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obus3d

Is this an under extrusion issue?

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Hi there, I keep on having problems with my UM 2 Ex for the last couple of months.

I re-calibrated numerous times, switched materials, installed new nozzles, I increased heter temp, etc. etc.

I don't know what to to anymore but prints keep on failing.

It seems that when printed extremely slow the results get better but not as it should be.

Please comment, what can I do and is this under extrusion or something else? I looked online and it seems that the under extrusion issue is hard to fix and increasing flow does not work obviously.

Is it possible that the heater is defective?

IMG_1345.thumb.JPG.71f29334b97aac154b382b6262d4c01b.JPG

IMG_1345.thumb.JPG.71f29334b97aac154b382b6262d4c01b.JPG

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Hi obus3d,

I'm very sorry to see this, also to hear that you've been struggling for such a long time with this problem.

This is more than "under extrusion", you have some serious error/problem here.

Looks like the skirt is OK. -and the first layer as well..

So first question, what kind of filament are you using here? And what is the temperature setting you're using for this print? Did you monitor the temperature to see that it is correct? This is a low speed print, what speed then?

Then, -during filament insert/feed and extrusion, -there is some signs that can alarm if something is wrong!

This pre feeding with the plastic extrusion out of the nozzle, is it going very fast without any kick back of the feeder? It should continiue with same speed as it started with without any slipping or feedback (assume using 0.4 mm nozzle), can you confirm this?

The question I'm ask here is "valid", -if you're using PLA. PLA is the best filament to use for measuring/testing, -this is also the one that's create less problem in general..

Does the feeder grind your filament, preventing feeding properly?

Yes, sure I'm asking a few question here, but we need some answers in order to help.

Here's many people with lot's of experience, so I'm sure your printer problems soon to be fixed. :)

Thanks.

Torgeir.

Edited by Guest

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Hi Torgeir,

Thanks for your reply, here are my answers to your questions:

- I'm Using Colorfabb PLA/PHA

- Nozzle temp: standard @ 210 degrees but I went up to 225 and even 230 degrees, achieving slightly better results.

-Nozzle temp seems to be have normal during printing, temp only fluctuates 1-2 degrees from setting.

- Printspeed was 50 mm/sec (20 mm/sec worked a few times for smaller prints)

- Feeder doesn't grind

- Only when feeding new material, sometimes the fever slips/kicks just a little but this can't be heard during printing.

- I'm using the Olsson block with 0.4 mm nozzle.

- Feeder does not seem to find material other than normal during printing.

I hope it can be fixed soon, but I don't know where to start anymore and I'm not able to invest in all sorts new parts so I hope that I can find an "easy" way... :-)

Thanks for your help so far!

Mickael

 

Hi obus3d,

I'm very sorry to see this, also to hear that you've been struggling for such a long time with this problem.

This is more than "under extrusion", you have some serious error/problem here.

Looks like the skirt is OK. -and the first layer as well..

So first question, what kind of filament are you using here? And what is the temperature setting you're using for this print? Did you monitor the temperature to see that it is correct? This is a low speed print, what speed then?

Then, -during filament insert/feed and extrusion, -there is some signs that can alarm if something is wrong!

This pre feeding with the plastic extrusion out of the nozzle, is it going very fast without any kick back of the feeder? It should continiue with same speed as it started with without any slipping or feedback (assume using 0.4 mm nozzle), can you confirm this?

The question I'm ask here is "valid", -if you're using PLA. PLA is the best filament to use for measuring/testing, -this is also the one that's create less problem in general..

Does the feeder grind your filament, preventing feeding properly?

Yes, sure I'm asking a few question here, but we need some answers in order to help.

Here's many people with lot's of experience, so I'm sure your printer problems soon to be fixed. :)

Thanks.

Torgeir.

 

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I've had similar problems before (we've all been there!). Here's what I've seen in the past:

My PTFE coupler deformed over time. This is easy to check, remove the bowden and the nozzle from the head and straighten out a piece of filament, does it pass through the head with no resistance?

I have had the feeder get clogged with dust from filament on my first printer. I blow it out with canned air every week when I do my weekly checks/maintenance.

Check to make sure there are not filament strings/debris inside your bowden tube.

