Ultimaker 2 Poor Print Quality at Random Layers

[MasterMikey001 0]

Hello,

     I am an owner of an Ultimaker 2 and have had the printer for about a year. In recent prints the quality of the prints have seemed to drop. In my last two prints  (pictures attached; attempted bullets 1&2) random layers have become all messy and I can not figure out why as the printer prints layers like it should afterwards until another mess seems to randomly appear. (If I didn't explain well for you look at the pictures they tell the story)

Here are the images: (first two are of attempted bullet prints and third is of a larger print I did last week)

Note: I manually stopped the second bullet after the layer mishap.

https://drive.google.com/open?id=0B27jITm4Ud_9MWh1Rm1Sc0xSTXc

All the prints were printed at 220 C with Colorfabb PLA/PHA (red). (70C build plate; I didn't have any adhesion issues)

Here are the settings for each print:

Completed Bullet (tip);

layer height: 0.08

shell thickness: 0.8

enable retraction: yes

bottom/top thickness: 0.8

fill density: 30%

print speed: 50mm/s

no support

brim

nozzle size: 0.4mm

initial layer thickness: 0.15mm

initial layer line width: 100%

travel speed: 150mm/s

minimal layer time (cool): 5 seconds

enable cooling fan: yes

- The layers at the top cut off abruptly at certain spots and seemed to offset a bit as well(I tried this again to see if it was a model error but it appeared not to be)

Half Printed Bullet:

layer height: 0.06

shell thickness: 0.8

enable retraction: yes

bottom/top thickness: 0.8

fill density: 30%

print speed: 25mm/s

no support

brim

nozzle size: 0.4mm

initial layer thickness: 0.15mm

initial layer line width: 100%

travel speed: 150mm/s

minimal layer time (cool): 5 seconds

enable cooling fan: yes

- Mid-way through the layers got all contorted for a bit before returning to normal quality. (I am at quite a loss on this. The layers didn't write offset all that much but rather just got all messy)

Large Print:

layer height: 0.2

shell thickness: 0.8

enable retraction: yes

bottom/top thickness: 0.8

fill density: 30%

print speed: 50mm/s

no support

brim

nozzle size: 0.4mm

initial layer thickness: 0.15mm

initial layer line width: 100%

travel speed: 150mm/s

minimal layer time (cool): 5 seconds

enable cooling fan: yes

- I didn't pay much attention to this at first as i printed at low resolution and didn't need anything pretty for its application, however it does show holes and messy layers at points so I thought I would through it in.

I am looking for help on fixing these layers or at least know what is going on to better my search on the internet (If something really similar already exists to this post my apologies, but i am not sure what exactly to look for; links would be much appreciated).  Could this be extrusion problems? Slight layer offset problems? Print software/setting issues? Motor Issues? etc. If i can't get a direct answer, anything pointing in somewhat of a direction to at least generally improve quality is still welcome. Any help is much appreciated.

Things I have already done to the printer recently:

- Level Build Plate

- Replace PTFE Coupler

- Clean Nozzle

- Clean Build Plate

Note: I am fully aware of the fact thatI have not re-lubricated any of the parts since I got the printer (I am waiting to get some sewing machine oil for the X and Y axis). I do not know if this may be the cause of some of my print quality issues.

[DidierKlein 729]

Hi and welcome,

This looks like underextrusion, you can find a detailed explanation here

I would have advised to replaced the coupler but you did that already, so maybe the nozzle is the problem here... does it do the same with other filaments?

220°c seems quite hot for colorfabb, i usually go for 210°c or lower

[fbrc8-erin 272]

The first photo almost looks like it's not getting enough cooling time (though I see the under extrusion in the second two). Have you tried printing more than one at once? Do all of your fans seem to be fully operational?

I would definitely recommend lubricating all three axes as soon as you get the sewing machine oil in. In general, it does make a world of difference to the functionality of the machine. Has the Z-screw been lubricated with magnalube since you've had the machine?

Have you made any adjustments to the feeder on the back of your printer? Is the knurled sleeve on the feeder motor shaft still securely in place? You might try slacking off the 4 screws holding the feeder on by about 1/4 of a turn if you're using the standard UM2 feeder.

Also, are you nearly at the end of that roll of ColorFabb? If you are and the filament is more tightly coiled, the feeder will have to fight harder to unspool it.

Have you checked out your bowden tube for any signs of damage or resistance?