N2 filament feeder chews semiflex / tpu when loading

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flexrc
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N2 filament feeder chews semiflex / tpu when loading

Postby flexrc » Tue Sep 06, 2016 10:18 pm

N2 filament feeder has a bad tendency to chew flexible filament when I load it, it starts to extrude a little bit and seems like because of high speed and some design flaw of the feeder filament goes around feeder's gear and then it is very hard to get it out.
On unload it makes a knot.

Is there a way to adjust speed of the feeder or are there any other solutions to prevent it from happening?

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Billucas
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby Billucas » Tue Sep 06, 2016 11:23 pm

Attachments
Picture 1.jpg
Picture 7.jpg
3908966_orig.png

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Vicky@Raise3D
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby Vicky@Raise3D » Wed Sep 07, 2016 4:30 am

The speed the adjustable. You can edit the flowrate to control how much filament to be loaded.

But your problem should be due to extrusion resistance.
Which flexible filament are you using? What temperature?

Increase a little temperature may help reduce the extrusion resistance.
Print with front extruder cover.
Only use flexible filament at the left side. The distance between gear and loading tube is much further than left.

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walshlg
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby walshlg » Wed Sep 07, 2016 2:49 pm

I think that I understand - using the LOAD function moves the filament very quickly.

Instead, set the steps to 1mm and use the screen that shows the extruders in red to load it 1mm at a time.

I'm using the polymaker flexible filament and it is extremely tough, the gear never seems to be able to chew it up - when it jams it will actually stall the feed stepper instead. Certainly looks like it made a pile when I unload a jam. I just cut that off and load it again. It might help by pulling back up on the filament as it loads - although that may just be my superstition - it seems to prevent the jams.

flexrc
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby flexrc » Wed Sep 07, 2016 7:14 pm

Billucas wrote:You can read these topics:

viewtopic.php?f=2&t=879
viewtopic.php?f=2&t=493

Last image exactly demonstrates the issue I have, actually I also had this issue when used longer retraction.

Seems like this printer needs higher temperature than my other cheap printer to print Semiflex.

I see that people are suggesting to get bondtech ? Is it the only option in order for it to work smoothly without need to make magic tricks?

walshlg wrote:I think that I understand - using the LOAD function moves the filament very quickly.

Instead, set the steps to 1mm and use the screen that shows the extruders in red to load it 1mm at a time.

I'm using the polymaker flexible filament and it is extremely tough, the gear never seems to be able to chew it up - when it jams it will actually stall the feed stepper instead. Certainly looks like it made a pile when I unload a jam. I just cut that off and load it again. It might help by pulling back up on the filament as it loads - although that may just be my superstition - it seems to prevent the jams.


Also a good idea. I will try that.

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Billucas
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby Billucas » Wed Sep 07, 2016 10:08 pm

For the Gap, it is better closer, to touch the small pulley. I realign the step motor to have a better alignment, straight.
For me, after that, it never did again. Please use only the left extruder. So see the picture below to know how to adjust your
stepper motor. The idea is to let the less space possible between the gear and the pulley. Don't forget not using the guides
tubes, because there is to much restriction with your filament.
Luc
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extruder head.jpg

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walshlg
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby walshlg » Wed Sep 07, 2016 10:20 pm

Another thing I did is I moved my left isolation tube up as high as it would go thinking that perhaps there was a gap there where filament could get stuck - didn't make any difference.

I also cranked up the temperature - to 250 on filament rated to 235 - and it was like trying to extrude liquid butter

What did work is that I had stainless steel nozzles. If you are using those then go back to brass. I also had to block the bottom of the fan duct that blows on the freshly extruded material. In addition, if you haven't insulated your extruder, you should do that as well since maintenance of the temperature throughout the extrusion process seems to be the crucial step.

flexrc
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby flexrc » Thu Sep 08, 2016 5:34 am

I've adjusted distance between gear and wheel and it did not help. I think issue is that gap between feeder cover and gear is too big, so flexible filament find easier place where to go.
I don't think that it is correct behavior for filament to create a jam if it is hard for it to exit from extruder. My other 3D printer does not do it, never had a jam in direct driver extruder before N2 :)
Did anybody try to redesign this cover to solve the problem?
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photo 1_7.JPG

socke
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby socke » Thu Sep 08, 2016 6:53 am

Not only the cover, but the whole extruder! Please see this topic: viewtopic.php?f=4&t=181

flexrc
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby flexrc » Thu Sep 08, 2016 3:53 pm

socke wrote:Not only the cover, but the whole extruder! Please see this topic: viewtopic.php?f=4&t=181


I already saw it, but I'm not sure yet if I want to spend another $200 for a new extruder, also second extruder seems to become bowden type with this solution.

