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Another under extrusion issue

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Oke this is driving me seriously crazy.

After posting my walls not touching issue, things have become worse and seriously think indeed it is under extrusion.

(https://ultimaker.com/en/community/50191-cura-261-walls-not-touching)

Instead of keep trying atomic pulls which all looked fine anyway, i changed the nozzle for a race nozzle.

No change

I openen up the extruder and adjusted the knurled wheel a bit back as it was not perfectly in line where the filament goes trough and cleaned it all out and though that would be the issue as the knurled wheel could possibly slip easier.

No change.

i retightened all belts, including short ones.

No change

Reoiled all rods

No change

I opened up the head and found a piece of plastic wedged between bowden and the piece of ABS i printed instead of the spring.

No change

Again opened up the head.

The glass filled teflon part looked perfectly fine, maybe also due to the I2K and never print hotter then 210C-215C

The heater (35w) had come out about 5mm so i thought it wouldnt be hot/heat up enough and that would finally be the issue solved.

No change

changed the skin overlap from the standard 5% to 20% but still the walls are not touching and the top/botoom line had become too seperate in certain areas more then i have ever been used to.

Slightly better wall overlap between outer and inner wall, still top/bottom lines are not touching.

Bought a bunch of MatteForge PLA via Kickstarter which came in yesterday and have used that instead of my usual Colorfabb

Guess what, no change

I feel like getting rid of it this way :angry::angry::angry:

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I know it's frustrating but... oiling the rods? lol. Okay here are some ideas for you - my latest list of possibilities to run through:

CAUSES FOR UNDEREXTRUSION AND HOW TO TEST FOR THEM AND REMEDY THEM

As far as underextrusion causes - there's just so damn many. none of the issues seem to cause more than 20% of problems so you need to know the top 5 issues to cover 75% of the possibilities and 1/4 people still won't have the right issue. Some of the top issues:

1) Print slower and hotter! Here are top recommended speeds for .2mm layers (twice as fast for .1mm layers) and .4mm nozzle:

20mm/sec at 200C

30mm/sec at 210C

40mm/sec at 225C

50mm/sec at 240C

The printer can do double these speeds but with huge difficulty and usually with a loss in part quality due to underextrusion. Different colors print best at quite different temperatures and due to imperfect temp sensors, some printers print 10C cool so use these values as an initial starting guideline and if you are still underextruding try raising the temp. But don't go over 240C with PLA.

2) Shell width confusion. Shell width must be a multiple of nozzle size. For example if nozzle size is .4mm and shell width is 1mm cura will make the printer do 2 passes with .5mm line width which is possible but requires you to slow down much more to make a .5mm line out of a .4mm nozzle. If you really want this then set nozzle size to .5mm so it's clear what you are asking Cura to do for you.

3) Isolator - this is most common if you've printed extra hot (>240C) for a few hours or regular temps (220C) for 500 hours. It gets soft and compresses the filament under pressure. It's the white part touching the heater block. It's very hard to test when not under full pressure (spring and bowden) so sometimes it's best to just replace it. Also if you notice parts of it are very soft (the blacker end where it touches higher heat) then it's too old and needs replacing.

4) Curved filament at end of spool - if you are past half way on spool, try a fresh spool as a test.

5) curved angle feeding into feeder - put the filament on the floor -makes a MASSIVE difference.

6) Head too tight? Bizarrely MANY people loosen the 4 screws on the head by just a bit maybe 1/2 mm and suddenly they can print just fine! Has to do with pressure on the white teflon isolator.

6b) Bowden pushing too hard - for the same reason you don't want the bowden pushing too hard on the isolator.

6c) Spring pushing too hard. Although you want a gap you want as small as possible a gap between teflon isolator and steel isolator nut such that the spring is compressed as little as possible.

7) clogged nozzle - the number one problem of course - even if it seems clear. There can be build up on the inside of the nozzle that only burning with a flame can turn to ash and remove. Sometimes a grain of sand gets in there but that's more obvious (it just won't print). Atomic method (cold pull) helps but occasionally you need to remove the entire heater block/nozzle assembly and use flame. Or soak it in acetone overnight (after removing 90% of the material with cold pull).

