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Subject: Re: [Homebrew_PCBs] Making PCB using these new 405nm LASER Diodes

From: Adam Seychell <a_seychell@...>
Date: 2009-11-13

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.