Re: Absorb UV Light?

From: Ken (
Date: Wed Feb 11 1998 - 21:30:42 EET

Most Plexiglass will absorb wavelengths below 380nm. I have tested Cyro
UF-7 which starts transmitting at 390nm, OP-2 & OP-3 which starts at about
400nm. Use OP-2, since its cast, its easier to machine.

You can contact Cyro at 203-799-4066.

If you want, I can fax you a copy of the Spectral Transmittance chart.

Also you may take note that Aluminum reflects UV about 85% so be careful of
the reflection.

Good luck,

Ken Tashiro
2790 Skypark Drive
Suite 201
Torrance, California 90505
tel: 310-257-0300
fax: 310-257-0309
"A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet,
balance accounts, build a wall, set a bone, comfort the dying, take
orders, give orders, cooperate, act alone, solve equations, analyze
a new problem, pitch manure, program a computer, cook a tasty meal,
fight efficiently and die gallantly. Specialization is for insects."
- Robert A. Heinlein

-----Original Message-----
From: Douglas Mitchell <>
To: Miller, Michael W <>; 'RP Mail List'
Date: Wednesday, February 11, 1998 4:57 AM
Subject: Re: Absorb UV Light?

>On Feb 10, 3:58pm, Miller, Michael W wrote:
>> Subject: Absorb UV Light?
>> We are getting surface skinning (cured resin) in the right front corner
>> of our SLA500 near where the laser parks between layers. Our 3d
>> maintenance person believes it is caused by laser reflection off all the
>> resin spills on the cover plate. It has been suggested we dip the cover
>> into hot water to soften and then remove the spilled resin. An
>> alternate solution might be to paint? or apply some material in the area
>> that would absorb rather than reflect the UV. Any suggestions as to
>> what cheap and readily available material effectively absorbs UV?
>> Thanks,
>> Michael W Miller (
>> The Boeing Company MS 17-PE B-XT62
>> Propulsion Experimental Hardware 206-655-3289
>> Rapid Prototyping 655-4366 Lab 655-4365
>> For more information about the rp-ml, see
>>-- End of excerpt from Miller, Michael W
>When I went through SLA500 training back in the early days (Oct. 1990),
>3D had placed a small square of plexiglass at the corner for the laser
>to rest on. They claimed that the plexiglass disbursed the beam and
>kept it from bouncing back into the vat. I don't believe that they
>are still using this, but it would be a simple thing to try. It was
>a square of about 50 mm per side.
>Doug Mitchell
>For more information about the rp-ml, see

For more information about the rp-ml, see

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