Check your filament diameter. You're using good stuff, but if the problem seemed to start when you started a new roll or new brand, it's always worth checking. I once had a single roll out of a batch order that was out, the other nine were great.

Check your feeder tension. There are a couple different settings and you can find the proper one for the build date of your printer with a quick search of the forums, I forget when the split was. As a rule, I power down the printer and see if I can move the filament manually with the motor de-energized without too much pressure. You want to be able to push the filament, but not crimp it so tight it is out of round/grinding.

My nuclear check for extrusion paths error if all this doesn't solve it is to start with the bowden pulled out of the head, heat the head and push filament through by hand. There shouldn't be too much resistance and you should be able to get a steady stream of filament out the nozzle. If this works, secure the bowden to the head, remove it from the feeder and repeat while pushing the filament through the bowden. This will indicate if there's friction in the bowden somewhere. Next, pass through the feeder and see if you can still feed. Basically, eliminate problem areas from the head back one by one.

Also, if you have a space you can do it, print a spool holder and feed the printer from the floor. Running a straight angle into the feeder does wonders. I use my spoolholder when I am visiting schools or taking the printer somewhere, but at the office, my printer sets on a cabinet with a hole in the top where my filament feeds from a spool holder sitting on a shelf underneath. I had seen GR5 mention before how great it was and I saw him post it again and again and it took me an embarrassingly long time to finally do it and I wish I had done it a year ago.

When printing a spool holder, don't over-think it. Lots of models out there have bearings, adjustable spacers and such. I just use one that lets the spool turn on a shaft. None of the printers I've ever run came with spool-holders with bearings, so I always figured if it made that big of a difference the manufacturers would be one of the first to adopt it. I believe this is the one I am running right now:

http://www.thingiverse.com/thing:32204

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Hin Yoter,

Thanks for your reply!

My PTFE couples was changed recently and I replace them frequently. I hav't checked it hey but I expect it to be ok.

Bowden is ok and manual material feed works ok.

I will however clean the feeder just to be sure and I haven't checked it's tension yet, I have to dig in to this.

I was already planning to print a spool holder because especially the large spools do not work great on the standard spool holder. But first I need that thing to work again...

I've had problems with other filaments as well, the best result I can achieve now is with regular UM PLA @ 20 mm/sec. But still the quality is not the same as it was.

The nozzle I'm using is also a new one from Maker Point, so that should be ok as well.

Thanks again for your helpful feedback!

Regards,

Mickael

 

I've had similar problems before (we've all been there!).  Here's what I've seen in the past:

My PTFE coupler deformed over time. This is easy to check, remove the bowden and the nozzle from the head and straighten out a piece of filament, does it pass through the head with no resistance?

I have had the feeder get clogged with dust from filament on my first printer.  I blow it out with canned air every week when I do my weekly checks/maintenance.

Check to make sure there are not filament strings/debris inside your bowden tube.  

Check your filament diameter.  You're using good stuff, but if the problem seemed to start when you started a new roll or new brand, it's always worth checking.  I once had a single roll out of a batch order that was out, the other nine were great.

Check your feeder tension.  There are a couple different settings and you can find the proper one for the build date of your printer with a quick search of the forums, I forget when the split was.  As a rule, I power down the printer and see if I can move the filament manually with the motor de-energized without too much pressure.  You want to be able to push the filament, but not crimp it so tight it is out of round/grinding.

My nuclear check for extrusion paths error if all this doesn't solve it is to start with the bowden pulled out of the head, heat the head and push filament through by hand.  There shouldn't be too much resistance and you should be able to get a steady stream of filament out the nozzle.  If this works, secure the bowden to the head, remove it from the feeder and repeat while pushing the filament through the bowden.  This will indicate if there's friction in the bowden somewhere.  Next, pass through the feeder and see if you can still feed.  Basically, eliminate problem areas from the head back one by one.

Also, if you have a space you can do it, print a spool holder and feed the printer from the floor.   Running a straight angle into the feeder does wonders.  I use my spoolholder when I am visiting schools or taking the printer somewhere, but at the office, my printer sets on a cabinet with a hole in the top where my filament feeds from a spool holder sitting on a shelf underneath.  I had seen GR5 mention before how great it was and I saw him post it again and again and it took me an embarrassingly long time to finally do it and I wish I had done it a year ago.

