Homebrew PCBs

I've used a 400 watt hi-bay lamp (480V ballast) without an envelope 
since 1973 - same bulb still going strong.  Just keep it in a complete 
enclosure with a slot to insert the PCB sandwich.

Norm

guja wrote:
>
> "envelope or not?" poll question.
>
> Leon Heller <leon.heller@... 
> <mailto:leon.heller%40bulldoghome.com>> wrote: ----- Original Message 
> -----
> From: "Stefan Trethan"
> To:
> Sent: Saturday, October 14, 2006 8:01 PM
> Subject: Re: [Homebrew_PCBs] Mercury lamp for UV exposure
>
> > On Sat, 14 Oct 2006 19:51:57 +0200, Leon Heller
> > wrote:
> >
> >>
> >> It will be mounted in a light-tight box.
> >> Leon
> >
> >
> > But in case it does no good (or little good) what is the point in 
> breaking
> > the envelope?
> > Does it really speed up exposure that much?
>
> Everyone else using them does it. It will also help with collimation 
> as it
> will be more like a point source. The high-speed exposure units used 
> by PCB
> manufacturers use much more powerful mercury arc lamps with special 
> optical
> systems consuming 3.5 kW or more and delivering 15 mW/sq cm of UV at the
> PCB!
>
> Leon
>
> Be sure to visit the group home and check for new Links, Files, and 
> Photos:
> http://groups.yahoo.com/group/Homebrew_PCBs 
> <http://groups.yahoo.com/group/Homebrew_PCBs>
>
> If Files or Photos are running short of space, post them here:
> http://groups.yahoo.com/group/Homebrew_PCBs_Archives/ 
> <http://groups.yahoo.com/group/Homebrew_PCBs_Archives/>
> Yahoo! Groups Links
>
>
> ---------------------------------
> Get your own web address for just $1.99/1st yr. We'll help. Yahoo! 
> Small Business.
>
> [Non-text portions of this message have been removed]
>
>  


[Non-text portions of this message have been removed]