Jump to content
Ultimaker Community of 3D Printing Experts
arapp

Persistent Under Extrusion Problem!

Recommended Posts

Hello,

 

This would be my first post and I am really in need of help.

To give you some context: We are running a Ultimaker2 and a Makerbot Replicator2 at a start up company. We have had the Makerbot for sometime and use it as a production machine for small parts. After many bad interactions with the Makerbot company and several bad printers we looked elsewhere. This brought us to the Ultimaker2. Out of the box the Ultimaker2 ran well, minor adjustments were needed but that was all. Now things only look bleak.

 

My default print settings are, 0.2mm thick, 50mm/s and z-hop 0.075mm, everything else I have left on the default Cura settings.

 

After a short amount of time it started to have a large under extrusion problem. Slowing it down helped but was not an answer I was looking for (speed is important to us). I tried the Atomic method and had good success, it pulled out a lot of gunk and seemed to help with under extrusion.

 

It did not solve the problem though, prints will do fine and then have a couple layers of under extrusion. It was always seemed to occur more in larger/taller prints than the smaller test prints.

 

I kept battling with this problem for a week or so, using the ultimaker2 for experimental prints and occasionally large prints to test how its working.

 

Two days ago I changed the fan mount on it, printed up one I found online that better directed the right airflow to the single print nozzle. http://imgur.com/mAYb0Nr Everything seemed fine. Left a large print over night and found it the next day EXTREMELY under extruded. http://imgur.com/h8UXrN7 All of yesterday I spent trying any method I could find online to correct it, nothing worked. It was odd, all the preset ultimaker files (such as the robot and tetrawire) would print fine but my files would come out terribly. Finally, out of desperation, I replaced the original fan mount back on and it printed fine again but because I was curious to why the fan mount would change it soo much. So I put the new fan mount back on the machine... and it printed fine. For the life of me I dont understand why it started working again.

 

I set the temperature up to 215C after adding the new fan mount because it seemed like it was running lower than before.

 

Now, the machine is closer to how it was printing before, it seems fine but leaves layers of under extrusion. http://imgur.com/TE32dwG http://imgur.com/EgWBwk0 It has been a huge pain in the butt and a huge waste of material.

 

When I do the atomic method hardly anything pulls out anymore and I can see straight through the print nozzle hole. http://imgur.com/NRk4dMr I have yet to stick a pin in from the outside but I dont think it will help that much.

 

Even when I print something small at .2mm and 25mm/s it left a layer of under extrusion. http://imgur.com/YJqzkIo Something has to be wrong, that print took 5 min longer than the makerbot set at equivalent settings and it didn't even print correctly. From what I have read it also seems like the ultimaker2 should be able to go faster than 50mm/s anyways.

 

Please let me know if anyone knows what may be the problem. All help would be much appreciated .

 

Share this post


Link to post
Share on other sites

Are you printing PLA?

I just replaced my nozzle, teflon spacer and cold end on my UM2 which temporarily solved the underextrusion issue. After a few prints, however, the problem came back. It seems that switching between ABS and PLA is a problem for these printers.

I'm still not sure it is a 100% solution but I put some vegetable oil on my PLA filament and have run a couple of very good prints in PLA after doing that. It seems that vegetable oil is a known cure for PLA's stickiness to just about everything.

 

Share this post


Link to post
Share on other sites

@arapp: You may try if you can push the filament through the heated hotend manually. If you feel a significant resistance, your problem is with the hotend. If you don't, it's likely with the feeder. Don't forget to test with and without the Bowden tube. If the filament is changed with the 'change filament' option, a very fine string is deposited in the Bowden tube. This string can make your filament being stuck in the Bowden.

 

Share this post


Link to post
Share on other sites

Leon- Sorry I forgot to mention my material but yes I am printing with PLA. I have read about the PLA/ABS problems with the Ultimaker2 but we havent ever run ABS through the machine and shouldnt be having that issue.

