Hi,
After successfully getting my CNC rig working for PCB drilling runs
(updated info/photos at
http://www.freenet.org.nz/cnc), I tried using
the rig to draw etch-resist artwork directly onto the copper surface.
Following recommendations on other websites, I'm using a Staedtler
Lumocolor 313 superfine red pen, which is wonderfully etch-resistant,
dissolves quickly with acetone, writes finer and is more easily
available and 1/3 the price of 'dedicated etch-resist pens' from
electronics shops.
However, the result was not good. Even the 'superfine' variant of this
pen writes a 0.7-0.9mm line, way too thick for my layouts. Also, with
the relatively slow speed of my CNC transport, the pen tends to bleed
out to a thicker line.
I notice from some pcb sites that some people rip the guts from the pen
and insert the ink-bearing felt into a plotter pen. That might be an
option, but such pens might be hard to get given that plotters are no
longer in vogue.
I've thought of mutilating a Staedtler 0.1mm black felt-tip pen, pulling
out the black felt tank, running the pen dry, then inserting the red
lumocolor in its place. But I thought I'd ask here before destroying
$7-$10 worth of pens.
Are there any simple ways to get this pen to deliver a thin (<0.4mm)
line? Or should I stick to the thermal toner transfer which I've already
got working?
--
Cheers
David