Printed DRO scales
Posted by
Randy Gordon-Gilmore
on 2000-04-07 08:33:49 UTC
At 05:21 PM 4/7/00 +0800, Wayne Bengtsson wrote:
"desired" pixel onto the nearest "physical" pixel. Assume the dot pitch is
.003" even. Two lines at, say, .0031" spacing, but evenly spread around an
acutal pixel location, could end up .006" apart.
I have not tried to print scales, but ran into this problem early in my
photoetching experimenting days. Even a 1200dpi printer had noticable
"wandering" when I was printing out parallel lines for the artwork for the
corrugated roof of my Pioneer Zephyr train model.
A much better solution would be to make a file to print out on a
phototypesetter. The result is on film already, and the resolution is 2540
or better dpi. I get my artwork done at a local
desktop-publishing-oriented place, but there is a company in the Northwest
(I'll look up the URL when I get to work) that does large sheets and
guarantees (if I remember right) .001" accuracy over the whole sheet.
The pattern for a linear scale would be a pretty simple Postscript program
(yes, Postscript is actually a programming language...there's a little
program I wrote on my webpage--the "Railroad Easement Template".) I'd be
happy to get involved in such a project (I have a Sherline mill and lathe
and a Taig lathe) if it can result in true movement (rather than
leadscrew-based) DRO for not much $$$ :-)
Best regards,
Randy
Randy Gordon-Gilmore ,----.___________ ______________ _________________
ProtoTrains // = = === == || == == == = || == == == = == =|
Rio Vista, CA, USA /-O==O------------o==o------------o==o-----------o==o-'
zephyrus@... http://www.rickadee.net/~zephyrus
>I am assuming a resolution of 300 DPI would translate into .003" accuracy,for
>at a minimum. If anyone here has actually tested the output of a printer
>accuracy, I would be very interested to see the numbers.Unfortunately, not quite. The way a matrix printer works, it maps the
"desired" pixel onto the nearest "physical" pixel. Assume the dot pitch is
.003" even. Two lines at, say, .0031" spacing, but evenly spread around an
acutal pixel location, could end up .006" apart.
I have not tried to print scales, but ran into this problem early in my
photoetching experimenting days. Even a 1200dpi printer had noticable
"wandering" when I was printing out parallel lines for the artwork for the
corrugated roof of my Pioneer Zephyr train model.
A much better solution would be to make a file to print out on a
phototypesetter. The result is on film already, and the resolution is 2540
or better dpi. I get my artwork done at a local
desktop-publishing-oriented place, but there is a company in the Northwest
(I'll look up the URL when I get to work) that does large sheets and
guarantees (if I remember right) .001" accuracy over the whole sheet.
The pattern for a linear scale would be a pretty simple Postscript program
(yes, Postscript is actually a programming language...there's a little
program I wrote on my webpage--the "Railroad Easement Template".) I'd be
happy to get involved in such a project (I have a Sherline mill and lathe
and a Taig lathe) if it can result in true movement (rather than
leadscrew-based) DRO for not much $$$ :-)
Best regards,
Randy
Randy Gordon-Gilmore ,----.___________ ______________ _________________
ProtoTrains // = = === == || == == == = || == == == = == =|
Rio Vista, CA, USA /-O==O------------o==o------------o==o-----------o==o-'
zephyrus@... http://www.rickadee.net/~zephyrus