Interestingly, I do use veggy oil on the Makerbot Replicator2, the oil resolved many problems we had with the machine. I dont know why I hadnt thought to try it on the Ultimaker2. From my experience I only add oil to the filament every third or so filament change on the makerbot, I've had too much built up before and it is a hassle to undo. I will start adding veggy oil during filament changes now on and see how it performs.

Dim3nsioneer- There were occasional times that the hot end was hard to push through manually but usually the atomic method resolves that problem, for the most part it feels fine when I manually feed the hot end.

I have taken note of that long stringy filament left behind after using the "change filament" option and am always sure to remove it before inserting new filament.

I was concerned it may be my feeder but all forums show it is properly set up. The white dial is all the way up in the "minimum" position. If needed i could post a video/photo of it to show the group.

Update: I have been printing at 230C (.2mm and 50mm/s) today with no under extrusion although as you could guess there is a significant amount of stringing occurring. This doesn't fall well on gr5's temp vs speed graph which he posted here.

 

Share this post


Link to post
Share on other sites

have you checked the thickness of your filament? Which brand you are using) As mentioned somewhere in this forum, you can feed 3,0 mm filament but 3,0001mm filament will get stuck. Feeder can and will squeeze the filament, so that can cause jamming also.

I had under extrusion problems and the reason was switching between ABS and PLA. I got a lot of stuff from the nozzle. Some of that looked like copper.

 

Share this post


Link to post
Share on other sites

Dim3nsioneer: I adjusted the feeder dial. When it was UNDER the middle line it would jump back so often it could not push the filament through. When it was AT the middle line it would push the filament slowly and would still jump back very frequently. I have found that in between the top and middle is a good spot for it. Although it did not change the extrusion much at all.

ilsaarin: The filament is from ultimaker themselves and it all falls within +/-0.05 of 2.85mm. I have also never used ABS in this machine but I am open to try anything that may work. What method did you use to clear out the clog? Also where do you think the copper came from?

 

Share this post


Link to post
Share on other sites

Could this be a broken heater problem? Ill post more photos but it will go from doing good small prints to a half good large print to a fine large print and then back to bad everything... We had a bad heater on the makerbot, it caused many inconsistencies like these.

 

Share this post


Link to post
Share on other sites

It has been a while since I posted as things have been going better.

Here is a photo of it set at 50mm/s with 213C. As you can see it goes through periods of under extrusion to acting relatively fine. (the solid middle part was warped)

 

I finally added veggy oil to the filament before loading, this has seemed to help. Here is a large print from after (photo), in it you can see it printed very well until it hit a point, I think some large piece of dirt was stuck in it, it took a lot of force for me to push through.

I recommend veggy oil for all 3d printers.

It seems to print a lot better now. Although not without problems. As you can see in the "post structure" this photo, it will still under extrude at random layers. Also in that photo you can see it changes texture on the "tower" above and below the point where the "post" ends.

I still cannot seem to keep the machine operating consistently.

 

Share this post


Link to post
Share on other sites

arapp,

Could you post some photos of the printer itself? Feeder and hot end mainly. It your feeder starts eating filament it is a good idea to check whether there is ground up filament reducing the efficiency of the knurled wheel.

Seeing the result of your atomic cleaning the main residue seems to come from the interface between the PTFE- isolator and the integrated nozzle. If there is a gap between the isolator and the nozzle this could be the source of your problems causing temporary blockages.

/J

 

Share this post


Link to post
Share on other sites

Hello all,

Long time no response but I got to the bottom of my problem. The problem was in the feeder/filament/bowden tube.

I discovered the issue as I was changing the feeder over to this one (youmagine), which I highly recommend. It turned out that the end of my bowden (the side inserted in my feeder) was slightly crimped adding a great deal of friction to the system. This, along with the poor stock feeder design that comes with the UM2, was preventing a consistent flow of filament to the hot end, thus a spotty under extrusion. I recommend every/anyone to use this replacement feeder, it is easier to fine adjust and it has a quick release feature. The quick release allows me to skip the "change material" prompts and hand feed it while using the "move material" in advance settings.

