There are at least two problems to be solved when using the plotter to produce artwork
on a blank PCB.
1. Fixing the PCB to the plotter.
2. Using a pen with permanent ink. The original pens for a HP7475A are no longer
available.
Problem 1 can be solved by using double sided 'Sellotape' to fix the PCB
onto an A4 sheet of paper. I have had no problem with this bearing in mind
that the boards are small (4" X 4") or less.
Problem 2 was solved by using a 'Staedtler Lumocolor permanent ink' fibre
tip pen. These are available in at least three tip widths, this will set
the minimum track width irrespective of what has been defined in the software. See the
hints page.
The pen obviously has to be fitted into the plotter's pen holder. I sorted
this by hollowing out a genuine plotter pen and pushing the Lumocolor pen
through the plastic barrel of the original pen. This may have been overkill
as I think maybe with the use of plastic tape and a washer forming the
shoulder, the Staedtler pen can be made to resemble the HP pen, albeit
much longer. This later fact requires the pen to be fitted to the plotter after
the software has selected a pen. Fortunately the Easyplot program pauses before
plotting which allows the long pen to be fitted.