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JATMN

Ultimaker 2 - Extruder jamming and grinding up filament.

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I am still in the middle of my Love-Hate relationship with my Ultimaker 2.

Got it in October (2015) and have yet to enjoy the honeymoon stage of owning a Ultimaker.

My printer basically has ADHD, at times it will print for days with no issues. At times I will spend days trying to get to print past the second layer.

I have read thru -every single- topic on the forums that I can find for this issue.

Either the fixes have no effect on my issue. Or the topics are abandoned.

Randomly (sometimes continuously) my extuder will make a skip which directly causes a defect in the print surface (beads instead of lines), this really sucks when its doing it on the outer perimeter and if its a small print the whole print is ruined because now the middle of the part is weak and breaks in half with no issue.

Sometimes this issue rectifies itself, which is still and issue as now my print has defects, which at times has ruined the print anyhow.

Sometimes this issue does not rectify itself which results in print failure because either the head or the extruder is now jammed and will no longer print for the rest of the print.. I have had countless prints fail like this.

What makes no sense at all.. Is most of the time. If I happen to catch the issue and cancel the print right away.. I can preheat the nozzle and extrude filament as normal.. (so why the heck did it stop during printing??)

When I don't catch the issue obviously it just grinds its way all the way thru the filament. (this as honestly cost me nearly a roll in wasted material combined when this issue occurs)

The printer has done this with the stock extruder an with Roberts v2.. with the stock nozzle and with the olsson block.

At first I tried to blame this issue on my filament.. But I still have the original Ultimaker filament that came with the printer and I have had the same issues with this filament as well. I have about 12 rolls across 3 or 4 different brands of filament and they are all PLA and they all have this issue randomly.

Most of the time I have no clue what fixes this issue when it starts working again.. It just starts working after 2min - 6hrs of messing with the printer to get it to print.

My Wanhao Duplicator 4 is direct drive and prints without fail.. why does this thing skip on material ALL the time..

- I have honestly spend over 100hrs monitoring and troubleshooting this issue.

- I have Maxed out the extruder temp (I am only printing PLA!)

- I measure all my filaments before loading and have set the material size right at, smaller, and larger in the printer settings.

- I have adjusted print speeds from 20mms - 150mms

- I have adjusted material flow rate during prints as far as 70%

- I have used Cura and Simplify3D, with both default settings as well as tweaking flow, diameters and nozzle settings.

- I have a olsson block but the stock block had same issue as well.

- I have run the speed test ring I seen posted here before that tests how fast I am able to get the extruder going and can make it all the way to the end with no defects in most cases. (unless I am having this issue then sometimes I cant even finish the first zone)

- I have replaced the stock extruder with a Roberts v2 (re printed this a few times even)

- I have adjusted the spring to be barely touching the material and also wrenched

- I have maxed out the amps setting on the printer for the extruder motor (no difference)

- I have moved the spool off the printer to a stand which holds the rolls on bearings to reduce friction as well as used Roberts spool holder.

- I have replaced the bowden tube with a longer one with a larger ID to attempt to reduce friction.

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hey @jatmn

A long list of check-ups you did already :) But did you also check your PTFE coupler?

How many print hours do you have with the ptfe without changing it? Mine lasted like 250 hours sometimes and it was already black on the sides with small deforming...

check here : https://ultimaker.com/en/support/250-disassembly

Until Ultimaker decides to sell their new TFMs separately, I suggest you buy the ones from 3Dsolex (or it's resellers) because they last much longer :)http://3dsolex.com/teflon-replacements

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hey @jatmn

A long list of check-ups you did already :) But did you also check your PTFE coupler?

How many print hours do you have with the ptfe without changing it? Mine lasted like 250 hours sometimes and it was already black on the sides with small deforming...

check here : https://ultimaker.com/en/support/250-disassembly

Until Ultimaker decides to sell their new TFMs separately, I suggest you buy the ones from 3Dsolex (or it's resellers) because they last much longer :)http://3dsolex.com/teflon-replacements

 

I have considered the PTFE coupler but not touched that part as.. this started happening.. literally in the first 1 1/2hrs of the printer's life. Soooo if the PTFE is shot.. it was shot when I got it..

Otherwise mine has about 400hrs+ on it. I -usually- print bellow 220c

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I was just thinking about your comment..

For the most part if the PTFE is indeed worn out.. this would mostly come into play during retractions right?

But I will have some of these skips/jams in the dead middle of a surface print that has not had a retraction at all in quite some time. Pressure from printing on the glass shouldn't be the issue. as I can have this issue on any surface.. or even long perimeters which has not had a retraction in awhile due to the perimeter being so long.