8) Temp Sensor bad - even the good ones vary by +/- 5C and bad ones can be any amount off - they usually read high and a working sensor can (rarely) fail high slowly over time. Meaning the sensor thinks you are at 220C but actually you are at 170C. At 170C the plastic is so viscous it can barely get out of the nozzle. You can verify your temp sensor using this simple video at youtube - on you tube search for this: mrZbX-SfftU

9) feeder spring issues - too tight, too loose

10) Other feeder issues, one of the nuts holding machine together often interferes with the feeder motor tilting it enough so that it still works but not very well. Other things that tilt the feeder motor, sleeve misaligned so it doesn't get a good grip. Gunk clogging the mechanism in there.

11) Filament diameter too big - 3mm is too much. 3mm filament is usually 2.85mm nominal or sometimes 2.9mm +/- .05. But some manufacturers (especially in china) make true 3.0mm filament with a tolerance of .1mm which is useless in an Ultimaker. It will print for a few meters and then clog so tight in the bowden you will have to remove the bowden from both ends to get the filament out. Throw that filament in the trash! It will save you weeks of pain

11b) Something wedged in with the filament. I was setting up 5 printers at once and ran filament change on all of them. One was slowly moving the filament through the tube and was almost to the head when I pushed the button and it sped up and ground the filament badly. I didn't think it was a problem and went ahead and printed something but there was a ground up spot followed by a flap of filament that got jammed in the bowden tube. Having the "plus" upgrade or using the IRobertI feeder helps you feel this with your hand by sliding the filament through the bowden a bit to see if it is stuck.

12) Hot weather. If air is above 30C or even possibly 25C, the air temperature combined with the extruder temperature can soften the filament inside the feeder such that it is getting squeezed flat as it passes through the feeder - this is obvious as you can see the problem in the bowden. The fix is to add a desk fan blowing on the back of the printer. Not an issue on the UM2 "plus" series.

13) Crimped bowden. At least one person had an issue where the bowden was crimped a bit too much at the feeder and although the printer worked fine when new it eventually got worse and had underextrusion on random layers. it's easy to pull the bowden out of the feeder end and examine it.

14) Small nozzle. Rumor has it some of the .4mm nozzles are closer to .35mm. Not sure if this is actually true. I'm a bit skeptical but try a .6mm nozzle maybe.

15) CF filament. The knurled sleeve in the extruder can get ground down smooth - particularly from carbon fill. 4 spools of CF will destroy not just nozzles but the knurled sleeve also. Look at it visually where the filament touches the "pyramids". Make sure the pyramids are sharp.

16) Hot feeder driver. I've seen a more recent problem in the forums (>=2015) where people's stepper drivers get too hot - this is mostly a problem with the Z axis but also with the feeder. The high temps means the driver appears to shut down for a well under a second - maybe there is a temp sensor built into the driver chip? The solution from Ultimaker is that they lowered all the currents to their stepper drivers in the newer firmware. Another solution is to remove the cover and use desk fan to get a tiny bit of air movement under there. TinkerMarlin lets you set the currents from the menu system or you can send a gcode to lower the current. Ultimaker lowered the default currents in July of 2015 from 1300ma to 1200ma for X,Y,Z but left extruder at 1250. Other people (I think the support team of a major reseller but I forget) recommend X,Y,Z go down to 1000mA.

