Issues with long prints

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Flole
Posts: 9
Joined: Sun Aug 27, 2017 10:37 pm

Issues with long prints

Postby Flole » Sun Sep 03, 2017 6:29 pm

Hi,

I got my Raise3D N2 Plus with Bondtech Extruder on Friday and was really excited at the beginning. Now I am just disappointed as it is causing many issues and hasn't completed a single "big" print yet. Everytime I try to print something which takes a few hours, somewhere in the print is misses some layers and then the following layers don't stick. I've tried to increase the flow rate -> No success. Also tried higher temperature -> No success. At one point I was able to see what was actually going on: The filament was not being fed in the extruder, it was moving in until it moved back very quickly, same thing over and over again. I tried to support it by pushing it in but that didn't help. Also tried adjusting the screw on the side of the bondtech, no change.

I'm about to just send this thing back, it is not fun at all. It's huge but can't even print small parts. Is there anything else I could try before I give up?

JeffS
Posts: 12
Joined: Tue Dec 13, 2016 2:25 am

Re: Issues with long prints

Postby JeffS » Sun Sep 03, 2017 10:06 pm

Hi Flole,

I have an early production vintage N2+ which I recently upgraded to the Bondtech dual direct extruder. It worked great for harder materials like PLA and PETG, but did not extrude flexibles at all. I contacted Bondtech directly and they advised to do an "atomic" pull (a.k.a. cold pull) to clean the nozzles, verify good heat bar contact with heat block and a few other things but none of these resolved the problem.

I found after closely investigating the extrusion failures that the flexible material was getting caught just below the extruder gears because the filament was swelling diametrically (Poisson's effect in compression for the engineers in the group) due to the pushing of the filament against some resistance and it was not able to push through the narrow passages of the extruder body below the gears and into the guide tubes.

Anyway, long story short, contrary to conventional 3D extruder design wisdom, I drilled out the extruder passages just below the extruder gears to 2.2 mm diameter and now all works great. I have printed several 1-2 hour prints using Inland eLastic and Flexible materials with no problems. I have also printed numerous 12-20 hour prints with Inland PETG and PLA with full success after this simple mod to the Bondtech extruder.

For harder materials, I set the idler gear tension screw to about 1/2 tension and for flexibles, I crank it down until the spring is solid. I tried many different spring settings for soft flexibles and it seems anything less than maximum spring force allows the filament to get under the idler gear and cause a mis-feed.

Anyway, just my experience and solution with the Bondetch Dual Direct. Hope it helps you as well.

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Julia Truchsess
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Location: Connecticut
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Re: Issues with long prints

Postby Julia Truchsess » Sun Sep 03, 2017 11:46 pm

No problem here running 24-hour and longer PLA and PETG prints using the stock extruder on my N2.

Flole
Posts: 9
Joined: Sun Aug 27, 2017 10:37 pm

Re: Issues with long prints

Postby Flole » Mon Sep 04, 2017 12:50 am

I am printing normal PLA at 205°C. I just spent the last hours since I originally posted here leveling the bad. That made me even more mad as it's just stupid work and if I turn a screw, the other end is just magically completely off. Anyways, somehow managed to get that damn thing levelled, now printing again but I think I set the extruder a little too low. If this fails I will move it up and try again.

For some reason I had to heat my buildplate to about 60-70°C to make the PLA support stick to the plate, otherwise the turns would just come up and the second extruder would pick them up and rip them off the build plate. Also set flow rate to 100% to prevent underextrusion.

Flole
Posts: 9
Joined: Sun Aug 27, 2017 10:37 pm

Re: Issues with long prints

Postby Flole » Mon Sep 04, 2017 1:30 am

Just had an issue again, so I opened the bondtech and just pulled out the fillament, it looks like this:

Image

As you can see the tip is thicker than the rest of it. What happened there? What are the possible reasons for this?

After taking the picture, I just pushed it back in and it was extruding without issues again. What the hell is wrong with this thing? I had to pull really hard to make it come out, probably because of the thicker part at the end, that was also hard to get in.

I'm starting to loose fun with this printer, it arrived with fingerprints all over it, the touchscreen has to be hit hard to recognize my touches and now this issue.

EDIT: Also what might be important, the extruder motor is getting a little hot, almost too hot to touch. This should not be an issue with the bondtech I think, but I still wanted to mention it.