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The extruder system on the UMO used to grind filament a lot when you printed with too much pressure/force on the filament. The UM2 was designed to be able to control this filament such that the feeder would skip back rather than grind the filament. It skips so far back it can take a while before the filament starts coming out again.

This "improvement" was really a tradeoff that isn't clear if it's better or worse. For a really rough print the skip backs aren't a disaster but it does indeed make the part weaker.

Regarding the feeder current - you can only raise it a little bit. Default current on my older UM2 was 1250ma. 1300ma was stronger. 1350 started to get weaker again plus it got too hot and the filament can get above glass temp and start slipping/grinding. So I recommend you stick with 1250ma.

It's not 100% clear to me if you get clogs or something else. Also check how brittle your filament is - you should be able to bend it 90 degrees with your fingers without it breaking. If not you might have to throw away all your old filament as brittle filament can break in the bowden and then get stuck in a few locations when it gets to the print head.

Even though you don't think it's the ptfe coupler you can and should test it. Since you have the olsson block it's easy. First do a cold pull to get most of the filament out of the nozzle - then heat the nozzle to 160C (or hotter) and remove the nozzle while hot. Then let it cool down to below 50C and then take some fresh filament - preferable some that has been through the feeder with the pattern on it. Pull back any filament from the back of the printer so the bowden is mostly empty then feed a fresh piece up from the head to feel the resistance in the ptfe. The resistance can quickly go from 1 ounce of pressure to 3 pounds of pressure if the filament is curved so try the most curved piece you have. Consider also testing it as it goes through the top of the bowden arch.

It's not clear to me if it stops printing for 20 seconds or completely fails a print. I can give you causes for each of these - not sure which problem happens more often for you.

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I mostly stopped having issues with my printer when I got more than one because at that point I felt less rushed because I had a second (and third and fourth) printer I can fall back on if the first printer is busy.

Now I usually print at 30mm/sec and 220C for PLA for either .1mm or .2mm layer height. This takes longer but there is less pressure in the print head and so failures are less common because there is plenty of margin for error.

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The extruder system on the UMO used to grind filament a lot when you printed with too much pressure/force on the filament.  The UM2 was designed to be able to control this filament such that the feeder would skip back rather than grind the filament.  It skips so far back it can take a while before the filament starts coming out again. any way to over ride this feature? .. any how.. soon as I hear the feeder skip even once my head hits the table because my print is ruined.

This "improvement" was really a tradeoff that isn't clear if it's better or worse.  For a really rough print the skip backs aren't a disaster but it does indeed make the part weaker. only time this -wasn't- a disaster was when it happen during the random infill and was flowing correctly by time it was at the shell again.. other wise.. its -always- disaster

Regarding the feeder current - you can only raise it a little bit.  Default current on my older UM2 was 1250ma.  1300ma was stronger.  1350 started to get weaker again plus it got too hot and the filament can get above glass temp and start slipping/grinding.  So I recommend you stick with 1250ma. I have read about this as well.. heat appears to not be a factor.. and I have backed the ma back to stock again as well.. and besides this some times happens before the motor can get warm enough to even consider heat factors.

It's not 100% clear to me if you get clogs or something else.  Also check how brittle your filament is - you should be able to bend it 90 degrees with your fingers without it breaking.  If not you might have to throw away all your old filament as brittle filament can break in the bowden and then get stuck in a few locations when it gets to the print head. I can almost tie my filament in knots without breaking it. I have also never had filament break on me so far with this printer.. with the exception of it snapping when I go to pull it out of the exruder after it had just spent all night grinding away at the filament due to a failed print.

Even though you don't think it's the ptfe coupler you can and should test it.  Since you have the olsson block it's easy.  First do a cold pull to get most of the filament out of the nozzle - then heat the nozzle to 160C (or hotter) and remove the nozzle while hot.  Then let it cool down to below 50C and then take some fresh filament - preferable some that has been through the feeder with the pattern on it.  Pull back any filament from the back of the printer so the bowden is mostly empty then feed a fresh piece up from the head to feel the resistance in the ptfe.  The resistance can quickly go from 1 ounce of pressure to 3 pounds of pressure if the filament is curved so try the most curved piece you have.  Consider also testing it as it goes through the top of the bowden arch. I will do this test when I get home tonight, but during manual feeding (example doing atomic pulls) It takes little effort to get the filament flowing by hand so.. but I will preform this test as I have never done it.

It's not clear to me if it stops printing for 20 seconds or completely fails a print.  I can give you causes for each of these - not sure which problem happens more often for you. Answer is Yes. Basically both happen equally. Some times happens first layer (at glass level) some times other layers sometimes not until a few hours into the print. I have all these issues around equally same.

 

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I mostly stopped having issues with my printer when I got more than one because at that point I felt less rushed because I had a second (and third and fourth) printer I can fall back on if the first printer is busy.

