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Quite bad print quality with ultimaker 2 :(

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Hi There,

I am new to this community. I just got a UM2 and i am really excited. I am working with the latest version of Cura 13.12. I am not able to figure out what the right settings are to get a decent enough print. The material i am testing right now are blue PLA 3mm and translucent green 3mm.

photo 3

photo 2

photo 1

I am testing out the settings as follows. I got these settings from UM2 forum but i dont see that the print quality to be appreciable.

100 mm/sec @.1mm

 

200 C

 

More info

Fill Density: 15%

Bottom/Top thickness: .6

Shell thickness:.8

Initial layer thickness: .2

Cut off Object: 0.0

Dual Extrusion: 1.5

Travel Speed: 250mm/s

Bottom layer speed: 20 mm/s

infill speed: 0

Cooling fan: enabled

Expert settings

Combing: enabled

Minimum travel (mm) :1

Minimal Extrusion before retracting: 0

I am just disappointed with the print quality. I am sure UM2 can do better.Please help me get there.

Thanks

Uma

 

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Top image: I have no idea what it is supposed to look like so I don't know what to say.

bottom image: the robot looks fine - maybe problem is too blurry to see?

Middle image: that infill is underextruded quite a bit. You can fix this by either slowing down to say 50mm/sec or increasing temp to say 220C. In general you get better quality at slower speeds but you will definitely also get a huge improvement in this particular issue (underextrusion) by raising the temperature.

If the extruder is clicking (slipping steps backwards) then you need to either raise temp or slow down print speed. I'm sure that was happening quite a bit here.

 

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Hay!

Thanks for the feedback.

The first image is a stratum vase

http://www.thingiverse.com/thing:104120/#files

I will try with 50mm @ 220 C to see whether the Vase prints out fine.

I have seen in youtube videos that UM is shockingly fast in printing. Is UM2 not a fast machine? But in all those videos the quality of print has not been discussed. What i am trying to get is what are the optimal settings Speed and temprature to get a decent finish.

Uma

 

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Uma, there's no one answer to the 'what are the optimal settings' question. It all depends on the object that you are printing.

Generally speaking, the slower you print, the better your results will be, but you should be able to go quite fast and still get good results. The key thing in most cases is not the linear speed of the head, but the volume per second being extruded - which is equal to speed x layer height x width of bead (usually equal to the nozzle size; 0.4mm). Aim to keep that around 2 or 3 mm³ per second for best results.

One thing to check: is the fan on the back of your print head running all the time (even when not printing)?

 

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@illuminarti Thanks for the feedback. The fan in the back is running 100%. What is the significance of that fan? i thought it is to cool the head as necessary?

The formula you have given is helpful. I will try to do the vase again with the settings you have mentioned. Recently, i did the infamous frog at a very low speed 30mm/s @ 220C and .1 layer thickness. The top portion of the frog came briliantly smooth but the underbelly was coarse and over extruded ? is that normal?

 

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h but the underbelly was coarse and over extruded ? is that normal?

 

That's normal. It's difficult to print overhangs as you are sort of asking to print in thin air and the layer you are printing is just barely touching the layer below so it can dip down a bit and cause minor ugliness. There's lots of solutions such as never print overhangs (lol - easier said than done). For example cut the frog cad model in half, print each half and glue together. Or sometimes, for example on models of humans you can just lean them back a bit so their chin and nose don't overhang quite so steeply.

 

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What i am trying to get is what are the optimal settings Speed and temprature to get a decent finish

 

It depends how you define "decent". For most prints I don't care how it looks so I print at 100mm/sec and 240C. For some prints I care more and print slower. In general, the slower you print, the better the quality. Mostly because your extrusion rate is more consistent and the pressure in the print head is lower. Also I prefer the quality of .2mm layers over .1mm layers. So maybe I'm the wrong person to answer this question, lol.

 

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The fan on the back is to cool the top of the heater/feed tube assembly, so that the plastic doesn't soften sooner than intended and then stick against the walls of the tube. PLA especially starts to deform above about 60ºC, and at some temps gets quite sticky; the extruder needs to keep it cool right up until the point where it gets heated quickly to working temp, otherwise bad things can happen. So that fan needs to run all the time to help with that. Originally mine didn't, and I had all sorts of quality problems, but once I sorted it out, I started getting really good results.

On the overhanging parts you need to make sure the plastic has enough time to cool. Setting the minimum layer time in Cura to, say, 5 seconds for 0.1mm layers should help there - it will slow down even more if needed to ensure the plastic has time to cool before more hot plastic gets laid on top.

You should be able to print simple/large/fairly straight sided parts at much higher throughput rates - up to about 8 or 9 mm³ per second, but you may need to increase the temperature to 240º or more for those - the hot zone is very, very small, so at fast print rates the plastic spends very little time in the heater before being extruded. You need the heater set extra-hot so that the plastic can at least get to a reasonable working temp before it is extruded. The downside is that as soon as you stop, or if the print slows down, then the plastic spends longer in the head and can overheat.

But for best quality, I'd stick to 30 or maybe 40 mm/s and 0.1mm layers, at least until you get a hang of things.

 

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