tilt bed UV issue

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rasamaya
Posts: 5
Joined: Thu Sep 03, 2015 2:41 pm
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tilt bed UV issue

Postby rasamaya » Thu Sep 03, 2015 2:47 pm

Hi guys, first post!

I was going over the instructions for the tilt bed addon as I purchased one.

I noticed it uses a Cast acrylic GP(standard non extruded acrylic, not FF).
Naturally, Acrylic is UV resistant, and is used for preserving art and paintings.

When we require uv to transmit, we usually pay extra and purchase products like Acrylites UV transmitting acrylic aka OP4.

Has the current source been tested against a high transmission acrylic?
Have you noticed longer required exposure times or loss of quality with the tilt addition?

Also a cast sheet, which this was sent from has very low thickness tolerances. From one end of a full 4x8ft sheet, I can be out an 8th, and get physical dips etc(been working with it for 5 years) The FF vs GP is more accurate but not as optically clear as GP. You should always inspect GP parts for thickness and adjust appropriately. You dont want skewed light transmission from another angle messing with your source. One bounce off a mirror is bad enough.

FYI, I have a huge stock of UV transmitting acrylic I would let go for cheap cheap cheap Its pretty much just off cuts, but large enough by any means.

Let me know your thoughts :)

Thanks!

goopyplastic
Posts: 236
Joined: Sat Mar 29, 2014 6:16 pm
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Re: tilt bed UV issue

Postby goopyplastic » Fri Sep 04, 2015 12:58 am

Well here is my take, we are using the term "UV" pretty liberally with DLP resin printers. For example with the Acers we use on the LittleRP most of the UV output is >400nm so we are pretty much in the bottom of the visible range. At this wavelength even standard clear acrylic is pretty transparent. We are probably getting something like 92% transmission through even the 1/4" acrylic. I am curious if people notice much difference in curetime using UV specific acrylic. Also if people are curious I use Chemcast GP for my acrylic (exception being the shutter because I was sent the wrong stuff).


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