Waffling top

[taleo11 2]

Hi,

I'm a new owner of a UMO+ and so far my prints have been turning out pretty great! The only problem is that I'm getting some waffling on the tops of the parts. Any suggestions on how to fix this problem?

Settings:

hot end: 210

Bed: 60

Speed:50

Top thickness: 0.8mm

Layer height: 0.2mm

I'm using the filament that came with the printer and using the stock nozzle 0.4mm.

Thanks for the help!

[DidierKlein 729]

Maybe increase the number of top layers, 6 is recommended.

You can also maybe check this post it could be related

[taleo11 2]

Alright I'll try that out. Thanks for the help

[avogra 68]

Maybe it is slightly underextruding. Have you checked that the filament diameter matches the diameter dialed into the UM? A micrometer gauge is great to check this.

[yellowshark 153]

I am wondering what infill% you are using? Less dense infills will normally require a thicker depth for the solid "top". As @DidierKlein suggests, 1.2mm is a good starting point

[taleo11 2]

Maybe it is slightly underextruding. Have you checked that the filament diameter matches the diameter dialed into the UM? A micrometer gauge is great to check this.

 

Yeah i checked that and its between 2.85 and 2.90 so i should be alright there

[taleo11 2]

The infill ive been using is 20 percent which i would think would be alright and increasing the top layer thickness didnt help much you can still tell the parts wont be waterproof. Should i play with the extrusion percentage? The bottom layers have been pretty good and each pass has been overlapping well.

[Labern 774]

Yeah it looks under extruded a bit. Its not normally best just to increase the flow % as it might mask your issue. might be caused by a problem in your hotend or feeding path so this will need a good checking over first.

[yellowshark 153]

OK if you using 20% infill then yes your original settings were no thick enough. When you say you increased the top did you use 1.2mm as suggested? May I suggest that you run at 1.2mm again but use 40% infill. If that makes no difference then I am guessing your problem lays elsewhere. With 40% infill, which is what I use mostly, 6 layers of .200 will cover it.

[taleo11 2]

Okay I ran a print with 50% infill and 1.2mm bottom top thickness, .2mm layer height and the same thing is happening. There some parts seem to be over extruding as you can kinda tell from this picture. I thought about upgrading the hot end on my UMO+ but I couldn't find a real good thread talking about it. Would you suggest the e3d v6 hot end? I'm just not really interested in printing a whole new carriage and installing it since my printer is only a month old.

[yellowshark 153]

Can you go to the Cura menu and select the Expert tab and Open Expert settings. Under Infill have you got Solid Infill Top and Solid Infill Bottom both ticked?

[taleo11 2]

Yeah they're both ticked.

[yellowshark 153]

Ok, you said the first layer was fine, did you watch layers 2,3,4,5, were they OK?

[gr5 2,167]

You are underextruding on the top infill by quite a bit. The top few layers should be "solid" infill but you have 30% to 50% underextrusion. Usually this is caused by printing too fast or too cold. Is your infill speed different from the normal speed? I recommend you set all those optional speeds to zero so they default to the printing speed (infill speed, inner shell speed). 210C, 50mm/sec, .2mm layer height is too much. Try either 30mm/sec or increase temp to 240C (more below). but 210C and 30mm will give better quality than 50mm/sec at 240C.

Also you may have shell messed up - it MUST be a multiple of nozzle size or it does weird things and you can get this problem shown. So if nozzle is .4mm shell should be .8mm I think in this case. If shell is .9mm then that would explain your issue.

Here are my recommended top 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.

[yellowshark 153]

Yup I probably strongly agree with @gr5 which is why I asked my last question to ascertain what was happening at the bottom, which will also be running at 50. The only thing that confuses me is that it looks so regular/neat which is something I have not seen before with under-extrusion.

[gr5 2,167]

UMO tends to have more regular (perfect? consistent?) underextrusion than UM2.

[taleo11 2]

Okay I'll try those settings out and see what happens. Thanks!

[yellowshark 153]

Interesting concept, good under-extrusion and bad under-extrusion . It will be interesting to see what @taleo11 says about those earlier layers