When printing a spool holder, don't over-think it.  Lots of models out there have bearings, adjustable spacers and such.  I just use one that lets the spool turn on a shaft.  None of the printers I've ever run came with spool-holders with bearings, so I always figured if it made that big of a difference the manufacturers would be one of the first to adopt it.  I believe this is the one I am running right now:

http://www.thingiverse.com/thing:32204

 

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Hi Mickael,

You've already got lots of good advices here from Youter, in order to get your printer performing better. It will for sure perform better doing this.

I think all your settings is about right, a temp fluctuation of +- 1 to 2 deg C. is quite normal, so no issue here.

The only thing that’s not seems to be right is your feeder that skipping a little during bleed feed of a newly installed filament in order to clear the nozzle.

I would like to know your feeder current setting. You'll find this adjustment in the firmware at the "advanced setup menu". The current here is normally approx. (1200-1300)mA for the feeder stepper motor. Also, the Z-axis -could it be a down jump in here that start this. Just to be sure..

You'll need a short time print job that's take the printer to the limit.. Yes, I'm thinking about the flow test. It will take about (17 to 20) minute, so this one is easy to do and the answer come right away!

Your printer should be able to do this print perfectly, but I do not think so..

To observe what's going on, you should remove the left cover inside your printer, the cover that's hiding the stepper motor for the feeder.

Now You have to put a black line (straight radius line from center of the back of the stepper shaft) on the stepper shaft so you easily can observe how the stepper behave during the flow test.

You can find the printer flow test here:

https://www.youmagine.com/designs/test-print-for-ultimaker--2

If you can’t finish this full test, don’t worry, there is a solution that do not cost an arm or a leg.. :)

Show what does it looks like when your print finished? Well, -then we'll see how to take the next step.

Good luck.

Thanks

Torgeir.

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Hi obus3d,

Sorry to hear about this, but this is one of the things can happen..

There is two end stop switches, located L/H inner corner. The one on the left side panel is the Y axis stop and the one fixed to the top panel is the X axis stop.

I'll assume it go either to the left or to the bottom, say half way home?

In other word if on of the switches is activated, the "little computer" think this axis is already home, so no movement needed here..

As the switches make contacts when operated (pressed in), there must be a short of one of the two switches (making contact all the time). This could be the switch itself or simply a short between the feeding wires for the switch.

People have found wires clamped between the stepper motor and the attachment walls that's caused failure like this.

In order to do a first easy check, try to activate the switches by pressing on the actuator arm. This is best done by moving the extruder head from right side to the left side until you hear a click (X-axis). Same with the Y-axis, from mid position and into the printer until you hear this click.

A faulty micro switch may not click, so do not use force here, just observe when the shaft hit the Y switch actuator arm or when the inner sliding block hit the X switch actuator arm.

If this test go OK., there is a good possibility that the switch is in good condition (but not always like this).

Next is to check the wires from both micros witches is in good condition and not clamped some places on the way to the main board.

The last thing is to measure the two switches from the connector that's connect them to the main board(yes the connector is to be removed (pulled out) before measuring).

Wish you good luck.

Thanks.

Torgeir.

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Thank you all, I think the issue is solved however I have a new one...

Suddenly the head does not return to home anymore...

This is so frustrating! My Printer has only printed less than 400 metres but I have so much trouble with this machine... :angry:

Hi, could u please explain how u managed to solve the under extrusion issue?

I have almost the same bad printings as your picture, so I'd like to know how u fixed it.

Thanks

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@replikant - underextrusion can be caused by about 30 different things. What kind of printer do you have? Here is my standard list of possible underextrusion causes for UM printers:

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

17) third fan broken. This tends to cause complete non-extrusion part way through a print. In the rear of the head for UM2 and the front of the head for UM3. Without this fan several things can go wrong. It can take a while as usually you also need several retractions to carry the heat upwards. There are a few failure mechanisms and I don't understand them all. One of them is probably that the molten PLA spreads out above the teflon and sticks to the metal in a core or fills the gap at the base of the bowden in UM2. Later it cools enough to keep the filament from moving up or down.

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