Homebrew PCBs

On Sat, 10 Aug 2013 01:26:06 -0000, you wrote:

>And yet another problem is that the "pulsar" type toner transfer paper stretches with heat and moisture.  I found that no matter what printer I used I could never get double sided artwork to line up close enough for cnc drilling.  This is exacerbated on large boards and hardly noticeable on very small boards.  I finally gave up on boards bigger than 3" in either dimension and went first to direct inkjet printing (which was never very reliable) and finally back to the negative photo method.

You can get closer registration (perhaps not exact) by matching up the
distortions.  For the top, use mirror and rotate, for the bottom, use
neither of them.  That gets the board to line up vertically and
horizontally.  Hopefully, if you are having problems with the board
lining up due to printer problems, this at least gets the two to line
up when printed.

Harvey


>
>Anyway, my 2 cents.
>
>--- In Homebrew_PCBs@yahoogroups.com, kabowers@... wrote:
>>
>> On Fri, 09 Aug 2013 23:44:44 -0000, you wrote:
>> 
>> 
>> >> <SNIP>
>> >
>> >Unfortunately not true.
>> >
>> >Laser printers will get the X axis spot on 
>> >and repeatable every time.
>> >
>> >They often have slip on the paper as it is
>> >fed through and the Y axis may on some
>> >printers be totally uncontrollable.
>> >
>> >Some are worse than others.  The OP may
>> >have one of the very bad Y axis printers.
>> >
>> If it's an older printer the rubber rollers may
>> have dried out or developed a glaze.
>> 
>> A good place to start might be the paper pickup mechanism.
>> 
>> Keith Bowers WB4LSJ- Thomasville, NC
>>
>