Laser plotter for PCB artwork

[rozon]

The need for exact artwork when making PCBs is extreme, even when just doing hobby usage. My laser printer is not worthy this simple task any more, it is just too inaccurate.

I found this this link in my search for a cheap photoplotter. It seems doable even for a worm like me.

A commercial unit is like £6500, and thats way more than I'd be willing to spend. Here is a link to a professional system.

How difficult would this build be? What cost should I estimate for laser/optics? If I want 4000 DPI i guess i should have a focal point equal to a size of 6.35 micrometer. Is this doable?

As you probably guessed already, I'm a noob on lasers. Any pointers to get me running would be greately appreciated.

[Konstantin]

I had a glance at the photoplotter on the first link. Nice. Have he got it working, cause I didnt understood if it was 100% or what.
How about the software? Is it public domain?

[rozon]

It isn't finished.

The sourcecode for the software is linked on the page.

[MacGyver]

You're not going to get that kind of resolution with a CO2 laser, if that's your plan... even a YAG would have a difficult time getting there without some very high quality optics.

I don't see why you're having an issue getting the resolution you need out of the laser printer... a good quality 1200 dpi printer will get you 5mil trace/space lines without a single issue, 3mil is easily doable with some careful planning.

[rozon]

Laser printer is good for 10mil, no question. With smaller sizes your luck comes into consideration, especially on large designs.

On the width (x) axis the laser is always spot on, but the height (y) axis is often less accurate. I suppose thats why (cheap) lasers often has 1200x600 resolution, I don't know? I see this when doing large designs (y axis).

From the old days I used a HP LJ4 with 600DPI and I produced excellent artwork for through-hole. My current laser produce worse results than I had on the old printer. When looking at the artwork you see that the printer dither (I think thats the right word) the lines. The dots are distinct with no toner overflow, but the dots would make the PCB trace smaller than designed.

1200DPI and 10 mil is 12 dots and should be doable. Why I'm not able to do it must be related to the printer and it's settings. If you have an exact model or brand I should try I'm willing to do that - It would be much easier and cheaper for me.