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Filament hole is clogged. No way to clear it  

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rogerinhawaii
(@rogerinhawaii)
Trusted Member
Filament hole is clogged. No way to clear it

While doing a print on my PRUSA i3 MK3S kit it ran out of filament and stopped. I attempted to insert new filament but it wouldn't take it . It felt like the filament couldn't get down far enough into the printhead.  I can see that the gears are moving but it never grabs the filament. And, yes, I properly trimmed the end of the filament into a sharp point. I opened up the area where the gears are and could see that the filament does indeed get down into the gears but hat there was a chunk of old filament just below the gears and at the top of the channel that then leads the filament down into the heated print head. I did my best to remove that chunk of filament, using a needle nose plier, but there's still a chunk of it down inside that channel.

I heated the print head up to 260 degrees (PLA) as suggested in one article I found online and then pushed the smallest hexkey (also as suggested) down through where you insert the filament and pressed it down against that chunk of filament, but it wouldn't budge.

What do I do now? I can't seem to clean out the old chunk of filament.

PS: I took a photo with the intention of including it in this posting, but there seems to be no way to get it uploaded. When I select the add an image to the posting it has a blank field for specifying the "Source", but whatthe heck am I supposed to put in there? A URL of some photo on the web? How do I just UPLOAD my image from my own computer, like every other forum like this allows you to do?

Posted : 09/02/2020 9:10 pm
holmes4
(@holmes4)
Estimable Member
RE: Filament hole is clogged. No way to clear it

Images: Below the subject line is a button "Add Media". That's what you want. The one you found wants a URL of an externally hosted image.

Heat it up again and remove the nozzle. You can then try the hex key thing. When you got your printer you should have received what is often referred to as an "acupuncture needle" - a long wire with a grip. This can be pushed down into a heated hot-end or even up into the nozzle to help clear a clog. But most likely you have solidified filament inside the heatbreak, and the Prusa-modified E3DV6 heatbreak, with a wider section towards the bottom, is more prone to this. You'll need to disassemble the hotend, separating the heatsink and heatbreak from the heatblock. In the past when I had this issue, I used a hot air gun to heat the problem part enough to push out the blockage. (Now I use a Mosquito hotend that never ever clogs.)

With the E3DV6 design, it is critical that the nozzle be tight against the heatbreak so that there are no gaps.

Posted : 09/02/2020 10:33 pm
rogerinhawaii
(@rogerinhawaii)
Trusted Member
Topic starter answered:
RE: Filament hole is clogged. No way to clear it

Thank you for responding to my query. Are there clear instructions or ideally a video somewhere of how to disassemble and then reassemble the hotend? 

As for actually removing the nozzle, the handbook that came with my printer has a section about replacing/changing the nozzle and strongly suggests visiting a specific website, https://support.3dverkstan.se/article/66-the-olsson-ruby-instructions-for-use , before dealing with the nozzle, and that website cautions about using the proper tool to do it, and instructs the user to PRINT a special tool for for unscrewing and rescrewing the nozzle. But, yoiks, how do I print that out when my printer isn't working? I'm really concerned about following the instructions with all the cautions about damaging something.

Posted : 09/02/2020 11:21 pm
rmm200
(@rmm200)
Noble Member
RE: Filament hole is clogged. No way to clear it

Don't use the Ollson Ruby directions unless you have an Ollson Ruby nozzle.

If you are like us regular nozzle users, use the instructions on the E3D web site.

You do not need a special tool to remove the nozzle. Just a hex socket the right size and something to keep the hot end from twisting.

Posted : 10/02/2020 12:52 am
jberk_1234
(@jberkson1)
Active Member
RE: Filament hole is clogged. No way to clear it

It could also be particle build up in the ptfe tube, ive had the same issue and couldn't understand why cleaning the nozzle had no effect. Turned out to be a complete blockage halfway down the heatsink.

Posted : 10/02/2020 5:12 pm
rogerinhawaii
(@rogerinhawaii)
Trusted Member
Topic starter answered:
RE: Filament hole is clogged. No way to clear it

I was able to get the nozzle unscrewed. But that hasn't helped.

The clog appears to be right up at the top, the opening that's just below the gears. Even though I've heated the whole thing up to 275 degrees, that section does not appear to actually heat up, so the filament remains cold and solid.

How exactly do I " disassemble the hotend, separating the heatsink and heatbreak from the heatblock". I don't even know what parts are the "hotend", "heatsink", "heatbreak" and  "heatblock".

I have posted the photo, pointing to where the problem is, on my Facebook page: 

https://www.facebook.com/photo.php?fbid=10216591097957613&set=gm.2658371940937513&type=3&theater&ifg=1

 

 

Posted : 10/02/2020 7:56 pm
rmm200
(@rmm200)
Noble Member
RE: Filament hole is clogged. No way to clear it

Take a look at directions for removing the PTFE tube.

It is held in place by a plastic collet. Push the collet in and you should be able to grab the PTFE tube and pull it up and out. Maybe.

Have a spare tube on hand; the old one is likely toast if deformed by all this. If it is just clogged, you can salvage it by using a heat gun and pushing the mess out.