Now I usually print at 30mm/sec and 220C for PLA for either .1mm or .2mm layer height.  This takes longer but there is less pressure in the print head and so failures are less common because there is plenty of margin for error.

 

My normal is .15 layers usually.. and around 210-225C for PLA.. normal print speeds around 40-55mm/s

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Can you serve some photos from your prints? When we see a photo ,we can share your and our thoughts.

 

Honestly not sure what that will help with as it looks like any other print failure I have seen, But as I guess you should see what im talking about I will take one when I get home.. I have a failed print from last night still on the print bed waiting for me to clean it up after work.. I believe it failed during one of the first solid infill layers on this failure.. around 5min or so into the print.

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When I see photos from other users prints what ended nice or failed there so many Points to see. Especially when print lays on the print bed. Start from colour of filament, how brim or skirt Looks. I started many prints with perfect first layer, after 40-50 layer failure. Only caused because of a little low temperature. To make sure I'm using 10 degree more to override any extruder Problem, If there is a little stringing but I can dremel it away in second.

Edited by Guest

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When I see photos from other users prints what ended nice or failed there so many Points to see. Especially when print lays on the print bed. Start from colour of filament, how brim or skirt Looks. I started many prints with perfect first layer, after 40-50 layer failure. Only caused because of a little low temperature. To make sure I'm using 10 degree more to override any extruder Problem, If there is a little stringing but I can dremel it away in second.

 

Niyoki, I know what you mean.. But this isn't my only printer.. but my other is a direct drive.

I also spend a better part of my free time giving my time back to the community groups helping with extrusion issues I am very active in flashforge and wanhao communities on facebook and google groups.. but one main thing that is different.. nearly all the people I help use direct drive extruders...  And also like I mentioned.. I have tried running PLA at 230C and still had this issue..  Its really a silly issue to me.. My wanhao duplicator 4 has a direct drive.. I have had one extrusion failure in 250 print hours and that was because a tangle on the spool..  I have had about 30 or so extrusion failures in 200hrs on my UM2.

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Okay I understand. Like you know there is really much possibilities(more than much). My other problem with clogged nozzle or underextrusion was happeining because of Bowden Tube. Somehow it was pressed to much (maybe 0.1 or 0.2 mm) and filament was hanging just there not always sometime but just only sometime.

 

Lots of possibilities, and with bowden extensively more.. :(

pressed too much with the bowden? not sure I follow you on this? can you explain more..

I have also adjusted retractions from 0.5 to 6.5mm (figured my new over-sized ID tube might have material slack in it, but did these tests as well with stock bowden)

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When you take bowden tube away  take a magnify glas  and long piece of filament. Move filament until it comes out of tube hold this against light source look carefully if there is any balloon form at the end of bowden (End is where it goes to hot-end. @gr5 explained this little different somewhere in forum.

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When you take bowden tube away  take a magnify glas  and long piece of filament. Move filament until it comes out of tube hold this against light source look carefully if there is any balloon form at the end of bowden (End is where it goes to hot-end. @gr5 explained this little different somewhere in forum.

 

well your the first to mention something like this.. in fact my filament does usually have a "mushroom" type head on it usually during these jams.. but could not figure out what caused it..

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The extruder system on the UMO used to grind filament a lot when you printed with too much pressure/force on the filament.  The UM2 was designed to be able to control this filament such that the feeder would skip back rather than grind the filament.  It skips so far back it can take a while before the filament starts coming out again.

This "improvement" was really a tradeoff that isn't clear if it's better or worse.  For a really rough print the skip backs aren't a disaster but it does indeed make the part weaker.

Regarding the feeder current - you can only raise it a little bit.  Default current on my older UM2 was 1250ma.  1300ma was stronger.  1350 started to get weaker again plus it got too hot and the filament can get above glass temp and start slipping/grinding.  So I recommend you stick with 1250ma.

It's not 100% clear to me if you get clogs or something else.  Also check how brittle your filament is - you should be able to bend it 90 degrees with your fingers without it breaking.  If not you might have to throw away all your old filament as brittle filament can break in the bowden and then get stuck in a few locations when it gets to the print head.

Even though you don't think it's the ptfe coupler you can and should test it.  Since you have the olsson block it's easy.  First do a cold pull to get most of the filament out of the nozzle - then heat the nozzle to 160C (or hotter) and remove the nozzle while hot.  Then let it cool down to below 50C and then take some fresh filament - preferable some that has been through the feeder with the pattern on it.  Pull back any filament from the back of the printer so the bowden is mostly empty then feed a fresh piece up from the head to feel the resistance in the ptfe.  The resistance can quickly go from 1 ounce of pressure to 3 pounds of pressure if the filament is curved so try the most curved piece you have.  Consider also testing it as it goes through the top of the bowden arch.