M907 E1250

Above sets the extruder max current to the default - 1250mA. So try 900mA. This will only change until next power cycle so if you like your new value and want to save it use M500. You can just put these into an otherwise empty gcode file and "print" this and it will change. Or get tinkergnome marlin! You will wonder how you lived without it: https://github.com/TinkerGnome/Ultimaker2Marlin/releases

M907 E900

M500

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I know it's frustrating but... oiling the rods?  lol.  Okay here are some ideas for you - my latest list of possibilities to run through:

CAUSES FOR UNDEREXTRUSION AND HOW TO TEST FOR THEM AND REMEDY THEM

As far as underextrusion causes - there's just so damn many.  none of the issues seem to cause more than 20% of problems so you need to know the top 5 issues to cover 75% of the possibilities and 1/4 people still won't have the right issue.  Some of the top issues:

1) Print slower and hotter!  Here are top recommended speeds for .2mm layers (twice as fast for .1mm layers) and .4mm nozzle:

20mm/sec at 200C

30mm/sec at 210C

40mm/sec at 225C

50mm/sec at 240C

The printer can do double these speeds but with huge difficulty and usually with a loss in part quality due to underextrusion.  Different colors print best at quite different temperatures and due to imperfect temp sensors, some printers print 10C cool so use these values as an initial starting guideline and if you are still underextruding try raising the temp.  But don't go over 240C with PLA.

2) Shell width confusion.  Shell width must be a multiple of nozzle size.  For example if nozzle size is .4mm and shell width is 1mm cura will make the printer do 2 passes with .5mm line width which is possible but requires you to slow down much more to make a .5mm line out of a .4mm nozzle.  If you really want this then set nozzle size to .5mm so it's clear what you are asking Cura to do for you.

3) Isolator - this is most common if you've printed extra hot (>240C) for a few hours or regular temps (220C) for 500 hours.  It gets soft and compresses the filament under pressure.  It's the white part touching the heater block.  It's very hard to test when not under full pressure (spring and bowden) so sometimes it's best to just replace it.  Also if you notice parts of it are very soft (the blacker end where it touches higher heat) then it's too old and needs replacing.

4) Curved filament at end of spool - if you are past half way on spool, try a fresh spool as a test.

5) curved angle feeding into feeder - put the filament on the floor -makes a MASSIVE difference.

6) Head too tight?  Bizarrely MANY people loosen the 4 screws on the head by just a bit maybe 1/2 mm and suddenly they can print just fine!  Has to do with pressure on the white teflon isolator.

6b) Bowden pushing too hard - for the same reason you don't want the bowden pushing too hard on the isolator.

6c) Spring pushing too hard.  Although you want a gap you want as small as possible a gap between teflon isolator and steel isolator nut such that the spring is compressed as little as possible.

7) clogged nozzle - the number one problem of course - even if it seems clear.  There can be build up on the inside of the nozzle that only burning with a flame can turn to ash and remove.  Sometimes a grain of sand gets in there but that's more obvious (it just won't print).  Atomic method (cold pull) helps but occasionally you need to remove the entire heater block/nozzle assembly and use flame.  Or soak it in acetone overnight (after removing 90% of the material with cold pull).

8) Temp Sensor bad - even the good ones vary by +/- 5C and bad ones can be any amount off - they usually read high and a working sensor can (rarely) fail high slowly over time.  Meaning the sensor thinks you are at 220C but actually you are at 170C.  At 170C the plastic is so viscous it can barely get out of the nozzle.  You can verify your temp sensor using this simple video at youtube - on you tube search for this: mrZbX-SfftU

9) feeder spring issues - too tight, too loose

10) Other feeder issues, one of the nuts holding machine together often interferes with the feeder motor tilting it enough so that it still works but not very well.  Other things that tilt the feeder motor, sleeve misaligned so it doesn't get a good grip.  Gunk clogging the mechanism in there.

11) Filament diameter too big - 3mm is too much.  3mm filament is usually 2.85mm nominal or sometimes 2.9mm +/- .05.  But some manufacturers (especially in china) make true 3.0mm filament with a tolerance of .1mm which is useless in an Ultimaker.  It will print for a few meters and then clog so tight in the bowden you will have to remove the bowden from both ends to get the filament out.  Throw that filament in the trash!  It will save you weeks of pain

11b) Something wedged in with the filament.  I was setting up 5 printers at once and ran filament change on all of them.  One was slowly moving the filament through the tube and was almost to the head when I pushed the button and it sped up and ground the filament badly.  I didn't think it was a problem and went ahead and printed something but there was a ground up spot followed by a flap of filament that  got jammed in the bowden tube.  Having the "plus" upgrade or using the IRobertI feeder helps you feel this with your hand by sliding the filament through the bowden a bit to see if it is stuck.

