[AO-100] Infill strands lifting or missing

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Gemini64
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[AO-100] Infill strands lifting or missing

Post by Gemini64 » Tue Jun 11, 2013 8:31 pm

Hello,

Two days ago I started having this problem. It happened after I switched from hairspray (which caused bottom of parts to shrink) to lulzjuice, although it may not be related. I have great adhesion of the first solid layer to the bed. Starting with the second solid layer I get missed spots (with third as well). Then on partial infill I get strands lifting up. Then I have missed spots again on the top solid layers. The result can be seen in the pictures.

When this first happened (see picture with part labeled "0.35") I had filament jam due to the hobbed bolt eating into the filament. I cleaned the hobbed bolt with the metal brush then reduced the pressure from the 2 idler screws. But it still continued to do that on other parts. (I really, really hate that part of the extruder and how it's a PITA to put the idler back in place with the flat washers and springs!!!)

I'd be glad to get some pointers on how to solve this. I have to print 8 parts like the big one for a coworker (the smaller ones were puzzle joint tolerance tests) and I'm getting tired of working on this instead of on my own parts!

Some info that may be of use:
Thanks in advance! :)
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lotw
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Re: [AO-100] Infill strands lifting or missing

Post by lotw » Wed Jun 12, 2013 4:15 am

What temp are you printing at and what size nozzle?

1013
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Re: [AO-100] Infill strands lifting or missing

Post by 1013 » Wed Jun 12, 2013 7:43 am

for the annoying springs and washers thing.

Print out the "extruder latch" that is standard on the TAZ
http://devel.lulzbot.com/TAZ/printed_pa ... der_latch/

If you zoom in on the pictures of the TAZ, you can see it.

jebba
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Re: [AO-100] Infill strands lifting or missing

Post by jebba » Wed Jun 12, 2013 9:14 am

You may just have a dirty hobbed bolt. You can clean it out with the wire brush & pick.

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Gemini64
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Re: [AO-100] Infill strands lifting or missing

Post by Gemini64 » Wed Jun 12, 2013 6:19 pm

Thanks for the replies.

lotw: I knew I was forgetting something. I'm printing at 230º and I have the default 0.50mm nozzle.

jebba: as I said I already cleaned the hobbed bolt and right after that it continued missing spots and delaminate strands on the large print shown in the pictures. I just heated up the hot end and had another look, and the filament is ground again by the hobbed bolt. I guess I'll try to loosen the screws even further.

I read on the RepRap forum that humidity can affect plastic. Could that be a factor? I've had this plastic (shipped with AO-100) since past January. Since the outside temperature rose and I stopped heating the appartment it's been consistently more than 60% RH inside.

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Gemini64
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Re: [AO-100] Infill strands lifting or missing

Post by Gemini64 » Wed Jun 12, 2013 7:21 pm

OK I think the problem was the exact opposite of what I thought earlier: the idler screws were not tightened enough. I repeatedly pushed the "extrude" button in Pronterface and the filament was having trouble feeding, with the hobbed bolt scraping small pecks out of the filament, which when I saw that at the bottom of the extruder led me to believe there was too much pressure on the filament.

I cleaned the hobbed bolt more thoroughly this time, applied more pressure on the screws and printed the TAZ extruder latch without a hitch. I'm about to resume printing my coworker's arched plates, I'll see what happens next.

BTW with the extruder latch, shouldn't the springs be shorter? I haven't installed it yet but those springs will compress a lot...

Thanks again for the responses.

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Gemini64
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Re: [AO-100] Infill strands lifting or missing

Post by Gemini64 » Wed Jun 12, 2013 8:47 pm

The print went better and mostly perfect until the last two top solid layer where it started acting up again. I paused the print and checked the hobbed bolt, it was filled with plastic... I made an "emergency" clean of the hobbed bolt and was able to finish the print. My friend is going to have to live with those imperfections because I am not scrapping those parts!

I'm definitely having a hard time getting the right balance of idler screw pressure on the filament. :|
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antfurn
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Re: [AO-100] Infill strands lifting or missing

Post by antfurn » Thu Jun 13, 2013 6:11 am

Have you taken the nozzle and clean out the inside of it. When mine started doing what you are seeing, I took the nozzle off, cleaned it out and it's all good again now.

Antony

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Gemini64
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Re: [AO-100] Infill strands lifting or missing

Post by Gemini64 » Thu Jun 13, 2013 8:53 pm

I have not cleaned my nozzle. How do you do that? Submerge it in acetone and leave it for some time?

The outside of the nozzle is very dirty and I've been wondering how to clean that out as well.

Norm

antfurn
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Re: [AO-100] Infill strands lifting or missing

Post by antfurn » Fri Jun 14, 2013 4:49 am

Yes that's what I did. Took the nozzle off and let it sit in acetone for an hour or more.
Use the pointy stick tool, supplied with the all the other tools, and picked out anything stuck inside.
I just scraped off the worst from the outside and gave it a quick sanding with fine sandpaper to get the rest off.

Don't sand the very tip though! That needs to be left as flat, level & smooth as possible. Only clean that with acetone.

2nd warning; the thread on the hot-end is way to easy to mess up. Follow the guides to nozzle changing and use plumbers tape when putting it back on.

Antony

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