Horizontal lines in print

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Vulwulf
Posts: 17
Joined: Sat Apr 01, 2017 5:33 pm

Horizontal lines in print

Postby Vulwulf » Fri May 19, 2017 11:54 am

Thanks to the people in this forum I'm actually having success printing but I have one more problem.

I have horizontal lines in my print that appear as grooves then the slice above (or same slice?) is off center causing a ledge. I did a lot of searching but I couldn't​ find much, some about flexvat tension but that was before the acrylic plate was part of it so I don't know if it's valid anymore.

Only happened twice in this print but it was enough to notice and likely ruin one of my more detailed prints:

20170519_163947.jpg

goopyplastic
Posts: 231
Joined: Sat Mar 29, 2014 6:16 pm

Re: Horizontal lines in print

Postby goopyplastic » Fri May 19, 2017 12:06 pm

What kind of computer are you using, are you using it while printing? is power saving turned off? making sure not to bump the printer during printing? tight vats generally result in fine shift lines not something this severe. Do those layers flare out on the reverse side too? (ie. do the layers seem overgrown, or does a segment seem shifted to one side.

Vulwulf
Posts: 17
Joined: Sat Apr 01, 2017 5:33 pm

Re: Horizontal lines in print

Postby Vulwulf » Fri May 19, 2017 2:30 pm

goopyplastic wrote:What kind of computer are you using, are you using it while printing? is power saving turned off? making sure not to bump the printer during printing? tight vats generally result in fine shift lines not something this severe. Do those layers flare out on the reverse side too? (ie. do the layers seem overgrown, or does a segment seem shifted to one side.


Thanks for your reply goopyplastic,

I'm using my own desktop pc, windows 8.1, pretty standard gaming/3d workstation. I did use it while short prints were being printed and never had this issue but during this long print I went and did something else, just checked on it regularly.

Power saving is turned off so the screens never turns off, alt tabbing etc will swap the screen to the desktop briefly​ but I wasn't using it, any way to stop this by the way?

When I check on it I did open the lid because I thought the print had failed, and thinking about it that could time well with where the slices are... I'm not even sure how, I was so careful.

Here is the ring from the other side, while the upper band has no flare, just a groove but at the tip of one of the curls it flares quite dramatically dispite having only a very shallow groove in the upper band. It had flared on the inner edge of the ring also.

20170519_191055.jpg


It definitely seems more like a segment has shifted rather than overgrown, though it seems like the error layer is quite thick.

goopyplastic
Posts: 231
Joined: Sat Mar 29, 2014 6:16 pm

Re: Horizontal lines in print

Postby goopyplastic » Fri May 19, 2017 2:57 pm

What do your supports look like on that model?

Vulwulf
Posts: 17
Joined: Sat Apr 01, 2017 5:33 pm

Re: Horizontal lines in print

Postby Vulwulf » Fri May 19, 2017 4:48 pm

goopyplastic wrote:What do your supports look like on that model?


Honestly, pretty terrible. I'm embarrassed to show it but it worked, I used meshmixer to generate supports and most looked like they would never survive so I kept adding until it seemed strong, it was a spiders web. My next one I will try to be neater.

This is the only photo I have before I removed the supports which was a right pain in the ass:

20170519_211228.jpg


Actually I am just noticing that it has a small printing fail, those 2 large curls that touch at the left the bottom one should be longer, the shifting layer removed the supports.

goopyplastic
Posts: 231
Joined: Sat Mar 29, 2014 6:16 pm

Re: Horizontal lines in print

Postby goopyplastic » Fri May 19, 2017 7:09 pm

Waxcast will generally require much stronger supports than other resins will, due to it being easily distorted. It's possible the build lines visible are from the print shifting due to stress events, shrinking / some supports releasing etc. Meshmixer is actually not all that good in my experience when it comes to small prints with small details. Often the attachment points do not penetrate into the model. I would try b9 layout maybe, also rotating the model in more than one axis will help breakup concentrated stress events on the model while printing, just a little bit will help. Probably not an issue but also make sure the build plate, vat holddowns, and z-arm are snug and secure.

Is this a tall or normal height LittleRP2? Both are pretty susceptible to movement, bumps etc the tall variant even moreso. If you do need to open the hood etc make sure you try and do it during the lift phase.

What is your lift / retract speed?

Vulwulf
Posts: 17
Joined: Sat Apr 01, 2017 5:33 pm

Re: Horizontal lines in print

Postby Vulwulf » Sat May 20, 2017 8:13 am

Thanks for your advice on waxcast resin. I did notice that half or so of the supports at the bottom wernt attached at all, maybe that was makerjuice needing stronger support, maybe it was meshmixer, I don't know how it succeeded really, I'll look into b9 layout.

Mine is the tall version, and my lift speed is 50, return is speed 200.

Thanks for all your advice.

Vulwulf
Posts: 17
Joined: Sat Apr 01, 2017 5:33 pm

Re: Horizontal lines in print

Postby Vulwulf » Mon May 22, 2017 8:20 pm

It's all working as it should be now, I did a few things at once but I'm sure adding horizontal(ish) support was what sorted it, tilting in 2 angles helped too. It was as you said, and the ring was splaying apart at a few points when going down to the flexvat. I just made them in 3ds max, it seems complex but it wasn't too bad to remove:
20170523_005344.jpg


And the finished ring, no errors:

20170523_005508.jpg


Thanks for all the help.

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James
Posts: 148
Joined: Mon Dec 02, 2013 1:56 am
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Re: Horizontal lines in print

Postby James » Thu May 25, 2017 10:10 am

I have no idea what caused that either. Is your house is sitting next to a gravity vortex that kicks in intermittently throughout the day? HAHA! :D

Maybe the STL had some bad vertices that got read by the slicer incorrectly is about all I can come up with.

Nice design by the way.
I prefer to know nothing about everything rather than everything about nothing. :)