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Mecha_Monster
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Location: Mexico
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Re: Issues with long prints

Postby Mecha_Monster » Mon Sep 04, 2017 5:17 am

When I got my printer, I had to go through a very hard 3 month period of all failed prints, but eventually i learn how to use the printed. What i see in your picture is an incomplete filament pull, it broke mid way. There is still melted plastic adhere to the inner walls of your extruder, Ill sugets to disasemble it and clean it with fire. Anyway, what really help me a lot is to realize that the filament swapping procedure is inadequate for this printer, everytime that you pull the filament it adheres to the walls of the extruder. What I suggest is to avoid using the unload function; when you have to use a different filament, just feed the new one after the old one, and forget about fulling, never ever do it again. Knowing that, please dissasemble your extruder and clean it with fire (be extremely meticulous and be 100% sure that all the plastic an debris have been cleaned), second Please confirm that you have not damaged your nozzle (very very important), if you drop it or hit it, almost certainly you have damaged the pinhole and it no longer meassure 0.4mm, the diameter is reduced and that greatly increase the inner pressure required to extruder (thats a big possibility considering that you had to dissasemble your extruder to install the bondetch ex.), after you have cleaned your extruder and confirm that your nozzle is in good shape, you should print without problems, and thereafter never use the unload function. Thats what I did and its been about a year without mayor issues. So far my longest print was a 92+ hrs, ABS print, and it was flawless.

I hope that you find dis info useful, and if what I say is not the problem, please let us know so I can keep learning

Targo
Posts: 15
Joined: Fri Aug 25, 2017 9:09 am

Re: Issues with long prints

Postby Targo » Mon Sep 04, 2017 6:15 am

Hi,
sometimes the filament is not properly gelled. I had times as PLA gelabeltes ABS get and am almost desperate. The nozzle is permanently frozen because of too low a temperature. This can be tested by means of a flammprobe (odor) or solubility in acetone.

Flole
Posts: 9
Joined: Sun Aug 27, 2017 10:37 pm

Re: Issues with long prints

Postby Flole » Mon Sep 04, 2017 11:00 am

Why would that happen during a print? It suddenly stopped extruding without any reason.

I did not have to install the bondtech myself, i bought it like this so i probably didn't damage the nozzle.

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Julia Truchsess
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Location: Connecticut
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Re: Issues with long prints

Postby Julia Truchsess » Mon Sep 04, 2017 4:52 pm

A thicker tip on filament removal is normal, as the filament path inside the extruder is typically 2mm, not 1.75mm. I use unload all the time without issue, but I don't use a very wide range of filaments on the N2 - generally only PLA and PETG, and never ABS. 60ºC PEI bed for PLA and 80ºC for PETG. Second extruder hitting the print is a tough problem; I removed the nozzle on my second extruder and find I really have not much use for dual extrusion after all.

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walshlg
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Re: Issues with long prints

Postby walshlg » Tue Sep 05, 2017 1:58 pm

you may have an isolation tube mess with filament sticking to the sides without a complete blockage. This is more likely if you have drilled it out. Heat up to 250C for an hour, remove the nozzle, then repeatedly pass the 1mm wide wire down from top to bottom through the hotend/isolation tube assembly until there is no more plastic stuck to the metal rod. It helps to let the rod cool between passes. If it never comes clean pass 2mm wide brass tubing brushes the same way top to bottom. These brushes only cost about $2 each and you can get them from McMaster Carr.

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Brandon
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Joined: Fri May 05, 2017 1:22 pm

Re: Issues with long prints

Postby Brandon » Tue Sep 05, 2017 2:47 pm

Everyone here is trying to help. That is a positive thing however I think this may have been overlooked -

"I got my Raise3D N2 Plus with Bondtech Extruder on Friday and was really excited at the beginning.

I did not have to install the bondtech myself, i bought it like this so i probably didn't damage the nozzle."

Who modified the printer? Where did it come from? Is it possible it had problems previously? Why was this printer modified then sold?

@Flole - What do you know of the history of the machine. What can you share about it's history?

Flole
Posts: 9
Joined: Sun Aug 27, 2017 10:37 pm

Re: Issues with long prints

Postby Flole » Tue Sep 05, 2017 6:30 pm

I got it directly from a German Reseller. I also have kinda figured out where the Problem is: The 2 Raise3D Filament spools that came with it are working fine, the other spool that came with it (the Reseller gave it to me for free) is causing the issue. I probably have to contact the Reseller and ask about the Filament issue, unless someone of you guys has an idea on what can be done to make that Filament work aswell (I tried higher temperature, that didn't really work).


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