I have also found more success by increasing the temp to 215-225C and slightly increasing speed, this being said it reduces x & y accuracy. My Replicator2 (PLA at 230C) usually prints a wall 0.2mm more than what I entered, I enjoy the Ultimaker2s (210-220C) precision as it often measure much closer to the true value.

I hope this helps others. Feel free to message me if you are having similar results and I will do my best to assist.

 

Share this post


Link to post
Share on other sites

Hi arapp,

I have a similar problem, but replacing the tube has not solved it. Just curious as to whether you used a cheap or higher priced filament at the time of this problem. My current filament is cheap and I'm considering something more costly (and hopefully better).

Regards,

Rossgve

Share this post


Link to post
Share on other sites

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):

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) Isolator - this is most common if you've printed extra hot (>240C) for a few hours or regular temps (220C) for 100 hours. It warps. It's the white part touching the heater block. Test it by removing it and passing filament though it by hand.

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

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

5) 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.

5b) Bowden pushing too hard - for the same reason you don't want the bowden pushing too hard on the isolator.

5c) 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.

6) 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.

7) 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 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

8) feeder spring issues - too tight, too loose

9) 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.

10) 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

10b) 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.

11) 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.

12) 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.

  • Like 1

Share this post


Link to post
Share on other sites

This helped me with a similar problem but I am still having underextrusion, especially in the beginning of the print.

I have been trying to print a tiny rectangular channel. In the first attempts, no material came out of the nozzle but the printer worked fine with models that came in the SD card that came with it (except that for some of the models, the rim around it looked spotty and not continuous).

After finding this info here, I raised the temperature to 220 C and used a 30 mm/s speed, 0.08mm layer heigth. I also heated up the nozzle before printing and extruded some filament to see if it was coming out properly and maybe help. The tricks helped but when printing the rim it was spotty, so I lowered the plate height with the front screws (maybe it was too close to the extruder?), increased the temperature to 222C, increased the flow to 104% and decreased the speed to 80% (24mm/s). It finally printed my block, but I checked in the middle and saw some spotty layers (picture). At the end, it was OK.

I did the same thing to print the rectangular channel with even smaller dimensions ( inner rectangular cross sectional area is 1.6x1.2 mm). But I had the same spotty rim as before and also, one of the openings ended up blocked (stringing?). I used 0.06mm layer, 24 mm/s speed, 220C and also increased material flow to 105% and extruded some material before starting the print.

Any idea of what can be causing my underextrusion problems? It's been exhausting to having spent so much time on trouble-shooting it (I've done many atomic clear thinking it was clogged, but it was not)

20151015_113726.thumb.jpg.bac2595d6181fbdc4d652bf87453c7eb.jpg

20151015_113416.thumb.jpg.654c60716a239a491028ad093d88e08e.jpg

20151015_111027.thumb.jpg.d4ec5792a6c9ee7c4fc00d8e2cf009be.jpg

20151015_100116.thumb.jpg.8dea9896475a06c7a10be63086f76e62.jpg

20151015_113726.thumb.jpg.bac2595d6181fbdc4d652bf87453c7eb.jpg

20151015_113416.thumb.jpg.654c60716a239a491028ad093d88e08e.jpg

20151015_111027.thumb.jpg.d4ec5792a6c9ee7c4fc00d8e2cf009be.jpg

20151015_100116.thumb.jpg.8dea9896475a06c7a10be63086f76e62.jpg

Share this post


Link to post
Share on other sites

I gave up trying to achieve more than 3mm3. I am using Robert's feeder and this is a huge improvement to prevent filament jamming, but does not help with extrusion, no matter what temperatures i use. The speed cylinder test fails above 3mm3. So i print everything very slowly. :-(

Share this post


Link to post
Share on other sites

@lab I think your bed is too far from the nozzle on your bottom layer. it could be underextruding but I suspect you just need to move the bed closer. Don't use the leveling routine - just turn the 3 screws a full half turn counter clockwise.