12) Hot weather.  If air is above 30C or even possibly 25C, the air temperature combined with the extruder temperature can soften the filament inside the feeder such that it is getting squeezed flat as it passes through the feeder - this is obvious as you can see the problem in the bowden.  The fix is to add a desk fan blowing on the back of the printer.  Not an issue on the UM2 "plus" series.

13) Crimped bowden.  At least one person had an issue where the bowden was crimped a bit too much at the feeder and although the printer worked fine when new it eventually got worse and had underextrusion on random layers.  it's easy to pull the bowden out of the feeder end and examine it.

14) Small nozzle.  Rumor has it some of the .4mm nozzles are closer to .35mm.  Not sure if this is actually true.  I'm a bit skeptical but try a .6mm nozzle maybe.

15) CF filament.  The knurled sleeve in the extruder can get ground down smooth - particularly from carbon fill.  4 spools of CF will destroy not just nozzles but the knurled sleeve also.  Look at it visually where the filament touches the "pyramids".  Make sure the pyramids are sharp.

16) Hot feeder driver.  I've seen a more recent problem in the forums (>=2015) where people's stepper drivers get too hot - this is mostly a problem with the Z axis but also with the feeder.  The high temps means the driver appears to shut down for a well under a second - maybe there is a temp sensor built into the driver chip?  The solution from Ultimaker is that they lowered all the currents to their stepper drivers in the newer firmware.  Another solution is to remove the cover and use desk fan to get a tiny bit of air movement under there.  TinkerMarlin lets you set the currents from the menu system or you can send a gcode  to lower the current.  Ultimaker lowered the default currents in July of 2015 from 1300ma to 1200ma for X,Y,Z but left extruder at 1250. Other people (I think the support team of a major reseller but I forget) recommend X,Y,Z go down to 1000mA.

M907 E1250

Above sets the extruder max current to the default - 1250mA.  So try 900mA.  This will only change until next power cycle so if you like your new value and want to save it use M500.  You can just put these into an otherwise empty gcode file and "print" this and it will change.  Or get tinkergnome marlin!  You will wonder how you lived without it: https://github.com/TinkerGnome/Ultimaker2Marlin/releases

M907 E900

M500

Hi gr5,

Hahaha frustrating enough to oil them ????

1) I printed down to a 40mm/s with 210 to 215 degrees at 0.16mm

2) not confused about the wall thickness which is always at 0.8mm with 4mm nozzle

3)got a tft isolator matched for the waver spacer and normally never print hotter then 210 with PLA and currently have not used another material for the last year.

4)tried a new spool and unrolled quit a bit so it has 0 resistance.

5) unrolled filament from new spool so should not make a difference.

6)a/b/c knew about this and adjusted all to see if there was any difference

7)changed nozzle to new race nozzle already.

8 ) tried it and seems to be about right temp, although it's not really a good scientific approach  off course.

9) had the feeder removed, cleaned, adjusted and spring tension adjusting while printing.

10)It can also still push a good deal of force. When trying harder types of PLA it skips when I try to do the feed with the dial manually and the nozzle is not hot enough.

With the somewhat softer PLA colorfabb has its doing the underextrusion for sure which makes me believe the feeder might be the culprit !

11)filament is the right diameter. Colorfabb measures in between 2.79-2.83mm and my Matteforge is around 2.72-2.76mm and machine is adjusted accordingly.

12) no issues here with temperature as it is 23 till 25 degrees

13) bowden is still the original and there is no feel of any resistance when I put some filament in by hand

14) switched nozzles and no difference.

15)never used CF

16) it's indeed on 1250 but checked with my finger on the feeder while printing and when it needs to feed it moves I think I will try thinker gnome this weekend.

