Extrusion issues, where do I go from here?  

RE: Extrusion issues, where do I go from here?

I have had this this happen a couple times.  For me, it happens always with either brand X of ABS or a single spool of Prusment.  Not all of a color of Prusament just this one roll of Prusament Galaxy Purple.  No idea why.  I will unclog it and get 1-2 print and then, bam, it happens again if I try those filaments.  

I use accupuncture needles and tunsten welding rods to undo the clog.  A cold pull will not work.  

RE: Extrusion issues, where do I go from here?

I am having similar problems. I thought the problem to be leaked filament. So i disassembled the hotend, and drilled out all the residual in the heatbreak/pipe. There were a lot of stuff left. A coldpull was not possible. The filament was really stuck in my case.

But that did not solve my problem as well. I also have the same issue, i prints, but totally underextruded.

Can you push filament through the hole in the heatbreak manually? I think the hole from the PTFE and the Heatbreak either does not line up, or the hole is too small or otherwise not aligned. Can you do a coldpull?

It may help to drill it out?

An explenation i found was that the ptfe tube is not pushed hard enough in the heatbreak, and with a lot of retraction, the filament gets stuck and leaks out in the space between ptfe and the heatbreak. And as there, the temperature is low, it does not really melt well and clogs.

(i have ordered the bondtech upgrade heatbreak... heard good things, waiting to find out)

(sorry that i do not have a real solution, but maybe this helps a bit.... )

RE: Extrusion issues, where do I go from here?

Thanks for the response.  What confounds me is that I've actually replaced the nozzle twice and the PTFE in the heat break twice.  I did follow the instructions where you back off the top coupler 1/4 turn,  loosen the 3 screws, push up on the nozzle, tighten the screws then tighten the coupler.

This first started when I was printing with white Hatchbox PLA, a spool of red from which I got many great prints is now having extrusion problems.  I think I may contact Prusa as this point.

The nozzle I'm using now is a 3rd party nozzle, I'm not sure why that would be a problem, but I ordered some genuine Prusa nozzles, I'll try one of those when I get one.

-Bob

RE: Extrusion issues, where do I go from here?

@bob-2

That is because it is not the nozzle.  There are filaments that just jam and there is also a well documented issue with the shape of the heatbreak that causes certain filaments to jam.    

RE: Extrusion issues, where do I go from here?

Let me know what they say.

I argue, its neither the tube nor the nozzle, but the heatbreak. (At least i hope or i spent the money in the wrong place 😆 )

I changed the nozzle to e3d stainless steel in between, with no luck also.

@cwbullet, thats a shame, as i had the first and biggest problems with prusament pla... also i just retried with the PETG, which ran really good before the problems with the pla, same problem. not as significant, but still the same.

RE: Extrusion issues, where do I go from here?

I concur with @cwbullet. I’m pretty sure it’s not the nozzle (although personally I prefer to stick with genuine E3D nozzles). More likely—as @bob-2 suggested, the well-known issue of the PTFE tube not being seated properly. If you think that is okay, I’d get the Bondtech or one of the titanium heat breaks on Amazon.

Also, make sure the tension on the idler screw is set correctly. While I can’t claim I can see any significant differences in print quality between stock and Bondtech dual drive extruder, the Bondtech extruder seems less sensitive to filament differences. Didn’t really have to adjust it since installed, whereas with the stock extruder I had to do it for some filaments.

RE: Extrusion issues, where do I go from here?

@cwbullet

I'm beginning to think this is the best response.  I decided to try a cold pull with some ABS and found it very easy hand push the filament through the nozzle.  After a couple pulls I went back to the Hatchbox red PLA to try a cold pull and when I pushed the PLA through the nozzle instead of getting a nice thin stream the filament blobbed up around the nozzle.  I cleared the blob and tried again and got another blob, nothing I did gave me a nice stream it all blobbed up.  When that failed I tried again with some PETG and that, like the ABS, worked just fine.  So, I printed a CHEP cube with the PETG and it printed perfectly.  I'm now printing a Benchy with the PETG and so far so good.

Looking at the Hatchbox it seems kind of brittle, it breaks like dry spaghetti.  I already threw out the white Hatcbox as it was pretty close to the end of the spool so it's too late to see if that's brittle too.  I have another open spool of Hatchbox red and some Overture green, both of which have printed well, but I'm now thinking that the after being exposed to the air for some time the Hatchbox deteriorated and has been the source of my problems.

If anyone continues to follow the thread I'll post my findings.

-Bob

RE: Extrusion issues, where do I go from here?

