Possible underextrusion problem?

[shape 0]

Hi everyone!

I've had my Ultimaker 2 for a couple of months now and have been relatively successful in getting good quality prints. However, recently I've been encountering what I believe is an underextrusion problem. I tried a few things including re-leveling the bed and cleaning the nozzle, which seemed to work temporarily but today's print is as bad as ever.

Here are some pictures of the print:

This was printed with the Silver PLA that came with the Ultimaker, with the following settings:

Layer Height: 0.3mm

Shell Thickness: 1.2mm

Retraction: On

Fill Density 10%

Print Speed: 50mm/s

If anyone has any idea what could be causing this problem, your help would be greatly appreciated!

[Labern 775]

Hi, What temperatures were you printing with?

were you printing with the default speeds in expert settings?

[ultiarjan 1,223]

with that layer hight and speed your really pushing it To much for the stock feeder. So slow down or reduce layer hight or print an alternative feeder.

You may also encounter an issue with not enough top layers. What top/bottom thickness did you set? Rule of thumb set at least 5 or 6 layers to close the top surface... so In this case 0.3 X 6 = 1.8mm

[DidierKlein 729]

I agree with UltiArjan slow down, and increase the value of top/bottom thickness.

Also if your spool is close to the end it may cause underextrusion, only solution is to slow down. (Assuming your nozzle isn't partially clogged)

[shape 0]

Hey guys, thanks for you replies!

I am using the default PLA temerature settings (210C with 60C bed). And yes, I was using the default print speeds in expert settings.

This makes a lot of sense now, as I upped the layer height of the "fast print" settings to 0.3 from 0.15, effectively doubling the amount of material I'm asking the printer to extrude at the same speed. Top/Bottom thickness was also set at 0.6mm which is only 2 layers so that was probably part of the problem as well.

I was trying to get a fast print, but I guess I got too greedy. I'll try again with a slower speed/ lower layer height, and increasing the top/bottom thickness and see if that solves it. Thanks everyone!

[Labern 775]

You can get away with high layer heights but you need to adjust the speed and Temps accordingly along with top/bottom multiplied by the layer height a few times. The expert speeds can make a large impact on this as in new cura versions as the inner speeds are to fast.

The extruder has a limit on how fast it can pump out the plastic 2 but after a few trials you can still end up with some pretty fast prints.