New to LittleRP, some basic questions

Forum dedicated to discussion and technical support centered around the LittleRP affordable, open source 3D resin printer.
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Mattasmack
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Joined: Thu Dec 17, 2015 1:11 pm
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New to LittleRP, some basic questions

Postby Mattasmack » Thu Feb 25, 2016 9:06 pm


cew
Posts: 28
Joined: Tue Jan 05, 2016 5:36 am
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Re: New to LittleRP, some basic questions

Postby cew » Sat Feb 27, 2016 6:07 am

I've also recently setup a couple of littlerps. Below are some suggestions:

Focus? I used a piece of wet tissue in the dish. If you use the red calibration grid in creation workshop it is not too bright and easy to work with. Depending on your eye sight you may also want to use a lense or usb microscope to fine tune the focus at higher resolutions.

Calibration block curling? Yes I had the same problem. The following can help reduce this issue; hollowing to a wall thickness of ~1mm, low shrinkage resin such as B9 black, tilting the part and using full supports.

Resin dripping? The new solid build platforms reduce this a lot. With the older hollow platform I modified the build platform arm spacer stl so that the platform could be tilted for draining into the dish. You can also add a line of gcode to automatically elevate the part clear of the resin at the end of the build. However I keep a stack of paper towels next to the printer..

Design rules for overhangs? Formlabs have a design rule pdf that is quite useful. Meshmixer and autodesk print studio can usefully automatically generate most supports for overhangs if you use the 'ember' dlp printer settings. If you look closely at your prints you can increase exposure levels and lower lift or return speeds (eg 70mm/min) to help a bit.

cerriousdesign
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Re: New to LittleRP, some basic questions

Postby cerriousdesign » Sun Feb 28, 2016 4:45 pm

I can only answer the one about overhangs. I make prints with severe overhangs. This of course requires supports. The best support generator out there in my opinion is the free software Meshmixer. There are several tutorials on Youtube on how to use it.

Mattasmack
Posts: 25
Joined: Thu Dec 17, 2015 1:11 pm
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Re: New to LittleRP, some basic questions

Postby Mattasmack » Sun Feb 28, 2016 9:48 pm

Thanks to both of you for your replies!
Cew, regarding focusing, I discovered after emptying out the vat that I could faintly see text projected directly on the bottom of the vat this time, without adding anything. So it looks like the film is getting a little cloudy; I don't know if that's a problem but it certainly made focusing easier this time. I did try using a magnifying lens as you recommended and that helped.

That's good to hear about the calibration block! I did try angling it up and putting it on supports and it printed fine that way; I was just concerned that its curling when laid flat meant I had something set up wrong.

Do you have a picture or .stl handy for your modified arm spacer? I'm using a hollow platform and the resin draining from inside is indeed a pain. I can turn the platform 90 degrees and tilt it back as I loosen the thumbscrew to get the resin inside the platform to drain back into the vat, but then resin dripping off the print itself tends to hit the projector.

Regarding overhangs, I'm not concerned so much about design rules for making models, as I am about optimizing machine settings. I did try turning down lift speed and added a bit extra delay at the top of the lift and after the return, and that seemed to help some. Thanks to both of you for the Meshmixer recommendation. I haven't looked at it since trying it once or twice to prepare parts for printing on my old FDM printer; I guess it's time to give it another look!

cew
Posts: 28
Joined: Tue Jan 05, 2016 5:36 am
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Re: New to LittleRP, some basic questions

Postby cew » Wed Mar 02, 2016 6:04 am

Below is a link to the spacer stl that has been modified to help with draining after a print. It was based on one from thingiverse by Wookbert. Note its best to print in PLA since the resin softens the ABS.



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