Don’t keep your filament exposed to open air. At minimum, put it back into the plastic bags they came in and add some packets of silica gel dessicant. Or better, invest into some airtight storage boxes and some mini dehumidifiers. Here’s what I use:

https://www.amazon.com/Ziploc-WeatherShield-Quart-Storage-Clear/dp/B00MWTJXHS/

https://www.amazon.com/gp/product/B00LVN7BM0/

Maybe pricey but I have had filament in there for a year (who wants to print anything in PINK?), and it’s like new. 

RE: Extrusion issues, where do I go from here?

Posted by: @fuchsr

Don’t keep your filament exposed to open air. At minimum, put it back into the plastic bags they came in and add some packets of silica gel dessicant. Or better, invest into some airtight storage boxes and some mini dehumidifiers.

I agree, moisture could easily be a cause.

Maybe pricey but I have had filament in there for a year (who wants to print anything in PINK?), and it’s like new. 

I bought a dozen spools of a very cheap, surgical-appliance-pink PLA from Hobby King. I assume it was cheap because no-one liked the colour.  I used it for prototyping for over a year, it printed well. OK, I did get comments when testing: "Why is your fishing reel pink?" - a good icebreaker cue for some interesting conversations.

Use your odd colours for first prototypes or any part that will be painted.

Cheerio,

RE: Extrusion issues, where do I go from here?

Posted by: @fuchsr

Don’t keep your filament exposed to open air. At minimum, put it back into the plastic bags they came in and add some packets of silica gel dessicant. Or better, invest into some airtight storage boxes and some mini dehumidifiers. Here’s what I use:

https://www.amazon.com/Ziploc-WeatherShield-Quart-Storage-Clear/dp/B00MWTJXHS/

https://www.amazon.com/gp/product/B00LVN7BM0/

Maybe pricey but I have had filament in there for a year (who wants to print anything in PINK?), and it’s like new. 

I concur.  I have both of these products and strongly agree.  You can't go wrong with storing them in plastic bins with a humidity adsorber.  

RE: Extrusion issues, where do I go from here?

@diem

So true. Alas most rolls of filament come in 1 kg size, and I have more than a dozen “odd” ones whose only purpose in life now has become to serve as material do prototyping, after I used the few meters I needed at one point... 

i wish there were more options to buy smaller amounts, at a reasonable price. 

RE: Extrusion issues, where do I go from here?

@fuchsr

My pink ones were 1Kg but about a third of standard price, I would buy more if it were available.

For short odd coloured runs have you tried Sharpie-printing?

Load white filament, strap a coloured fibre-tip pen (or blend several) to the extruder so that a line of ink is painted onto the filament as it is drawn in and Hey Presto! your very own colour is extruded.

Cheerio,

RE: Extrusion issues, where do I go from here?

@fuchsr

I understand about filament being hygroscopic, I have some very large Ziplock bags I use to store filament after I've used it but want to go to another color.   It may be a difference in Prusa filament compared to others that set my expectation.  My Prusa I3Mk2 came with a spool of sliver filament, I printed a bunch of stuff with it when I first started then began buying other colors from different vendors.  My biggest problem with buying Prusa filament is that it takes a couple of weeks to get stuff from Prusa and shipping is pricey.  I can get other brands from Amazon for a little less, but more importantly with free shipping and in a matter of days.

Anyway, that first spool of Prusa I put aside and when I got a new printer or after I upgraded my Mk2 to Mk2.5s I'd use that original spool to print a Marvin or Benchy and they'd print fine.  That first roll is over 4 years old now, has always been exposed and has about 3 turns left on the spool and I've never had an issue printing with it.

This white and red Hatchbox I used to print many things back in December, they were freshly opened and I printed several very large prints with the white before I started having extrusion problems.  Up until very recently the red was printing just fine.  The reason I didn't pack either of these in a Ziplock bag was I was still using them.  My plan was to continue to print with them until they were used up.  Just last week I'd printed a lithophane with the white that printed just fine, it was when I went to print a stand for a puck light for the lithophane with the white that I started having extrusion problems.  That led me to replace the heat break PTFE and after that the nozzle.  When the white continued to print poorly after that I tried the red and at first that seemed to be OK, but then it showed the same problems.

So, I am fully aware that moisture can be an issue but this seemed to go from printing well to failing almost over night.  The change happened so quickly it seemed unlikely it could be the filament, but as I write this I'm printing out a print with PETG and other than a bed adhesion problem in one area of the print it's printing fine.  My Benchy with PETG last night came out perfectly.  

When this print is finished I'm clearly going to have to tend to the bed, my Mini has had issues with bed adhesion from day 1 and using a proper amount of glue stick seems to to the trick.

To me the take away from this is that filament can be more finicky than you might expect and even a company like Hatchbox, which I've used many spools, is probably different from batch to batch. 