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Billucas
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby Billucas » Thu Sep 08, 2016 4:25 pm

flexrc wrote:I've adjusted distance between gear and wheel and it did not help. I think issue is that gap between feeder cover and gear is too big, so flexible filament find easier place where to go.
I don't think that it is correct behavior for filament to create a jam if it is hard for it to exit from extruder. My other 3D printer does not do it, never had a jam in direct driver extruder before N2 :)
Did anybody try to redesign this cover to solve the problem?


From my side, I exactly know what you are saying. I asked support team to have the 3d drawing of the front cover to
do it with smaller holes. I did not get it. I drew and printed a small bushing to fill this gap. I does not work.
This is why after I have adjusted the stepper motor and it works. I don't know how to tell you more, but I know
it is really frustrating. There is a bad conception and it should be revised.

flexrc
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby flexrc » Sat Sep 10, 2016 6:49 pm

I've experimented with this issue for the last few days and there seems to be some kind of fundamental flaw with N2 extruder, so here are my observations:

If I move gear closer to the wheel and more to the bottom, then it can push filament better and does not seem to spin filament around the gear anymore, BUT filament is getting clogged somewhere deeper, so behavior is like this:
- filament comes out of the nozzle for about 10 seconds in a row with a good flow but then gear starts to struggle to push it further and that is pretty much the end of extrusion
- if I do unload for a couple of seconds and then load again, then flow resumes for another 10 seconds

What is happening there? Does it create too much pressure? Does it make a knot somewhere inside?

The distance between left gear and nozzle seems quite long, much longer than on other direct drive printers I have. Perhaps this is the problem?

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Billucas
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby Billucas » Sun Sep 11, 2016 4:10 pm

Did your tried to put 250-260°C instead?

flexrc
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby flexrc » Tue Sep 13, 2016 6:46 am

Yes, I did. But now I've broken nozzle, it seems like it is made from such a soft material, which I never seen before, that I've tried to clean, which I thought was a clogged nozzle, and needle went right through the hole and effectively made it 1mm, now filament goes through it very well :) but quality is not acceptable.

I'm wondering what kind of other surprises should I expect from N2.

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Vicky@Raise3D
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby Vicky@Raise3D » Wed Sep 14, 2016 10:16 am

The nozzle is made by copper.
Did you heat the nozzle before cleaning? What is the size of your needle?

flexrc
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby flexrc » Wed Sep 14, 2016 10:36 pm

Filament was curling, so I've figured that it got clogged.
Yes, I've heated nozzle and used thin needle, the same way I've done for my other nozzles, I've just gently scratched holes with thin side of the needle and then I've noticed that it goes through the hole. I have stock nozzle which I believe is 0.4mm.

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walshlg
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby walshlg » Thu Sep 15, 2016 3:57 pm

flexrc wrote:Yes, I did. But now I've broken nozzle, it seems like it is made from such a soft material, which I never seen before, that I've tried to clean, which I thought was a clogged nozzle, and needle went right through the hole and effectively made it 1mm, now filament goes through it very well :) but quality is not acceptable.

I'm wondering what kind of other surprises should I expect from N2.


look on amazon. you can buy all diameters of piano wire. I use that to plunge out the nozzles.

flexrc
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby flexrc » Thu Sep 22, 2016 9:49 pm

I've been experimenting with it for relatively very long time already, finally able to print something, so here are my findings:

1. Putting gear too close to the wheel does not help but makes things worse, so it is a challenge to find right balance when it can drag filament but does not push too too hard so in case of the blockage gear will slide without forcing filament into gaps.

So should be not too tight and not too loose to allow a bit of sliding when filament just can't go through.

2. I've changed nozzle to 0.6 micro-swiss, it made a huge difference

3. I've switched to use Ninjaflex Cheetah which seems to be harder and works better, so far I can have good speed print on 250C

One weird thing I've noticed that with N2 I need in average 10C more than on my other printers in order to achieve similar results.


I'd say that main issue with N2 is QC, they should come pre-configured, pre-balanced, pre-leveled which was not the case in my experience and also necessary instructions should be included in the package so people will know how to troubleshoot common issues, instead of spending a month trying to figure it all out.

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Vicky@Raise3D
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Re: N2 filament feeder chews semiflex / tpu when loading

Postby Vicky@Raise3D » Mon Sep 26, 2016 6:28 am

We are so sorry to bring you so much troubles.

We have tested PLA and ABS in our factory to check whether the gear distance is ok. It is a little hard for us to test a lot different kinds, brands of filament on our side. We only have our filament in our factory for testing.
For the bed leveling problem, we have check the leveling and printed a 305*305mm box in our factory with every printer before sending it out. We are trying to find out whether there is better way to hold the leveling well during long-time shipping.

We will prepare more instruction documents and videos in the coming days.


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