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carmamir

Ultimaker filament glueing to hotend. Fail to print every time after big failure of cold bed

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So I wanted to print some parts, I left it and after 3 hours of printing one part just felt off and destroyed all other parts causing that hot end start hitting other parts and PLA were all over hot end....

Since that failure I can't print anything on Ultimaker... Every time PLA is sticking to hot end and no matter how much I tries to clean it up it will stick to hot end again, and again...

I can't find information hot to clean hot end properly...

And BTW why you're advertising Ultimaker as printer which can print in ABS ? It can't. Not hot bed no prints on ABS, PLA is very difficult to print on some models not mention ABS...

And why Ultimaker is without hot bed ? I have another printers (cheap, under £600 kits) and all them has hot bed...

I'm just asking as I'm very curious why you decided to save £10 and loose a lot of clients because of that...

 

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Maybe you damaged the hot end somehow when you hit the other pieces during the print?

It might help to post some photos so we can see what it looks like and/or what is going wrong now. To clean the hot end, I usually just heating up the hot end and then wiping the nozzle (very carefully) with some thick paper towel or cotton pads (I use (dry) make-up remover pads for most of my clean-up and blue tape wiping needs).

I'm not exactly clear what you problem is now - is the problem that you have PLA on the hot end, or that parts are coming loose from the bed? Post some photos, please.

In my opinion, you really don't need a heated bed to ever print PLA on an Ultimaker. For ABS, yes, it's going to make life a lot easier. Lots of people add their own heated beds for that purpose.

 

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Sure here is photo:

http://s15.postimg.org/o38mr0yij/FAIL2.jpg

I can't imagine how brass could be damaged by hitting PLA model.

Well maybe I don't know appropriate techniques but any small models are coming off after few minutes top (on blue tape) where same models on heated bed on much cheaper printer are printed fine.

Backing to topic. PLA will glue to nozzle on start, after 10-20 second it will leave it on bed (of course line printer around object looks like some dots made from PLA), then it will start printing few lines and when nozzle will go up and move into another place will leave some strings of PLA and again PLA won't stick to blue tape for x seconds as it will glue to nozzle...

Something is really bad with nozzle and I can't understand how PLA could damage brass especially that on home position it will go down to bed straight into PLA which is coming off nozzle for 10-20 seconds before it starts printing (after it reach appropriate temperature PLA is coming from nozzle so when printer is ready it will put nozzle into big pile of plastic and go to it's position to start printing dragging huge string of PLA)....

 

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The nozzle looks fine to me. It's inevitable that it's going to get a little bit of plastic on it. You can heat it up and clean it off if you want, but I don't really see a need.

It sounds like there are a few things going on.

Firstly, the initial extrusion in the home position is done to prime the head. Any plastic that comes out should get wiped off as the head moves to start printing, or at the very start of printing the 'skirt' - the first few extra loops around the outside of the object. I generally take a pair of tweezers, and wipe all of that off right at the start of the print to keep things cleaner. (Hold the tweezer arms open, either side of the nozzle in the home position. As the head moves to the middle it will wipe over the inside arm of the tweezers, and wipe itself on them, pushing them out of the way as it does so.)

It sounds like the main problem is that your first layer isn't sticking to the bed properly. Which means the bed isn't level and/or at the proper height. You need to heat the nozzle, autohome the bed, and then move the head to each corner and check that the head is just touching the bed. Some of us just use a sheet of paper as a feeler gauge, but you could also try using the bed leveling wizard in Cura if you want.

When you are printing, the first layer should appear slightly squashed into the blue tape in order to get good adhesion - the bead should look slightly fatter than normal, due to it being pressed down and spread out.

To ensure good adhesion, you should also the widest blue tape you can find (I use 6") and wipe the tape down with isopropyl alcohol prior to starting the print. That will make anything stick so well you have a hard time getting it off the bed when you're done (and the tape will probably tear, and then you can just soak the bottom of the print in more alcohol for a few minutes, and the tape will slide right off).

 

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I don't have any shop with that alcohol around me

 

What country do you live in? You probably know it by another name. Tell me the country and I'll tell you what they call it in your country. It's sold at any store that sells bandages.

http://www.instructables.com/files/deriv/F4O/57VU/FAQCIOXU/F4O57VUFAQCIOXU.LARGE.jpg

 

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(of course line printer around object looks like some dots made from PLA),

 

This is a very common problem. Either the bed is too high or too low.

How to level:

Levelling here is defined as setting the Z height and also levelling. It's one procedure that does both at once.

Optionally heat up the nozzle to 180C if first layer is .1mm or less because a cold nozzle shrinks and you will be setting the bed to the wrong height. Make sure tip of nozzle doesn't have any plastic on it or you may level to the wrong height.

Home the z axis only. If you must home all 3 then you need to disable the steppers once it's done so you can move the print head by hand. Move the head as close as possible to each of the 4 screws in turn. Once at a screw tighten the screw and then slip a piece of paper between the nozzle and the print bed. Make sure the paper slides very freeley. Then loosen the screw until the paper gets slightly stuck. You want the paper to easily be able to slide in and out under the nozzle with one hand pushing the paper. If the paper gets stuck it's probably too tight under there.

Repeat this procedure for the other 3 screws. Then go back to the first screw and repeat on all 4 screws again. Then repeat on all 4 screws again. Then again. It may take you 20 minutes to do this the first time but the second time you do this it should take much less time because you are both better at it, faster at it, and because there isn't much to adjust the second time.

If you levelled with a cold nozzle you are done. If you levelled with a hot nozzle you should then loosen the 4 screws 1/8 of a turn to compensate for the thickness of the paper.

