Techy PCB plotter discovery....

[Chris Crosskey]

Hi...this is a bit off topic, but bear with it...


I've just  got a plotter to use with a PCB package on my Atari ST, and 
have madwe the following discoveries....


The pen used for final ouput, made by Rotring, cost as much as the 
plotter, a bunch of fibre-tip pens and a couple of boxes each of 
darfting OHP film and coated paper.....ie about 50 UKP. The plotter is 
an old HP7475A serial device. It might be old but the build quality is 
great....


Using a 0.5mm tipped Rotring pen and hi-contrast NC600FP ink on OHP 
film gives you a usable UV master without stalling the plotter driving 
program on the ST at 2cm per second. Speeds of 1cm per second or 
slower stall the program, speeds of 15cm/s are possible, but the 
output isn't dense enough for a final master, but would be OK for 
checking...


I've got a Windows driver for this plotter on my PC, and will attempt 
to drive the plotter at slower speeds for denser output by getting the 
ST to save the ploter data as a file, transferring it to the PC and 
firing it through print manager. I will report back as and when this 
has been tried, though it might be a while yet. The quality of output 
I'm getting already is way higher than I used to achieve on a 
Laserjet5 onto OHP Laserfilm, which has previously been what I was 
doing. I am going to attempt a double print onto the same film to 
increase ink density as well, adn as it will save me from towing the 
plotter from room to room, it might be a better plan.....
Moral of the story.....cheap gear aint necessarily useless, the PCB 
package I'm using is called PLATON, and it does Gerber etc too, it's 
not too slow, PCB Designer on my 486DX2/66 runs slower and doesn't 
support Gerber....will try it with plotter as well sometime....
As analogue synth circuits are rarely complicated this kit seems to 
work quite well, and is a cheap bedroom setup....


chrisc