Also in your last picture it looks like you need a bit more fan. Make sure fans are well above 50% by the time it gets to that layer being shown. This probably means you need the fans at 100% by the time you are up to 1mm. You want them to come on slowly because if not the nozzle cools too fast for the PID controller to compensate (the PID controller needs a little time to adjust to the increased need for power).

I'd like to see more photos @lab to see if you have underextrusion issues on other parts of the print.

Share this post


Link to post
Share on other sites

Thank you very much @gr5

I have not had time to print, so I just tried again today. I checked the fan settings and they should be at 100% by 0.5mm, so it is fine.

Today I releveled the bed just turning the screws to make sure the plate was close enough. So I tried to print the same square thin block (20x20x1.6mm) with 30 mm/s and 0.06 layer heigth. Something very weird happened, it looked like the printer started printing my old rectangular model so the print has a rim with smaller rectangular shape. Then it started advancing toward the bigger square shape .

Check the pictures below, especially the one that shows the bottom part of the print comparing with my previous models.

I also adjusted the screws that hold the feeder to make sure they were not too tight, so I left them a little bit looser to see if it would facilitate the flow of material.

Thank you very much!

[media=6815][/media

]20151019_103630.thumb.jpg.584707943ef2b649e4c77f00e47c5f56.jpg

20151019_111221.thumb.jpg.1795b4e4cc000c3e1162f22c30e126b9.jpg

20151019_104926.thumb.jpg.7f51249b32e503c07b3e38566d2999c2.jpg

20151019_103630.thumb.jpg.584707943ef2b649e4c77f00e47c5f56.jpg

20151019_111221.thumb.jpg.1795b4e4cc000c3e1162f22c30e126b9.jpg

20151019_104926.thumb.jpg.7f51249b32e503c07b3e38566d2999c2.jpg

Share this post


Link to post
Share on other sites

You should always look at your part in layer view before copying it to the SD card. You would have seen that your part wasn't as square as you thought. It probably is rotated by 1 degree or something similar.

Only a small part of your "cube" was actually within the bottom layer height (.06? .3mm?) of the bed. So it did the skirt around the part that *was* touching.

Share this post


Link to post
Share on other sites

Yes! I checked that later and realized I should have checked the layer view before. Thanks!

I got to print it perfectly later. But I always need to go to maintenance and move some material before printing anything, then I heat up the nozzle to keep it warm and finally put it to print. All that have helped me. Otherwise, when the nozzle starts moving to print, anything comes out until almost 1 min, then it gets all messed up and piled around the nozzle. Is that normal?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Our picks

    • Introducing Ultimaker Cura 3.6 | Beta
      Ultimaker Cura 3.6 | Beta is available. It comes with new features, bug fixes, and UX improvements. We would really like to have your feedback on it to make our stable release as good as it can be. As always, you can download the beta for free from our website, for Windows, MacOS, and Linux.
        • Like
      • 95 replies
    • Print Core CC | Red for Ruby
      Q: For some users, abrasive materials may be a new subject matter. Can you explain what it is that makes a material abrasive when you are not sure which print core to use?
      A: Materials which are hard in a solid piece (like metals, ceramics and carbon fibers) will generally also wear down the nozzle. In general one should assume...
        • Like
      • 30 replies
    • "Back To The Future" using Generative Design & Investment Casting
      Designing for light-weight parts is becoming more important, and I’m a firm believer in the need to produce lighter weight, less over-engineered parts for the future. This is for sustainability reasons because we need to be using less raw materials and, in things like transportation, it impacts the energy usage of the product during it’s service life.
        • Like
      • 12 replies
×

Important Information

Welcome to the Ultimaker Community of 3D printing experts. Visit the following links to read more about our Terms of Use or our Privacy Policy. Thank you!