Posted : 10/02/2020 9:32 pm
rogerinhawaii
(@rogerinhawaii)
Trusted Member
Topic starter answered:
RE: Filament hole is clogged. No way to clear it

OK, I look around and finally found the "directions for removing the PTFE tube". I followed all the directions and have it all put back together.

 

I then started up the Calibration Wizzard, just to make sure that everything was still OK. In fact, in the directions for removing the PTFE tube there was a comment (NOT actually part of the insutructions) noting that you really ought to do a calibration after the tube process.

It got through the initial fan tests OK, It did the X-axis and Y-axis calibration just fine, but FAILED on the Z-Axis. It moved the print head all the way down to plate and even pushed the plate down a bit (uh-oh!!), the motors chattered for a second and stopped, and it reported a FAILED Z-axis, with "endstop not hit" error. The print head was near the left end of the X-axis but the whole X-axis was now tilted down to the right. I turned the whole thing off and manually turned the vertical Z-Axis shafts to place both ends of the X-axis precisely at the very top of their extent. I ran the Calibration Wizzard again and got the exact same error, with it again impacting on the bed and pushig down on it, motor chatter, and error message.

Now what do I do?

Posted : 10/02/2020 11:55 pm
rmm200
(@rmm200)
Noble Member
RE: Filament hole is clogged. No way to clear it

Did you remove the nozzle? How did you reinstall it?

Did you set the PINDA height again? One zip tie distance above the nozzle? If you lower the nozzle to the plate, what does Z read?

Kind of going on the idea that the printer does not know how far above the plate the nozzle is now.

 

Posted : 11/02/2020 1:10 am
holmes4
(@holmes4)
Estimable Member
RE: Filament hole is clogged. No way to clear it

Reset the live Z to zero and try again. You'll then need to redo the Live Z calibration. I use the method shown in https://forum.prusa3d.com/forum/original-prusa-i3-mk3s-mk3-assembly-and-first-prints-troubleshooting/life-adjust-z-my-way/#post-22992

Posted : 11/02/2020 1:13 am
rogerinhawaii
(@rogerinhawaii)
Trusted Member
Topic starter answered:
RE: Filament hole is clogged. No way to clear it

@robert-rmm200 & @holmes4

I had indeed removed the nozzle, in order to get the whole thing cleaned out.  I replaced it as best I could, but it does appear that the relationship between the end of the nozzle and the end of the PINDA got off-kilter. After a number of attempts I was able to get a successful re-calibration of the whole thing and am currently doing what looks like will be a successful print. So, finally back to work.

 

But, YOIKS!

This is an excellent printer and I've been able to do some amazing things with it using my own CAD designs, but I really wish it did a better job of AUTOMATIC calibration rather than relying on the user to set this thing right and set that thing right and turn that screw just a teensy bit and and make sure this is only X mm from that other thing and watch the first lines drawn on the bed and manually adjust the Z-height so the lines have the "best" cross section, and so on.  A few more position sensors would really help.

Posted : 11/02/2020 1:50 am
rmm200
(@rmm200)
Noble Member
RE: Filament hole is clogged. No way to clear it

"Replaced it as best you could"... The nozzle is one of those fiddly things you hate, that has to be done right.

The E3D web site has excellent instructions.

When you finish and have it tight - the shoulder must not touch the heat block. It is tightened against the heat break.

Do this wrong - and you will have filament leaking around the nozzle.

Posted : 11/02/2020 2:07 am
rogerinhawaii
(@rogerinhawaii)
Trusted Member
Topic starter answered:
RE: Filament hole is clogged. No way to clear it

@robert-rmm200

In the print that I'm doing right now, to test whether it's all working OK, I do seem to be getting some globs of filament on the print (which has never happened before). So maybe it IS leaking around the nozzle.

I just think that this could be designed so that it can ONLY be screwed in correctly.

Posted : 11/02/2020 2:20 am
rmm200
(@rmm200)
Noble Member
RE: Filament hole is clogged. No way to clear it

Here are the E3D instructions for the V6.

Start at Step 3, and make sure you read Step 26 (hot tightening).

Best thing about this guide are the pictures. They give you a good idea of how things go together - and why.

https://e3d-online.dozuki.com/Guide/V6+Assembly/6?lang=en

 

Posted : 11/02/2020 2:26 am
bobstro liked
bobstro
(@bobstro)
Illustrious Member
RE: Filament hole is clogged. No way to clear it
Posted by: @robert-rmm200

[...] Best thing about this guide are the pictures. They give you a good idea of how things go together - and why.

https://e3d-online.dozuki.com/Guide/V6+Assembly/6?lang=en

Agreed. The visual is as important as any precise measurement. I got hung up on "precision" and following someone's description of measurements rather than going visually the 1st time and wound up re-doing it. E3D's picture of the appropriate gap is spot-on. 

 

My notes and disclaimers on 3D printing

and miscellaneous other tech projects
He is intelligent, but not experienced. His pattern indicates two dimensional thinking. -- Spock in Star Trek: The Wrath of Khan

Posted : 11/02/2020 2:07 pm
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