If reading this back my best guess would be the feeder, what do you think and is there a cheaper way to check then just buy a new one, because then it would go for bondtechQR but that's a lot of money.

Thanks for your support gr5 much appreciated!

Greetz Barry

Edited by Guest

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I'm thinking TFT or bowden. Talk about feeder in a minute.

40mm/sec at 210 with .16 layers is definitely at the absolute limit I like to print at. It should be able to do about double this but still. This requires about 2kg of force. The feeder should be able to do 5kg. Either the feeder is the problem or something in between is adding a few kg of resistance.

TFT/head resistance:

Do a cold pull, then remove the nozzle and let it cool to below 40F. Pull the filament out and once cool insert some filament up from below. Feel how much resistance there is in the head.

bowden resistance. These get scratched up and the resistance can get pretty high. I'm not sure how to test this though.

feeder

Really the best test for this is to do a weight test. Tell it to extrude slowly with varying weights. It should be able to do about 10 pounds or 5kg. Here's my setup. With a scale underneath and with bungee, I can have the extruder lift more and more weight until it grinds or slips.

5a330e8975f5e_DSC_7471copy.thumb.jpg.f7b3f625dbb3fac305a404ae81052bbd.jpg

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Hi gr5,

I did the following.

Changed to a new Teflon coupler and removed the I2k waver.

Printed at 0.1mm at 207C degrees and then changed to tinkergnome, i made some adjustments and printed the same part to compare. Slight improvement over the firmware cura 2.7 comes with but no major difference in any way.

Bowden tube is fine, pushed some filament through it with the feeder of and it does not take much force to push it trough the back it was very easy and smooth.

I tested with tinkergnome to push 100mm of filament trough the head at 210C and it made it to only 70mm. I tried again an with my fi gers over the filament I felt it sometimes did not move and it was being grinder.

However when I take a small piece of filament which is not long enough to reach the head and I measured 200mm's it will be at 201.7mm on the display so it's only about 1.7mm short.

The filament I'm using is a bit on the soft side (colorfabb pla/pha and the matteforge) so I'm thinking the feeder is the issue here.

I can't yet get to hanging weights on the filament but seeing the above results make me seem like the feeder is the culprit. Agree or am I still missing something?

Thanks for your help and feedback ????

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Is this the black feeder or the white one? Are you sure you got the tension screw installed right? The head goes below a wall, not above (for both black and white feeders). I guess you know it is correct if you can adjust the pressure to the half way mark.

Here's a photo with the black feeder at the weakest tension. You want it half way usually.

2gofeed.JPG

Pushing 70mm when asking for 100 is normal if you are using "MOVE" menu command because it's easy to get the pressure too high and the feeder can slip (you hear a click) or the filament can slip/grind a bit (nothing to hear).

Did you try doing a cold pull, removing the nozzle, letting it cool and inserting filament through the open olsson block? That can tell you a lot!

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It's the black feeder, the second one that needed the least tension set. But also tried to make it more tight and it did not do anytime flattening the filament a bit en too much teeth where showing.

No I did not use the move function but the function of putting 10 mm of filament trough the feeder in tinkergnome firmware.

Going to the head it did only 70mm as it was grinding which is also the reason for underextrusion I think. Doing a piece without it going trough the head it did close to the full 10 mm.

Yes I did the cold pull and even removed the olson block completely and took a peak inside but all is normal. TFT isolated has been replaced for new one also.

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>No I did not use the move function but the function of

> putting 10 mm of filament trough the feeder in tinkergnome firmware.

That's what I meant.  I call that the MOVE function.

>Yes I did the cold pull and even removed the olson block completely

>and took a peak inside but all is normal. TFT isolated has been replaced

>for new one also.

But did you stick some filament up through the bottom (while cold)?

Left image shows not enough tension. Right shows too much. You want it part way between.

filament1.thumb.jpg.536eeea5733a82f2af83084d26ac02a7.jpg

Edited by Guest

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