Volkan Sahin wrote:
>
> Good idea. How to make reliable electrical power and video connection
> to the laser?
You could use a circular pcb with 2 big circles made off copper tracks
and some electric motor brushes to connect power. The signal must be
made with a two parts optocoupler on center. Once I saw the pcb with 3
brushes to implement one 2seconds per turn malfunction sensor.
But isn't this sensitive to distance from the laser and photoresist?
Comercial machines like this print small portions off the artwork each
time, needing 2 linear axis, and (i guess) mirrors on the rotative axis.
>
> --- On Fri, 11/13/09, Adam Seychell <a_seychell@...> wrote:
>
> From: Adam Seychell <a_seychell@...>
> Subject: Re: [Homebrew_PCBs] Making PCB using these new 405nm LASER
> Diodes
> To: Homebrew_PCBs@yahoogroups.com
> Date: Friday, November 13, 2009, 12:47 PM
>
>
>
> Volkan Sahin wrote:
>
> >
>
> > I added laser to the side of inkjet head and I'm using raster
> scanning
>
> > method to expose photoresist.
>
> > I've the same idea to use polygon mirrors of a old laser printer.
> I've
>
> > one Brother printer which has an aluminum mirror (most of them have
> a
>
> > copper or gold plated mirror on aluminum because of IR laser) and
>
> > plastic lenses it seems it is possible to use with blue laser. I
> did
>
> > some rough measurements and I saw that on optical path I'm loosing
> ~30%
>
> > of the power most of it is because of diagonal mirrors because of
> that I
>
> > left it for a future project.
>
> >
>
> The polygon mirror concept sounds more difficult to implement.
>
> How about a large diameter disc with a laser diode mounted on the
>
> perimeter. The PCB moves linear to the disc. Software would
> compensate
>
> for uniform exposure energy.
>
> Assume that:
>
> Resolution = 0.005cm (50um)
>
> Disc diameter = 15cm
>
> Energy = 60mj/cm^2
>
> Laser power = 85mW
>
> Then
>
> maximum disc RPM
>
> = 60 ∗ 1cm/0.005cm / (60/85 ∗ 15∗1)
>
> = 1133
>
> 1000 RPM sounds reasonable.
>
> [Non-text portions of this message have been removed]
>
>
>
>
>