Once done levelling rotate the z screw by hand to keep the nozzle off your bed. This makes it less likely to damage your bed surface and gives the nozzle room to leak.

On a new ultimaker repeat this procedure before every print (at least every hour) because the print bed can move/droop like a new guitar string. After many months the droop slows down.

 

 

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This sounds very much like a symptom I was experiencing with my printer before I found out it was my nozzle. It looked fine with plastic on there but it was really just shooting out the side and glueing to the nozzle like yours because it actually had a hole on the side.

gallery_7531_65_766788.jpg

I didn't actually notice the nozzle was flawed till I took it apart. Another telltale sign that it's a similar issue is if you watch it print, it'll squirt plastic a little differently depending on which direction the print head is traveling. In my case, when the head was moving from right to left, it would seem like nothing was coming out, and left to right, it would not stick to the bed. The first layer, instead of flat would be stripey almost.

my 2 cents.

 

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Well nozzle is fine, it's still gluing to nozzle and I can't stop it... Difficult to print anything as everytime I have roulette if it will stick to the bed...

And it isn't problem of levelling it is just ***** ultimaker bed without heating. I have also much cheaper Prusa i3 and no problem at all... But I guess you're not always getting what you paid for...

At this moment there is no reason to use it this way as most of prints going to bin (and we are talking about PLA, ABS can't be used with Ultimaker... I guess lucky guys they are not in UK as they would be sued for false advertising (heated bed is necessary for ABS not recommended)

I just hate companies like that, hopefully for all of us soon someone will introduce something similar to Ultimaker but what would be with heated bed and better quality...

Any way problem exists, PLA won't stick to bed for most of time (on 0.1mm is better, biggest problems I have on 0.2/0.3)...

Few moments ago whole printer would just would start fire as start smoking from nozzle and hot end... Something after a week start pulling out cable from sensor and just disconnected it, Ultimaker developers had no idea that that can happened and they haven't prepared firmware for that problem, so hot end start increasing its temperature until around 300 and probably more, I have no idea as I immediately shut down that "printer" and thank god I were at the room with my girlfriend as normally I leaving that room (I'm using it as second office) and I wanted go to start barbecue so I would be alarmed by smoke alarm god know after what time....

I'm soft developer and I hate to see when some people developing product/service and can't look for possible problems and to make sure that those problems wan't occur... Is it really that hard to think ???

 

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Regarding the overheating issue first.. I'm sorry to hear that that happened. Once it cools down, you'll need to see what, if any, damage was done to the inside of the hot end - it's possible that the PEEK and/or Teflon parts might be damaged. But they may be fine. Also, then recheck all of the connectors, and run some tests to see if the heater is stable again now. It's always a good idea to check the connections regularly, just to be sure.

What happened is scary, and not unheard of, but pretty rare. I assure you the Ultimaker developers are well aware of the possibility of it overheating, and its my understanding that they have tested it quite a lot. There is quite a bit of code in the firmware that deals with thermal limits, and tries to identify the various failure modes, although there are technical reasons why it can be hard to detect all the possible failures. I've also read on here that they have disabled all the safeties and let the heater overheat, and it doesn't appear that the 40W heater can get hot enough for anything to catch fire. I think they're also looking at ways to make the system ever more robust. I totally understand your concern about this having happened, but such failures are rare, based on the few reports I've seen, and I think it's unfair to say that UM hasn't given this any thought.

Regarding the question of printing with PLA on the standard Ultimaker bed, there's absolutely nothing wrong with the general design - it's something about your set-up specifically. PLA sticks fine to the standard bed if you cover it with Scotch 2090 ('Blue') tape, and if you wipe that tape with isopropyl alcohol before you start the print, it will stick so well that you will struggle to remove the print afterwards.

I can see a few possible causes:

1) Something weird about your nozzle - but you assert that your nozzle is undamaged

2) You bed isn't flat - such that when then bed is properly leveled in the corners, its too far away from the head in the middle, where prints start. Flipping the bed over might help with this.

3) Your bed isn't at the right height. When you home the print head, you should end up with the head just touching the bed. If you move the head to the corners, and the middle, it should continue to just touch the bed. Use a piece of paper as a feeler gauge to check the distance. When the head is hot, you should have to just flex the bed down slightly on it's springs (light fingertip pressure) to slide a sheet of ordinary printer paper under the nozzle.

4) The plastic you are using isn't PLA.

Using blue tape and alcohol, I can print my PLA first layers at 210 - 230ºC, with anywhere between 0.1 and 0.2mm thickness, at 75mm/s and get 100% adhesion every time. Other plastics are harder for sure. Laybrick seems particularly fiddly in my testing so far, but it does stick if I print much slower - maybe 15-20 mm/s. So, maybe you need to print slower. I don't know. But in general, it works really well. There's not some fundamental design flaw. There's something specific about your printer that you're going to have to troubleshoot. You said that it started after a failed print that caused parts to get dragged around the bed. I suspect that knocked something out of whack about your head or bed.

It might be helpful for you to post some video of the start of a print, so that we can get a better idea exactly what is happening.

 

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There was one time where I had changed the 'initial layer thickness' setting to 0.1 thinking it was 0.1 "extra" plastic in addition to the first layer thickness thinking it would stick to the build plate better with a bit of extra material. I soon found out that it was shooting out a .1 layer of plastic whereas my print height layers were at .21, resulting in the first layer underextruding by about 50%, the Z-height 2 times higher than it should on the first layer causing exactly what you described. PLA sticking to the nozzle and just slipping off the buildplate.

Pretty much agree with everything illuminarti has said as well. I've never had problems with PLA sticking to the blue tape except for the two instances where I describe above. And with a bit of alcohol, you can ensure it sticks so tight to your blue tape will tear for certain.

 

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