Homebrew PCBs

"envelope or not?" poll question.

Leon Heller <leon.heller@...> 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 



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