Echoing what others have said in this thread it would be nice to be able to buy short spools, I could have figured this out more easily had I been able to try some known good filament to see if it's a filament or nozzle problem.  Lord knows I don't want to open a 1KG spool I'm not ready to use just to do a check.

Cheers

-Bob

RE: Extrusion issues, where do I go from here?

I dont think that 2-3 months should be a problem for PLA. All what i saw in the all of the youtubes, PLA should not be a problem in the first year...

After a lot of reading, i came to a conclusion, that the whole construction of the hotend is flawed. All the threads about this extrusionproblem seem to be about symtoms, not the problem itself. Changing, nozzel, heatbreak, ptfe tubes, for me this comes down to the problem about the ptfe tube is just wrong and should be removed.

I received my bondtech heatbreak, and when looking at the ptfe tube, it seems the bondtech tube is TOO SHORT! WAY TO SHORT. So i measured the old one and the spare, the used one is 1mm shorter than the spare, which seems to be a known problem. This may be a result of heat, thats why the bondtech heatbreak may help, as the tube should stay cooler, but the pressure stays there nonetheless.

So i came to the conclusion (and maybe you should prepare for this as long as the printer is running well), that i will use my spares and the new heatbreak and the first thing i will print, after testing, will be this: https://www.thingiverse.com/thing:4642107 and getting a e3dv6 hotend and put both in a drawer. IF the extrusion problem comes back, i will do the change, going all-metal-hotend and getting rid of those chamferd tubes and hopefully all the resulting problems. I dont know why prusa does not just offer an all-metal-hotend upgrade kit. Should not be too complex. Hotend, mounting part, PTFE Tube with connector.... Or an i3 hotend upgrade, whatever.

I changed to the Prusa Mini from the Monoprice Mini, that hat lots of issues, but extrusion was none of them (only when the nozzle was plowing through the bed), and they had a all metal hotend, for a 200€ printer.

RE: Extrusion issues, where do I go from here?

@sango

I dont think that 2-3 months should be a problem for PLA. All what i saw in the all of the youtubes, PLA should not be a problem in the first year...

In really humid weather two weeks is enough.  Normally you have a few months.

After a lot of reading, i came to a conclusion, that the whole construction of the hotend is flawed. All the threads about this extrusion problem seem to be about symtoms, not the problem itself.

Bear in mind there are several thousand Minis in use, we see very few of them here. Only those with problems have any need to post and most of them have compounded their problems by taking inappropriate actions they have found on line without understanding the underlying cause.

For example: Many arrive with blobbing, stringing or clogging and, becase the machine worked for months with the same filament they assume it's a worn nozzle or extrusion problem when more than half just need to clean the print surface thoroughly and most of the rest have damp filament; and of the ones who actually do have an extrusion problem many just need to tweak their extruder idler pressure.

The few remaining are the interesting problems.

Cheerio,

RE: Extrusion issues, where do I go from here?

Posted by: @cwbullet

@bob-2

That is because it is not the nozzle.  There are filaments that just jam and there is also a well documented issue with the shape of the heatbreak that causes certain filaments to jam.    

  ...but please note that some third party nozzles have the wrong length thread and some do not have the correct width of  flat face around the central hole.

Cheerio,

RE: Extrusion issues, where do I go from here?

@diem

Sure, sure. Only the ones with problems will complain. But as always, those few, but loud voices, make a whole lot of difference. A lot of people have voiced their concern about the design choice in regards to the hotend.

The Mini is a very good machine. I really really enjoyed it, and i hopefully will enjoy it once again. But remember i have it for ONE week on the spot now. And i had the biggest problems with fresh, out of the box, prusament pla from the same delivery. My oldest spool is from december and stored dry in silicat.

I installed the bondtech heatbreak now, and the e3dv6 holder printed fine in petg. Lets see how this progresses. I just want a machine i can fire and forget, which was the case with the mini very much... until it wasnt anymore. I did lots of prints, even a >10h print on day 3. All well and good. Want to do that again without this nagging feeling something might go wrong. That kills the fun for me.

But on the other side of the medal, the Prusa is really good in regards of maintainability. The Monoprice Select Mini was a nightmare, i could almost do nothing. The Prusa, i feel confident, that i can do things and it does not break the whole printer. That feels very good to me. Which is nice.

RE: Extrusion issues, where do I go from here?

The PLA may not have gone bad — it might have been bad from the start. I’ve pulled brittle PLA from trusted brand manufacturer out of the plastic just to find it break apart just by looking at it. The good thing about Amazon, I just send them right back and have my money back in no time. 

RE: Extrusion issues, where do I go from here?

@diem

That might be true for some.  No true for all.