Hello Dave,
There are some poor man's method for the power measurement check Sam's Laser, so many information exist. I'm always using goggles during tests. Here is the trick for the focus adjustment, print on thermal fax paper and check it under microscope.
Volkan
--- On Fri, 11/13/09, pork_u_pine2000 <wittend@...> wrote:
From: pork_u_pine2000 <wittend@...>
Subject: [Homebrew_PCBs] Re: Making PCB using these new 405nm LASER Diodes
To: Homebrew_PCBs@yahoogroups.com
Date: Friday, November 13, 2009, 12:31 PM
--- In Homebrew_PCBs@ yahoogroups. com, Volkan Sahin <v_sahin@... > wrote:
>
> There is nothing wrong with dryfilm. Only side effect can be its thickness.
> It is thicker than liquid photoresist. I've used dichromated PVA in order to avoid shelf life limitation. Whenever you need photoresist you can mix PVA with dichromate and it is ready, the problem is dichromate is not an environmentally safe chemical. Now I'll try AQ 3000.
> I used dryfilm before and faced a lot of problems to protect PTH holes but it was ~8 years before may be new ones are better.
> 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.
...
One difficulty that I have worried about using diode lasers is focusing and power measurement. I don't have any tools that are specifically useful for this. Besides not wanting to stare at a focused UV laser spot while doing adjustments, at 405 nm a lot of materials (including the laser potting) begin to fluoresce and emit visible wavelengths in random directions.
What do you use?
-- Dave
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