It's not clear to me if it stops printing for 20 seconds or completely fails a print.  I can give you causes for each of these - not sure which problem happens more often for you.

 

The material moves effortlessly thru the PTFE and olssen block when cooled to 45c

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IMG_20160125_175552.thumb.jpg.8efadbc03d76461998919eb76e90412f.jpg

This material is not brittle at all.. Even this extream barely started to put stress marks in the Filament.. And this is PLA

This by the way is the section of material that was in the bowden tube after that failed print.. as noted by the chewed up filament at the bottom of the picture where the extruder gnawed thru it.

IMG_20160125_175552.thumb.jpg.8efadbc03d76461998919eb76e90412f.jpg

Edited by Guest

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What is the stepper motor like I also have issues like this I am wondering if the motor is losing power just a thought that's rattling around my head, wrong or Wright I only have a few things left to try, and it seems you do too.

 

Not sure what you mean by what does it look like.. I mean it doesn't look damaged.. the wires are secure and don't look damaged or burnt or anything.. Motor doesn't get nearly as hot as the X & Y motors.. The hob is clean and still quite sharp..

Glad to see someone else stepping up with this issue, Everywhere I look even on other forums it seems this issue just disappears or gets ignored..

Something that makes no sense right now.. During my 6hrs of test printing last night I was able to get 1 print that was -ok-.. I was screwing with settings like crazy mostly trying to cause under extrusion or force a immediate jam..

My print that was -ok- had some interesting settings..

.4 nozzle from official Olsson Block set (the one that came with it not a replacement).. Atomic pulled clean and perfect prior to running print..

Simplify3D settings..

Nozzle: .25 (its a .4 and measures as so when extruded!)

Auto Sized to .30 by S3D

Print speed 60mm/s

Print temp 230C - PLA (this material brand sweet spots at 220-225C on ultimakers recommended temp is 230C per manufacture. I print it all day long at 200-210C on my Duplicator 4)

Some how running at .25 nozzle setting has prevented -most- of the extrusion skipping.. Still has issues though..

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You have two completely different issues and should think of them as different. One is that you grind filament causing failure. The other is "skip backs". I don't think the problems are related.

The grinding issue is most likely either caused by too many retractions in your print (that interlocking print you showed appears to have very few) or bad tension on the feeder. (again - I've only had grinding due to too many retractions - like nonstop retractions - thousands - one very few seconds) So please confirm that you have few retractions and lets move onto tension.

Probably not tight enough. How is the tension set? At the top is loosest, bottom is tightest, different springs require different tension. You want the pattern some where between the 2 patterns below - more like the right one than the left one.

filament1.thumb.jpg.536eeea5733a82f2af83084d26ac02a7.jpg

4.5mm retraction should be about the right distance - this is factory default. If you watch a print with lots of retractions you should see the filament at the top of the arch stop pushing up on the tube and rest on the bottom - looking through the bowden at the top of the print head you should see no retraction there - just pressure relief.

.5mm retraction is appropriate for a feeder mounted on the print head - not for an ultimaker.

You can also get grinding because you are printing too fast and this can also cause skip backs so your issues might be related but I doubt it. If that's the issue then just change feedrate to 50% in the tune menu and see if that helps.

Don't compare the temperatures of different printers by different companies. 210C on a Makerbot is not the same as 210C on an Ultimaker. I sell temp sensors - I test them in bunches of 10 or 20 at a time. I made a test aluminum block and heat it with a heater/sensor pair and with an ultimaker electronics to 260C. I then insert a temp sensor in an extra hole and check it's resistance. I can usually tell you if the sensor will read low or high just by how far it sticks out the hole and more importantly how tight it is in the hole. If tight in the hole (and if I have trouble getting out at the end) it typically reads 10C high. If loose, 10C low. If not all the way inserted, another 5C lower.

I recommend you print at least at 220C as long as the quality doesn't go down. 230C or 240C is safer and likely you will have less kick-backs aka "skipping" of the feeder.

Your print speed for .15mm layers is reasonable but too fast if you switch to .2mm layers. You are printing at the limit of the recommend speed for 210C. Which is half what the printer should be able to do without feeder skipping. If your temp sensor is off by 10C from my printer then going to 220C should help quite a bit.

skipping on the bottom layer is different than all the other layers. It is much more common because if you level it .1mm low then you have .3mm vertical of filament squished into .2mm of space which is actually what I recommend to get the part to stick well. But it can cause feeder skipping. For that reason and because you are printing double volume (.3mm thick instead of .15mm layer height) you need to print the bottom layer much slower - 20mm/sec is about right.

Also I recommend you go up to 1300ma for the feeder.

filament1.thumb.jpg.536eeea5733a82f2af83084d26ac02a7.jpg

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