doesn't come easily to me. I usually check two hole locations with
a caliper after transfer to make sure the sides are aligned before
etching.

ST


On Tue, Jan 26, 2010 at 8:02 PM, Peter Harrison
<peter.harrison@...> wrote:
> Is it possible to pre-drill some of the holes and align the artwork overlay against them?
>
> Peter Harrison
>
>
>
>
> On 26 Jan 2010, at 18:44, Stefan Trethan wrote:
>
>> The problem with this is the non-zero width of the PCB. Depending on
>> how you hold things together the films can shift one side relative to
>> the other. A better method is to stick the films to PCB cutoff strips,
>> or an L-shape. Insert a piece of clear acrylic or glass while aligning
>> the two sides instead of the PCB. This gives very exact results,
>> probably the best you can get without alignment pegs.
>>
>> Vacuum holddown is highly recommended, it is easy to make by covering
>> the film/artwork stack with a framed sheet of flexible clear plastic
>> and applying vauum to that.
>>
>> ST
>
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