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tukl

Ultimaker 2 Extrusion Problem?

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Yes, I can see your stepper is slipping. It doesn't have the power to push hard enough on the filament.

The first thing you should fix is it looks like you have the white indicator of pressure at the maximum. That should be closer to the minimum to get more power. It seems counter intuitive but other's have said this so I assume it to be true. So turn the screw so that the white indicator moves up until it is more near the top. This force causes friction in the motor I assume.

Secondly you are probably printing too fast or too cold or too thick.

Try not going over 2mm^3 per second at 210C or 5mm^3 per second at 10mm^3. So if you are doing thick layers (.2mm) at 100mm/sec (with the standard .4mm nozzle) that works out to 8mm/sec (2X4=8). This is difficult at a temp less than 230C. So try going slower, or hotter, or thinner layers.

As Robert asked, What is your layer height, temp, and print speed?

 

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If it were a grip issue it wouldn't be springing backwards (like in the video). It is springing (and spinning) backwards because the PLA filament in the bowden tube is like a big compressed spring and once it slips a little it moves back quite a bit until the pressure is relieved.

 

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Hey,

is the pla allready at the bowden tube? Probably you need to push and pull a little bit the transparent pipe at the bowden tube. Sometimes the PLA didn't go into the bowden tube. Than you need to bounce a little bit.

Got that problem at the material change also on the um2.

 

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Hello,

 

please watch the video:

 

http://vimeo.com/78170319

 

I guess I have a problem with the extrudor motor causing the filament not feeding to the hot end. This results in too less material.

Any suggestions how to fix?

 

That's the same issue I was having with my UM2, even at 0.15 layer, but yours has tension set at maximum, try 1st at lowest.

 

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Hey guys,

thank you very much. Be sure I read EVERY of your answers. The reason why I didn't answer is that the colleaque who printed is ill and not at work. In the meanwhile I got the printing seetings:

- 0,2mm Layer Height

- 100 mm/s

- 225° Head, 60° Bed.

Now I know this is to fast. I tried a few prints after him with lower settings and the slipping is gone. Also I reduced the friction to minimum (but I don't know why this should be "better" to get a highter friction, but it works...).

I'm sorry but how do you calculate your printing speed according to the layer thickness?

Thank you!!

 

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100mm/sec X .2mm layer height X .4mm nozzle width = 8mm^3/Second

This is the height times the width times the length-speed.

This is the volume of plastic per second.

The ultimaker original can print this fast but it is difficult. I don't know about Ultimaker 2.

 

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I have the same Problem, with the slipping stepper.

I printed the hole morning with the same settings and had no problems.

Layer 0,2mm, 90mm/sec, 230C, 60C Bed. It worked fine in the morning. But now i have problems with the stepper.

The "white indicator" is on top, i didn't change anything on the screw for the white indicator. So the tension is on lowest point.

I reduced my Flow down to 80%, then the first layer has no problems with a slipping stepper. But for the following layers there is not enough Filament coming out to close the layers to good surface.

 

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...because the PLA filament in the bowden tube is like a big compressed spring and once it slips a little it moves back quite a bit until the pressure is relieved.

 

To this point i agree.

 

 

- 0,2mm Layer Height

- 100 mm/s

- 225° Head, 60° Bed.

Now I know this is to fast. I tried a few prints after him with lower settings and the slipping is gone.

 

But to this point i don't agree, because slower printing causes more slipping in my case.

The Filament is a big compressed spring in the bowden tube, the pressure can only escape through the nozzle or by a slipping stepper. In my opinion only faster printing helps to relieve the pressure because more Filament is needed for the print.

I tried to print faster and it helped a bit, but the slipping isn't completely gone. Almost in the first layer the stepper slips very often while the print speed is lower. Tomorrow i will try the same print speed at the first layer.

Or what can i do else to solve the problem with the slipping stepper?

 

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Since you say that it's slipping more in the first layer I'd say you should check your bed leveling. Sounds like your nozzle is a little bit too close to the platform at the start of the print.

And printing faster will not relieve pressure, it's the exact opposite.

 

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You need to make sure you aren't extruding too much plastic per second, for the temperature that you are printing at. Since the first layer is normally printed thicker, you have to print it slower, to keep the volume per second the same.

Are you just doing a normal print, or do you have 'Spiralize' turned on. If you have spiralize, it will put out a lot more plastic per second - so you need to slow down.

As it is, printing 0.2mm layers at 90mm/s is 0.2 x 0.4 x 90 = 7.2 mm³/s. That might be a little bit much for your extruder. Try slowing down the print a bit, and/or using thinner layers.

See this thread:

http://umforum.ultimaker.com/index.php?/topic/3418-um2-extrusion-rates/?p=25866

 

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I'm doing a normal print, "spiralize" is not turned on.

I've seen the post from George and with my 90mm/sec at 230C it should work, because i tested the 103mm/sec and it worked also fine.

I also slowed down my print, but that didn't help. I'm wondering why i could print the hole morning with the same settings without having any problems.

 

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You *could* lower the bed by .05mm which might reduce the click/slips but I wouldn't bother. I actually like this "feature" (is it a bug?) for the first layer as I get a perfect first layer. The clicking occurs occasionally because there isn't room to put all that filament. But then... for the remaining layers... clicking is bad.

I know my test showed you could go up to 103mm/sec .2mm layer at 230C but that is an unobstructed hole. If you are doing normal printing the pressure is probably a little higher as you are pushing the plastic down onto the layer below. So I would keep it under 50mm/sec. Plus maybe my extruder is slightly (20%?) stronger than yours? I doubt that but it's a possibility. Did you use the same UM blue filament that came with your UM? All filament colors (and manufacturers) have different viscosity at a given temperature.

I know you think printing faster should be less plastic but when you speed up the feed rate it *also* speeds up the extruder "axis". Marlin does 4 axis linear printing - it prints straight 4 dimensional lines where the Extruder is the 4th dimension.

Why it worked in the morning, but not the afternoon? I have no idea. Probably something about the bowden. Or the extruder stepper was too hot in the afternoon? I really don't know. It shouldn't make any difference.

 

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Wow. I think you just created an open source makerbot! Maybe you could post this part on Youmagine with a free-to-copy license??

Ultimaker is working hard on solutions to underextrusion issues and I've seen a few things they are working on and it's very promising.

 

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Very interesting..... if done right this could improve printing of Flex filaments in terms of speed and extrusion reliability by 3-4 times, maybe even more... though i have some concerns about the stress that is put on the belts with higher speeds.... also the smaller rods could bend over time which would be a dire situation. But i have some ideas how to eliminate these risks though.

Atleast for flexible filaments this could be a very viable solution.

 

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Hello,

I have the same issue, but I'm experiencing some radical solution: moving the extruder motor directly over the nozzle:

 

 

I've been thinking of placing the feeder motor half-a-meter (or so) above the UM roof (in the middle of it) and the feeder itself on top of the printing head - pretty much as you have done. In order to transfer the power from the motor to the feeder, there would need to be a telescopic shaft in between - basically this kind of structure:

http://www.directindustry.com/prod/ktr/telescopic-universal-joint-shafts-14739-546986.html

Did you consider this kind of an approach as well - or is the extra weight of the motor not such a big deal in your opinion?

 

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very cool looking modification. It does look a little heavy on the top... but I do like the idea of direct hotend feeder combo !

please let us know how the prints come out ?

Also have you posted this on thingiverse ?

very nice work !

Ian :-)

 

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