Re[3]: SLA 250 laser remelts - etc. etc.

From: Stahlhut, Todd A. (
Date: Wed May 22 1996 - 20:39:00 EEST

Not to beat a dead laser but ...

How are people doing remelts:

     1) Only when they see a power drop of "x milliwatts"

     2) Every "x hours" whether it appears to need it our not.

if (1) what is the targeted mw drop and if (2) what is the period of hours.

Also, what are peoples opinions of the stability of the high powered lasers
the low powered lasers. We have seen that the high powered lasers are much
more temperamental than the lower ones.

Regards, Todd Stahlhut
From: rp-adm
To: ralott; rp-ml
Subject: Re: Re[2]: SLA 250 laser remelts.
Date: Wednesday, May 22, 1996 11:18AM

The remelt thing in the middle of a build has happened to me. Fortunatly not

very often. If it was a long build already and I didn't want to start over I

would make that decision. The effect on accuracy...You will probably notice
as well as a power drop the beam fidelity will be affected as well. That
the beam diameter as well as the x/y ratio. Changes to these two
will most certainly affect the desired beam compensation value as well as
"shrink" compensation value. Also when doing a remelt, the rods that align
mirrors are heated as well, possibly causing the mirrors to shift ever so
slightly. Which is why the service techs tune the mirrors after a remelt to
optimise the power output. What does this have to do with the accuracy? It
move the apperture(where the beam comes out)slightly, which after bouncing
all the mirrors might hit the vat in a slightly different location. This is
pertinent if you are trying to achieve accuracys of -+ .005 over 10 inches.

Andy at AccentOnDesign.

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